Root
Research

ISSN 0919-2182

Vol.20,No.5

Japanese Society for Root Research
目

次根研究会創立20周年シンポジウム
主催者からのメッセージ
組織委員会より‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥１６７

第35回根研究集会

特別講演要旨2011年度根研究会賞
20周年記念式典‥‥‥‥‥‥‥‥‥‥１６７受賞講演要旨記念講演要旨20周年シンポジウム‥‥‥‥‥‥‥‥‥‥‥１６８‥‥‥‥‥‥‥‥‥‥１７０‥‥‥‥‥‥‥‥‥‥‥１７３

招待講演要旨‥‥‥‥‥‥‥‥‥‥１７４

第35回根研究集会・20周年シンポジウム
ポスター発表要旨‥‥‥‥‥‥‥‥‥‥‥１８２「根「根の研究」第20巻
究 第 巻

総 次
総目次

‥‥‥‥‥‥‥‥‥‥‥‥‥２３８根の研究
根研究会(JSRR)

根研究会創立 20 周年シンポジウム
主催者からのメッセージ
During the 20-year history of the JSRR, many studies have been performedon plant roots, contributing new evidence to root science and technology. The
JSRR has played an important role in enlarging the international network ofroot studies as a member of the ISRR in Asia. I look forward to celebrating the
JSRR's 20th Anniversary Symposium in the coming November. I hope that theroot research network will continue to expand on an international scale,particularly in Asia, and produce many useful results.
Jiro Tatsumi
President of Japanese Society for Root Research
Professor, Kyoto Institute of Technology
The Japanese Society for Root Research (JSRR) was founded in 1992, and it
has operated for two decades. We are holding an international symposium todevelop a network of root researchers in Asia in order to advance efforts tosecure healthy food, a safe environment, and peace. Come join us!
Shigenori Morita
Chair of Organizing Committee
Professor, The University of Tokyo
このメッセージは，シンポジウムの開催案内から再掲しました．

－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－-

組織委員会より
本号は，2011 年 11 月 5 日・6 日に東京大学農学部で開催した第 35 回根研究集会（特別講演，
根研究会賞授賞式・受賞講演，ポスター発表）と創立 20 周年の記念事業（記念式典，祝賀会，記念シンポジウム）での講演・ポスターの要旨を掲載しています．当日は，下記の冊子として要旨を配布しましたが，この号に掲載の要旨が，一部修正を加えた最終確定版となります．
JSRR ed. 2011. Abstracts for JSRR's 20th Anniversary Symposium, “The Latest Frontiers of Root
Research in Asia” and 35th JSRR Biannual Meeting (The University of Tokyo, Tokyo, Japan;
November 5-6, 2011). Japanese Society for Root Research, Tokyo.
ISBN978-4 931358 09 6
（根研究会編 2011. 根研究会創立 20 周年記念シンポジウム「アジアの風－アジアにおける根研究の最前線—」及び第 35 回根研究集会要旨集．根研究会，東京．
）
なお，開催の趣旨や全体のプログラム，当日の様子などについては，本誌の第 20 巻第 4 号に報告を掲載しましたので，そちらをご参照下さい．

組織委員会（五十音順）
阿部淳・大橋瑞江・小柳敦史・大門弘幸・村上敏文・森田茂紀（委員長）・山内

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講演要旨

Special Lectures

福島県いわき市における東日本大震災の影響と対策
笹川正樹
福島県いわき農林事務所農業振興普及部（連絡先：E-mail: sasagawa_masaki_01@pref.fukushima.jp）
１．はじめに2011 年３月１１日（金）に発生した東日本大震災では、福島県いわき市は、地震、津波及び福島第一原発事故により甚大な被害を受け、農業への影響は深刻なものとなった。本講演では、東日本大震
災の影響とその対策について報告する。
２．地震及び津波被害と対策
いわき市の地震による農業被害は、3 月 11 日の本震と 4 月 11 日・12 日の余震で発生した。主な被害は、断層による水田の亀裂や陥没、液状化現象による水田の噴砂及び津波による塩害であり、被害が甚大なものは、今後、大型土木工事等による水田修復が必要になってくる。
津波による塩害は、海岸部を中心にいわき市内の全水田（H22 現在 約 4,610ha）の約 8%に当たる水田で被害を受けた。このうち、約半数以上の水田が塩害対策（除塩対策）を施すことで、今年度の作付けが可能となった。しかし、一部で除塩対策が不完全な水田や堤防、用水路破損等による高潮被害
水田では塩害による生育不良が見られた。そのため、今後、それらの水田では収穫後、次年度作付けまでの除塩対策が必要となってくる。
３．東京電力福島第一原子力発電所事故による被害と対策
福島第一原子力発電所事故では、放射能汚染による「直接被害」や「風評被害」が発生した。
「直接被害」への対策は、作付け前にいわき市内で水田の空間放射線量と土壌放射能を測定し、後者の値が基準値（5,000 ベクレル/kg）以下であったことを確認し、今年度の水稲作付けを行った。その後、秋の収穫後に玄米の放射能を測定（サンプル数は、いわき市の旧 37 市町村で 80 点）し、多くの地点で放射能は未検出であったが、一部で暫定基準値（500 ベクレル/kg）以下だが微量の放射能が検出された。そのため、今後の対策は、作付け前の水田の空間放射線量測定と土壌放射能測定を行い、その結果を基に放射性物質の吸収抑制対策に取り組むなど集落全体で放射能対策を徹底することで、放射能が検出されない米作りを行うことである。また、同時に「農産物の長期モニタリング検査」と「農用地等の除染」も行うことも重要になってくる。
「風評被害」対策は、農産物の放射線モニタリング検査を通して農産物の安全性を確認し、その情報を逐次、県やいわき市の HP、テレビ CM 等を通して公開することで、消費者目線での「安全・安心」
に関する情報を提供することである。また、その対策を通して、いわき産農産物の販売促進につなげていくことが重要になってくる。
４．今後の復興に向けて
この度の東日本大震災ではいわき市の水田農業は、甚大な被害を受けた。今後、風評被害等により米の販売は、極めて厳しい状況になることが予想される。そのため、今後、飼料用米、稲 WCS 等の新
規需要米の作付けを増やすことで生産調整を達成し、農業者戸別所得補償制度等の政策を活用しながら、水田農業の復興を図っていくことが重要になってくる。

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Special Lectures

東京大学農学部における震災復興支援研究
根本圭介
東京大学大学院農学生命科学研究科（E-mail: unemoto@mail.ecc.u-tokyo.ac.jp）

本年３月に発生した東日本大震災および福島原発事故によって我が国は未曾有の被害を受けたが、東京大学大学院農学生命科学研究科では３月末より、被災地の農林水産・畜産・漁業の復興支援に向けた組織的な研究活動（座長：放射性同位元素施設・中西友子教授）を進めてきた。活動内容は、以下のように放射線汚染関連とそれ以外の復興支援の２つに大別されるが、いずれも本研究科の多様な専門分野の教員が単独あるいは共同して、現場を重視した研究を展開してきている。
（１）高放射能の農畜水産業への影響についての研究開発（影響調査ならびに回復研究）
関係各専攻・附属施設の有志の教員が附属施設内あるいは福島県農業総合センターとの共同でそれぞれの研究を進めており、放射能の測定は本研究科の放射性同位元素施設で行っている。以下のそれぞれの分野について、①獣医・畜産学、②作物生産・土壌学、③水産学、④放射線測定・放射化学、⑤フィールドモニタリング科学・科学コミュニケーション、等の専門的立場から研究開発を行っている。現在、研究結果が 5 つの速報として Radioisotopes 誌の 8 月号に掲載されている。うち三編が農学生命科学研究科と福島県農業総合センターとの共同研究、残り二編は農学生命科学研究科附属牧場
および農学生命科学研究科附属生態調和農学機構での研究である。
（２）被災地農業回復についての研究開発
大震災によって食料生産が不可能となった農地を活用したバイオマス資源作物の栽培とバイオマス
エネルギーの生産による農業の再生支援、および東北地域の森林で生産された木質バイオマスを利用した木材供給・加工とバイオマスエネルギー生産による林業の再生支援を目指す。

本講演ではこれらの活動を、とくに演者の所属する作物生産・土壌学グループに焦点を当てて紹介
したい。

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2011 年度根研究会賞（学術奨励賞）受賞講演

Award lectures

樹木の微細根形態からみた森林炭素動態に関する研究
牧田直樹
京都大学大学院農学研究科（E-mail: macky@kais.kyoto-u.ac.jp）
はじめに
現在、二酸化炭素(CO2)濃度の上昇に伴い、大規模な気候変動が危惧されている(IPCC, 2007)。これを緩和するため、森林のもつ炭素固定蓄積機能に注目が集まり、森林生態系における炭素動態の解明が重要な課題となっている。炭素資源の吸収は、樹木が光合成によって大気中の CO2 を固定するという、植物の最も基本的な営みとして行われ、幹・枝・葉・根などの有機物として樹体に蓄積される。一方で、樹木に利用可能な形でエネルギーを作り出す呼吸代謝機能として CO2 は大気へ放出される。すなわ
ち、森林生態系における炭素動態を正確に評価するためには、樹木がどれぐらいの炭素を吸収・固定・放出にしているかを定量的・定性的に調査する必要がある。
私は研究室に配属されて以降、樹木の根系に魅せられ、気づけば博士課程に誤って迷い込むまで夢中になっていた。私の研究テーマは、どのような機能の根っこがどのように土壌中に分布しているのか？その分布が、樹木自体にそして森林生態系にどのようなインパクトを与えるのか？ということを解明することである。樹木根は、樹体を支持する太い根（粗根）と水や栄養塩類の吸収を担う細根(一般に直径 2 mm 以下)に分けられて研究されることが多い。このうち細根は、粗根に比べて非常に呼吸速度が高く、また回転速度(成長－枯死－分解サイクル)も早い。しかし、最近の樹木細根の研究では、
直径 2 mm 以下の根を同じ生理特性や生活史戦略を持つものとしてひとくくりに扱うのでは、根の機能を正確に捉えることはできないことが分かってきた。例えば、直径 2 mm 以下の根の分枝位置や直径の違いによって、化学組成、あるいは枯死率や分解速度は大きく異なることが明らかにされてきた。したがって、森林生態系における根の役割を正確に評価するためには、直径 2 mm 以下の形態と機能の関係をより詳細に見ていく必要がある。そこで私は、広葉樹二次林(山城水文試験地)のコナラとソヨゴの直径 2 mm 以下の根をより詳細に分類し、①形態と呼吸速度の関係を明らかにした。また、②根現存
量・形態・生理機能を土壌深度ごとに調査した。ここでは、その成果を紹介したいとおもう。
材料と方法
調査は、京都府南部のコナラとソヨゴが優占する里山広葉樹林（山城水文試験地）で行った。
①根呼吸と形態の関係
成木の樹冠下で傷つけないように採取した細根系(末端根を含む手のひらサイズの細根ひとかたまり)を丁寧に水で洗い、現場ですぐに、小型閉鎖型容器と CO2 ガス変換器を組み合わせた測定システム
で根呼吸を測定した。その後、サンプル根を実験室に持ち帰り、根形態測定システム WinRHIZO Pro 2007aを用いて細根系の形態（根直径・根長）を測定し、乾燥重量、比根長(SRL:m g-1)をもとめた。
②根現存量・形態・生理機能の垂直分布
根現存量をもとめるため、対象成木の樹冠下で、深さ 10cm 間隔の合計 5 層(50cm まで)、ブロックサ
ンプリングを行った。その後、土壌ブロックを実験室に持ち帰り、土壌から根系を取り出し、すべてのサンプル根系を 4 つの直径階級 (<0.5、0.5－1.0、1.0－2.0、>2.0 mm)に分類した。次にそれらの170

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講演要旨

2011 年度根研究会賞（学術奨励賞）受賞講演

Award lectures

根直径・根長を、根形態測定システムを用いて測定した。形態測定が終わったサンプル根は、70℃で48 時間、乾燥させて、乾燥重量、SRL (m g-1)、根窒素含有量をもとめた。

結果と考察①根呼吸と形態の関係
根直径が小さくなるほど根呼吸速度は高く、特に直径 0.5ｍｍ以下の根系における根呼吸量は、直径2mm 以下の細根の中でも非常に大きい値を示した（図 A）。また、SRL の値が大きくなるにつれて、呼吸量が大きくなるという正の相関が明らかとなった（図 B）。これらの結果は、根直径・SRL といった形動を規定していることを示している。さらに、これまでの根直径 2 mm 以下という便宜的なサ

12

12

(A)

10

根呼吸量
(nmolCO2g-1s-1)

態特性の違いが、細根系内の呼吸量変動の変

8

8

6

6

4

4

度が高くなることから、根呼吸速度を基にし22た細根の新たな機能的な分類法を提案できる

00.0

イズによる細根の分類法ではなく、例えば、コナラ根では直径 0.5 mm 以下を境に根呼吸速ことを示唆した。 (Makita et al. 2009 Tree
Physiology)。

(B)

10

0
0.4

0.8

1.2

0

20

40

60

80

100

根直径 (mm)
比根長 (SRL: m g-1)
図２ 里山広葉樹林の山城試験地で採取されたコナラ細根系の根呼吸量と(A)根直径および(B) SRLの関係 (n = 32)②根現存量・形態・生理機能の垂直分布
直径2mm以下の根現存量では，直径階級の違いにより、土壌深度に対する減少割合が異なった。コナ
ラとソヨゴにおける直径0.5 mm以下(微細根)の現存量は、それぞれ339.4、413.7 g m-2 であり、そのうち、およそ半分が表層に存在していた。さらに微細根の現存量は、表層から次層へと土壌が深くなるにつれて、他の直径階級の根と比べて、大幅に減少することが明らかとなった。
形態・生理特性の土壌深度に対する変化は、0.5mm以上の根では確認されず、微細根のみで確認された。形態特性において、コナラ微細根のSRLは土壌深度が深くなるにつれて低くなり、一方、ソヨゴ根
では土壌深度の違いによる変化はなかった。生理特性において、両樹種の微細根の窒素含有量は、土壌深度が深くなるにつれて低くなった。つまりコナラ微細根は、土壌深度ごとの栄養分布に対して、
生理・形態的可塑性を発揮し、一方、ソヨゴ微細根は、生理的可塑性のみを発揮することが明らかとなった。微細根は、土壌資源をより効率的に獲得するために、形態や生理機能を変化させながら樹種特有の最適な戦略をとっていると示唆された(Makita et al. 2011 Ecological Research)。

樹木根に関する知見は未だに限られており、森林生態系の構造と機能および炭素循環を理解する上での大きな空白を生み出している。本研究の微細根の生理・形態特性およびその分布を考慮した評価は、
これまで量的な研究が主流であった物質循環の研究と生理的機能の研究の架け橋となり、森林炭素動態の解明に重要な示唆を与えると考えられる。

最後になりましたが、推薦してくださった檀浦正子さん、および共同研究者・神戸大学森林資源学研
究室・京都大学森林水文学研究室・森林総研関西支所のみなさんに深く感謝の意を申し上げます。

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2011 年度根研究会賞（学術奨励賞）受賞講演

Award lectures

コムギ種子根の誘導的通気組織形成の形態・生化学的解析
モハマド エムダドゥル ハック
農研機構

作物研究所

麦研究領域

（＊E-mail: mehaque@affrc.go.jp）

Morphological and Biochemical Analyses of Aerenchyma Formation in Seminal Roots of
Wheat
Md. Emdadul Haque (NARO Institute of Crop Science, Japan)
Introduction: Plants can adapt to waterlogging condition(s) through the multifaceted alterations incellular and organ structure. One such response is the formation of aerenchyma in the root cortex, thetissue containing enlarged gas spaces, which thought to provide not only an internal pathway foroxygen diffusion, but also simultaneously reduces the number of oxygen consuming cells. The laterfeature is thought to assist in metabolic adjustment during waterlogging. Here we developed hypoxic
pot-culture conditions, and used a combination of morphological and biochemical approaches tounderstand the mechanism of aerenchyma formation with a view to overcome wheat constraints in thewaterlogged field in Japan.
Results:
1) We grew Bobwhite cv. SH 98 26 in conditions, a well-drained control, a water depth 15 cm below(T-15) and 3 cm above (T+3) the soil surface. The root growth was reduced in T+3 plants while theshoot growth did not change significantly during 72 h waterlogging. Root anatomy study showed that
wheat formed no aerenchyma under our control condition, but formed aerenchyma initially at 2 to 5
cm behind the root tip after 72 h in T-15 and 48 h in T+3. The aerenchyma in T+3 plants then extended
by an additional 5 cm towards root base during the next 24 h; they extended approximately 8 cm longin T-15 and 14 cm long in T+3 from 2 cm behind the root tip after 7d waterlogging. Evans blue
staining indicated that wheat aerenchyma was lysigenous which resulted from degradation of corticalcells. We also studied aerenchyma formation in Japanese cultivars.
2) To check the biochemical responses of root to waterlogging we used lysigenous aerenchymatous
seminal roots (discussed above). Roots of cv. Bobwhite were excised from T-15 and T+3 plants andsubjected to proteomics. 2-D electrophoresis showed that 29 spots changed in the expression levels
under waterlogging and 10 of them exhibited a reproducible up- or down regulated fluctuation. The
up-regulated proteins were involved in alteration in energy and redox status, defense responses andcell wall turnover. Down-regulated proteins were related to the glycolysis and respiration. Multiple
candidates for single spot were found by MASCOT search after mass spectrometry. Four candidate
proteins were found for the highest up-regulated protein spot #5. Further confirmation and functional
characterization of the candidates of spot #5 are now going.
Conclusion: Our results provide information on the variation in aerenchyma formation in
non-Japanese cv. Bobwhite and Japanese wheat cultivars. Correlation data on aerenchyma % with root
dry mass in Japanese cultivars implied that wheat aerenchyma might be immature or underdeveloped,
i.e., wheat aerenchyma is not formed constitutively. We have not yet found a good germplasm foraerenchyma formation in T. aestivum and its relatives. In addition to the waterlogging responsive
candidate genes from non-Japanese cv. Bobwhite, it may well be preferable to find the key gene(s) for
aerenchyma formation in distant species with a high capacity to form well-developed aerenchyma (e.g.,constitutive aerenchyma of rice) that can be introduced into a useful host wheat such as Bobwhitefollowed by gene introgression into elite Japanese cultivars by crossing.
Acknowledgement: This work was supported by the Program for the Bio-oriented Technology
Research Advancement Institution (Promotion of Basic Research Activities for Innovative Biosciences,
No. H20/seeds-01-01), Japan.
172

創立 20 周年記念式典

Root Research (根の研究) Vol. 20 No. 5

講演要旨

記念講演

農耕地の持続的生産機能と作物の根大門弘幸
大阪府立大学学術研究院応用生命系（E-mail: daimon06@plant.osakafu-u.ac.jp）
今から 20 年前の 1992 年 5 月 16 日土曜日に，第 1 回根研究集会が東京大学農学部で開催された．私の古い手帳には，13 時〜20 時と記してある．当日は生憎の雨だった．懇親会では初代会長の森田さんとお話させて頂きとても緊張したのを覚えている．この年は作物学会と育種学会が松戸にある千葉大で連続して開催され，作物学会に来られていた小柳さんから研究集会へのお誘いを受けた．育種学会で発表した｢線虫対抗植物ルドベキアの根系改良｣のスライドがあり，根にも関係あるので発表させてもらうことにした．これが私のこの世界への第一歩であった．毛根病菌の Agrobacterium rhizogenes（当時の呼称）の Ri プラスミドが保有する rol 遺伝子をキク科のルドベキアに導入して，殺線虫物質のα-ターテニールを根で産生させて線虫防除に応用しようという発想であった．A. rhizogenes は千葉県のメロン圃場から分離し，国内野生株 A-5,A13 と名付けた．ルドベキアの形質転換体は，分枝根が多く根毛も旺盛に発生し，ターテニール生産量も増えた．一方，地上部の生育量は著しく少なく，S/R 比の重要性をあらためて感じた．ラッカセイでは，主根の表皮が剥離するので一般に根毛が生じな
いが，rol 遺伝子を導入すると旺盛な根毛発生が認められた．ラッカセイの細胞壁がもつリンの溶解機能との関係やクラッキング感染という独特の根粒菌感染過程にも興味をもって研究を継続している．
これらの研究で根と向かい合うことになったが，私の専門分野である作物生産科学という領域では，当然のことながら栽培という出口を意識して研究を進めなければならない．農耕地の地力維持，休耕
地管理，水田転換畑での畑作物生産といった視点で，根の研究の成果を活かせればと思う．マメ科緑肥作物であるクロタラリアやセスバニア，被覆作物のヘアリーベッチ，水田転換畑に導入されるアズ
キやダイズといった作物の根を見ながらいつもそう思うのである．モンスーンアジアの特徴である雨期とその後の急激な乾燥は，この国で作物研究を進めていると必ず気になる問題である．二次通気組
織形成と胚軸根形成のいずれで湛水に適応するかはセスバニアの種によって異なった．梅雨時に播種される大納言アズキでは大粒の品種ほど不定根の発生が多かった．大規模農地だけでなく小規模農地
とりわけ中山間地の地力管理はこの国の重要な課題である．ヘアリーベッチの早期刈取りは地下部蓄積窒素を刈取り直後に土壌に放出し，休閑緑肥のイネ科作物の窒素栄養を補った．リン鉱石が自由に取引できなくなると農耕地のリンの再利用を考えなければならない．フィチンや難溶性無機リンの溶解能力をもつ根粒菌を見つけ，そのマメ科作物の根面での挙動とリンと窒素両者の供給力を評価した
いと研究を進めている．過剰施肥やハウス土壌で集積した硝酸塩は湛水流去でなく，クリーニング作
物で回収して有機物として再利用すべきである．ソルガムのようなイネ科も有用だが，根量が多く C/N
比が低いマメ科緑肥は，速効性有機物として野菜畑に組み込めると生産現場で試してもらっている．
雑多なことを並べたが，本講演ではその一部をご紹介させて頂く．低投入型の作物生産技術と農耕
地の持続的管理技術の普及は，まさに｢待ったなし｣である．根の研究に頭か首か半身か全身かを突っ込み 20 年が経つがなかなか成果は出ない．このところ，土俵際に追い込まれることもしばしばだが，徳俵に足がかかってももう少し踏ん張ってみようと思っている.

173

The JSRR's 20th Anniversary Symposium
The Latest Frontiers of Root Research in Asia
Abstracts of Invited Lectures
根研究会創立 20 周年記念シンポジウム「アジアの風－アジアにおける根研究の最前線－」
招待講演要旨Keynote lecture: The necessity of root research in Asia
Dr. Jun Abe (The University of Tokyo, Japan)････････････････

P.175

Invited lecture: Root biomass and respiration for Korean forests
Prof. Yowhan Son (Korea University, Korea)･･････････ P.176

Invited lecture: A primary study on the adapting mechanismsof cotton roots to saline soils
Prof. Xiaojing Liu (Chinese Academy of Science, China)･･････････ P.177

Invited lecture: Long-term monitoring root growth and soil water･･････････ P.178
uptake by winter wheat for efficient water use in the North China Plain
Prof. Xiyin Zhang (Chinese Academy of Science, China)
Invited lecture: IRRI’s drought stress research in rice withemphasis on roots: Accomplishments over the last 50 years
Dr. Amelia Henry (International Rice Research Institute, Philippines)･･････････ P.179

Invited lecture: Agricultural problems by waterlogging in Northeast Thailand
Prof. Anan Polthanee (Khon Kaen University, Thailand)
Importance of rice root research in Asian situations: A commentary
Dr. Roel Suralta (Philippine Rice Research Institutite, Philippines)

･･･

P.180

･･･････

P.181

Akira. Yamauchi(Moderator)

Jun Abe(Lecturer)

Yowhan Son(Lecturer)

Xiaojing Liu(Lecturer)

Xiyin Zhang(Lecturer)

Amelia Henry(Lecturer)

Anan Polthanee(Lecturer)

Roel Suralta(Commentator)

174

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
Invited Lecture

The necessity of root research in Asia
Jun AbeAE-Bio, The University of Tokyo, Japan (junabe@agrobio.jp)
The plant root is the organ that develops in the soil to anchor the plant body and absorb waterand nutrients. Roots are naked to the soil environments with being subjected to the ceaselesschanges of biotic and abiotic conditions. Moreover, many of our managements, such as tillage,
fertilizer application, and irrigation, approach plants through soil managements. In addition,
the widely increasing consciousness towards environmental problems such as global warming,
nitrogen oxide gas, and eutrophication enhances the necessity of studies on the root that is theinterface between the plant and the earth and also between the plant and the man. There were
not a few pioneers in root research in Asian countries who studied for example on rice, woody
plants and desert plants. But the whole activity and international communication among root
scientists in Asian countries have been limited in comparison with those in the West.
Asia includes wide and diverse areas that belong to different climatic divisions that ranges
from arid lands to tropical rainforests. In plant production industries like agriculture, forestry,herbal plant production and greening, soil drought and accompanying soil hardness andnutrient deficiency are often big problems not only in arid areas but in monsoon areas that
may have severe dry season and unstable precipitation in rainy season. In some of those areas,use of broad saline and alkali lands is also an important task, as fertile farming lands are
decreasing due to modernization and human population is increasing in many of Asian
countries. An agricultural specificity of Asia is that rice is the major staple diet, which issensitive to drought stress. Improvement of rice production in rainfed lowand rice as well as
in upland rice has been required for adequate food supply and increase of household incomeof small farmers. In rainfed lowand rice, the problem is difficult to solve, because the rootsystem is exposed to both drought and water saturation irregularly and repeatedly. Studies on
the tolerance of crop plants against drought are needed in the view of water saving, too. On
the other hand, waterlogging and excessive soil water often disturb plant growth and decline
yield and quality of agricultural products. They are rather complicated problem; not only theoxygen deficiency in soil but toxicity of chemical components caused by soil reduction andspread of soil pests also inhibit functions of roots. The problem of waterlogging and excessive
soil water is serious particularly in East, Southeast, and South Asian countries. Even in dry
season, excessive soil water problem occurs commonly in subsidiary upland crops cultivatedin drained paddy fields. In Japan, as the government encourages the conversion of paddy
fields to upland fields, scientists have struggled to improve the tolerance of wheat, soybean
and maize against the excessive soil water, and been focusing root morphology and function.
Studying plant anaerobiosis can also contribute to better understanding of importanthydrophytes in Asia such as paddy rice and mangrove trees.
Forest and farm lands are important research object when we discuss the global
environmental problems, relating to carbon and nitrogen cycles in the ecosystems. While
European forestry scientists have developed good community via international activities like
COST action, communication among Asian scientists seems still limited. In addition,communication between forestry and agricultural scientist should be important because Asia
also holds large areas of paddy fields as the source of methane generation.
This symposium can be the start point of close communication among root scientists in Asia.
175

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
Invited Lecture

Root biomass and respiration for Korean forests
Yowhan Son1*, Nam-Jin Noh1*, Myung-Jong Yi2, Young-Mo Son3, Kyung-Hak Lee3,
Rae-Hyun Kim3, Jaehong Hwang3
1. Department of Environmental Science and Ecological Engineering, Korea University,
Korea, 2. Department of Forest Science, Kangwon National University, Korea, 3. Korea
Forest Research Institute, Korea (yson@korea.ac.kr)
Investigating the response of terrestrial ecosystems to global climate change has become apriority for the scientific communities. However, the accuracy of nutrient and carbon (C)dynamics for forest ecosystems has been limited by the difficulties in obtaining reliable
estimates of belowground components compared with numerous estimates of abovegroundcomponents. Root biomass and its ratio to aboveground biomass for Korean forests were
investigated using the national forest C inventory data in Korea. Also studies on fine root
biomass, production, turnover rate and root respiration were reviewed. Average root biomass(Mg ha-1) of 40 to 50-year-old broad-leaved and coniferous forests in Korea was 54.0 (24.1135.8) and 43.6 (13.9-94.8), respectively. The average ratio of root to aboveground biomass
for Korean forests (0.31±0.01 for broad-leaved forests and 0.28±0.03 for coniferous forests)
was higher than those of other regions from the literature (0.25 for deciduous forests and 0.26
for coniferous forests) (Figure 1). Fine root ratio to aboveground biomass, production (kg ha-1yr-1) and turnover rates (yr-1) for broad-leaved and coniferous forests in Korea were 0.016 and0.017, and 2.58 and 2.53, and 0.73 and 1.33, respectively (Table 1). Based on a trenching
study it was reported that root respiration accounted for approximately 31% and 34% of soil
respiration for a Quercus-dominated forest and a Abies holophylla forest, respectively. The
intact root respiration rate of a mature Pinus densiflora forest using the CO2 sensors with a
newly designed small root chamber was estimated to be 6.28 nmol CO2 g-1 s-1. More studies
on investigating and quantifying forest belowground components in the East-Asian countries
would be needed to understand the global terrestrial ecosystem C dynamics.
Table 1. Above and belowground biomass (Mg ha-1), fine root
biomass (Mg ha-1), fine root ratio to above- and belowgroundbiomass, fine root production (kg ha-1 yr-1), and turnover rate
(yr-1) for broad-leaved and coniferous forests in Korea.

Mean age (yr)Broad-leaved
40 (39-42)

Coniferous
45 (36-75)

Aboveground biomass
Belowground biomass
Fine root

135.1 (35.7)
43.0 (2.3)
2.0 (0.3)

127.7 (8.9)
32.6 (3.9)
2.1 (0.3)

Fine root: aboveground
Fine root: belowground
Fine root production
Turnover rate

0.016 (0.002)
0.048 (0.007)
2.577 (0.352)
0.730 (0.150)

0.017 (0.003)
0.067 (0.012)
2.529 (0.602)
1.325 (0.334)

N

Figure 1. Root:shoot ratio of major tree species
in Korea. Vertical bars indicate the standard
deviations of the means and numbers inparenthesis indicate the numbers of study sites.

References

176

3
5
Son and Hwang (2003)
Park et al. (2004, 2010)
Noh et al. (2011)

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
Invited Lecture

A primary study on the adapting mechanisms of cotton roots to saline soils
Zhixia Xie, Xiaojing Liu*
Center for Agricultural Resources Research, Institute of Genentics and Developmental
Biology, Chinese Academy of Sciences, P. R. China (xjliu@sjziam.ac.cn)
Cotton is one of the most salt tolerant crops and growing large area in saline soils in theworld. The mechanisms of salt tolerance in cotton plant have been studies extensively inphysiological and molecular aspects. However, less study has being conducted on themechanisms of salt tolerance in cotton roots despite the inhibitory effects of salinity on root
length and the number of lateral roots. Based on our field investigation, we found that incoastal saline soil land, when surface soil salt leached to deeper soil layer by irrigation, thecotton can be grown and cotton roots are mainly distributed in desalinized soil layer. This
indicates that cotton roots may have some mechanisms to adapt to non-uniform salineconditions. Here we show that non-uniform salt stress modulates root growth orientation by
reducing the gravity response.
We design a double-layer Murashige and Skoog (MS) medium experiment in which
extreme high salt (400mM NaCl) MS was on the bottom and plain MS medium on the top.
The roots of cotton seedlings penetrated the interface of the layers and grew straight
downwards when both layers were plain MS media. In contrast, changes in the root growthorientation of the seedlings were observed in response to salt stress from the bottom medium.
The primary root did not pass the interface between normal MS and salt medium, and they
grew along the interface between two medium.
To better understand this tropistic response of cotton roots to salt stress, a time course
amyloplasts in columella cells of primary roots were visualized by staining withiodine-potassium iodide solution. We found that the amount and distribution of amyloplasts incolumella cells of roots was altered when root grow along the interface, but not degradation
completely.
Abscisic acid (ABA), as a critical regulator in gravitropism growth of root, increased
markedly about 3 times of control plants at the early stage of root cap reaching to the interface,
and then, it severely decreased. Abscisic acid concentration in root tap was recovered near tonormal level after root grew along with interface between two layers of MS medium without
regard to gravity. The changes of reactive oxygen species (ROS) were similar as ABA. The
result suggested that salt degree modulates cotton root system architecture, and theamyloplasts in columella cells, ABA and ROS may play critical role on the mechanism of salt
avoidance in cotton roots.

177Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
Invited LectureLong-term monitoring root growth and soil water uptake by winter wheat for
efficient water use in the North China Plain
Xiying Zhang*, Suying Chen, Hongyong Sun, Liwei Shao
The Center for Agricultural Resource Research, Institute of Genetics and Developmental
Biology, The Chinese Academy of Science (xyzhang@sjziam.ac.cn)
Intensive irrigated cropping systems in the North China Plain (NCP) resulted in not only
depletion of groundwater resources, but also nitrogen leaching. Efficient management ofwater in crop root-zone profile is important for reducing irrigation water use as well as
nitrogen leaching. This study was undertaken to investigate root growth and distribution, root
water uptake by winter wheat under different irrigation treatments, and possible ways toimprove soil water use efficiency from 1990 to the present. Root sampling results showed thatwinter wheat had a prolific root system with an average depth of 2 m. Most of the root system
was concentrated in the upper 40 cm of soil. Root length density (RLD) in the top layer of soil
(0-20 cm) was very high with values around 3 to 5 cm/cm3. The distribution of water uptake
from the soil profile under good soil moisture conditions was closely related to the
distribution of RLD. When RLD was less than 0.8 cm/cm3, the root was the main factor
limiting the complete utilization of soil water by crops. At maturity, over 100 mm of available
water remained in the root-zone for the rain-fed treatment, although the upper layers had
already entered water deficit, since the scarcity of roots in the deep soil layers restricted thefull utilization of soil water. For irrigated wheat, from 40% to 50% of crop water use wasfrom the stored soil water, and for the rain-fed wheat up to 80% of the water use was from thestored soil water in a dry season. Available stored soil water played an important role in thehigher production of wheat crops in the NCP.
The results also showed that the yield and evapotranspiration (ET) of winter wheat
gradually increased from 1990 to the present. There was no consistent change in total root
length (TRL) over time. The difference in root size among seasons and irrigation treatments
mainly occurred in the upper soil profile, where RLD was greater. No direct relationship was
found between root size and soil water use. Thus, TRL was not a factor that indicated thewater extracting capacity of crops. rather, the distribution of RLD along the soil profile plays
more important role in soil water utilization. Smaller root size in the upper soil layer did notaffect soil water uptake, and might be more economical in terms of production efficiency.
Effective measures to increase the utilization of stored soil water could improve crop
performance under conditions of limited water supply in the NCP. Recent measurements
showed that the bulky density was increased under the tillage layer and soil pan is becoming
thick and moving upwards with the application of minimum tillage practices in the NCP. The
increase both in bulk density and thickness of the soil pan significantly affected the
distribution of RLD, resulting in greater RLD in the tillage layer and smaller RLD in deep soil
profile. Results showed that changing cultivation practices were possible ways to break thesoil pan to improve root growth in the deeper soil layers that will benefit soil water use.

178

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
Invited Lecture

IRRI’s drought stress research in rice with emphasis on roots:
Accomplishments over the last 50 years
Amelia Henry
International Rice Research Institute (IRRI), Los Banos, Philippines (a.henry@cgiar.org)
A look back over IRRI’s 50-year history reveals that early research insights were key for ourcurrent progress in root research for drought. Early recognition of the importance of roots
for drought resistance, and the characterization of diversity in rice root architecture, provided
a strong foundation for drought research at IRRI. After direct selection for yield during thepast decade that is now approaching impact at the farm level, we are seeing that root traits areindeed involved in improved yield under drought. The first mention of drought in the IRRI
Annual Reports was in 1970, and by the mid 1970s large efforts were going into research on
root growth in response to drought. Deep root growth and formation of large-diameter nodal
roots was emphasized. Attempts to identify novel indirect selection methods for deep root
growth were initiated, including relationships between plant height and root depth, andevaluation of root pulling force. In the 1980s, an emphasis was on aeroponic studies for root
morphology and anatomy, and line-source sprinkler studies were commonly conducted in thefield. The use of crosses to better understand the genetics of root traits was initiated in the
1980s, and further efforts towards characterization of the genetics behind root traits wereconducted in the 1990s, specifically the use of molecular markers to select for root trait QTLs.
A shift towards rainfed lowland systems in addition to upland studies was initiated in the
1990s, with increased recognition of the different types of drought stress, GxE analysis, andcharacterization of water uptake by roots. In the 2000s, drought breeding efforts moved
from selection of root traits to direct selection for yield under drought. Physiological studies
on root function were strengthened, including experiments on root hydraulic conductivity andxylem vessel cavitation. Today, the links between genetics and physiology for roots anddrought continue to move forward: we have identified traits associated with two major
drought-yield QTLs to be root traits, and we are characterizing association panels that havebeen mapped/sequenced in order to pinpoint genes associated with specific root traits andfunctional parameters. Detailed characterization of the target drought-prone environments isthe current root/drought research need at IRRI, in order to link drought-resistance traits andgenotypes with the most appropriate types of drought stress occurring in farmers’ fields.

179

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
Invited Lecture

Agricultural problems by waterlogging in Northeast Thailand
Anan Polthanee* and Arunee Promkhambut
Faculty of Agriculture, Khon Kaen University, Muang, Khon Kaen 40002, Thailand*Corresponding author: panan@kku.ac.th
Although the Northeast region is known to have prevailing drought, waterlogging also
has serious economic consequences for productivity of much arable farmland. Severity andfrequency of waterlogging in Northeast Thailand vary over areas, within a year and between
years. However, its potential has been projected to increase in the future. Considerable
transient and more persistent waterlogging of the soil and deeper submergence of crops could
occur not only in irrigated farmlands but also rainfed areas due to intensity of rainfall,undulating land pattern and change in land use. A short-term waterlogging for a few days may
retard plant growth. Prolong waterlogging for 2-3 months due to flash flood, overflow ofwater from the rivers or extended wet season could result in submergence of the whole plantor some parts of it, which will severe increase in yield loss of crops. In 2010, paddy field,
occupied 66% the arable land of the region, is most affected by flooding resulting in about
US$ 540 million loss. Impact of waterlogging on crop growth and yield depend on crop
species, cultivar, duration of waterlogging and growth stage of plant at which waterlogging
occurs. Waterlogging initiated at early vegetative growth stage and long-term waterlogging
duration severely reduced growth and yield of fiber crop, castorbean, and sweet sorghum
Long-term waterlogging for thirty days at 9.5 months old sugarcane immediately reduced
tiller number, youngest leaf expansion rate, leaf number per plant and stem diameter ascompared to the control. However, stalk yield and yield-related traits were not affected bywaterlogging at harvest (12 months). Roots developed under soil surface die underwaterlogging conditions and adventitious roots were developed in water above ground level toreplace functions of the damaged roots. After water was drained, suppression of root growth
was persisted, particularly when waterlogging was occurred at early vegetative stage.
Aerenchyma tissues were formed in cortex layers of the newly developed roots ofinvestigated upland crops, fiber crop, sweet sorghum and sugarcane. Among studied fiber
crops, kenaf is high waterlogging tolerant species with its ability to form casparian strip in
endodermis and exodermis cells both under control and waterlogging conditions. In terms ofsweet sorghum and sugarcane, tolerance to waterlogging may be due to the interconnection ofgas spaces like of roots below soil, roots in water, belowground stem and stalk basal above
water level.

180

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
Invited Lecture

Importance of rice root research in Asian situations: A commentary
Roel R. Suralta
Philippine Rice Research Institute, Maligaya, Science City of Muñoz, Nueva Ecija,
Philippines (rrsmfs@yahoo.com)
World crop production must be increased to keep up with the demand of everincreasing population. Asia accounts for more than half of the world’s population but thesustainability of its crop production is affected by water scarcity problem brought about by
climate change and industrialization. Water stress is associated with salinity ingress, drought
and nutrient deficiency (or toxicity) which negatively affects crop production. In rainfed
agriculture such as in rainfed lowland rice, fluctuating soil moisture stress is also a problem
due to severe waterlogging brought about by heavy rainfall in between periods of drought. A
need to increase crop productivity amid water scarcity to sustain crop production is inevitable.

Roots being the plant part directly in contact with the soil, indeed play key roles forcrop adaptation under stress to maintain crop productivity. Thus, root research is an importantcomponent for improving crop productivity under water stress-prone environments. It is very
timely that the issue on the necessity of root research in Asia has been raised. Each Asian
country may have unique adverse soil problems affecting crop production but common points
for establishing and/or strengthening root research collaborations among countries is crucial.
This could maximize sharing of expertise, experience, and resources which will expectedly
improve the efficiency of conducting root research.
Rice being one of the common crops grown among Asian countries may serve as the common
platform for creating root research collaborations for identifying the ideal root ideotype
specifically tailored under various stress prone rice environments. The ideotype of the rootsystem is the key for stable/increased rice production under such environments. A typicalexample of root research collaboration is the ongoing joint research done by Nagoya
University, PhilRice, University of Tokyo, IRRI and JIRCAS. Since root ideotype is dynamic,
detailed characterization of each target rainfed lowland sites is a must to identify the ideal root
ideotype required for each site. Once detailed characterization has been done, it is only thenthat the G (or QTL) x E studies will become more relevant and substantial. This type of
research would be more efficient when expanded and conducted by different networks ofresearchers from different ecosystems in Asia, who share common understanding and interestson this concept. This type of root research collaborations among Asian countries can be also
replicated to other soil stress factors and crops.

181

Poster presentations (Titles and presenters)
ポスター発表 表題・発表者一覧
第 35 回根研究集会 35th JSRR Biannual Meeting
番号
P01A
P02B
P03A
P04B
P05A

表題
2 層栽培・根系分割灌水による高糖度トマトの栽培法の開発（第 2 報） 上下
層の土壌容積の違いがトマトの生育に及ぼす影響
根径からみたバスケット法によるテンサイ品種根系の簡易判別法について
ジベレリンによるシロイヌナズナの根における鉄吸収関連遺伝子の発現誘
導浸透圧ストレス環境下におけるイネ科作物の水利用機能研究
World Rice Collection を用いた塩ストレス条件下での初期生育反応の品種
間差異

発表者
浩之

ページ
184

今野弘規
松岡啓太

185
186

辻 伸弥
天野寿紀

187
188

林

20th Anniversary Symposium (The Latest Frontiers of Root Research in Asia)
No.
P06B
P07A
P08B
P09A
P10B
P11A
P12B
P13A
P14B
P15A
P16B
P17A
P18B
P19A
P20B
P21A
P22B
P23A
P24B
P25A

Title
Periderm formation in roots of monocotyledonous medicinal plant
Merwilla plumbea (Lindl.) Speta. under stress conditions
Field investigation of root and ground conditions for native licoriceat Mongolia
Seasonal changes of starch grain accumulation in roots ofErianthus
The accumulation of cadmium is suppressed by apoplasmic
barriers of roots
Identification of an ATP-binding cassette (ABC) transporter that isrequired for formation of suberin lamellae and the apoplastic
barrier at the hypodermis in rice (Oryza sativa)
The shift of isoelectric point of beta-1,3-glucanases possibly
involved in aluminum toxicity in soybean root
Effect of PolySilicate-Iron sludge on rice roots at organic farming
Physiological performance of direct seeding using iron-coatedrice seeds under submerged and drained conditions
The effects of compost and phosphorus supply on onion growth ofroot and shootInfluence of different maturation periods of hairy vetch
incorporated as green manure on growth of maize inoculated with
Gigaspora margarita
Growth and N2 fixation of soybean plants grown under different
soil moisture contents in FRP pots
Using technology of shoot and residue for green manure andforage production by leguminous crops and barley mixtures at
paddy
Effect of root-deposited N of hairy vetch on the growth and N
uptake of mixed-cropped oat
Effect of rhizobia primed with naringenin on root development andnodulation in Pisum sativum L.
Morphological changes of Sesbania rostrata root under different
soil properties
Nitrogen fixation by endophytic bacteria isolated from sweet
potatoInfluence of excess soil water during early growth stage on soil
microbial community structure in soybean fieldRespiration rate and sugar concentration of wheat root affectedby waterlogging in field and by root zone hypoxia in hydroponic
cultureAre roots involved in poor grain filling of wheat in Western Japan?
Waterlogging tolerant teosinte (Zea nicaraguensis) has a large
volume of aerenchyma and a barrier to radial oxygen loss in root

182

Presenter
Alexander Lux

Page
189

Kiyoshi Omine

190

Fumitaka Shiotsu

191

Michal Martinka

192

Katsuhiro Shiono

193

Eri Soga

194

Ryosuke Tajima
Shinsuke Mori

195
196

Hiroyuki Tsuji

197

Naoko Yamada

198

Sohei Asakura

199

Weon-Tai Jeon

200

Arata Tarui

201

Satori Nakamura

202

AtsushiMatsumura
Junko
Terakado-Tonooka
Rintaro Hattori

203

205

Asami Hamada

206

Hideki Araki
Tomomi Abiko

207
208

204

P26B
P27A
P28B
P29A
P30B
P31A
P32B
P33A
P34B
P35A
P36B
P37A
P38B
P39A
P40B
P41A
P42B
P43A
P44B
P45A
P46B
P47A
P48B
P49A
P50B
P51A
P52B
P53A
P54B

Variation for the capacity to form root aerenchyma and selection
for highly aerenchyma forming lines in the rare teosinte Zea
nicaraguensis
Root system development and hydraulic conductance in soybean
plant grown under waterlogged conditions
Dynamic regulation of the root hydraulic conductivity of barely
plants under salinity/osmotic stress
Water permeability of protoplasts derived from different portion ofseminal root system in rice
Promotion of aerenchyma formation in rice primary roots bytreatment with 1-Aminocyclopropane-1-carboxylic acid
Recovery and compensation of nitrogen uptake by change of root
morphology and gene expressions for ammonium transport under
the osmotic stress condition in rice seedlings
Cultivar differences in root development under water deficit
condition and its association with water uptake capacity in rice
qSOR1, a major rice QTL involved in soil-surface rooting in paddy
fieldsQTL for the plasticity in root system development triggered by soil
moisture fluctuation stress in rice
Identification of QTLs on lateral root development and theimportance under soil moisture fluctuation stress conditions in rice
Role of plasticity in lateral root development triggered by mild
drought stress in dry matter production using OryzaSNP panel ofrice
Investigation into molecular mechanisms of crown root formationand its application for improvements in root architecture in rice
Inhibition of auxin transport changes the morphology of rootsystem and distribution of auxin in root system of rice seedlings
Identification and characterization of reduced biomass production
mutant of rice accompanied with reduced root elongation
Non-destructive imaging of aerenchyma development in the
primary root of rice using X-ray Computed Tomography – A trial
for time-course observation –Different gene expression of the creeping-rooted type of a kind of
Alfalfa (Medicago varia)
Variation of 13C natural abundance in CO2 released from the rootsof rice and maize plants
Stable carbon isotopic ratio (δ13C) of fine roots in tropical forests
Growth and development of birch (Betula sp.) roots grown underelevated CO2 in FACE (A preliminary result)
Can microbial respiration explain mass loss, morphology, andchemical properties of dead fine root?
Mycorrhizal hyphae respiration
Relationships between morphology and respiration of fine roots
Tea roots changed respiratory activity in response to irradiatedlight information
Coarse root respiration measurement using automatic chambersystemFine root respiration for Pinus densiflora forests in Mt. Jukyeob of
Korea and Mt. Fuji of Japan
Linkage between under- and above-ground of three kinds of larch
species grown under different levels of nitrogen and phosphorous
Do trees growing on the steep slope have different root to shootratios from those on the flat site?
Inter-specific robustness and intra-specific flexibility of wholeplant metabolic scaling from seedlings to giant trees
Comparison of the mesh material in a root mesh method

183

Yoshiro Mano

209

Keiko Ota

210

Maki Katsuhara

211

Azumi Suganuma

212

Kenta Yukiyoshi

213

Kyoko Toyofuku

214

Maya Matsunami

215

Yusaku Uga

216

Jonathan Niones

217

Satomi Ohashi

218

Emi Kameoka

219

Yuka Kitomi

220

Atsushi Ogawa

221

Mitsuhiro Obara

222

Tadafumi Bando

223

Xiaona Wang

224

Aki Kuribayashi

225

Masaharu Sakai
Hirotaka Ito

226
227

Ayumi Kawamura

228

Frida Andreasson
Saki Yamamoto
Tomoo Homma

229
230
231

Masako Dannoura

232

NamJin Noh

233

Qiaozhi Mao

234

Nobuhiko Kasuya

235

Shigeta Mori

236

Aiko Nakano

237

第 35 回根研究集会

Root Research (根の研究) Vol. 20 No. 5

P01 ポスター発表 要旨
2 層栽培・根系分割灌水による高糖度トマトの栽培法の開発（第 2 報）
上下層の土壌容積の違いがトマトの生育に及ぼす影響
林 浩之１＊・豊福恭子２・田口多喜子１・小川敦史２１
秋田県農林水産技術センター農業試験場、２秋田県立大学生物資源科学部（E-mail：Hayashi-Hiroyuki@pref.akita.lg.jp）
高糖度トマトは、根域制限下での少量灌水や高濃度養液を与え、根系に水分ストレスを付加させる
栽培法によって経済生産されている。地床栽培では、トマトは上層土が乾燥すると下層根に吸水を依存するが、下層根が少ない条件では長期間水分ストレスが付加され糖度が高まることがある。そこで、毛管水の影響の少ない上下 2 層の容器を用い、上下層の土壌容積を変えた条件でトマトを栽培して、上層土の乾燥後に付加される水分ストレス強度や果実の糖度、1 果重への影響を検討した。
試験は、2008 年に農業試験場内のガラス温室で実施した。栽培は前報（引用文献）と同一の上下 2層のアルミ製容器を用い、3 月 6 日に中玉トマト品種‘ルイ 60’を定植し、5 段果房上の本葉 2 枚を残して主枝を摘心した。試験区は、上下層の土壌容積によって (1) 上層 1 区（上層 19L：下層 38L）、(2)
上層 2 区（上層 38L：下層 19 L）、(3) 対照区（上層 38 L：下層 19 L）、の 3 処理を設け、4 反復で実施した。灌水は、定植後から 4 月 8 日までは上層容器に適宜灌水し、4 月 9 日以降は点滴チューブ（Stream
Line、Netafim 社）により上下層の各容器に 1 日 2Ｌを灌水した。4 月 22 日以降、対照区を除く区で上層容器の灌水を停止し乾燥処理を開始した。葉柄水ポテンシャルは、プレッシャーチャンバー法により 3 段果房下の側枝の小葉 2 枚で計測した。果実調査は、5 段果房までの全ての良果で、果実糖度と 1
果重について測定した。
葉柄水ポテンシャルは、対照区では調査期間を通して－1.1 MPa から－0.9 MPa まで緩やかに上昇した。上層 1 区では乾燥処理直後に－1.4 MPa まで低下した後－1.2 MPa まで上昇し、下層根からの吸水が増えることにより水分ストレスが緩和されたとみられた。
上層 2 区では、対照区と同程度の－1.2 MPaから－1.6 MPa まで低下し、水分ストレスが長期間付加されていることが示された。
果実糖度は、上層 1 区では 2 段果房果実から糖度が 9 度(Brix%)を超えたが、4 段から 5 段果房果実の糖度は対照区と有意な差がみられず、平均糖度は対照区と同等であった。上層 2 区では、2 段から 5
段果房果実の糖度が対照区より高く、平均糖度は対照区より高い 9.3 度であった。 1 果重は、上層 1
区では、2 段から 4 段果房で対照区に比べて小さく、上層 2 区では 2 段から 5 段果房で対照区に比べ小さかった。平均 1 果重は、いずれの区でも対照区に比べて小さかった(表 1)。
前報の結果とあわせて葉柄水ポテンシャルと果実糖度及び 1 果重の関係を検討した。糖度 8 度となる葉柄水ポテンシャルは－1.1 MPa に相当し、1 果重が 40g となる葉柄水ポテンシャルは、－1.0MPaに相当した。
葉柄水ポテンシャルが－1.3 MPa 以下では、果実糖度と 1 果重の変化は認められなかった。
これらの結果から、2 層容器を用い根系を分割し灌水管理したトマトでは、上層根が乾燥処理された
直後は下層根からの吸水が少なく、地上部の水ポテンシャルが急激に低下して果実糖度が高まるとみられた。しかし、下層の根域が大きい条件では、下層の根量の増加により再び水分ストレスが緩和されることから、高糖度トマトの生産には下層の土壌容積を上層の 1/2 以下として水分ストレスを持続させる必要があることが示唆された。また、高糖度果実の生産に適する水分ストレスは、乾燥処理後の葉柄水ポテンシャルを指標とすることができ、適当な水ポテンシャルは－1.0 MPa から－1.3MPa の範囲にあると推定された。
表1

土壌容積の異なる2層容器で栽培したトマトの果実糖度と１果重
1段
2段
3段
4段
１果重 糖度１果重 糖度１果重 糖度１果重 糖度区名(g) (Brix%)(g) (Brix%)(g) (Brix%)(g) (Brix%)

5段
１果重 糖度(g) (Brix%)

平均
１果重 糖度(g) (Brix%)

上層１

38.8a

8.3a

29.0a

9.1a

27.8ab 9.2a

23.2a 9.3ab

28.7ab 9.0ab

29.9a 9.0ab

上層２

41.9a

8.2a

30.3a

9.1a

25.3a

9.4a

23.9a 10.1a

22.1a 10.0a

29.5a

9.3a

対

44.3a

7.8a

36.7a

7.9b

34.7b

7.9b

40.6b

44.5b

39.9b

7.8b

照

7.9b

7.4b

注) 同一英小文字を付した区間には、5%水準でTurkey検定による有意差がないことを示す。

（引用文献）
林浩之・小川敦史・豊福恭子・田口多喜子・高橋善則 (2010) 第 33 回根研究集会研究発表要旨集

184

第 35 回根研究集会

Root Research (根の研究) Vol. 20 No. 5

P02 ポスター発表 要旨
根径からみたバスケット法によるテンサイ品種根系の簡易判別法について
今野弘規 1※・吉富啓悟 2・笠島真也 2・吉田穂積 2・伊藤博武 2
1
東京農業大学生物産業学研究科・2 東京農業大学生物産業学部（h-ito@bioindustry.nodai.ac.jp）
1.はじめに網走市における土壌タイプ間の収量格差を解決するために筆者ら（2011）は小柳ら(2001）のバスケ
ット（ザル）法を応用したテンサイ根系分布の初期判別の可能性について検討したところ，伊藤ら(2008）によって根系分布の差が明らかにされている「アセンド」(浅根型)，「カブトマル」(深根型）
および「スタウト」（中間型）を用いた実験にて，根数および発根角度に明確な差を認めている．しかしながら，他の遺伝資源を評価してみると，ここまでの検定では圃場での現象と適合しない場面も観察された．一方，吉田ら（2011）は，田中ら(1994)や有馬ら(1995)が提案したルートモデルを用いて土壌タイプ間での根系発達を「アセンド」を用いて解析したところ，淡色黒ボク土では生育の後期になると根系の骨格である 1 次側根や 2 次側根の発達が停止し，養水分吸収を行う 3 次側根の生育が進むのに対し，土壌物理性に劣る褐色森林土では生育後期になっても 1 次側根は発達を続け，2 次側根や3 次側根の親根として機能していたことを観察しており，土壌物理性に応じた太さの根を発達させていることを明らかにした．この結果は根系の初期判別には根径の発達も加味することで，より正確に判別できる可能性も示しており，本報告では先の 3 品種を用いて，根径も観察し，バスケット法による簡易判別について再検討した．
2.材料および方法
実験は 2011 年に研究会で報告した方法に準じて行った．供試材料には「アセンド」「スタウト」および「カブトマル」のそれぞれ 7 個体を用いた．根は催芽日を 0 日として 30 日間，毎日の 10 時にザ
ルの表面から 5 ㎜以上突き抜けた根をハサミで切り取り保管し，またザル上表面中央から切り取った根とのなす角度を記載した．根径は 30 日間に採取した「アセンド」66 本，「カブトマル」129 本，「ス
タウト」99 本について解析した．ルートスキャナー（EPSON-Perfection49902.68）と解析ソフト(win，RHIZO）により最大根径を計測し，その根の根径とした．そして根径の仮想円盤を算出してルートマッ
プを作成した．
3.結果および考察
催芽後 30 日目のルートモデルをみると，「カブトマル」では太い根から細い根まで確認されたのに対し，「アセンド」では主に細い根のみ，「スタウト」では両品種の中間の傾向が認められた．次数が異なるとみられる側根数は品種で異なり，3 つの「カブトマル」が最も多く，次いで「スタウト」が 2
つ，最も少ない「アセンド」が 1 つであった．本研究では，このルートモデルを詳細にみて「カブトマル」は根径の太い方の 9 ㎜のピークを 1 次側根，0.7 ㎜のピークを 2 次側根，以下 3 次側根として，「スタウト」は 0.8 ㎜を 1 次側根，0.7 ㎜を 2 次側根，以下を 3 次側根として，ピークの判別が困難であった「アセンド」では最大根径の 0.6 ㎜を 1 次側根とし，以下を 2～3 側根とした．さらにザルの表面から突き抜けた角度によって垂直根(90～70°)と水平根(70°～)に区別した．10 日ごとに作成した
ルートモデルから，その成長量を算出したところ，「カブトマル」と「スタウト」では 1 次側根の成長量の増加パターンに違いがあった．すなわち，「カブトマル」では 0～10 日目の垂直根に限って成長した．「スタウト」の垂直根では 10～20 日目に，水平根でも 20～30 日目に成長が認められた．2 次および 3 次側根の成長では両品種間に大きな違いが認められなかった．アセンド」の 1 次側根の成長は垂直根をみると，10～20 日目にかけてやや増加し，20 日目以降に大きく増加した．2 次側根の垂直根では 10～20 日目に大きく増加し，20 日目以降には頭打ちとなった．水平根では 20 日目以降に大きく増加した．
以上の結果から，深根型の品種は生育の早い段階から 1～3 次側根まで並行して成長するのに対して，浅根型の品種は 1 次側根を十分に成長させてから 2 次側根，3 次側根と順次成長していくものと推察された．また，実験によって根径に品種間差が認められたことから，根系の簡易判定法に根径の測定の必要性が示された．

185

第 35 回根研究集会

Root Research (根の研究) Vol. 20 No. 5

P03 ポスター発表 要旨
ジベレリンによるシロイヌナズナの根における鉄吸収関連遺伝子の発現誘導
松岡啓太 1＊・古川純 1・ビダディ ハニエ 1・朝比奈雅志 2・佐藤忍 1
1

筑波大学生命環境科学研究科

2

帝京大学理工学部（＊E-mail: snow_in_april@ies.life.tsukuba.ac.jp）

植物の微量栄養素の一つとして鉄が存在する。鉄は植物においてクロロフィルの生合成やシトクロ
ムなどの補因子として必要であり、鉄が欠乏すると葉に白化が生じることが知られている。土壌中の鉄は主に三価鉄の状態で存在しており、水への溶解度が低いために獲得することが困難である。これに対して植物は土壌からの鉄の吸収の仕組みを備えている。双子葉植物においては、土壌中に存在す
る三価鉄-キレート複合体を細胞膜上の三価鉄還元酵素(FRO2)により二価鉄に還元し、根の表皮に局在する二価鉄トランスポーター(IRT1)により植物内へと鉄を取り込んでいる。FRO2 と IRT1 の発現は根における短距離シグナルと地上部の鉄含量によって制御される長距離シグナルの両方により調節されている。シグナルの候補として植物ホルモンが考えられ、オーキシンやエチレン、サイトカイニンなどの様々な植物ホルモンが IRT1 と FRO2 の発現を調節していることが報告されている。
我々は植物ホルモンの一つであるジベレリン(GA)に着目している。GA は発芽や細胞の分裂や促進、花芽形成の促進に関わっているが、GA による IRT1 と FRO2 の発現への調節作用についてはまだ明らかにされていない。MS 培地で生育したシロイヌナズナの GA 欠損体(ga3ox1 ga3ox2)の地上部に活性型のGA である GA4 を与えて 3 日後の根における IRT1 と FRO2 の遺伝子の発現量を RT-PCR で調べた結果、GA投与により顕著に増加することが示された。また、IRT1 と FRO2 の発現調節は鉄欠乏条件における応答の研究から bHLH 型の転写因子により直接制御されることがわかっている。これらの転写因子の発現についても GA 投与による誘導を調べてみたところ IRT1、FRO2 と同様に促進されることがわかった。このことから GA 投与も鉄欠乏と同様に bHLH 型の転写因子を介して IRT1、FRO2 の発現誘導に関わっていると思われる。さらに、遺伝子発現の誘導だけではなく酵素活性においても上昇が見られるのかどうかを調べるために、三価鉄還元活性と鉄の蓄積量の解析を試みている。GA が鉄欠乏のシグナルとして
bHLH 型転写因子の上流で機能しているかを明らかにするために、鉄欠乏条件下での野生型(WT)と GA
欠損体において、IRT1 と FRO2 の発現の誘導に違いがあるのかどうか検証する。また、鉄欠乏応答の研究から示されているシグナル伝達における一酸化窒素(NO)の関与が地上部 GA 処理によっても見られるのかを調査することで GA の作用が既知のシグナル経路を介しているのかどうかを考察する。

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Root Research (根の研究) Vol. 20 No. 5

P04 ポスター発表 要旨
浸透圧ストレス環境下におけるイネ科作物の水利用機能研究辻伸弥 1＊・且原真木 1・柴坂三根夫 1
1

岡山大学資源植物科学研究所（＊E-mail: gag422014@s.okayama-u.ac.jp）

近年、イオン毒性回避機構に関与するイオン輸送体等の分子機構が明らかになってきているが、それに比べて浸透圧ストレスに際して根から脱水が起こる分子メカニズムは、大部分が未知である。細
胞内外への水輸送は主に水チャネルであるアクアポリンによって行われている。細胞内への水輸送においては PIP（Plasma membrane Intrinsic Protein）が主要な役割を果たしていることがこれまでの研究で分かっているが、水ストレス時の脱水防御機構を司る分子種の同定やメカニズムの解明には至っていない。本研究では、浸透圧ストレス環境下におけるオオムギ（Hordeum vulgure）、イネ（Oryza

sativa）の根の水輸送に関して分子生物学的、植物生理学的観点から研究し、水ストレス時の脱水防
御メカニズムを総合的に解明することを目的としている。
播種後 4 日目のオオムギ（はるな二条）を基準とし、マンニトール 0mM、180mM、360mM の下、24 時
間後の root、shoot の成長を測定した。180mM では 0mM と比べて若干 shoot の成長度が下がったが、ほとんど変化がなかった。一方、360mM では、0mM と比べて shoot で 85.3％、root で 45.0％の成長度の減少が見られた。
同じ濃度の浸透圧環境下で根におけるオオムギ PIP 遺伝子の転写制御について調査した。発芽後 4日齢のオオムギの根においては HvPIP1;3 の転写レベルが最も多く、HvPIP2;3 の転写レベルが最も低かった。浸透圧ストレスとして 180mM マンニトールを与えた場合、いずれの PIP 遺伝子の転写レベルにもコントロール（0mM マンニトール）と比較して顕著な差は見られなかった。一方 360mM マンニトールを与えた場合、HvPIP1;2、HvPIP1;4、HvPIP2;1、HvPIP2;2 の転写レベルが処理後 2 時間以降で減少した。これは高濃度の浸透圧ストレスに対し原形質膜における水の透過性を減少させ、細胞外への脱水を防ぐため発現が抑制されると考えられる。塩ストレス下でもほぼ同様のアクアポリンの発現量が大幅に減少することがすでに分かっており、つまりは、塩ストレスによる HvPIP の減少は塩によるイオ
ンストレスの影響ではなく浸透圧ストレスによるものであることが分かった。
一方、根水透過性（Lpr）においては浸透圧ストレスによる著しい Lpr の抑制が見られタンパク質リ
ン酸化、細胞内輸送等による制御であることが当研究室で明らかにされてきている。
今後は強時ストレス時における発現制御が脱水回避にどのような影響をもたらすのかを解明することが今後の課題となっている。
イネにおいても明暗条件下の根水透過性（Lpr）を測定した。明条件下、暗条件下開始 2 時間目において Lpr が高くなった。180mM マンニトールによる浸透圧ストレスを付与したところ一時的にわずかな

Lpr 抑制が見られたもののオオムギ程の著しい根水透過性の制御は見られなかった。イネはオオムギのように水ストレスに強くなく、Lpr の制御による脱水防御応答はほとんどないことが示唆される。
上記のように根水透過性は浸透圧ストレスだけでなく光によって大きく変動する。故に現在は恒明
条件下においても調査中である。今後は、水ストレス時 OsPIP2 群の発現が制御されるように設計された RNAi 系統を用いて水透過性の変動を観察する予定である。

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第 35 回根研究集会

Root Research (根の研究) Vol. 20 No. 5

P05 ポスター発表 要旨
World Rice Collection を用いた塩ストレス条件下での初期生育反応の品種間差異
天野寿紀1*・豊福恭子1・松波麻耶2,3・森田弘彦1・小川敦史11

秋田県立大学生物資源科学部，2東北大学大学院農学研究科，3日本学術振興会特別研究員
E-mail: 111111@akita-pu.ac.jp［背景］世界の開発途上地域では干ばつや塩害等により，毎年イネの栽培面積の約7,500万haに相当する作物の生育がきわめて不安定である (飯山，2008)．塩類集積の影響を受けた耕地は，最大で毎年200万haずつ増加していると推定もされており，これによる生産量の減少は灌漑施設の整備による生産量増加に匹敵すると報告されている (Postel，1999)．本研究では，世界各地のイネの対立遺伝子の多様性
を90%カバーするWorld Rice Collectionを用いて塩ストレス条件下での地上部・根の初期生育反応を調査し，品種間差異を明らかにすることを目的とした．
［材料と方法］供試材料として，World Rice Collectionのうち48品種，および他の３品種 (Azucena, Dular,
Akita-komachi)を用いた．次亜塩素酸で殺菌処理した種子を暗黒条件下で３日間催芽した後，1/2
Hoagland水耕液の入った1Lビーカー上のネットに移植し，人工気象器内 (28℃，湿度70%，日長12時間)で栽培した．移植７日後に，水耕液の濃度が 50 mMになるよう塩化ナトリウムを添加し，塩ストレス処理を行った (以下，Stress区)．対照として塩ストレス無処理区を設けた (以下，Ctrl区)．移植14日後にサンプリングし，地上部および根乾物重，根の活性の指標であるα-ナフチルアミン酸化活性，根数，
総根長，根の表面積および体積を測定した．
［結果と考察］塩ストレス条件での地上部乾物重は，Ctrl区とStress区を比較した相対値 (Stress/Ctrl)が１以上の塩ストレス耐性を示す品種が９品種あった．一方，相対値が0.4以下の塩ストレス感受性を示す品種が６品種あった．根乾物重は，４品種で相対値が１以上であった．一方，根乾物重の相対値が0.4以下であった品種が６品種あった．また，供試した全品種の地上部乾物重と根乾物重および総根長の間では５%水準，根の表面積の間では１％水準で有意な相関を示した．一方，地上部乾物重とα-ナフチルアミン酸化活性の間では，有意な相関は示さなかった．これらの結果から塩ストレス条件下では地上部の生育と根の生育の間で有意な相関を示し，根の生育が維持される品種が地上部の生育も維持される品種であることが明らかになった．

［引用文献］
1. 飯山賢治 (2008) 国際貢献のための農林水産技術開発，第８回農林水産技術会議資料．
2. Sandra Postel (1999) Pillar of Sand: Can the Irrigation Miracle Last?
Series，W W Norton & Co Inc．

188

Worldwatch Environmental AlertRoot Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P06 Poster presentation

Periderm formation in roots of monocotyledonous medicinal plant Merwilla
plumbea (Lindl.) Speta. under stress conditions
Alexander Lux1,2*, Marek Vaculík1, Michal Martinka1, Johannes Van Staden3
1. Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in
Bratislava, Mlynská dolina B-2, SK-842 15 Bratislava, Slovak Republic; 2. Department of
Glycobiotechnology, Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9,
SK-845 38 Bratislava, Slovak Republic; 3. Research Centre for Plant Growth andDevelopment, School of Biological and Conservation Sciences, University of KwaZulu-Natal
Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa (lux@fns.uniba.sk)
RESULTSIn the present contribution two types of cultivation of Merwilla plants, highly traded
medicinal plant in South Africa, were tested for the evaluation of uptake and translocation of
Cd. Anatomical study was performed to investigate the possible effect of Cd treatment on theroot structure.
It was found that hydroponical cultivation is not convenient for this species. The growth ofplants cultivated in Perlite in control conditions was adequate and after Cd application thegrowth of M. plumbea plants was retarded. Roots accumulated considerably higher amountsof Cd when compared with the bulbs and leaves. Compared to control plants, theconcentration of Cd in the roots treated with 1 mg Cd L-1 was significantly higher andincreased when higher Cd stress (5 mg Cd L-1) was applied.The adventitious roots of M.
plumbea seedlings show the typical structure of a monocotyledonous root when grown incontrol conditions or in nature. The oldest part of M. plumbea root, close to the bulb, ischaracterized by the presence of a contractile zone.
Cadmium application at higher concentration (5 mg Cd L-1) induced the formation of cork
cambium in the periphery of cortical tissues, adjacent to the exodermis. Cells divided
periclinally from approx. 5 mm from the root apex and the derivatives impregnated their cell
walls with suberin. Periderm is only rarely developed in roots of monocotyledonous plants.
This is the first observation of periderm formation in monocotyledonous species in reaction toabiotic stress induced by toxic metals.
ACKNOWLEDGEMENTS
We thank National Research Foundation RSA-Slovak Collaborative Project, South Africa
and the Slovak Research and Development Agency (contract No. APVV SK-ZA-0007-07).
The work was also supported by Grant VEGA (1/0472/10) and by the Slovak Research andDevelopment Agency, contract No. APVV 0140-10.
REFERENCE
Lux A, Vaculík M, Martinka M, Lišková D, Kulkarni MG, Stirk WA, Van Staden J. 2011.
Cadmium induces hypodermal periderm formation in the roots of the monocotyledonous
medicinal plant Merwilla plumbea (Lindl.) Speta. Annals of Botany 107: 285–292.

189

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P07 Poster presentation

Field investigation of root and ground conditions for native licorice at Mongolia
Kiyoshi Omine1*, Noriyuki Yasufuku1, Zentaro Furukawa1 and Haruka Kiyotomo1
1. Faculty of Engineering, Kyushu University, Japan (oomine@civil.kyushu-u.ac.jp)
Desertification which is caused by climate change, overfishing, and overgrazing is remarkable recently. Regardingwith greening, this research paid attention to the medicinal
plant licorice (Glycyrrhiza uralensis:Kanzo). Licorice lives
wildly in semi-arid lands especially located in China andMongolia, and its root which contains active ingredientglycyrrhizin (GC) is highly demanded as herbal medicine.
However, amount of licorice decreases recently due to overfishing and overgrazing and desertification.
To grasp the environment of semi-arid land where licorice
lives, root and ground conditions were investigated in
Mongolia in May and September 2010.
Distributions of root in the ground and root nodule oflicorice are confirmed.

Front
Photo 1 Excavation of ground at
semi-arid land in Mongolia

Back

Left-hand side

Front

Right-hand side

Fig. 1 Sketch of licorice root on the
cross-section of excavationroot
noduleモンゴルにおける甘草自生地の根と地盤調査
大嶺 聖・安福規之・古川全太郎・清塘 悠（九州大学）

190

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P08 Poster presentation

Seasonal changes of starch grain accumulation in roots of Erianthus
Fumitaka Shiotsu1*, Jun Abe2, Kaien Ra3 and Shigenori Morita3
1. The College of Agriculture, Ibaraki University, Japan (shiotsu@mx.ibaraki.ac.jp).
2. AE-Bio, The University of Tokyo, Japan.
3. Institute for Sustainable Agro-ecosystem Services, The University of Tokyo, Japan.
Erianthus species, perennial C4 grasses, perform huge biomass in abandoned lands and hightolerance to environmental stresses. Therefore, Erianthus may serve as a cellulosic biomass
crop for bioethanol production. So far, we noted that Erianthus roots have tolerance toenvironmental stresses (Shiotsu et al. 2010b，Shiotsu et al. 2011), and found that the nodal
root stele deposited starch densely (Shiotsu et al. 2010a).
In preparation for commercialization, we must establish a low input sustainable cultivating
system of Erianthus to supply its biomass as stable fuel resources all through the year. For
this purpose, we need to examine the planting or cutting time of Erianthus, which could be
related with the accumulation and translocation of carbohydrate within the Erianthus plants.
The aim of this study is to show the seasonal changes of starch grain accumulation in roots ofErianthus compared with napier grass and sugarcane. In addition, we investigated therelationship between cutting time and regrowth of the aboveground parts, and discuss results
in relation to the starch accumulation in roots.
Material and Methods The field experiment was conducted at the Institute for Sustainable
Agro-ecosystem Services of The University of Tokyo. After applying the chemical fertilizer,
stocks of the Erianthus, napier grass, sugarcane were transplanted in a field on May 31, 2010.
The three crop plants with basal part of roots were harvested using a shovel at 42 (July 12),126 (October 4), 158 (November 5) and 187 (December 24) days after planting (DAP). The
nodal roots were randomly chosen from three plants of each species for anatomical
observation and their hand cross sections at ca. 5 cm from the base were observed using alight microscope. The nodal roots were stained with potassium iodide solutions to detectstarch.
Results and Discussion The accumulation of starch grains was observed in the stele of
Erianthus roots but varied with the seasons. Meanwhile no or limited starch grains wereobserved at 42 and 126 DAP, the deposited starch grains increased remarkably toward winterseason; dense accumulation of starch grains was observed in all the examined roots at 158 and
187 DAP. Napiergrass also accumulated starch grains in root stele but not as much as
Erianthus. Sugarcane did not accumulate starch grains at any stage of the growth.
In another field experiment, in which Erianthus plants were harvested in either of August,October, December or February, the plants once harvested in October resulted in the poorest
regrowth in the second year. Because, Erianthus plants reserve carbohydrate into the roots in
October, the cutting of leaves (i.e., photosynthetic organ) in October could decline theregrowth in spring season due to the shortage of starch stock in roots.
Acknowledgements The present study is supported by the New Energy and Industrial Technology Development
Organization with a grant for “Research and Development for Innovative Production System of Cellulosic Ethanol (Researchand Development of an Integrated System for Bioethanol Production)”. We thank S. Hatano, S. Kamikawa and H. Teshima(technical staff of The University of Tokyo) for the field management, and Dr. M. Gau and Dr. T. Hattori (National
Agricultural Research Center for Kyushu Okinawa Region, NARO) for providing the seedlings of Erianthus and Sugarcane,respectively.
Reference Shiotsu et al. 2010a．Jpn. J. Crop Sci. 79 (Extra 1):152-153.; Shiotsu et al. 2010b．Jpn. J. Crop Sci. 79 (Extra2):212-213.; Shiotsu et al. 2011．Jpn. J. Crop Sci. 80 (Extra 1):172-173.

191

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P09 Poster presentation

The accumulation of cadmium is suppressed by apoplasmic barriers of roots
Michal Martinka1*, Alexander Lux1, Monica Pernas-Ochoa2, and Liam Dolan2
1. Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in
Bratislava,
MlynskádolinaB2,
842
15
Bratislava,
SlovakRepublic,
martinkambio@yahoo.com;
2. Department of Developmental and Cell Biology, John Innes Centre, Norwich Research
Park, Colney Lane, NR4 7UH, Norwich, UK.
The aim of this study was to elucidate the development and the function of apoplastic barriersin endodermal cells of Arabidopsis thaliana primary roots based on comparison of 7-days oldplants of the wild type Ler and genotypes with modified endodermal development - shr, scr3,
and scz. The anatomy of primary roots and endodermal development on cytological level
were analyzed and their relationship to the biomass production, growth rate, cadmium uptake
and translocation were compared after 0µM (control), 10µM and 100µM Cd(NO3)2 · 4 H2O
respectively.
The main results are:♦ Endodermal cells of primary roots in wild type Ler develop in two stages. In the first stage
Casparian bands develop on anticlinal cell walls closer than 2 mm from the root apex.
Thereafter suberin lamellae develop on the inner surface of primary cell walls with position
effect starting opposite to the phloem poles in the distance of 7 mm from the root apex.
♦ Primary roots of shr genotype form neither endodermal cells nor Casparian bands
and suberin lamellae. However, electrondense Casparian band-like material is depositedectopically to the middle lamellae between the cell walls of almost all root tissues.
♦ Primary roots of scr3 genotype form unstable number of endodermal cell files (3 – 6 oncross section). Separately developed endodermal cell or non-differentiated/non-divided
cortical cells deposit the Casparian band-like material to the connection of its anticlinal cellwall and cell wall of neighbouring pericycle cell. In case of two developed neighbouring
endodermal cells the typical Casparian band is formed in their conjunct anticlinal cell walls.
♦ The endodermal cells of scz genotype are atypically multiplicated. The primary roots form
one or more additional endodermal cells or even the whole additional endodermal layer.
♦ Cadmium nitrate at 100 µM concentration inhibits fresh and dry biomass production
and has xeromorphic effect (decreases the amount of water) in the roots, shoots and the wholeplants of Arabidopsis thaliana.
♦ Endodermal cells with apoplastic barriers help to maintain the water in the plants andsuppress the xeromorphic effects of cadmium. Genotype shr, characteristic by the absence oftypical endodermis, accumulates the highest amount of cadmium compared to the otherinvestigated genotypes. Under the influence of cadmium nitrate the shr genotype has thelowest ability to maintain the water compared to the other investigated genotypes.
This work was supported by grant V-1/0472/10 from Slovak Grant Agency VEGA, and by
Slovak Research and Development Agency, contract No. APVV-0140-00. We thank for theopportunity to use the equipment of BITCET.

192

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P10 Poster presentation

Identification of an ATP-binding cassette (ABC) transporter that is required forformation of suberin lamellae and the apoplastic barrier at the hypodermis inrice (Oryza sativa)
Katsuhiro Shiono1*, Miho Ando2, Motoaki Nakamura2, Yuichi Matsuo2, Naoko Yasuno2,
Hirokazu Takahashi3, Shunsaku Nishiuchi3, Masaru Fujimoto2, Hideki Takanashi3, Kosala
Ranathunge4, Rochus Franke4, Nobukazu Shitan5, Naoko K Nishizawa2,6, Itsuro Takamure7,
Nobuhiro Tsutsumi2, Lukas Schreiber4, Kazufumi Yazaki8, Mikio Nakazono2,3, Kiyoaki Kato9
1. Faculty of Biotechnology, Fukui Prefectural University, Japan, 2. Graduate School of
Agricultural and Life Sciences, The University of Tokyo, Japan, 3. Graduate School of
Bioagricultural Sciences, Nagoya University, Japan, 4. Institute of Cellular and Molecular
Botany, University of Bonn, Germany, 5. Graduate School of Pharmaceutical Sciences, Kobe
Pharmaceutical University, Japan, 6. Research Institute for Bioresources and Biotechnology,
Ishikawa Prefectural University, Japan, 7. Graduate School of Agriculture, Hokkaido
University, Japan, 8. Graduate School of Agriculture, Kyoto University, Japan, 9. Departmentof Agro-Environmental Science, Obihiro University of Agriculture and Veterinary Medicine,Japan. (*shionok@fpu.ac.jp)
Suberin is a complex of aliphatic polymers modified by phenolic compounds that is aconstituent of apoplastic plant interfaces. In many plant species, cells in the hypodermis form
a suberized cell wall in the form of the Casparian strip and suberin lamellae. These structures
inhibit apoplastic transport of water and ions and protect the cell against pathogen infection.
Suberin is accumulated in response to environmental stresses, including waterlogging.
However, no mutants defective in suberin biosynthesis have been studied in rice, and so there
is no direct genetic evidence that suberin forms an apoplastic barrier at the hypodermis. Here,
we show that a rice mutant of an ATP-binding cassette (ABC) transporter, reduced culm
number 1 (rcn1), does not form suberin lamellae at the hypodermis under waterlogged
conditions. RCN1 is located at the plasma membrane of hypodermis cells and is involved in
the synthesis of long chains of two of suberin's major monomers (fatty acids and ω-OH fattyacid). The rcn1 mutant has a defective apoplastic barrier at the hypodermis and develops shortand frangible roots under waterlogged conditions. These results show that the apoplastic
barrier helps rice to tolerate waterlogged environments.
Acknowledgements: We thank Dr. Jun Abe and Ms. Ann-na Ureshi for useful comments andexperimental support. This work was supported in part by a grant from the Bio-oriented
Technology Research Advancement Institution (Promotion of Basic Research Activities forInnovative Biosciences), a grant from the Ministry of Agriculture, Forestry and Fisheries ofJapan (Genomics for Agricultural Innovation, IPG-0012), and grants-in-aid from the Ministryof Education, Culture, Sports, Science and Technology of Japan.

193

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P11 Poster presentation

The Shift of Isoelectric Point of Beta-1,3-glucanases Possibly Involved in
Aluminum Toxicity in soybean root
Eri SOGA*, Hiroaki IWAI, Shinobu SATOH, Jun FURUKAWA
Life Environ. Sci., Tsukuba University, Japan (soga30352@ies.life.tsukuba.ac.jp)

On the acid soils, which comprise 30–40% of the world's arable soils, crop yields are reduced
because of the existence of Al3+ ion. Aluminum is the most abundant metal in the earth's crust, however,under acidic condition, Al is solubilized to its ionic form, which shows severe toxicity to plants. Especiallyinhibition of root elongation is the most critical matter for plants and is considered as a result of directinteraction between Al3+ ion and cell wall components including protein. To identify the protein affected by
Al3+ ion, we focused on the protein weakly bound to cell wall and specifically extracted from the apoplastof root elongation zone.
At first, extracted proteins by 20 mM MgCl2 from the apoplast of elongation zone was comparedwith those of adjacent non-elongation zone with SDS-PAGE. The protein profile indicated that the band of
27 kDa protein was observed only at the elongation zone. To identify this elongation-zone-specific protein,mass spectrometry analysis was performed with MALDI-TOF-MASS. The result of PMF identification
indicated that the protein was supposed to be one of the -1,3-glucanases and no other candidate protein
was identified. For verifying this identification, immunoblotting with tobacco -1,3-glucanase antibody
was carried out, and the bands indicating 33 and 27 kDa were detected. These results indicate that the
-1,3-glucanase is abundant in the apoplast of root elongation zone and it interacts weakly with other cellwall components.
The relationship between -1,3-glucanases and Al toxicity was investigated with 2D-PAGE andimmunoblotting. The extracts from the elongation zone prior treated with and without 20 μM Al for 2 h
were compared. The result showed isoelectric point of -1,3-glucanases were shifted in Al-treated root,
suggesting -1,3-glucanases located at the apoplast might be involved in Al toxicity because of thestructural change inducing the shift of isoelectric point after Al treatment. Based on these results and-1,3-glucanase functions, the involvement of -1,3-glucanase in Al-induced inhibition of root elongation
will be discussed.

194

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P12 Poster presentation

Effect of PolySilicate-Iron sludge on rice roots at organic farming
Ryosuke Tajima*, Keita Tsushima, Kodai Kamo, Toyoaki Ito and Masanori Saito.
Field Science Center, Tohoku University, Japan (tazy@bios.tohoku.ac.jp)
Organic rice farming, without chemical fertilizer and agrochemicals, is expected as one ofenvironmentally-friendly farming systems. However, it has a number of agronomical
problems. One of them is lower nutrient uptake than conventional farming, which causes tolower yield. We focused on enhancing root activity for solving this problem using anapplication of PolySilicate-Iron (PSI) Sludge. PSI is flocculant for water purification and iscomposed of FeCl3 and poly-silicic acid. The sludge from water purification plants using PSI
contains ferric iron (Fe) and silicon (Si). Fe is often applied for the mitigation of the reduction
condition on paddy fields. Si is a very important nutrient for a rice plant and enhancessuberization and lignification of rice roots in relation to the root activity. In previous studies,
PSI sludge has the possibility of effective amendment for paddy soils. However, there is little
information about the effects on roots. In this study, we investigated the effect of PSI sludge
application on rice root at organic farming using the ingrowth core method and monitoring the
bleeding sap for the indicator of root activity.
Materials and methods: A field experiment was conducted at the Field Science Center,
Graduate School of Agricultural Science, Tohoku University, Kawatabi, Miyagi. Rice (Oryza
sativa L.) plants (cv. Hitomebore) were grown in paddy fields. The 18 square frames (27.5 x
27.5 x 15 cm depth) were placed in the paddy field. Soil in the frame was exchanged for theequivalent amount of soil with organic fertilizer (ORG treatment: N, P2O5, K2O = 7, 7, 5 g/m2,
suzuka yuki) or organic fertilizer + PSI sludge (PSI treatment). PSI sludge was applied at rateof about 1.5 kg m2. Two hills (three plants per a hill) were transplanted into each frame andtwo mesh bags were placed in each frame estimating the production of roots using the
ingrowth core method. Three frames of each treatment were taken three times: 48, 63 and 78
days after planting (DAP). At each time above ground plant parts were harvested, dried andweighted. After the aboveground parts were removed, the bleeding saps were collected fromtwo hills of the frame and the soil monolith with roots was taken from the frame. The soils
were washed carefully on a 1-mm mesh screen. After removing debris, the root were dried
and weighted. Between 63 DAP and 78 DAP, two mesh bags were taken from the frame. The
dry weights were measured as the production of roots.
Results and discussion: The differences between ORG and PSI treatments were not significant
in the number of tillers and shoot dry weight at three sampling dates. The difference in totalroot dry weight was also not significant but the root dry weight of PSI was higher than of
ORG at 63 DAP. Similarly in total root dry weight, the rate of bleeding sap per a tiller of PSI
was higher than of ORG. In the production of roots per a plant and a tiller estimating with theingrowth core method, PSI treatment was significantly higher than ORG treatment from 48 to
63 DAP. On the other hands, two treatments were almost same in mortality of roots estimating
as the difference between total roots and production of roots. In this study, the effect of PSI
sludge as Fe amendments for mitigating reduction condition is unclear in the dynamics ofroots. However, the effect of PSI sludge as Si fertilizer must be effective at the organic
farming because the production of roots become higher, which causes to keep the higher root
activity during early growth stage.
Acknowledgment: This work was supported by a Grant-in-Aid for Scientific Research (No.
22580065) from the Japan Society for the Promotion of Science.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P13 Poster presentation

Physiological performance of direct seeding using iron-coated rice seeds undersubmerged and drained conditions
Shinsuke Mori*, Hiroshi Fujimoto, Akinori Okabe, Masahiro Kamei and Minoru Yamauchi
1. NARO Western Region Agricultural Research Center, 6-12-1, Nishi-fukatsucho,
Fukuyama City, Hiroshima Pref. 721-8514 (morishin@affrc.go.jp)
Introduction: Recently, direct seeding cultivation using iron-coated rice seeds has been paid
much attention in Japan because this technique has some merits such as prevention of flow
seedling and bird eaten. Re-dried rice seeds after soaking in tap water (seed priming
technique) are usually used in the production of iron-coated rice seeds because a rapid
seedling emergence and establishment are essential for successful direct seeding cultivation.
However, physiological performance of direct seeding using iron-coated rice seeds primed has
not been characterized well. We thus examined physiological characteristics of iron-coatedrice seeds under submerged and drained conditions.
Materials and Method: Rice seeds (Oryza sativa L. cv. Koshihikari) were soaking in tap
water at 20℃ for 3d and its seeds were dried at 50℃ for 2d. These seeds were coated with amixture of iron powder and calcium gypsum. Three hundred grams of dry paddy field soils
were put in pot and water was submerged in the pot. Twenty iron-coated rice seeds per eachpot were placed at soil surface. Seedling emergence, establishment and roots length were
examined under submerged and drained conditions for 14 d. Root length was determined by aruler or a root scanner. To examine coleoptile elongation under anoxia condition, a stream of
N2 (99.9%) was passed continuously through plastic container at 200 ml min-1 for 4d. After 4d,
coleoptile length was determined by a ruler.
Results and Discussion: Seeds germination rate was higher in rice seeds priming
treatment(20℃-3d) than in control. Seeds germination rate of rice seeds without iron coating
was slightly higher than that with iron coating. Coleoptile elongation in rice seeds priming
treatment(20℃-3d) was approximately 2.7-fold higher than that in control under anoxia
condition for 4d. Seedling emergence and establishment were higher in iron-coated seeds ofrice seeds priming treatment(20℃-3d) than in iron-coated rice seeds of control. In addition,roots growth of iron-coated rice seeds of priming treatment was higher than that of control
under drained condition. These results indicated that in direct seedling cultivation usingiron-coated rice seeds, use of primed rice seeds is advantageous to germination, seedlingemergence and establishment, assuming that iron-coated rice seeds using seed priming
technique are able to start acquisition of nutrition and photosynthesis at early growth stage.
196

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P14 Poster presentation

The effects of compost and phosphorus supply on onion growth of root andshoot.
Hiroyuki Tsuji*, Takato Muro, Kazuei Usuki, Shizuko Ishikawa, Nobutaka Someya and
Makoto Takenaka
Hokkaido Agricultural Research Center, Japan (tuzihiro@affrc.go.jp)
Onion plants are transplanted at a density of 300,000 plants/ha in commercial production
Hokkaido Japan. The competitions of labor time and green house space for raising seedlingbetween onion and other crops will be severe. Direct seeding can avoid these competitions,however, seedling establishment and early growth in the field are retarded by stresses such as
excess or deficit soil water and low temperature in spring season. We aim to improve theonion growth in early growth stage to establish onion direct seeding production system. The
objective of this study was to evaluate the influence which fused magnesium phosphate andcompost on onion growth in early growth stage.
Field experiments were conducted at the Memuro station of Hokkaido Agricultural
Research Center in 2011. Experimental onion variety was `Kitamomiji 2000' which is mostpopular variety in Japan, and these were seeded on 21 April 2011. The seeding distance was
kept 30 x 10 cm and plot size was 2.4 x 6m. Each treatment was replicated three times in a
split-plot design, consisting of nine phosphate treatment plots (applied 0, 1 and 6 Mg/ha fusedmagnesium phosphate‘0P, 1P, 6P’ x 3 replications), with two subplots (applied 0 and 20Mg/habark compost ‘0C, 20C’) in each. And in all plots, compound fertilizer (200N - 300P2O5 200K2O kg/ha) was incorporated. Onion growth was investigated on 17 June (57 days after
seeding) and 2 August (103 days after seeding). Root cutting was done at 13 September andyield parameters were measured at 6 October.
Root length and shoot dry weight at 57 DAS were improved by compost supply. Fused
magnesium phosphate application effect on onion growth was not obviously. Relationshipbetween the root length and the dry weight of shoot was closely correlated (R2=0.90, n=18).
Leaf number, leaf diameter, plant height and dry weight of shoot at 103 DAS wereincreased in compost applied (20C) plots than in 0 compost (0C), and maximum compost
benefits on onion growth was noticed in the 0 P. Relationship between the root length at
57DAS and shoot dry weight at103DAS in 0P treatments was closer (r=0.96, n=6) than that in
P input treatments.
The date of the bulb maturity in 20C plots was 9 September, and this date in 0C plots waslater than root cutting. Bulb yield in 20C was significantly higher than in 0C.
In conclusion, the compost input improved onion growth and yield, and this improvement was
expressed clearly in lower P input treatment.

197

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P15 Poster presentation

Influence of different maturation periods of hairy vetch incorporated as green
manure on growth of maize inoculated with Gigaspora margarita
Naoko Yamada*, Atsushi Matsumura, Hiroyuki Daimon
Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Japan(yamadan@plant.osakafu-u.ac.jp)
Green manure legumes have recently been recognized as valuable constituents for low
input cropping systems. As hairy vetch (Vicia villosa Roth), a winter legume, contains
polyphenolic compounds and organic acids which suppress weed growth, the incorporation ofthis legume species often inhibits the growth of the following summer crop. To prevent the
inhibition, it is recommended to plant the following crops after several weeks of incorporation.
Enough days for maturation of the green manure should be kept, but the seeding date would
need to be delayed in this case. In order for alleviating the growth inhibition immediately afterincorporation, the possibility of inoculation with arbuscular mycorrhizal (AM) fungi known
as stress alleviating microorganisms was examined on the following maize crop.
Wagner pots (1/5000 a) were filled with soil of ‘Akadamatsuchi’ supplied with chemicalfertilizer (N, P and K). Shoots of hairy vetch were incorporated into the pots at the rate of 0, 8
and 25 g/pot (-GM, +GM8 and +GM25). Water soaked seeds of maize cv. ‘Gold dent KD850’
were planted into the pots with (+AM) or without (-AM) inoculation of ‘Gigaspora margarita(Becker & Hall)’. To compare the different periods of maturation of green manure, the seeds
were planted immediately after incorporation (-MRN) and 34 days after incorporation(+MRN). Those pots were kept in a greenhouse, and supplied phosphorus solution as needed.
Plant height, the SPAD value and number of leaves of maize plants were measured weekly.
Five uniform plants were sampled from each treatment at 20 and 40 days after seeding. Root
length was analyzed using the Win-RHIZO software. Small parts of roots were also taken toinvestigate colonization rate of AM fungi.
At 20 DAS, dry weights of shoot and root of maize plant in +GM25 pot were greater than those in -GM
pot in +MRN. In addition, the SPAD value was higher in +AM pot than in –AM pot. At 40

DAS, dry weight in +AM pot showed double to seven times higher than that in –AM pot inboth GM treatments (+GM8 and +GM25). On the other hand, growth inhibition was
definitely observed in +GM/-MRN pots. An alleviating effect of AM fungi on the maize
growth was found in those pots. Based on these findings, it appears that inoculation techniqueof AM fungi might lead to shorten planting dates after hairy vetch incorporation. We havebeen analyzing the fatty acid profiles of the soil amended with AM fungi to understand how
soil microbial biomass changed during maturation of hairy vetch green manure.

198

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P16 Poster presentation

Growth and N2 fixation of soybean plants grown under different soil moisture
contents in FRP pots
Sohei Asakura1, 2*, Atsushi Matsumura2, Hiroyuki Daimon2
1. Life Science Research Institute, Kumiai Chemical Industry Co., Ltd., Japan,(s-asakura@kumiai-chem.co.jp) 2. Graduate School of Life and Environmental Sciences,
Osaka Prefecture University, Japan
Wet injury of soybean is a major problem in an upland field converted from paddy
farming system in Japan. This is because soybean is sown in the rainy season, e.g. between
late June and early July. Some researchers have reported on the effect of soil moisture
condition on growth and yield through field trial. If we can more easily control the soil
moisture conditions, we can more clearly define the relationship between soil moisture andgrowth for each growing stage. Fiber Reinforced Plastics (FRP) pot was developed as theexperimental instrument for the paddy crop by Kumiai Chemical Industry Co. Ltd.. Water
leakage level at flooding condition is controlled using this system. As a drain plug at thebottom was attached to adjust the levels of water table in FRP pot, it would be also possible tocontrol soil moisture contents under upland condition. In the present study, 1) we constructeda system to control soil moisture contents in a FRP pot experiment for field crops, 2) weinvestigated the growth and nitrogen fixation of soybean plants grown under different soil
moisture contents from the cotyledon stage to before flowering stage under theseexperimental conditions.
Materials and Methods
Experiment was conducted outside with a roof made of ultraviolet transmitting film at
Kikugawa, Shizuoka, between June and July, 2011. Gravels were added above 15 cm from thebottom of FRP pot (inside dimension W500×H500×D500 mm), and the paddy soils (clayloam soil) were filled to 10 cm from top of the pot. TDR sensors were set at 5-10 cm below
the soil surface (BSS). At 17 June, 2011, 16 seeds (cv. Fukuyutaka) inoculated with rhizobia
were sown in each pot. The pots were irrigated with 1.25 L of water, and then covered withcheesecloth to retain moisture. Seven days after sowing (DAS), the seedlings were thinned to
9 plants per pot, and the pots were subjected to two different soil moisture contents using aslanted pipe adjusted at 0 cm and 15 cm BSS. Three plants were selected from each plot, andstem length, number of stem node and SPAD value were measured. At 17, 27 and 41 DAS,
shoot dry weight was measured from two plants per pot. Xylem sap was also sampled andanalyzed for NO3-N, amino acids-N and ureide-N contents. This experiment was conductedwith four replications.
Results and Discussion
Soil moisture contents were remained approximately 0.21 and 0.40 m3/m3 in irrigation at
15 cm and 0 cm BSS, respectively. Wet injury of shoot growth was markedly found in
irrigation at 0 cm BSS. Length and number of the main stem and dry weight of shoot in
irrigation at 0 cm BSS were lower than in 15 cm. At 17 DAS, total N contents of leaves andstems were also lower in 0 cm BSS than in 15 cm. The differences in N content between in 0
cm and 15 cm BSS increased at 28 and 41 DAS. Dependency on N2 fixation(Ureide-N/Total-N) of shoot was lower in 0 cm BSS than in 15 cm. At 41 DAS, it increased inboth water levels. The FRP pot system would be available for wet injury experiment insoybean.
199

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P17 Poster presentation

Using technology of shoot and residue for green manure and forage production
by leguminous crops and barley mixtures at paddy
Weon-Tai Jeon*, Ki-Yeong Seong, In-Seok Oh, Min-Tae Kim, Bong-Su Choi,
Yong-Hwan Lee, Ui-Gum Kang
Crop Environment Research Division, National Institute of Crop Science, RDA,
Suwon, Korea (jeon0tai@korea.kr)
The competition between green manure and forage crops frequently occurred at agricultural
field because of soil fertility and livestock feeding selection. These experiments were carriedout to evaluate the effects shoot and residue for green manure andforage production by leguminous crops and barley mixtures at paddy. Field experiments wereconducted at paddy soil (fine loamy, mixed, nonacid, mesic family of Aeric Fluvaquentic
Endoquepts) in 2008 to 2009 at the National Institute of Crop Science (NICS), Rural
Development Administration (RDA), Suwon, Gyeonggi province, Korea. Treatments
consisted of mixture and interseeding of barley and leguminous crops (hairy vetch andcrimson clover). These treatments were divided into cutting height of 8 and 25 cm for usingof green manure and forage at once. The shoots biomass of hairy vetch and crimson clover
mixtures were higher than intercropping seeding. The shoot biomass of hairy vetch and barleymixture was the highest at 8 cm cutting height. The biomass of hairy vetch with barleymixture was higher than that of crimson clover with barley at all of the cutting heights. The
shoots and roots biomass of residues showed slightly high at barley and crimson clover
mixture of 25cm cutting height. The residues biomass of same cutting height were no
significantly difference. The mixture of hairy vetch and barley showed the best biomass ofshoot and residue for green manure and forage using at 25 cm of cutting height. Also thistreatment could be possible to rice cultivation by no fertilization. Therefore, we suggested that25 cm cutting of hairy vetch and barley mixture could be used for green manure and forage at
the same time under rice-based cropping system.

200

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P18 Poster presentation

Effect of root-deposited N of hairy vetch on the growth and N uptake of
mixed-cropped oat
Arata Tarui*, Atsushi Matsumura, Hiroyuki Daimon
Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Japan(sr203012@edu.osakafu-u.ac.jp)
The legume-cereal combination is often used in a mixed-cropping system. Generally,
cereals in mixed-cropping with legumes uptake more N than in sole cropping, because oftransfer from rhizodeposit-N of legume to the associated cereal crop. In mixed-cropping,
cutting the aboveground parts of legume may increase N transferred from legume throughturnover of roots and root nodules. We previously showed that cutting the aboveground partsof hairy vetch (Vicia villosa Roth) before flowering markedly increased the stem number of
mixed-cropped oat (Avena sativa). In the present study, we investigated the effects of N
released from belowground parts of hairy vetch on the growth and N content of
mixed-cropped oat plant.
The experiment was carried out in 2010/2011 at the experimental farm of Osaka
Prefecture University, Japan. The treatments were as the follow; sole cropping of oat (A); sole
cropping of hairy vetch (V); mixed-cropping (M); mixed-cropping with cutting hairy vetch atblooming stage (MC); sole cropping with cutting the half of oat (ACH). Each plot size was
1.8 x 2.6 m. The seeds were sown on 29 November 2010 with seeding rates of 4.3 kg/10 a (Aand ACH) and 2.9 kg/10 a (V). In mixed-cropping treatments (M and MC), the seeding rate ofeach component crop was half of the sole cropping rate. Ammonium sulfate was applied at therate of 3 kg N /10 a. The cutting treatment for MC and ACH was conducted on 21 April 2011
(20 weeks after sowing) and the shoots were removed immediately after cutting. To know the
aspects of light competition between two crop species in mixed-cropping, relative amounts ofaccumulated solar radiation at interrow space was measured. Shoots of the two plants were
harvested on 22 May 2011, dried for 48 h, weighed and then total N contents were
determined.
In spite of one-half seeding density of oat in MC, the shoot dry weight of oat in MC was
68% in A. The number of stems of oat increased in M, MC and ACH compared to A.
Maximum stem number was obtained in MC. Cutting the hairy vetch markedly increased
relative amounts of accumulated solar radiation at interrow space. Total N content of shoot of
oat considerably increased after cutting of hairy vetch. Cutting of oat in ACH, on the other
hand, had no effect on total N content of the residual half of oat. These results suggest that
cutting hairy vetch at blooming stage results in higher stem number and total N content of
mixed-cropped oat, indicating that large amounts of N derived from root deposition of hairy
vetch were transferred to the associated oat.
201

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P19 Poster presentation

Effect of rhizobia primed with naringenin on root development and nodulationin Pisum sativum L.
Satori Nakamura1*, Yasuhiho Tanaka2, Hisao Nakanishi2, Kuniyuki Sakamoto, Satoshi
Takada2, Tomoaki Taira2, Atsushi Matsumura1, Hiroyuki Daimon1
1. Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Japan(sr203015@edu.osakafu-u.ac.jp) 2. Incorporated Nonprofit Organization ‘Nanko-ume-no-kai’Root nodule formation and N2-fixation in legume-rhizobia symbiosis are often limited
by various environmental factors, such as low temperature and excess nitrate in medium. Oneof such causes is related to decrease of flavonoid compounds which are released from legume
roots and lead to nod gene activation. Previously, pre-incubating method of rhizobia withflavonoid (priming method) has been proposed, but the effective priming technique has notbeen established since the effect of priming is different among plant species. This work is
focused on whether pre-incubation of rhizobia with naringenin affects nodulation and root
development of pea crop, which is often grown under low temperature condition in Kinki
region, Japan.
Seeds of pea cv. Usui, leading varity in Kinki, were surface sterilized in 5% sodium
hypochlorite solution and then rinsed several times with sterilized water. They were sown inplant boxes containing 0.8% ager medium. Six-day-old seedlings were transplanted into
sterilized plastic box containing Broughton & Dilworth medium supplemented withpotassium nitrate at 10 mg N/L and incubated in a growth chamber. Seedlings were inoculatedwith Rhizobium leguminosarum bv. Viciae isolate (OD620 0.2) on the next day. For preparationof R. leguminosarum primed with naringenin, 10 ml of a bacterial suspension from 3-day-old
subculture were aseptically added to 50 ml of sterile 10 mg/L naringenin solution in a 200 ml
flask and incubated at 30 °C for 48 h without shaking. The suspensions were filtered with
0.45 μm in pore size paper and centrifuged at 7000 g for 10 min, and then used for thefollowing inoculation. In order to remove flavonoid sufficiently, these processes wererepeated twice.
Nodules were found at 7 days after inoculation (dai) in both priming treatment (PA) andthe control. Although nodule numbers in PA were higher than those in the control at 14 dai,acetylene-reducing activity (ARA) was not significantly different between PA and the control.
At 28 dai, PA increased nodule numbers, ARA and flesh weight of shoot and root. Plants
inoculated with primed rhizobia showed alterative root structure such as higher rate of lengthof the first order lateral roots to total root length and the continuous nodule formation along
the root axis. Priming treatment with naringenin before rhizobial inoculation might promote
the growth of pea plant grown under unsuitable environmental conditions.
202

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P20 Poster presentation

Morphological changes of Sesbania rostrata root under different soil properties
Atsushi Matsumura*, Hiroyuki Daimon
Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Japan(matsu@plant.osakafu-u.ac.jp)
Sesbania rostrata has shown great promise as a green manure due to its fast growth rateand high biomass production, high N2-fixing activity, dual nodulation (both on stems androots), and tolerance of flooding. For cultivation of S. rostrata, an understanding of root
biomass and root morphology is important. The studies reported here have two overriding
objectives: 1. To show the root growth under several soil conditions, and 2. To investigate
specific roots formed under granular soil conditions.
Seeds of S. rostrata were sown in lowland paddy soil, volcanic ash soil (Kuroboku) or
granular clay soil (Akadamatsuchi) in 1/5,000 a Wagner pots. Plants were grown in a
glasshouse and watered as needed. After 90 days, plants were harvested. Roots were observedwith a microscope and were analyzed using the WinRhizo software. To investigate specificroots observed under granular clay soil conditions, small parts of root were also taken at thesame time for quantification of rhizoplane and rhizosphere microbials.
There was significant media effect on the growth of S. rostrata and root structure. S.
rostrata increased root biomass in granular soil compared to lowland paddy soil and volcanicsoil. Total root length was also highest in granular soil following to lowland paddy soil andvolcanic soil. The significant changes in root structure indicated the heavily branching root
like cluster roots (Fig. 1). Microscope observation showed as if soil particles were surroundedby heavily branched fine roots. These structures were formed randomly along the axis ofprimary or secondary lateral roots. A pH of soils surrounded by roots was clearly lower, andmineralized P concentration was higher than the otherBAparts of roots. The rhizoplane and rhizospheremicrobial population was also higher in the site ofspecific roots. Although we could not reveal why thisstructure was formed only under granular soil, theCformation of the specific root structure would be oneof the adaptation of S. rostrata roots to nutrient
acquisition especially P. The specific roots would
chemically modify the surrounding soil by exuding Fig. 1 Specific structure of S. rostrata roots
compounds such as carboxylate organic acids, acid formed under granular clay soil conditions.
phosphatases and mucilages.

203

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P21 Poster presentation

Nitrogen fixation by endophytic bacteria isolated from sweet potato
Junko Terakado-Tonooka1,2*, Shinsuke Fujihara1, Yoshinari Ohwaki1
1

National Agricultural Research Center, Tsukuba, Japan (jtera@affrc.go.jp)

2

JSPS Research Fellow

Sweet potato (Ipomoea batatas) is known for its ability to grow under nitrogen-limited
condition. It is also known that the total amount of N in sweet potato exceeds the amount of N
applied as chemical fertilizer. Recently, nitrogen fixation by endophytic diazotrophs has been
observed in a wide variety of plants. The sweet potato may also have special mechanisms forenhancing soil N mineralization and/or acquiring N derived from atmosphere. To clarify thepossible contribution of endophytic nitrogen fixation, we isolated and identified diazotrophic
endophytes associated with sweet potato grown in Japan. The isolates which possess nifH, agene encoding one of the subunits of nitrogenase were identified as strains of Bradyrhizobium
sp. AT1, Paenibacillus sp. T16 and Pseudomonas sp. AS2 based on their 16S rRNA genesequences. These isolated are nitrogen-fixing bacteria as demonstrated by the acetylene
reduction method in a semi-solid malate medium. Moreover, B. sp. AT1 showed acetylene
reduction activity in liquid as well as in semi-solid culture medium containing sweet potato
tuber extracts, although addition of 3mM glutamine to the medium inhibited acetylene
reduction activity. We also examined the infection of isolated B. sp. AT1 in sweet potato andtheir influence on the growth and N2-fixation as assessed by acetylene reduction method.
After 55 days of inoculation, inoculation of B. sp. AT1 resulted in an increase in the shoot androot fresh weight compared to uninoculated control. The acetylene reduction activity was also
detected in the stems of inoculated plants. These results suggested that the isolated B. sp. AT1
may contribute to the N input in sweet potatoes.

204

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P22 Poster presentation

Influence of excess soil water during early growth stage on soil microbialcommunity structure in soybean field
Rintaro Hattori*, Atsushi Matsumura, Hiroyuki Daimon
Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Japan(hattori@plant.osakafu-u.ac.jp)
Soybean plants are mainly cultivated in upland field converted from paddy in Japan.
They often suffer wet injury, especially during early growth stage. Excess soil water causes
loss of soil oxygen, and it suppresses root growth, nutrient absorption, and yield of the plants.
Soil microbial organisms are playing an important role in nutrient absorption of plants. The
objective of this study is to investigate the influence of excess soil water in the paddy
converted upland field on soybean growth and soil microbial community structure.
A field experiment was carried out on the Experiment Farm at Osaka Prefecture
University in Sakai, Osaka, Japan in 2011. Both wet plot and the control plot were establishedprior to seeding of soybean. Seeds of cv. Fukuyutaka were sown on 15 June. Fertilizer wasapplied at the rate of N : P2O5 : K2O = 3 : 10 : 10 g m-2. TDR sensors were set at 5-10 cm
below the soil surface. Soil and roots were sampled by core sampling methods (5 cm indiameter×20 cm in depth) on 21 July (vegetative stage) and 2 September (reproductive
stage). Soil cores were divided into two layers by soil depth (0-10, 10-20 cm). To evaluate
microbial biomass and community structure, phospholipid fatty acids (PLFAs) from eachsoil layer were extracted as indicated by Sakamoto et al. (2005). The extraction was analyzed
with an Agilent 6890 Plus Chromatograph and the Sherlock system software (MIDI Inc,
Delaware, USA). PLFAs were identified by retention time according to the MIDI method.
During early growth stage, soil moisture contents were approximately 0.30 and 0.20
3
3m /m in wet plot and the control plot, respectively, and thereafter they were approximately
0.20 m3/m3 in both plots. Shoot growth of soybean in wet plot was significantly less than in
the control plot. Distribution of the roots in 0-20 cm soil layer was markedly different
between the wet and control plots, and biomass and lateral branching of the roots in 0-10 cm
layer was remarkable in wet plot. Basically, the total microbial biomass increased along withthe growth of soybean. At vegetative stage, the biomass in both soil layers showed higher
abundance in the control plot than in wet plot. At reproductive stage, gram-positive andgram-negative bacterial biomass in 0-10 cm soil layer showed higher abundance in wet plot
than in the control plot. In 10-20 cm layer, on the other hand, it was greater in the control plot
than in wet plot. Actinomycetes, fungi and AM fungi biomass also affected by soil moisture
condition, they showed lower abundance in wet plot than in the control plot. Further study onchanges in microbial community structure is now in progress.
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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P23 Poster presentation

Respiration rate and sugar concentration of wheat root affected by waterlogging
in field and by root zone hypoxia in hydroponic culture
Asami Hamada 1*, Hideki Araki 2, Md. Alamgir Hossain 3, Naoki Yamauchi 2, Tadashi
Takahashi 2
1. Graduate School of Agriculture, Yamaguchi University, 2. Faculty of Agriculture,
Yamaguchi University, 3. Faculty of Agriculture, Bangladesh Agricultural University
Introduction
Root growth and respiration can be damaged by waterlogging or root zone hypoxia. In ourprevious pot experiment, wheat roots temporally waterlogged around anthesis exhibitedabnormally higher CO2 evolution rate until maturity stage. In this study, root oxidization
activity, as an indicator of oxidization respiration, was examined for drained and waterlogged
wheat at anthesis to test if the roots show abnormal respiratory activity. In the hydroponic
experiments, a relationship between sugar concentration and respiration rate or oxidization
activity was also examined in hypoxic and aerated wheat roots.
Materials and Methods
The field experiment was carried out at an experimental field of Yamaguchi University in2010 winter to 2011 spring. Wheat cultivars, Chikugoizumi and Kinuiroha, were grown. The
plants were exposed to waterlogging for 21 d in jointing stage, for 11 d in post-anthesis or
double. During the treatments, furrows beside 1.2 m wide ridges were flooded so that theroots 10 cm below surface were submerged. Roots 10 cm below soil surface were sampled at
pre-anthesis, 14 d post-anthesis and 21 d post-anthesis. Oxidization activity of the roots wasdetermined with the 1-naphtylamine method. In the hydroponic experiments, roots of wheat
and rice seedlings around 3rd to 5th leaf stages were imposed root zone hypoxia. Growth,
CO2 evaluation, O2 consumption, sugar concentration and oxidization activity of the roots
were investigated.
Results and Discussion
In the field experiment, the oxidization activity of roots that were waterlogged during jointing
stage was significantly high until 14 d post-anthesis, indicating that the abnormal oxidization
lasted for more than a month. In the hydroponic experiment, root dry weight and R/S ratio
were significantly reduced by hypoxia in both wheat and rice. The oxidization activity, CO2
evaluation rate, O2 consumption and sugar concentration of hypoxic roots were significantly
high in wheat, but not in rice. There was a significant correlation between sugar concentration
and CO2 evaluation in hypoxic and aerated roots. The high sugar concentration, probably
resulted from loss of root growth activity, may account for the high respiration activity in thehydroponic and field experiments.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P24 Poster presentation

Are roots involved in poor grain filling of wheat in Western Japan?
Hideki Araki 1*, Asami Hamada 2, Md. Alamgir Hossain 3, Koichi Hatta 4 and Tadashi
Takahashi 1
1. Faculty of Agriculture, Yamaguchi University, 2. Graduate School of Agriculture,
Yamaguchi University, 3. Faculty of Agriculture, Bangladesh Agricultural University, 4.
National Agricultural Research Center for Kyushu Okinawa Region (ahide@yamaguchi-u.ac.jp)
Background
In Western Japan, grain filling of wheat is sometimes poor because of early senescence ofleaves, stems and spikes. In some cases, the poor grain filling can be attributed to temporalwaterlogging during grain filling stages. This was the case in 2011 spring when heavy rainlasted for 2 days at a week after anthesis. Field soil structure aggravates the damage fromwaterlogging since wheat is cultivated in upland fields that are temporally converted frompaddy fields. In some cases, the grain filling goes poor without waterlogging during grain
filling. Locally, the abnormally early ripening (AER) is called “Kareure” and happens tocommercially important cultivars in Western Japan. At the moment, there are no measures toreduce AER except replacing cultivars, since causes of AER are not known.
Leaf senescence and grain filling of waterlogged wheat
We carried out field trials in which wheat was imposed waterlogging during jointing stage,
post-anthesis and double. Before anthesis, the waterlogging during jointing stage did notaffect leaf greenness and photosynthesis rate. The waterlogging during jointing stage andpost-anthesis induced quick leaf senescence during 2nd to 3rd weeks after anthesis regardlessof cultivars and years. It should be noted that the effect of waterlogging during jointing stage
became manifest beyond a latent period for more than one month. Leaf water content andnitrogen content in leaves also became low as the leaves senesced. Remobilization of stored
carbohydrate in straw to grain was inactivated.
Is AER induced by latent damage of roots?
AER wheat shows very similar symptoms, i.e. early leaf senescence, low carbohydrate
remobilization and poor grain filling, to the ones of waterlogged wheat. Therefore, we
assumed that latent damage of roots, as found in waterlogged wheat, may be involved in AER.
We investigated distribution of AER in local farmer’s fields in Yamaguchi city. AER fields
were concentrated on the area where the fields became readily waterlogged after rainfall.
However, AER happened without growth restriction by waterlogging, indicating thatwaterlogging may partly contribute to AER, but not be the necessary condition for AER.
Root researches can contribute to the poor grain filling caused by waterlogging and AER.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P25 Poster presentation

Waterlogging tolerant teosinte (Zea nicaraguensis) has a large volume of
aerenchyma and a barrier to radial oxygen loss in root
Tomomi Abiko1*, Lukasz Kotula2, Katsuhiro Shiono3, Al Imran Malik4, Mitsuhiro Obara1,
Timothy David Colmer5, Mikio Nakazono2
1. Biological Resources and Post-harvest Division, Japan International Research Center for
Agricultural Sciences (JIRCAS), Japan, 2. Graduate School of Bioagricultural Sciences,
Nagoya University, Japan (nakazono@agr.nagoya-u.ac.jp), 3. Department of Bioscience,
Fukui Prefectural University, Japan, 4. School of Earth and Environment, Faculty of Naturaland Agricultural Sciences, The University of Western Australia, Australia, 5. School of Plant
Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia,
Australia
Combination with a large volume of aerenchyma and barrier to prevent radial oxygen loss
(ROL) along the roots is one of important traits for waterlogging tolerance in plants. These
traits enhance transportation of oxygen from shoot to root tip under waterlogged condition.
Here, we report the formation of aerenchyma, barrier to ROL and barrier properties in roots ofteosinte (Z. nicaraguensis), one of wild relatives of maize, and maize (inbred Mi29). Whengrown in stagnant condition, these formations of aerenchyma near the root tip and ROL
barrier at the basal part of roots was observed in Z. nicaraguensis, but not in maize. The rootof Z. nicaraguensis grown under stagnant condition showed Casparian strip and the suberin
lamella and lignin deposition started to develop from near the tip. By contrast, root of maize
showed retarded development of Casparian strip and suberin lamellae and lignin was notdetected along the root. These dates indicate that the abilities to form aerenchyma and barrier
to ROL of Z. nicaraguensis are superior to that of maize in stagnant condition. Higher tolerant
to waterlogged condition of Z. nicaraguensis would be attributed to large aerenchyma
formation and tight barrier to ROL.
Acknowledgements: The authors thank the International Maize and Wheat Improvement
Center (CIMMYT) for providing seed of Z. nicaraguensis and the National Agricultural
Research Center for Kyushu Okinawa Region for supplying maize Mi29.We thank Dr. Y.
Mano and Ms. F. Omori for providing plant materials. And we are also grateful to Drs. Y.
Fukuta, N. Tsutsumi, A. Oyanagi, K. Kawaguchi, and F. Abe for helpful comments. This work
was supported by a grant of Program for Promotion of Basic and Applied Researches forInnovations in Bio-oriented Industry from BRAIN.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P26 Poster presentation

Variation for the capacity to form root aerenchyma and selection for highly
aerenchyma forming lines in the rare teosinte Zea nicaraguensis
Yoshiro Mano*, Fumie Omori
Forage Crop Research Division, NARO Institute of Livestock and Grassland Science, Japan(mano@affrc.go.jp)
Wild relatives have been used to improve tolerance to abiotic stress in many plant species.
The teosinte Zea nicaraguensis, a wild relative of maize, is considered to be a valuable
germplasm resource for the development of flooding-tolerant maize because this species is
adapted to flooded lowlands in Nicaragua.
Zea nicaraguensis has the capacity to form constitutive root aerenchyma underwell-drained conditions. A previous study suggested that the degree of constitutive
aerenchyma formation varied within a single accession of Z. nicaraguensis (PI 615697). The
objectives of this study were to search for variation in the capacity to form aerenchyma inseveral accessions of Z. nicaraguensis and to obtain progenies with higher and lower degrees
of aerenchyma formation by using phenotypic selection.
The degree of aerenchyma formation in the root cortex was evaluated in
six-leaf-stage seedlings of eight accessions and several S0–S3 populations in Z. nicaraguensis.
Seedlings of eight Z. nicaraguensis accessions showed an extremely wide and continuous
range of variation in the degree of aerenchyma formation within accessions, suggesting thepresence of genetic variation. By phenotypic selection within two accessions, lines withextensive aerenchyma formation (derived from CIMMYT 13451) and lines with little
aerenchyma formation (derived from PI 615697) were successfully obtained (Fig. 1).
In conclusion, the capacity to form constitutive aerenchyma was shown to be
heritable in the rare teosinte Z. nicaraguensis. The contrasting lines with higher and lower
degrees of aerenchyma formation will be useful to reveal the effect of constitutive root
aerenchyma on flooding tolerance in Z. nicaraguensis and to conduct physiological analysesof root aerenchyma formation.
Acknowledgments The authors wish to thank CIMMYT, Mexico and NCRPIS,
USDA-ARS/Iowa State University, USA, for providing seed of Z. nicaraguensis. This work
was supported by the National Agriculture and Food Research Organization (NARO), Japan,
and by grants from Sapporo Bioscience Foundation and the Programme for Promotion of
Basic and Applied Researches for Innovations in Bio-oriented Industry (BRAIN).

200µm(a) CIMMYT 13451(b) PI 615697

209

Fig. 1 Cross sections of adventitious
roots that emerged from the second
node of six-leaf-stage seedlings of Z.
nicaraguensis grown in non-flooded
conditions. Sections were taken 10–15cm from the root tip. Arrow indicates
an example of constitutive root
aerenchyma. (a) Radial formation
extended toward epidermis and (b)slight formation. The same scale wasused; bar = 200 µm

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P27 Poster presentation

Root system development and hydraulic conductance in soybean plantgrown under waterlogged conditions
Keiko Ota* and Akira Yamauchia
Graduate School of Bioagricultural Sciences, Nagoya University, Japan(a Corresponding author: ayama@agr.nagoya-u.ac.jp)
Yield reduction of soybean is often caused by excess water. Mochizuki (2000) pointed outthat secondary aerenchyma formation in root is an important trait for soybean plants tomaintain root system development under waterlogged soil. Araki (2006) showed the elevated
CO2 significantly reduced hydraulic conductance of soybean roots. These findings indicatethat both the root system development and its hydraulic conductance under waterlogged
condition need to be examined to evaluate the role of roots in waterlogging tolerance. We
therefore hypothesize that waterlogging tolerant varieties may have an ability to maintain theroot development and hydraulic conductance under excess soil moisture conditions. The aimof this study was to examine the functional roles of root function in waterlogging tolerance interms of root development and hydraulic conductance by comparing cultivars that differ inwaterlogging tolerance.
Material and Methods: Two soybean (Glycine max (L.) Merr.) cultivars were used; one was‘Tamahomare’ which is less tolerant to excess soil moisture conditions and the other was‘Fukuyutaka’ which is tolerant to the same conditions (Koumura et al. 1983). An experiment
was carried out in a green house at Nagoya University, Japan. 4.0 kg of air-dried sandy loam
soil was filled up in a plastic pot (190 mm high and 158 mm in diameter). Chemical fertilizer
was mixed with the soil at a rate of 0.25g kg-1 for P2O5, 0.25g kg-1 for KCl and 0.5g kg-1 formagnesium lime. Three seeds were sown on July 5, 2011 per pot. Seedlings were thinned to
one plant 14 days after sowing. After thinning, two water levels were applied; control (23%w/w) and waterlogged (33 % w/w). Each pot was weighed daily and the amount of water loss
replenished, which was recorded as evapotranspiration. Three pots were prepared in eachtreatment. Root hydraulic conductance was measured on August 27, 29 and 31, 2011 by usingpressure chamber method (Araki et al.2006). Then, shoot and root were sampled. Total root
length was determined by using WinRHIZO (Bouma et al. 2000).
Results and discussion: The reduction ratio of shoot dry matter under waterlogged condition
relative to control was 39% in Tamahomare, but Fukuyutaka maintain shoot dry matterproduction only 19% reduction in the same condition. Significant reduction in water uptake
was observed under waterlogged condition as compared with control in Tamahomare. But inFukuyutaka, there was no significant difference between the two treatments. Furthermore, thehydraulic conductance under waterlogged condition was significantly lower by 31 % than that
under control in Tamahomare while Fukuyutaka showed significantly higher hydraulicconductance under waterlogged condition. The total root length was significantly greater inwaterlogged condition than control in Fukuyutaka. But in Tamahomare, the opposite trend
was evident. These results indicate that the ability to maintain root system development andhydraulic conductance under waterlogged condition enables Fukuyutaka to uptake more waterand produce more biomass than Tamahomare under the same conditions.
Reference: Mochizuki et al., 2000. Jpn. J.Crop Sci. 69(1): 69-73; Araki., 2006. Field Crops
Research 96: 98-105; Koumura et al.,1983. Research bulletin of the Aichi-Ken Agricultural
Research Center. 15: 93-104; Bouma et al., 2000. Plant and Soil 218: 185-196;
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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P28 Poster presentation

Dynamic regulation of the root hydraulic conductivity of barely plants undersalinity/osmotic stressToshiyuki Kaneko1, Tomoaki Horie2, Mineo Shibasaka3, Maki Katsuhara3*
1. Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University,
Japan, 2. Faculty of Textile Science and Technology, Shinshu University, Japan, 3. Institute of
Plant Science and Resources, Okayama University, Japan (kmaki@rib.okayama-u.ac.jp)
The root hydraulic conductivity (Lpr) is significantly reduced by salinity stress in several plant
species including Arabidopsis. maize, and barley (Hordeum vulgare). Authors characterizedchanges in the Lpr of barley plants in response to salinity/osmotic stress in detail using apressure chamber. Although salt-sensitive I743 variety did not show any significant change of
Lpr during salt/osmotic stresses, a characteristic time-dependent change of Lpr was induced by
100 mM NaCl in cultivars Haruna-nijyo and K305. Rapidly repression of Lpr within 1 h after
exposure was observed, but Lpr transiently recovered peaking at around 4 h, followed with along-lasting re-repression. Further examination using cv. Haruna-nijyo plants in combination
with a pharmacological approach revealed that the same response was evoked by an
iso-osmotic 177 mM sorbitol. It was also suggested that the involvement of cellular processes
such as protein phosphorylation/dephosphorylation, endocytotic protein recycling, de novo
protein synthesis and protein degradation appear. Biochemical analyses using a peptide
antibody to HvPIP2;1 protein (a plasma membrane-localized water channel in barley)indicated that HvPIP2;1 channels were subjected to a time-dependent translocation within
cellular membranes after the exposure to 100 mM NaCl. Shutting down of the water transport
attributed to the Lp reduction should be essential to minimize water loss at the initial phase of
severe salt/osmotic stress for survival. In addition, Lp reductions may be a sign of conversionof the growth status of plant cells from the rapid growth mode with high water absorption to
the protect/tolerant one with less water uptake as a strategy for the survival under salinity
stress (Horie et al. PCP 52: 663, 2011).

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P29 Poster presentation

Water permeability of protoplasts derived from different portion of seminal rootsystem in rice
Suganuma Azumi* and Akira Yamauchia
Graduate School of Bioagricultural Sciences, Nagoya University, Japan (aCorresponding
author: ayama@agr.nagoya-u.ac.jp)
A root system of an individual plant consists of various types of component roots thathave different hydraulic properties, and therefore the hydraulic architecture of a whole rootsystem is complex. Ichikawa (2003) intensively examined the hydraulic architecture ofsorghum seminal root system and found out that the hydraulic architecture can not be fully
explained with only apoplastic architecture such as xylem vessel maturity, casparian band
development, and lateral root development, and pointed out the need to evaluate thecontribution of symplatic pathway to the entire water uptake and conductance. In this study,
we estimated root water uptake by measuring absorbance of sulphorhodamine G (SRG) that is
a apoplastic tracer, by plant grown in hydroponics, while symplastic pathway was determinedby measuring water permeability (Pos) of protoplasts that were taken from roots, which werethen calculated from the swelling rate in hypotonic solution. Rice plants were grown inhydroponic culture for 10 days, and then transferred in SRG solution for 4h. SRG was
extracted from the seminal roots by water, and its absorbance was measured with
spectrometry. To determine water permeability of protoplast, firstly, we examined 4 different
concentrations of the macerate solutions to find the most efficient one to take protoplast fromdifferent parts of the seminal root. Secondly, root segments from the tip to the base of theseminal roots were collected 10 days after sowing, and incubated with the appropriate
macerate solutions. The composition of macerate solution (Cellulase RS: Macerozyme R-10:
Pectolyase Y-23) are the following: 4%: 0.2%: 0.03% for the basal, 4%: 0.3%: 0.03% for the
middle and 2%: 0.1%: 0.03% for the tip of the seminal root. Lastly, the protoplast wastransferred from hypertonic to hypotonic solutions and the swelling rate was calculated basedon the images that were captured on the video monitor that is equipped with an inverted lightmicroscope (OLYMPUS, IX70). The water permeability was calculated using the equation of
Suga et al., (2003): dV/dt = PosSVw(C-C0). The following are legend of the equation: V,
protoplast volume; t, time; Pos, Osmotic water peameability (ms-1); S, surface area of theplotoplast; Vw, partial molar volume of water (18×10-6 m3 mol-1); C, solute concentration
inside (mol m-3); C0 , solute concentration outside (mol m-3). The accumulations of SRG weredifferent at various types of roots for seminal root with 169.0 nmol mm-2, S-type lateral rootwith 108.3 nmol mm-2 and L-type lateral root with 189.4 nmol mm-2.
In addition, the rate of water uptake was found to differ along the root axis depending on the
distance from the root tip. The largest SRG accumulation was observed at the basal portion of
the seminal root, which was 225.0 nmol mm-2 of SRG. The Pos of protoplasts along theseminal root axis (from the basal to root tip) ranges from 28.5-35.8 µm s-1(basal), 1.7-13.5 µm
s-1 (middle) and 1.2-11.6 µm s-1 (tip).Our results concluded that the water uptake ability of
10-day-old rice was higher in the older (basal) portion than in the younger (root tip) portion
along the seminal root axis. This higher water uptake ability was contributed in larger Pos andlarger amount of SRG at the basal part on the seminal root in rice plants.
Reference: Ichikawa R. 2003. Master thesis. Graduate school of Bioagriculture Science,
Nagoya University, 107pp. Suga S, et al., 2003. Plant Cell Physiol. 44: 277-286.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P30 Poster presentation

Promotion of aerenchyma formation in rice primary roots by treatment with
1-Aminocyclopropane-1-carboxylic acid
Kenta Yukiyoshi*, Ichirou Karahara
Department of Biology, Graduate School of Science and Engineering, University of Toyama,,
Japan (karahara@sci.u-toyama.ac.jp)
Wetland plants like rice adapt themselves to low-oxygen conditions by developing
aerenchyma in their roots. Induction of lysigenous aerenchyma formation and its mechanism
have been well investigated in maize root. When maize roots were exposed to low-oxygen
environment due to stagnant conditions, activities of 1-aminocyclopropane-1-carboxylic acid
(ACC) synthase and of ACC oxidase increased (He et al. 1997) and, as a result, enhanced
ethylene production induced cell death in root cortex and induced lysigenous aerenchyma
formation (He et al. 1996). In rice roots, aerenchyma is formed constitutively and, therefore,
it has long been discussed whether ethylene is involved in its formation (Webb and Jackson
1986, Jackson et al. 1985, Justin and Armstrong 1991). Recently, it has been shown that
aerenchyma formation is enhanced by stagnant conditions (Colmer et al. 2006, Shiono et al.
2010) and indicated that ethylene is involved in this process (Colmer et al. 2006). To
elucidate this issue, our group recently established a unique “sandwich method” whichenables to detect differences in development of tissues sensitively under different
environmental conditions. In this method, roots are sandwiched between two agar media
containing different constituents and, thereby, a comparison of development of tissues
between two different conditions, i.e., the control side and the treatment side, is possible ineach root. In this study, we have tested whether ethylene is involved in aerenchyma
formation in rice roots using this method.
Sterilized and imbibed rice (Oryza sativa ssp. japonica cv. Nipponbare) caryopses
were sandwiched between 2% (w/v) agar plates containing 1/10 strength Hoagland medium,
only one of which contained ACC and the roots were grown for 4 days. Cross sections of
100 µm thickness were cut using a microslicer at 5 mm intervals from root tip and wereobserved under a light microscope. Development of aerenchyma was monitored byquantifying areas of aerenchyma observed on cross sections. As a result, aerenchyma
formation was enhanced significantly in the ACC treatment side compared to the control side.
Next, rice caryopses sandwiched between two agar plates containing ACC only on one side as
described above were placed in an airtight container for 4 days in the presence of an ethylene
action inhibitor, 1-methylcyclopropene (1-MCP), so that its final concentration was 0.1 ppm.
In the presence of 1-MCP, growth inhibition of the roots by ACC was recovered and thesignificant enhancement of aerenchyma formation in the ACC-treated side of the roots
disappeared. These results indicated that ethylene signaling is involved in aerenchyma
formation in rice roots.
Acknowledgements
The authors are grateful to Rohm and Haas for kindly providing of 1-MCP.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P31 Poster presentation

Recovery and compensation of nitrogen uptake by change of root morphology
and gene expressions for ammonium transport under the osmotic stresscondition in rice seedlings
Kyoko Toyofuku1*, Atsushi Ogawa1
1. Department of Biological Production, Akita Prefectural University, Japan(kyotoyo@akita-pu.ac.jp)
Since soil nutrient availability of roots is high heterogeneity, and nutrient uptake
conditions are easily influenced by various environmental factors, plants encounter nutrient
deficiencies frequently during their life cycle. Therefore, plants require nutrient transportsystems with high flexibility to manage morphological and physiological responses to nutrient
deficiencies. Rice plants grown in paddy fields predominantly utilize ammonium, which is the
major form of inorganic nitrogen in hypoxic and anaerobic soils. Furthermore, ammonium isthe preferential form of nitrogen uptake when plants are subjected to nitrogen deficiency,
since ammonium assimilation requires less energy than that of nitrate. Plants have the ability
to change developmentally and functionally their form to survive and grow under various
environmental conditions. This phenotypic plasticity in root system morphology is an
important key for crop stress tolerance.
We studied sequential changes of rice root morphology and the gene expressions forammonium transport under the osmotic stress condition. The aim of this study is to evaluate
how rice root recover from and adapt the osmotic stress after the dissolving of nitrogen
deficit.
Rice (Oryza sativa L. cv Akita-komachi) seedlings were grown hydroponically in
distilled water for seven days and then transferred to nutrient solution (modified Hoaglandmedium) in the absence of a nitrogen source for ten days to consume their endosperms
completely. Seedlings were then transferred to three different solutions; nitrogen-free nutrient
solution, nutrient solution containing 0.15 mM (NH4)2SO4, and nutrient solution containing
0.15 mM (NH4)2SO4 and 10% polyethylene glycol 6000 (PEG). Plants were grown under 12
h light/12 h dark condition, at 70% relative humidity, and a temperature of 28℃. Roots were
sampled at 0, 1, 3, 24, 48, 96 and 168 h after the treatments to evaluate root systemmorphology and nitrogen content and to analyze gene expressions for ammonium transport.
The number of crown and lateral root increased after the treatment with the (NH4)2SO4
supplemented solution, and with this, total root length increased at 168 h after the dissolvingof nitrogen deficit. In contrast, total root length in the treatment with nitrogen-free nutrient
solution was compensated by extending lateral roots without increasing the number. In thetreatment combined with PEG and (NH4)2SO4, total root length did not increase due to theshort and small number of lateral roots. However, the number of relatively long lateral roots(L-type lateral root) increased. These suggested that the rice root attempted to compensate theroot expansion in a manner to increase root surface area under the unfavorable nitrogen
uptake condition.
Although the extension of root under the treatment combined with PEG and (NH4)2SO4
was stopped during 96 hours after the dissolving of nitrogen deficit, the ammoniumtransporter genes were expressed quickly in the duration, and consequently the nitrogencontent in seedlings was maintained similar to that of the PEG-free (NH4)2SO4 supplemented
treatment. Further experiments will be needed to evaluate the expression of root plasticity
when plants were subjected to multiple stresses.
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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P32 Poster presentation

Cultivar differences in root development under water deficit condition and its
association with water uptake capacity in rice
Maya Matsunami1,3*, Kyoko Toyofuku2, Atsushi Ogawa2, Makie Kokubun1
1. Graduate school of agricultural science, Tohoku University, Japan, 2. Akita Prefectural
University, Japan, 3. JSPS research fellow (maya@bios.tohoku.ac.jp)
Genetic improvement in water uptake capacity in rice cultivars is an option toenhance productivity under water-limited condition, however, root function and systems to
improve water uptake under water deficit are still remain unknown. The objective of thepresent study was to examine cultivar differences in root development and its association withwater uptake capacity among three rice cultivars, Azucena (upland japonica), Puluik Arang(lowland indica) and Akitakomachi (lowland japonica). Azucena and Puluik Arang wereobserved its great water uptake capacity under water deficit condition in our previous study
that examined genotypic variation of water uptake capacity among 70 rice cultivars(Matsunami et al., accepted).
Plants were grown in an environmentally regulated growth chamber: 12 h lightperiod, 28 ℃ of temperature, and 70% relative humidity. 10 germinated seeds per each pot(240 mm height, 90 mm diameter) were grown on a plastic net placed on the surface of a 1.2
L solution of 1/2 strength Hoagland nutrient solution for three days. Then polyethylene glycol
6000 was dissolved in water at concentrations of 0 (control) and 100 g per litter (PEG) toattain water deficit. The water potentials of the PEG treatment solution was -0.17 MPa. 7 days
after treatments, the amount of water uptake was measured by the reduction of pot weight,
and then plants were sampled and separated into shoot and root. Roots were scanned forimage analysis of total root length, surface area and lateral root number by using WinRHIZO.
Dry matter weight of shoot and root were measured after dying at 80℃ for more than threedays. The expression for six aquaporin genes (OsPIP1;3, OsPIP2;3, OsPIP2;4, OsPIP2;5,
OsTIP2;1, OsNIP2;1) in seminal root at 7 days after treatment were investigated by reverse
transcription-PCR. These six aquaporin genes showed specific expressions in roots among 33
rice aquaporin genes that were identified by Sakurai et al. (2005).
Puluik Arang exhibited higher dry matter production and maintained water uptake
under the PEG treatment. Root length and surface area were similar in the both regimes in
Puluik Arang, thus it was suggested that the maintaining of water uptake under the PEG
treatment was partly due to the root development. On the other hand, the root length andsurface area decreased in the PEG treatment in Azucena, however the amount of water uptake
did not decrease in Azucena. Thus, we suggested that the water uptake capacity per unit rootsystem in Azucena increased under the PEG treatment, hence maintained water uptake underwater deficit condition. Puluik Arang showed slightly higher expression of aquaporin genes
than the other two cultivars, but no clear differences between treatments were observed
regardless of cultivars. The expression of these genes seemed to have no relation with thewater uptake capacity. The participation of other aquaporin genes and/or other factors such as
osmotic adjustment to water uptake capacity was remained to be elucidated.
Matsunami et al. Plant Prod. Sci. accepted.
Sakurai et al. 2005. Plant Cell Physiol. 46: 1568-1577

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P33 Poster presentation

qSOR1, a major rice QTL involved in soil-surface rooting in paddy fields
Yusaku Uga1*, Eiko Hanzawa2, Shinsei Nagai2, Kazuhiro Sasaki2, Kaworu Ebana1, Masahiro
Yano1 and Tadashi Sato2
1. National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602,
Japan (yuga@affrc.go.jp), 2. Graduate School of Life Sciences, Tohoku University, 2-1-1
Katahira, Aoba-ku, Sendai, Miyagi 980-8577, JapanThe efficient acquisition of water and nutrients by plant root systems is very important,because the availability of these soil resources is a limiting factor for plant growth. Therefore,
the architecture of the root system determines the ability of a plant to exploit those resourcesthat are unevenly distributed in soil. Some of Indonesian lowland rice (Oryza sativa L.)
cultivars elongate thick primary roots on the soil surface of paddy fields. To clarify the genetic
factors controlling soil-surface rooting, we performed quantitative trait locus (QTL) analyses
using 124 recombinant inbred lines (RILs) derived from a cross between Gemdjah Beton, anIndonesian lowland rice cultivar with soil-surface roots, and Sasanishiki, a Japanese lowland
rice cultivar without soil-surface roots. These cultivars and the RILs were tested forsoil-surface rooting in a paddy field. We identified four regions of chromosomes 3, 4, 6, and 7that were associated with soil-surface rooting in the field. Among them, one major QTL was
located on the long arm of chromosome 7. This QTL explained 32.5% to 53.6% of the total
phenotypic variance across three field evaluations. To perform fine mapping of this QTL, wemeasured the basal root growth angle of crown roots at the seedling stage in seven BC2F3
recombinant lines grown in small cups in a greenhouse. The QTL was mapped between
markers RM21941 and RM21976, which delimit an 812-kb interval in the reference cultivar
Nipponbare. We have designated this QTL qSOR1 (quantitative trait locus for SOIL
SURFACE ROOTING 1). We used marker-assisted selection to develop a near-isogenic line,
designated qSOR1-NIL, in which small chromosomal segments of Gemdjah Beton including
qSOR1 was substituted into the genetic background of Sasanishiki. The qSOR1-NIL showedsoil-surface rooting in the paddy field while Sasanishiki did not show that. This indicates thatqSOR1 plays a key role in soil-surface rooting in the paddy field.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P34 Poster presentation

QTL for the plasticity in root system development triggered by soil moisturefluctuation stress in rice
Jonathan M. Niones* and Akira Yamauchia(Graduate School of Bioagricultural Sciences, Nagoya University)(aCorresponding author：ayama@agr.nagoya-u.ac.jp)
Fluctuating soil moisture can adversely affect rice growth. To cope with that negative effect,
plasticity in root system development is the key trait that plays an important adaptive role
against moisture stresses. Utilization of chromosome segment substitution lines enabled us todemonstrate the significant roles of root plasticity, as expressed by higher lateral root
production, in adaptation to soil moisture fluctuation stress. Moreover, our previous study, we
identified QTL at the short-arm of chromosome 12 regions that is associated with root
plasticity (Niones et al., 2010). This QTL controls the productions of L-type lateral roots with
the increase effect from Kasalath allele. In this study, we quantified the expression of QTL atchromosome 12 regions (referred as qLLRn-12) in relation to the total root length undervarious water stresses. The CSSL genotype with introgressed segment of Kasalath allele only
on chromosome 12 (referred as +KAS genotype) and Nipponbare were evaluated and grownusing root box method at the Nagoya University vinyl house for 38 days. Four water regimes
were applied in the experiment; well-watered (WW), transient drought (21d) to waterlogged(17d) (D20-W), transient waterlogged (17d) to drought (21d) (W-D20) and constant drought(38d) (C-D20) conditions. In the drought conditions, soil moisture content (SMC) was
maintained at 20%. Two coleoptile nodal roots were collected for root traits measurement
related to root plasticity. Tiller number and shoot dry weight were also measured. To further
demonstrate the effect and expression of qLLRn12, +KAS genotype was evaluated for plastic
root system development under various water stresses. The +KAS genotype showedsignificantly greater root system with the increase of total root length by 10% in W-D20 and
17% in D20-W compared to Nipponbare. On the other hand, these parameters were notsignificantly different between +KAS genotype and Nipponbare parent under non-stresscondition (WW) and C-D20. However in C-D, +KAS genotype root system development
significantly reduced by more than 45% compared to control +KAS. The +KAS genotype(with qLLRn-12) demonstrates better root system development based on higher total root
length in response to moisture fluctuation stresses (D20-W, W-D20). Longer total root length
was attributed to higher production of L-type lateral roots, which can effectively maintain the
uptake of water and nutrient in the soil. Such plastic root responses resulted to increased
stomatal conductance and photosynthesis, and eventually increase of shoot dry matterproduction with an average of 36% compared to Nipponbare parent. These facts clearlysuggest that the unique function of QTL at short-arm of chromosome 12 region (qLLRn12)
which regulates the production and branching of lateral roots (i.e., L-type lateral root) are
expressed only under fluctuating soil moisture stress. There have been reports on QTLs thatare associated with root length, root number, root dry weight and branching index traits (Priceet al., 2002; Horii et al., 2006; Gowda et al., 2011). However, with the best of our knowledge,
this is first report on QTLs at chromosome 12, which are related to lateral root production
under soil moisture fluctuation stress. Fine mapping is necessary to narrow down the distanceof the target trait.
Reference: Niones et al., 2010. Jpn. J. Crop Sci. 79 (Extra 1) 268-269; Price et al., 2002.
Field Crop Res. 76:25-43; Horii et al., 2006. Plant Breed. 125:198-200; Gowda et al., 2011.
Field Crops Res. 122:1-13.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P35 Poster presentation

Identification of QTLs on lateral root development and the importanceunder soil moisture fluctuation stress conditions in rice
Satomi Ohashi1*, Mana Nakata-Kano2, Hidemi Kitano3, Akira Yamauchi1, and Yoshiaki
Inukai1
1. Graduate School of Bioagricultural Sciences, Nagoya University, Japan, 2. International
Cooperation Center for Agricultural Education, Nagoya University, Japan, 3. Bioscience andBiotechnology Center, Nagoya University, Japan (inukaiy@agr.nagoya-u.ac.jp)
Rice (Oryza sativa L.) is an essential crop for global food security, but its productivity
is restricted to various factors. Especially, soil moisture fluctuation causes the yield decreasein rainfed lowland that occupies about 30% of rice cropped area in the world. We previously
reported that increased root length density is important in order to adapt to drought stressconditions and that KDML105, a rainfed lowland indica cultivar in Thailand, had muchhigher root length density compared to other investigated cultivars (Kanou et al., 2007; Kano
et al., 2011). Here, we report the identification of quantitative trait loci (QTLs) on lateral root
development and the importance under soil moisture fluctuation stress conditions.
First, we compared the responses of KDML105 to water stress with a lowland japonica
cultivar, Nipponbare. The result was that KDML105 clearly developed more vigorous lateralroots so much under water stress conditions than those in Nipponbare. Second, we conducted
QTL analysis using 59 DNA markers and 96 F2 lines derived from cross between Nipponbare
and KDML105 to detect the QTLs for lateral root responses to water stress. In consequence,
the QTLs were detected on chromosomes 4 and 6, 7.
To evaluate the contribution to water stress of those QTLs, we produced BC3F3 lines
through the repeated backcrosses with Nipponbare and self-pollination of the backcrossed
lines. We selected one of the BC3F3 lines, G1-1, substituted for three QTL regions fromKDML105 into the Nipponbare genetic background, and compared the growth of this linewith that of Nipponbare under drought stress conditions. The result was that G1-1 line showed
more developed lateral root system than that in Nipponbare under stress conditions.
Compared with Nipponbare, G1-1 line also tended to maintain the tiller number and the shoot
dry weight under stress conditions, suggesting that those QTLs are important for adaptation tosoil moisture fluctuation stress conditions. Now, we are going to perform fine-mapping theloci to make the useful DNA markers for Marker Assisted Selection (MAS).
<Reference>
Kanou et al., 2007. Proc. of The 2nd Int’l Conf. on Rice for the Fut., 216-220.
Kano et al., 2011. Plant and Soil 342: 117-128.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P36 Poster presentationRole of plasticity in lateral root development triggered by mild drought stress indry matter production using OryzaSNP panel of rice
Emi Kameoka*, Akira Yamauchia
Graduate School of Bioagricultural Sciences, Nagoya University, Japan(aCorresponding author: ayama@agr.nagoya-u.ac.jp)
Roots play an important role in rice adaptation to drought stress. Several studies suggested
that rice cultivar with deep root could enhance drought resistance, however such deep root
trait may not be expressed when soils are hard or hardpan exists. In this study, therefore, we
aim to evaluate the functional roles of root plasticity that contribute to dry matter production
under various intensities of drought stress in the field when roots are confined in relatively
shallow soil layer. We used five varieties of OryzaSNP panel (Cypress, Tainung67, LTH,
FR13A and Nippanbare) and two varieties (Rexmont and IRAT109). Seeds were provided byInternational Rice Research Institute, Philippines. The experiment was conducted at theexperimental farm of Nagoya University, Nagoya, Japan during the summer in 2010. The soil
depth of this field was about 20cm. Thirty-days-old seedlings were transplanted and grown in
the field up to maturing under soil moisture gradients ranging from 9 % to 34 % v/v of soil
moisture contents by using line source sprinkler system. Shoot were dried at 70°C for 72
hours and then shoot dry weights and panicle dry weights were measured. The root system
was sampled with the monolith method (Kang et al., 1994). Number of nodal root and nodal
root length were manually measured. Total root length and total lateral root length were
measured using NIH image analysis software (Kimura and Yamasaki. 2001). Most of rice
genotypes reduced shoot dry matter production as drought stress intensified, especially,
Nipponbare and FR13A severely reduced in dry matter production among all the genotypes.
Under mild drought stress condition (19-27 % v/v of soil moisture contents), Cypress,
Tainung67, LTH, IRAT109 and Rexmont increased total root length compared to Nipponbareand FR13A, while all the varieties reduced number and length of nodal roots. Increase of totalroot length of five varieties was attributed to higher total lateral root length, which increased
by 20–80% under mild drought stress. These results clearly indicate that promoted lateral root
development due to plasticity, which was triggered by mild drought stress played importantroles in relatively highly maintaining dry matter production.
References: Kang et al., 1994. Jpn. J. Crop Sci. 63: 118-124; Kimura and Yamasaki. 2001.
Plant Soil. 234: 37-46

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P37 Poster presentation

Investigation into molecular mechanisms of crown root formation and its
application for improvements in root architecture in rice.
Yuka Kitomi*1, Hiroko Ito2, Panhui Wang1, Takaaki Kojima1, Hidemi Kitano3, Yoshiaki
Inukai1
1. Graduate School of Bioagricultural Sciences, Nagoya University, Japan, 2. Faculty ofAgriculture, Nagoya University, Japan, 3. Bioscience and Biotechnology Center, Nagoya
University, Japan (Corresponding Author: inukaiy@agr.nagoya-u.ac.jp)
Monocot plants produce numerous adventitious (crown) roots from nodes and form
fibrous root system. Roots play essential roles in plant development by absorbing water andnutrient, supporting the plant body and so on. Rice is one of the most important crops because
it is a staple food for more than half of the global population. Therefore, it is necessary to
improve rice yield to attain a stable food supply worldwide, however, the yield of rice iseasily influenced by environmental stress, especially, drought. To overcome the drought stress,
improvement the roothold of rice is one of the most effective strategies.
Recent progress in the understanding of the molecular mechanisms of root formation
has revealed the elaborate regulations by plant hormones and their interactions. To investigate
the molecular mechanisms of crown root formation in rice, we have been identified somecrown rootless (crl) mutants. One of them, crl5, produced fewer crown roots and displayed
impaired initiation of crown root primordia. CRL5 gene encodes a member of AP2/ERF
transcription factor family protein. We found that CRL5 functions in downstream of
AUX/IAA and ARF-mediated auxin signaling pathways involved in crown root initiation.
Further analysis revealed that CRL5 up-regulates a type-A response regulator of cytokinin
signaling, OsRR1. These results indicated that auxin-induced CRL5 functions as a positive
regulator of crown root initiation through the repression of cytokinin signaling.
We observed that CRL5-overexpressing callus could regenerate numerous roots,
including not only adventitious roots from callus, but also lateral roots from adventitious roots.
This result indicated the ability of CRL5 for de novo root induction, expecting that CRL5 isuseful gene to improve the root architecture of rice. Now, we are investigating other factors
essential for crown root initiation acting downstream of CRL5 in addition to OsRR1. We havefound three candidate genes whose expressions are suspected to be directly regulated by
CRL5 protein, by using DNA beads display system. We hope to provide useful information
not only for investigation into molecular mechanism of root initiation but also for breeding
through our research that grasp more genetic information involved in root formation.
We thank the National Bioresource Project of Rice for providing the crl5 mutant line.

220Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P38 Poster presentation

Inhibition of auxin transport changes the morphology of root system anddistribution of auxin in root system of rice seedlings
Atsushi Ogawa1*, Yusuke Suzuki1, Shigeru Tamogami1, Hiroetsu Wabiko1, Kyoko Toyofuku1
1. Department of Biological Production, Akita Prefectural University, Shimosinjyou-nakano
241-438, Akita 010-0195, Japan (111111@akita-pu.ac.jp)
Auxin, a key plant growth hormone, has important roles in root system formation. In thisstudy, we investigated the change of distribution of the endogenous indole-3-acetic acid (IAA)by the inhibition auxin transport in some portions of root system of rice seedlings using
LC/MS/MS to clarify the relationship between the root system formation and the IAA
distribution. Additionally, the localization of endogenous auxin in the root tissue was detected
in detail by the immunocytochemistry method. We also showed the change of lignification inseminal root axis accompanied with the change of IAA distribution.
Oryza sativa L. (cv. Akita-komachi) seedlings were grown hydroponically in half
strength of Hoagland solution. The nutrient solution was supplied with 0, 0.1, 1 and 10 µM
N-1-naphthylphthalamic acid (NPA) to detect morphological changes and the changes of
distribution of auxin in the root system by inhibiting auxin transport. After seven days, roots
were sampled and total root length and the number of lateral root were measured. The apicalportion (0–1 cm from the root tip including the cell division cell elongating zones), the middle
portion (3–4 cm from the root tip where lateral roots had begun to emerge) and the basal
portion (0–1 cm from the basal portion of the seminal root) were collected. The endogenous
IAA contents in each portion were measured by the LC/MS/MS. IAA localization andlignification in apical and basal portion were detected by the immunocytochemistry using
anti-IAA monoclonal antibody and by the Mäule colour reaction methods, respectively.
Growth of seedlings was inhibited by the NPA treatments. The formation of crown roots
was also inhibited at higher NPA concentrations. Gravitropism in root system was diminishedwith increasing NPA concentrations. In the 1 and 10 μM NPA treatments, brown pigment was
deposited in the root axis. Total root length and lateral root number decreased with NPA
concentration. In the 10 μM NPA treatment, growth of lateral roots was hardly initiated.
Endogenous IAA contents were highest in the apical portion in all treatments and were
gradually dropped from the apical portion to the basal portion, except for the 10 μM NPA
treatment. In each portion, endogenous IAA contents were increased with increase in NPA
concentration to the 1 μM NPA treatment. In the 10 μM NPA treatment, the endogenous IAA
contents were lower than that in the 1 μM NPA treatment in the all portions. The distal
elongation zone (DEZ) transferred to the basal part of the cell under NPA treatment
accompanied by the increase of endogenous IAA content in the apical portion. The seminalroots in the NPA treatments, especially 1 μM NPA treatment, were enlarged in the middle
portion. IAA localization was detected around the distal elongation zone, in the cortex and in
the stele in all treatments. IAA localization was also detected in the primordia of lateral roots.
IAA localization was detected more strongly in the higher content portion of endogenous IAA.
In the all NPA treatments, it was observed that the initiated primordia of the lateral root turned
into the seminal root in basal portion, and lateral root tissue was elongated in the cortex of theseminal root. In this portion, lignification was detected at the hypodermis and stele in all NPA
treatments. From these results, we discussed the role of auxin for root system formation.
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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P39 Poster presentation

Identification and characterization of reduced biomass production mutant of riceaccompanied with reduced root elongation
Mitsuhiro Obara*, Tomomi Abiko
Biological Resources and Post-harvest Division, Japan International Research Center for
Agricultural Sciences (JIRCAS), Japan (mitsuobara@affrc.go.jp)
Biomass production at mature stage is one of important agronomical traits in rice. It is known
that biomass production of rice is controlled by many genes and its interaction at various
physiological and anatomical traits. For example, root is a sole organ to uptake water andnutrients from surrounding soils. We isolated a spontaneous rice mutant with reduced biomass
production of top portion at mature stage in the genetic background of ‘Koshihikari’,Japonica-type variety. The dry weight of the mutant grown in paddy field at mature stage
showed 64% or 23% reduction in top portion or root portion, respectively, compared withwild-type ‘Koshihikari’. Furthermore, the mutant showed significant reduction of maximum
length of top or root, respectively. Also, these reductions were observed at vegetative stage.
The biomass production in the mutant was controlled by one recessive gene demonstratingwith clear segregation of top dry weight in backcrossed progeny. Interestingly, tight linkage
between reduced biomass production at mature stage and maximum root length at seedlingstage was observed in BC1F2/ BC1F3 families. These data indicate a possibility that reduced
biomass production in the mutant would be caused by reduced root elongation. Toward better
understanding physiological and molecular mechanisms of the relationship between biomass
production and root elongation, gene responsible for root elongation were finely mapped
within a 330 kb region in the ‘Nipponbare’ genome by a mean of positional cloning strategy
in F2 plants developed from a cross between the mutant and ‘Koshihikari’.
Acknowledgements: This work was supported in part by a grant of Program for Promotion of
Basic and Applied Researches for Innovations in Bio-oriented Industry from BRAIN andgrant-in-aid for Scientific Research from Japan Society for the Promotion of Science(22780057).

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P40 Poster presentation

Non-destructive imaging of aerenchyma development in the primary root of riceusing X-ray Computed Tomography – A trial for time-course observation –Tadafumi Bando1, Ichirou Karahara1, Daisuke Tamaoki2, Daisuke Yamauchi2, Kentaro
Uesugi3, Yoshinobu Mineyuki2
1. Graduate School of Science and Engineering, University of Toyama Japan, 2. Graduate
School of Life Science, University of Hyogo, 3. Japan Synchrotron Radiation ResearchInstitute (karahara@sci.u-toyama.ac.jp)
Wetland plants, such as rice, develop intercellular space which are called aerenchyma in theirroots as pathways for diffusion of oxygen. To elucidate how these plants develop
aerenchyma is essential to understand the resistance mechanism of these plants towaterlogging stress as well as to improve capacity of crop plants to adapt themselves to water
logging stress. Synchrotron X-ray computed tomography (CT) has been shown to be usefulfor nondestructive observation of aerenchyma in pome fruits (Verboven et al. 2008). We
aimed to perform in situ visualization of aerenchyma and quantitative morphological analysis
of its development by using this technique. In this study, we have tried to establish an
experimental system to visualize aerenchyma in rice roots in situ and perform time-course
observation of its development in the same roots.
Rice (Oryza sativa ssp. japonica cv. Nipponbare) caryopses were sterilized in 2.5%(w/v) sodium hypochlorite solution for 5 min, washed with water, imbibed for the first 4 days
at 4ºC and then for 1 day at 30ºC for germination. Imbibed rice caryopses were placed onplastic tubes filled with agar containing Hogland medium. Roots were allowed to grow at
25ºC in darkness for four days. X-ray CT was performed at the experimental hutch No.1 ofa bending magnet beamline BL20B2 of SPring-8 in Hyogo, Japan (http://www.spring8.or.jp/).
Rice roots has been shown to develop traditionally classified two types of aerenchyma, i.e.,
schizogenous aerenchyma and lysigenous aerenchyma. Both types of aerenchyma wereclealy visualized using this experimental system. The same roots were further allowed to
grow for 3h or 8h, and then X-ray tilt series were obtained again. A comparison between the
tomographic images, corresponding to the same position of one root, sliced from thetomograms obtained at different time points showed the development of lysigenous
aerenchyma. Three-dimensional models of aerenchyma were reconstructed using IMOD
software package (http://bio3d.colorad.edu/imod/) and its quantitative morphometricalanalysis is currently in progress.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P41 Poster presentation

Different gene expression of the creeping-rooted type of a kind of Alfalfa(Medicago varia)
Wang Xiaona1*, Lu Xinshi2, Takayoshi Koike1
1. School of Agriculture, Hokkaido University, Japan, 2. Beijing Forestry University, China,*(miho54@163.com)
Alfalfa has the highest value of legume forages for cultivation as well as ecosystem
rehabilitation using in the world. The creeping-rootedness of alfalfa has importantsignificance to improving the ability of stress resistance and nurture new cultivar.
In this research we used the creeping-rooted alfalfa “BL-101” for the experimental
material and constructed the transcription library of creeping-rooted (CR) andnon-creeping-rooted (NCR) separately. Analyzing the library with next generation sequences(RNA-seq) and the differential gene expression through cDNA-SRAP technology in order tofind the molecular mechanism of creeping-rootedness in alfalfa and also to find the excellent
gene relevant. The results are as follow:
1. Separate the RNA from CR and NCR root tissue using the Trizol method and construct thelibrary. Through the analysis of library which sequenced with RNA-seq technology that we
obtain 15978 differently expressed genes totally. The highest multiples of differentiallyexpressed genes were GA3 related proteins, so we determined that the occurrence of
creeping-rootedness may be induced by GA3 preliminary. According to the FDR method, we
got 996 up-regulated unigenes and 970 down-regulated unigenes. The result of GO analysis
was that we could classify the unigenes from three aspects, there were 237 kinds of gene inmolecular function, 114 kinds of gene in cellular component and 584 kinds of gene inbiological process.
2. Find 5 unigenes were related with the root development from the biological process, two of
the five genes were up regulated unigene. Making sequence alignment through NCBI, we
concluded that one gene was RAV subtribe of AP2/EREBP transcription factor family and theother was transferrin receptor protein.
3. Using cDNA-SRAP technology screen the differently expressed genes, and spraying GA3
outside as induction. We chose 15 primers for PCR augmentation got 134 bands, 76 of themwere diversity. 42 bands were recycled which were stable repeatability and difference tosequencing. The result of sequence alignment for 42 recycled genes showed that 9 genes were
unknown genes, 26 were functional genes. Most of these functional genes were zinc finger
protein、thioredoxin h7、MYB transcription factor、AP-2 complex subunit beta-1、and
xyloglucan galactosyltransferase.
4. We determined that the occurrence of creeping-rootedness may be induced by GA3,
through signal transduction makes the RAV transcription factor expressed, protein kinases andenzymes participate in root metabolism, acetyl-CoA and pyruvate dehydrogenase participate
in root respiration, than the root node developed. Golgi membrane secreted the signal
substances, and ion exchange proteins on plasma membrane control the material exchange,
WRKY transcription factors and ubiquitin ligases promoted the performance of
creeping-rooted organization.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P42 Poster presentation

Variation of 13C natural abundance in CO2 released from the roots of rice andmaize plants
Aki Kuribayashi1*, Jiro Tatsumi2(1. Graduate School of Science and Technology, Kyoto Institute of Technology, 2. Center for
Bioresource Field Science, Kyoto Institute of Technology, Japan (tatsumi@kit.ac.jp)
A large amount of photo-assimilated carbon is allocated to the roots and utilized for growth,
respiration, nutrient uptake and other physiological processes. Recently much attention has
been focused on the distribution of 13C natural abundance (13C) in plant parts in relation tocarbon metabolism. The signature of 13C in CO2 released by dark respiration depends partly
upon the 13C content of the carbon pool available for respiration, and partly upon the isotopic
fractionation occurred in enzymatic reactions involved in respiration chain. The size andturnover rate of carbon pool for respiration may change with plant parts, growth stage, stressconditions and plant species, and the 13C isotopic signature of respiration may shiftconsiderably. However, little is known on the 13C signature in root respiration. In the present
experiment we tried to analyze the 13C value of CO2 released from roots by respiration ofrice and maize in both vegetative and reproductive stages.
Materials and Methods:
Rice (var. Nippon-bare) and maize (var. Yellow Pop) were grown hydroponically under
outdoor conditions from May to Aug. 2011. Plant were harvested and separated into the roots
and shoots (vegetative stage) or the roots, leaves and ears (reproductive stage), then theseparated organ placed in the airtight plastic chamber. The CO2 free air was supplied to thechamber from inlet tube by an air pump at constant flow rate (500mL/min) and the gas
flowing out the camber from outlet tube was introduced to the CRDS isotopic CO2 gas
analyzer (G2101-i, PICARRO). Then concentration of CO2 and 13C values of the sample gas
was analyzed.
Results:
Respiration rate of the roots and shoot organs was significantly higher in maize than rice atboth vegetative and reproductive stages. The 13C in CO2 respired by all the plant parts wasalways higher in maize than rice plants, due to the difference of photosynthetic system
between C4 and C3 plants. In maize 13C of the root respiration is not significantly different
from the shoots, leaves and ears in both vegetative and reproductive stages. On the contrary,in rice plants 13C of the root respiration is significantly higher than the shoots (vegetative
stage) as well as higher than the leaves and ear (reproductive stage). The results suggest thatin rice roots the size and turnover rate of carbon pool available for respiration is different
from shoot organs, as compared to maize.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P43 Poster presentation

Stable carbon isotopic ratio (δ13C) of fine roots in tropical forests
Masaharu Sakai1*, Thiti Visaratana2, RattanaThaingam2
1
Department of Forest Site Environment, Forestry and Forest Products Research Institute,Japan (kmsaaki@affrc.go.jp), 2Royal Forest Department, Thailand (ratana.t@hotmail.com)
We have been studying the decomposition rate of soil organic carbon (SOC) in Thailand byusing stable isotope analysis. To this end, we analyzed the carbon and nitrogen contents andthe stable carbon isotopic ratio in leaves and roots, which are the main sources of SOC. In thisstudy, we report the stable isotopic ratio of fine roots (<2-mm diameter) from 6 plots—anatural forest, 4 plantations, and a grassland.
The study sites were located at Sakaerat Silvicultural Research Station (14°28′06.1′′ N,
101°54′15.0′′E; altitude, 420 m), Nakhon Ratchasima Province, Northeast Thailand. The
meteorological conditions were as follows: annual mean air temperature, 26°C and annual
precipitation (including the dry (November–April) and wet (May–October) seasons), 1,100
mm. Six adjacent plots were chosen: a natural forest (Fo), an Eucalyptus camaldulensis (Ec)plot, an Acacia auriculiformis (Aa) plot, an Acacia mangium (Am) plot, a Dalbergia
cochinchinensis (DcII) plot, and a grassland (inhabited by Saccharum spontaneum,Yp).
The soil-root samples at each soil profile until 100 cm of depth were suspended in water, andpoured over fine-mesh sieves to retain the roots. After drying, the fine roots were selected toanalyze the stable carbon isotopic ratio. The δ13C values of the samples were analyzed with acontinuous flow isotopic ratio mass spectrometry system (Finnigan MAT 252 and Conflo II).
Fig.1 shows the vertical
distribution of the δ13C values offine roots. There was a large
difference between the δ13C
values of grass roots and treeroots, with the average δ13C
values being -28.4 ‰and-17.2 ‰ , ‰ respectively. Thisdifference is thought to bereflected in the δ13C values oftree leaves (C3 plants) and grassleaves (C4 plants). Among thetree species, the δ13C values of
the Aa and Am plots were lesser
than those of the DcII, Ec, andFo plots. The changes in thevertical distribution of δ13C
values of fine roots from thenatural forest and plantation plots
were less compared to that of thegrassland fine roots226Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P44 Poster presentation

Growth and development of birch (Betula sp.) roots grown under elevated CO2
in FACE (A preliminary result)
ITO Hirotaka1 ＊ ・NAKAJI Tatsuro2 ・Wang Xiaona1 ・WATANABE Makoto1 ・KOIKE
Takayoshi1
1:Silviculture & Forest Ecological Studies, 2:Field Science Center for Northern Hemisphereof Hokkaido University, Sapporo 060-8589, Japan, *E-mail: ito-0530@for.agr.hokudai.ac.jp

RML(mg cm‐1)

Atmospheric CO2 has been increasing at the rate of 2.0ppm/yr for recent decade. We
strongly expect the CO2 fixation capacity of forest ecosystems for moderating atmosphericCO2. Fine root production is estimated to be 1/3 of net primary productivity in terrestrial
ecosystems. In this sense, below-ground activities have an essential role in forest productivity.
Therefore, we should pay attention to fine root productivity as affected by elevated CO2. It isalso considered the turnover rate of fine root may be accelerated by elevated CO2 andconsequently it affects carbon cycling in a ecosystem. Needless to say, as fine root acts very
important role of water and nutrient physiology, we have been monitoring the root growth ofbirch species for predicting forest productivity.
Betulaceae plants are the representative component in cool temperate and boreal forest andcompose of about 40 species. Among them, mountain birch, Monarch birch and white birch
are common species in northern Japan and grow together. These species have strong
preference to sunny places after disturbance, and produce high quality timber and several
commercial products. In this report, we present tentative results of monitoring of root growthwith use of rhizotoron in these birch raised under elevated CO2.
We set the tube of rhizotoron of 30cm depth in May 2010, for monitoring root growth anddeath of birch seedlings from April 2011in FCAE (Free Air CO2 Enrichment: 500ppm) of
Hokkaido University Forest in Sapporo. With use of the photos, we estimated the root
productivity based on the allometric relationship between RML (Root Mass per unit Length)
and root diameter. For obtaining this relation, we sampled soil core (diameter 5cm depth30cm) from the bottom part of each species in July 2011 when the root activity of birches islargest.
After water-washing root was scanned, the sample root was oven dried at 60oC for 48 hrs.
We analyzed the root length and diameter with use
160
of software of WhinRHIZO in the photos obtained140by a scanner (Epson). We estimated the root dry
current[CO2]120
mass by way of root diameter (n=322).
elevated[CO2]100
Here we showed an example of allometric80
relationship between root diameter and RML in60
white birch. As no difference in white birch was
40
found in CO2 treatments, we pooled data obtained
y = 2.8762x2 + 1.0178x
20
two CO2 levels (Fig. 1). We noticed the critical
R² = 0.94950level of fine root diameter because number of
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
roots was decreased sharply at the point of 1.5mm
Diameter(mm)in root diameter.
Financial support in part by the JSPS Fig1. Allometric relationship between root diameterand RML in white birch
innovation research is gratefully acknowledged.
227

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P45 Poster presentation

Can microbial respiration explain mass loss, morphology, and chemical
properties of dead fine root?
Ayumi Kawamura1*, Naoki Makita1, Akira Osawa1
1. Graduate School of Agriculture, Kyoto University, Japan (kawayu@kais.kyoto-u.ac.jp)
Fine roots of forest trees have a rapid turnover and contribute considerably to carbon (C) andnitrogen (N) dynamics of ecosystems in the belowground. In previous studies, fine root
decomposition has mostly been characterized by microbial activity and dead root properties
such as mass loss and chemical compounds. Although we understand the change of dead root
properties occurs through catabolism by microorganisms, less is known about the direct
quantitative relationship between microorganisms and dead root properties. Therefore,
estimating root properties based on microbial activity can reveal mechanisms ofdecomposition processes. Recent studies report that the process of root decomposition differs
even within 2mm diameter due to different chemical and morphological properties. To clarify
responses of microbial activities to changes in dead root properties with decay time, we
examined specific microbial respiration and its relationships to mass loss and root chemicalcomposition (C and N) of fine roots across two diameter classes (<0.5mm, 0.5-2mm) of
Quercus serrate and Ilex pedunculosa in a broad-leaved temperate forest at “Ryukoku Forest”
in Shiga prefecture, Japan.
One-hundred and twenty root litterbags (2 species×2 diameter class×6 replicates×5 times)
were buried in the forest soil on 29 June 2010, and were sequentially collected at each 1 or 3
month-intervals. After collection, microbial respiration rate from root litter samples (n=3) was
measured using a closed dynamic chamber system in the field. For the remaining of litter
samples (n=3), microbial respiration rate was measured in the laboratory at fixed temperaturesof 10, 15, 20 and 25 °C to estimate fixed Q10 temperature coefficient. Then, mass loss andconcentration of C and N were analyzed using the same samples as used for the respiration
measurement.
Microbial respiration rate at 20 °C of all the roots increased with decay time. In both
species, <0.5mm root tended to higher respiration rate than 0.5-2mm root. When comparing
decomposition rates of mass loss between diameter classes, the <0.5mm root in both species
decomposed more slowly than 0.5-2mm root. The C/N dynamics of <0.5mm root in both
species were constant with the decay time, whereas that of 0.5-2mm root were not. For both
species, microbial respiration, mass loss, and chemical properties differed between diameterclasses. The respiration rate was correlated positively with mass loss and N concentration andnegatively with C/N within and among diameters and species. These results indicate thatmicrobial respiration reflects mass loss and chemical properties of dead fine root. We foundthat the relationship between microbial respiration and root properties enables us to predictthe process in the decomposition of dead roots, with consequences of accurate and consistentestimates of belowground C and N dynamics.
228

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P46 Poster presentation

Mycorrhizal Hyphae Respiration
Frida Andreasson1*, Masako Dannoura1, Yuji Kominami2, Yasuhiro Hirano3 and Naoki
Makita4
1. Laboratory of Forest Utilization, Department of Forest and Biomaterials science, Graduate
School of Agriculture, Kyoto University (andreasson_frida@hotmail.com)
2. Forestry and Forest Products Research Institute (FFPRI) 3. School of Bioagricultural
Science, Nagoya University 4. Laboratory of Forest Hydrology, Graduate School of
Agriculture, Kyoto University
In forest ecosystems, researchers have been challenged in recent years to measure carbon
storage and whether forest soils will be a sink or a source for carbon. One obstacle is that CO2
respiration from the soil to the atmosphere is a complex flux of roots, mycorrhiza and root
associated microbe (autotrophic respiration) as well as free-living soil microbes and animals
get carbon from decomposition of plant debris (heterotrophic respiration). The few works thatmeasured the part of soil respiration from mycorrhizal hyphae showed that it ranged between
3% in beech, 8% in spruce (Moyano et al. 2008) and 25% in pine forests (Heinemeyer et al.
2007). In order to verify this, measurements over a larger range of forest biomes and under
different climatic gradients need to be carried out. Ideally, this calls for comprehensive studies
that include pool sizes, turnover of the pools and metabolic activities.
This project aims at investigating belowground carbon allocation in a temperate mixed
forest dominated by the ectomycorrhizal forming Quercus serrata, in particular contributionof respiration and production by external mycorrhizal mycelium.
To this end, an ingrowth bag approach was used. In March 2011, 253 nylon mesh bagswith pore size of 41 µm filled with 60g dry sterile granite soil was installed in the top 5 cm of
the soil profile. 55, 1 µm pore sizes nylon bags were installed as well. The area for ingrowth
was 64 cm2 per bag. The pore size of 41 µm allows ingrowth of fungal hyphae but exclude
roots. The sterile granite sand filling of the bags makes it possible for mycorrhizal hyphae toenter the bag as their host tree supply C while hyphae from saprophytic fungi will not enter tothe same extent. For studies of seasonal variation and to get a gradient of hyphae biomass 20
ingrowth bags was collected after 2 (May), 4 (July) and 6 (September) months. Direct after
sampling the content of the ingrowth bag was emptied into a small respiration chamber (305
cm3) and the CO2 flux measured with an infrared gas analyzer (GMP343, Vaisala, Finland).
Preliminary results from these measurements will be presented on the poster.
This project is ongoing and sampling will be executed every 2nd month until March 2012.
Biomass, morphological and genetic analyses of the hyphae will start in winter 2011. In the
future this project will give an important insight in the relationship of carbon storage and themetabolic activity of mycorrhizal hyphae as well as seasonal variation contributing to a better
understanding of the carbon cycling in the temperate forest.
Heinemeyer A., Hartley I.P., Evans S.P., Carreira De La Fuentes J.A. and Ineson P. Forest soil CO2 flux : uncovering thecontribution and environmental responses of ectomycorrhizas. 2007. Global Change Biology 13, 1786-1797.
Moyano F.E., Kutsch W.L. and Rebmann C. Soil respiration fluxes in relation to photosynthetic activity in broad-leaf andneedle-leaf forest stands. 2008. Agricultural and Forest Meteorology 148, 135-143.

229

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P47 Poster presentation

Relationships between morphology and respiration of fine roots
Saki Yamamoto＊・Mizue ohashi
Department of Human Science and Environment, University of Hyogo, Japan（＊E-mail:nc08r194@stshse.u-hyogo.ac.jp）【Introduction】
Fine roots (< 2 mm in diameter) release a lot of carbon by their respiration, which has
important role in the carbon cycling of the ecosystem. Fine root respiration could have also
close relationships with root physiological functions such as nutrient and water uptake fromthe soil. Understanding of fine root variation is important to know those mechanisms. Makita
et al. (2008) reported that fine root respiration can change with their diameter and specificroot length (SRL). This study suggests that morphology is one of the factors explaining thevariation. However, there are still many root morphological indexes, which are not examined
how they correlate to the respiration. In this research, therefore, we aimed to clarify the
relationships between various morphology indexes and respiration rate of fine roots.
【Materials and Methods】
We used fine roots of mature Cryptomeria japonica and Zelkova serrata trees grown in
Shisou city in Hyogo prefecture, Japan. We sampled 60 fine roots from 12 mature trees ofeach species (120 samples in total). Respiration of fine roots (μmol h-1 g-1) was calculated
from the increase of CO2 concentration (ppm) in a respiration chamber with a fine root sample,
and dry mass of the sample root (g) was determined thereafter. Then, we took image of eachfine root by scanner. Morphorogy analysis of the fine root images was conducted usingmorphorogy analysis software (WinRhizo Reg, Regent). Here, we obtained data of mean
diameter (mm), length (cm), surface area (cm2), volume (cm3) and SRL (mg-1) of each fineroot for the morphorogy analysis using the software.
【Result and Discussion】
Respiration of fine roots Table.1 Relationship between morphorogy and respiration of fine root
related to many of the morphorogy index Total(n=120) C.japonica(n=60) Z.serrata(n=60)
mean diameter(mm) -0.40**-0.54**-0.29*
morphological indexes, length(cm)-0.20*-0.18-0.36**
such as diameter, length, surface area(cm2) -0.52**-0.61**-0.47**
3-0.49**-0.59**-0.52**
surface area, volume volume(cm )-10.70**
0.62**
0.74**and SRL of the samples. SRL(mg )significant **(p < 0.01) *(p < 0.05)
Only the length ofC.japonica did not have correlation to the respiration (Table. 1). Surface area, volume and
SRL had higher correlation with respiration than others. We conclude that morphology of fineroots is strong controller of fine root respiration.

230

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P48 Poster presentation

Tea roots changed respiratory activity in response to irradiated light information
Tomoo Homma1*, Taisuke Sugiyama1, Kiyoshi Matsuo2, Nobuhisa Kanemitsu3,
Hiroshi Sato3 and Hiroyuki Hiramoto3
1. Department of Biotechnology, Maebashi Institute of Technology, Maebashi, Japan,
2. National Institute of Vegetable and Tea Science, NARO, Shizuoka, Japan,
3. Yokohama Technical Center, Stanley Electric Co. Ltd., Kanagawa, Japan(thomma@maebashi-it.ac.jp)
We have examined the effects of LED light irradiation on the growth of tea plants in order
to use them as a kind of indoor plants, and got the results that the growth and function of tea
roots were changed by the irradiated LED light information1). In the present study, we
reported the effects of different wavelength and light intensity of irradiated LED light on
respiratory activity of tea roots.
Respiratory activity (RA: quantity of oxygen consumption) of roots excised from1-year-old (only white roots) or 2 years-old (white and lignified roots) rooted cuttings ofCamelia sinensis L. ‘Yabukita’ species was measured by O2 uptester (Taitec, 5B) with
continuous irradiation of LED light (Stanley Electric Co., Ltd.) during the measurement. As acondition of irradiated LED light, wavelength was blue, (main peak wavelength: 465 nm),green (502 nm), red (660 nm) or white (470 and 570 nm), and light intensity (photon flux
density) at each wavelength was adjusted to ~5, ~15, or ~30 μmol/m2/s, respectively. As acontrol, RA was measured under shade condition.
RA excised from 2-years-old rooted cuttings measured on each LED irradiation condition
was shown in Fig.1. By light irradiation, RA became smaller than the control except the cases
irradiated light intensity was weak at red and green LED lights (R5 and G5 in the figure). RAchanged variously depended on the irradiated light wavelength and intensity. Similar results(differences of RA depended on the irradiated light condition) could be obtained from theexcised roots of 1-year-old rooted cuttings. The results suggest that tea roots may recognize
the irradiated light information. Generally, roots should be shaded, but they may become able
to utilize light information for their growth and production effectively.
(μmol/hr/gDW)
30
Shade
25

Red

20

Green

15

Blue
White

10
5
0
C

R5

R15

R30

G5

G15 G30

B5

B15

B30

W5 W15 W30

Fig.1 RA obtained from excised roots of 2-years-old rooted cuttings.
1) T.Homma, et al., Proc.The 4th ICOS, Pr-P-15 (2010).
231

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P49 Poster presentation

Coarse root respiration measurement using automatic chamber system
Masako Dannoura1,2*, Alexandre Bosc2, Daniel Epron3
1. Laboratory of Forest Utilization, Graduate School of Agricultural, Kyoto University(dannoura@kais.kyoto-u.ac.jp)
2. INRA, UR1263 EPHYSE, Villenave d'Ornon, France
3. Nancy Université, Université Henri Poincaré, UMR Ecologie et Ecophysiologie Forestières,FranceRoot respiration(μmol m-2 s-1)

temperature(℃)

Root respiration is an important fraction of soil respiration that contributes to the forest
carbon cycle. However the difficulties lie ahead because root is living in rhizosphere withstrongly connecting with mixture of such as mycorrhiza, hyphae, and organic matter. In spiteof these difficulties, trials to separate root respiration from soil respiration have been doneusing several methods. One of these methods is destructive method, where the root isremoved from the soil and the root sample measures directly. This method is well suited todetect characteristics of root respiration according to root morphology (e.g. diameter) or root
chemistry (e.g.CN ratio). (ex, Dannoura et al., 2006, Marsden et al., 2008, Makita et al., 2009)
However this method has the shortage that measurement cannot be done continuously thus it
is not possible to estimate long term value considering response to environmental factors andseasonal variations. Thus, this study aims measuring root respiration directly andcontinuously.
This study was conducted in a pine (Pinus pinaster) plantation at the INRA domain of
Pierroton (44° 45’ N, 0° 42’ W, elevation 60 m) in France. The top soil on part of a coarse root
segment was removed and replace with sterilized sand. Respiration chambers were set on theroot segment and CO2 efflux was measured with a trace gas analyzer (TGA 100A; Campbell
Scientific) coupled to flow-through chambers during over one month. The target roots wereselected from 3 to 5 trees at each season (June, August, October 2009, and February 2010).
Finally, 27 roots which have 7.1 to 90 mm in the diameter were measured. After CO2 efflux
measurements, root samples were dug out and diameter, length and biomass of the root
segment inside the chamber were measured.
Figure 1 shows CO2 efflux from each root sample. Root respiration showed seasonal variation,and Q10 value also change seasonally.
30

Tair
Tsoil

20
10
0

6
4
2
0
100

200

300

400

DOY

500

Figure1. The seasonal change of air/soil temperature (upper) and root
respiration (daily average) per soil surface area (under)232

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P50 Poster presentation

Fine root respiration for Pinus densiflora forests in Mt. Jukyeob of Korea and
Mt. Fuji of Japan
Nam-Jin Noh1*, Yashiro Yuichiro2, TaeKyung Yoon1, Saerom Han1, Toshiyuki Ohtsuka2,
Hiroyuki Muraoka2, Yowhan Son1
1. Department of Environmental Science and Ecological Engineering, Korea University,
Korea, 2. Institute for Basin Ecosystem Studies, Gifu University, Japan(treeworld@korea.ac.kr)
This study was conducted to investigate the fine root and litter respiration rates for two
mature Pinus densiflora forests with different environmental conditions. The study stands
were located in Gwangneung region of central Korea (GNP, 37° 47´ N 127° 10´ E, 425 ma.s.l.) and Fujiyoshida city of central Japan (FYP, 35° 27´ N, 138° 46´ E, 1,030 m a.s.l.). GNP
was naturally regenerated following harvesting in Gwangneung Experimental Forests of Mt.
Jukyeob, whereas FYP was established on a lava surface of Mt. Fuji. Annual mean
temperature and precipitation were 11.3°C and 1,518 mm for GNP, and 10.9°C and 1,561 mm
for FYP, respectively. Stand density and basal area were 650 tree ha-1 and 54.3 m2 ha-1 for
GNP and 842 tree ha-1 and 46.8 m2 ha-1 for FYP, respectively. Soil respiration was measured
using the portable infrared gas analyzer (EGM-4, PP-systems Inc., UK). Fine root and litter
samples were collected using a core method (ø=10cm, n=9 or 10); fine root samples weretaken up to 10 cm soil depth after collecting litter samples in GNP whereas fine root and litter
samples were taken up to 10 cm depth in FYP. Fine root (< 2 mm diameter) and litter (plushumus) respiration were measured using the portable CO2 sensors (GMP343, Vaisala
CARBOCAP, Finland) with small root chambers on August 4, 2011 in FYP and on August 11,
2011 in GNP. Fine root respiration rates for both GNP and FYP were approximately four-foldhigher than litter respiration rates. Fine root and litter respiration rates were higher in GNP
than those in FYP while fine root mass was higher in FYP than in GNP (p<0.01) (Table 1).
Soil respiration rates (0.63 g CO2 m-2 h-1 for GNP and 0.68 g CO2 m-2 h-1 for FYP) might beinfluenced by the differences in fine root and litter respiration rates between two study sites
with the soil microbial respiration. These measurements and quantifications of thecomponents respiration rates (fine root, litter and soil) can provide useful information tounderstand the contribution of roots to belowground carbon dynamics in forest ecosystems.
Table 1. Fine root and litter mass (Mg ha-1), soil depth (cm), and respiration rates of root, litter (nmol CO2 g-1 s-1)
and soil (g CO2 m-2 h-1) for Pinus densiflora forests in Gwangneung region of central Korea (GNP) andFujiyoshida city of central Japan (FYP). Numbers in the parenthesis are the standard errors of means and thedifferent letters indicate the significant differences between GNP and FYP (p=0.05).
GNP
FYP
Fine root mass (Mg ha-1)
1.12 (0.12)b
3.48 (0.35)aLitter mass (Mg ha-1)
74.85 (6.19)a
75.76 (4.45)aSoil depth (cm)
< 100
< 20
Respiration rate

Fine root (nmol CO2 g-1 s-1)
Litter (nmol CO2 g-1 s-1)
Soil (g CO2 m-2 h-1)

8.23 (1.19)a2.21 (0.25)a
0.63 (0.06)b

233

4.03 (0.60)b
1.11 (0.15)b0.68 (0.05)a

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P51 Poster presentation

Linkage between under- and above-ground of three kinds of larch species grownunder different levels of nitrogen and phosphorous
Mao Qiaozhi1*, Watanabe Makoto1, Koike Takayoshi1
1. Faculty of Agriculture, Hokkaido University (maomerry@for.agr.hokudai.ac.jp)
The rhizosphere is a complex environment where roots interact with physical, chemical andbiological properties of the soil. Root system senses and adapts to changes in the nutrient
status of soils and supports canopy to accumulate bio-energy. Nitrogen (N) is one of the mostcommon limiting elements and the next is phosphorous (p), especially in Hokkaido wheremost soils are originated from immature volcanic ash or allophane. Larch is a deciduous
conifer, has fast growing characteristics and good tolerance to severe environment. It
distributes widely through northern hemisphere. Recently we developed a new larch hybrid(Larix gmelinii × L. kaempferi) crossing between Dahurian larch (L. gmelinii) and Japaneselarch (L. kaempferi).
On the other hand, nitrogen deposition is reported to be increasing yearly and reached to
be about 11 kg N ha-1yr-1 in central Hokkaido. For edaphic condition of Hokkaido Island,
volcanic ash soil is very common, which also is a phosphorous poor soil. How about larch
species response to the increasing nitrogen with limited amount of phosphorous loading? For
approaching this phenomenon, the linkage between above- and bellow-ground is necessary to
be clarified. We hypothesized that N and P loading may enhance three kinds of larch growth
and their canopy photosynthesis capacity via root development with symbiotic
micro-organisms.
Three years old seedlings, Dahurian larch, Japanese larch and the hybrid larch wereplanted in 15L pots in June 2010. Nitrogen (3 levels, 0, 50 and 100 N ha-1 year-1) and P (2levels, 0 and 50 kg ha-1 year -1) were supplied every two weeks until October 2011. Diameterand height were monitored for 2 years. Gas exchange rate of needles was conducted in everylate summer. In-growth core root samples were collected every 40 days interval from June to
October 2011 because of the small size of seedlings in the first year.
According to our observation, mycorrhizal infection was found in roots of three kinds oflarch. With invading of mycorrhizal fungi, larches can grow better. Fine roots at surface areaof hybrid larch were increased by 25.4% with high N and P loading, while the coarse roots at
surface area was decreased by 23.2% compared to control (i.e. no N and P application).
Based on these findings, we will discuss the essential role of N and P application on thegrowth and development of root-shoot in three kinds of larch species with particularreferences to the ectomycorrhiza infection. In our presentation, we would like to emphasis on
the responses of hybrid larch because it is economically important species in Hokkaido.
Moreover we also discuss problems in the in-growth method for applying to three kinds oflarch species.
Financial in part by the Grant-in-aid of Japanese Society of Promotion of Science(innovation research and Basic study type B to T.Koike) is gratefully acknowledged.

234

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P52 Poster presentation

Do trees growing on the steep slope have different root to shoot ratios fromthose on the flat site?
Nobuhiko Kasuya1*
1. Graduate school of life and environmental sciences, Kyoto Prefectural University, Japan(n_kasuya@kpu.ac.jp)
It is well known that the trees planted on the steep slope have deformed root systems,
especially in snowy regions. Every winter those trees at juvenile stages are subject to pressure
from the snow slide on the plant body (especially stem), forming basal bending and buriedstems. It is reported that the root to shoot (R/S) ratios of conifers get close to 0.25 (Fukuda etal. 2003) as the trees get larger, but to date no one has detected the effect of slopes on the R/Sratios of conifers in Japan, where the greater part of forests are located on slopes. The objectof the study is to determine if there is a change in R/S ratios derived from growth conditions
on slope. It is important to clarify the effect of slope on the R/S ratios in terms of measuring
precisely carbon storage in root biomass in the forest ecosystem.
The root samples were taken in two region of central Japan, The one with maximum
snow depth more than 2 m and the other with much less. The plant species was Japanese redcedar (Cryptomeria japonica D. Don), the most common conifer in Japan. The average tree
size was 21 and 26 cm in trunk diameter at breast height in snowy region (S) and non-snowy
region (NS), respectively. The gradient of the slope was 37 and 10 degrees. Annual ringwidths were measured of the coarse roots and stems at breast height and at the base (groundlevel). The eccentricity of radial growth was investigated as follows. The distances were
measured from the center to the outer rings in four directions on the same wood cross section.
The eccentricity was evaluated by the indices indicating variability between the four
directions.
The mass proportions of stump to total belowground were 0.69 and 0.59 for S and NS,
respectively. This may indicate the effect of buried stems in S. The yearly changes of annual
ring widths were similar between stems at breast height and ground base both in S and NS.
The eccentricity of the roots became smaller as it got further away from the tree center,reflecting that the eccentric growth was an adaptation for tree stability. It was suggested that
the R/S ratios were larger on the steep slope in the snowy region owing to basal bending andburied stems.
Key words: root to shoot ratio, root biomass, snowfall, slope, basal bending, buried stem,
deformed root system, eccentricity of radial growth, annual ring analysis

235

Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P53 Poster presentation

Inter-specific robustness and intra-specific flexibility of whole-plant metabolic
scaling from seedlings to giant trees
Shigeta Mori 1* (moris@ffpri.affrc.go.jp) [Whole-plant physiology team, Department of plant
ecology, Forestry and Forest Products Research Institute, Tsukuba 305-8687, Japan]
The scaling of respiratory metabolism with body mass is one of the most pervasive
phenomena in biology. Using a single allometric equation to characterize empirical scaling
relationships and to evaluate alternative hypotheses about mechanisms has been controversial.
We developed a method to directly measure respiration whole plants, spanning eleven ordersof magnitude in body mass, from small seedlings to large trees, and from tropical to boreal
ecosystems. Our measurements include the roots, which have often been ignored.
For evaluation of whole-tree respiration, we selected variously-sized trees spanning fromthe smallest to the largest trees in each forest. In that way, we were able to show the maximal
variation of individual respiration rates in the general plant metabolic scaling. However, it
must be noted that in any forest community the smallest trees are not always the depressed
trees. Therefore, some of the smallest trees have much of adventitious branches and roots
adapted with the environments under a canopy gap, and relatively high specific respiration
rates per individual weight in contrast to dominant trees. Such smaller trees may also play animportant role in keeping the sustainability of a natural forest community. Thus, theintra-specific flexibility of individual metabolism gathers into the inter-specific robustness of
metabolic scaling of plant communities.

(a)

Figure(b)

Quick excavation of roots (a) and measurement (b).

(References) : 1) Mori et al. PNAS 1073 (2010). 2) 森、山路 (2011) 農業および園芸 86. 3)
Mulder & Mori et al. (in press) Advances in Eol. Res. invited chapter. 4) 森 (印刷中) 生物科学.

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Root Research (根の研究) Vol. 20 No. 5
The JSRR's 20th Anniversary Symposium - The Latest Frontiers of Root Research in Asia
Abstract
P54 Poster presentation

Comparison of the mesh material in a root mesh method
Aiko Nakano1*, Yasuhiro Hirano2, Kyotaro Noguchi3, Hidetoshi Ikeno1, Mizue Ohashi1
1. Graduate School of Human Science and Environment, University of Hyogo, Japan
2. Graduate School of Environmental Studies, Nagoya University, Japan
3. Shikoku Research Center, Forestry and Forest Products Research Institute, Japan(nd10d020@stshse.u-hyogo.ac..jp)
1. Introduction
Accurate estimate of the fine root production is important for understanding the mechanismsof carbon cycling in ecosystems. However, it's hard to figure out the quantity of the fine root
production in the soil, so, various techniques have been developed so far.
The mesh method is one of the most recent techniques for measuring the root production(Godbold et al. 2003). This technique inserts a mesh sheet into the soil for a certain period,and measures the number and weight of roots that grow through the mesh. This technique isinnovative because of the simplicity with a few labors and little disturbance of soil. However,
the methodological protocol has still uncertainty: for example the effect of mesh quality on
the results is unknown. In this study, therefore, we aimed to clarify the influence of different
material of a mesh sheet on the results of fine root production.
2. Materials and methods
Six different kinds of mesh sheets were prepared (n=8) Table 1. Mesh list
Hardness(Table 1). The size of a mesh sheet was 10 cm × 20 cm, and Mesh No. Material
1
Polyamide
hard
the mesh size was 2 mm. We conducted field experiment in a 2
Polyamidesoft
3
Polyethylene
hard
Cryptomeria japonica plantation in Kamikawa-cho in Hyogo
4
Polyethylene soft
prefecture in Japan. We placed the meshes vertically into 5
Stainlesshard
6
Polyester
soft
forest soil in November 2008 and uptake them in December
2010. After taking the sample, soil was removed carefully. Then, the fine root grown-up
through the mesh was collected, and the number and dry weight (g) were measured for
calculated of the fine root production (g m-2 year-1) (Hirano et al, 2009).
3. Result
Average number of the fine root passed through the mesh andthe calculated fine root production (g m-2 year-1) was highest
Mesh 4 and lowest Mesh 3 (Table 2). In a previous study,
fine root production has been estimated 157-320 g m-2 year-1
in other Cryptomeria japonica plantation (Noguchi et al.
2007). The values of fine root production were 40 times
smaller than those values in this study.
237

Table 2. Average number of the fineroot passed through the mesh andthe calculated fine root production
Mesh No. Number Production
1
7 ±11 5 ± 72
9± 5 8± 6
3
6± 7 5± 5
4
14 ±19 11 ±115
8 ± 6 9 ±106
7± 6 7± 6
Average
9± 3 8± 2

根の研究
第２０巻（２０１１年）総目次
頁(号)巻頭エッセイ 会長挨拶
巽 二郎 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥2(1)
雑草の根
大段秀記 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥3(1)
会の名称変更と名誉会員創設の会長メモ
巽 二郎 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 46(2)ターニングポイント
小川敦史 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 47(2)根の営み
鴨下顕彦 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥110(3)会長退任のご挨拶巽 二郎 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥142(4)果樹の根の仕事
草塲新之助 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥143(4)
原著論文
ルートモデルによるテンサイ根系の構造と形成過程の解析
吉田渡・伊藤博武・吉田穂積・小松輝行 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥5(1)
オピニオン
わが国の食料自給率向上と環境保全に向けた根に関する研究課題
高橋智紀・中野明正 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥49(2)ミニレビュー イネ冠根形成の誘導過程を制御する分子機構
木富悠花・犬飼義明 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥61(2)短報
ツツジ属植物の根の内部構造の組織学的観察
岡本章秀・山下正隆‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥111(3)ナシ萎縮病発生に関する土壌肥料的要因調査
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トマト台木用品種の根系の特徴
中野明正・河本恵一・高橋努・龍勝利 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥144(4)報
告河野恭廣先生を偲んで－作物根系の構造とその機能的意義－
山内 章 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥19(1)
第 34 回根研究集会に参加して
濵﨑翔悟・太田景子 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥73(2)
第 34 回根研究集会発表要旨 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥74(2)
第 3 回植物アクアポリン研究検討会の開催報告
且原真木 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥93(2)XVIII 18th International Botanical Congress 参加報告
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improvement of rice under drought-prone ecosystems”参加報告
亀岡 笑‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥151(4)[アメリカ便り］顆粒の素性を求めて

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情

報

公

示

会

告

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239

根研究会

http://www.jsrr.jp/

根研究会事務局

根研究会創立 20 周年

http://www.jsrr.jp/20th/

E-mail: neken2011@jsrr.jp

根の研究 第 20 巻 第 5 号

2011 年 12 月 7 日印刷 2011 年 12 月 20 日発行

発行人：巽 二郎 〒616-8354 京都市右京区嵯峨一本木町 1
京都工芸繊維大学繊維学部附属生物資源フィールド科学教育研究センター
編集・印刷：根研究会創立 20 周年記念事業組織委員会（委員長森田茂紀）