ࢨࢱ㢦ࡡ✽⣪ฺ⏕࡞㛭ࡌࡾ⏍⌦≁ᛮ-⏍ឺ⣌ࡡᣚࡗ⥾⾢ᶭ⬗࡞࠽࠷࡙ࢨࢱ࠿ᯕࡒࡌᙲ๪Physiological characteristics of ferns regarding nitrogen use-the role of ferns in the buffering function of ecosystems◂✪௥⾪⩽㸯ᑚᒜ 㔓ዄ, ຐᡥ, ா㒌ኬᏕ᝗ሒᏕ◂✪⛁KOYAMA Lina, Assistant Professor,
Graduate School of Informatics, Kyoto University᳔∸ࡢࠉᚪ㡪ኣ㔖ඔ⣪ࡡୌࡗ࡚࠵ࡾ✽⣪ࢅᅰቫ࠾ࡼ↋ᶭឺ✽⣪ࡡᙟ࡚ᚋ࡙࠷ࡾࠊ᳔∸࠿ฺ⏕ࡌࡾᅰቫ୯ࡡ↋ᶭឺ✽⣪࡞ࡢ࢓࣓ࣤࢼ࢓ឺ✽⣪࡛◢㓗ឺ✽⣪࠿࠵ࡾ࠿ࠉࡆࡡ࠹ࡔ◢㓗ឺ✽⣪ࡢᅰቫ⢇Ꮔ࡞ྺ╌ࡈࡿ࡝࠷ࡒࡴ⏍ឺ⣌࠾ࡼὮฝࡊࡷࡌࡂࠉ᳔∸࡞ࡻࡾ◢㓗ឺ✽⣪㔖ࡡฺ⏕ࡢ᲻ᯐࡡᣚࡗὯ໩࣬⥾⾢ᶭ⬗࡞࠽࠷࡙㔔さ࡝ᙲ๪ࢅᯕࡒࡌࠊ᳔∸ࡡ⛸࡞ࡻࡖ࡙◢㓗ឺ✽⣪ࢅฺ⏕ࡌࡾ⬗ງ࡞ࡢⴥࡊ࠷ᕣ࠿࠵ࡽࠉ⏍ឺ⣌ࢅᵋᠺࡌࡾ᳔∸⛸ࡡ✽⣪ฺ⏕࡞㛭ࡌࡾ≁ᛮࢅᢍᥩࡌࡾࡆ࡛ࡢ⣌හࡡ✽⣪ᚘ⎌ࡡ≟ឺࠉࡥ࠷࡙ࡢ᲻ᯐࡡᣚࡗ⥾⾢ᶭ⬗ࢅᢍᥩࡌࡾࡒࡴ࡞୘ྊḖ࡚࠵ࡾࠊ ᮇ◂✪࡚ࡢࢨࢱ㢦ࢅᑊ㇗࡛ࡊ࡙ࠉ◢㓗ឺ✽⣪ฺ⏕࡞㛭ࡌࡾ⏍⌦≁ᛮࡡよ᪺ࢅ⾔࠹ࠊࢨࢱ㢦ࡢ᪝ᮇࡡ᲻ᯐୖᒒ࡞ᗀࡂฦᕱࡌࡾ࠿ࠉࡐࡡ⏍⌦≁ᛮ࡞ࡗ࠷࡙ࡢᮅよ᪺࡝Ⅴ࠿ኣ࠷ࠊᮇ◂✪ࡢࠉࢨࢱ㢦ࡡ◢㓗ឺ✽⣪ࢅฺ⏕ࡌࡾ⬗ງࠉ◢㓗ឺ✽⣪ྜྷ໩ࡡᏒ⟿ᛮ᳔࣬∸మහ࡚ࡡ㒼ฦ࣬⛸㛣ࡡ㐢࠷࡝࡜ࢅ᪺ࡼ࠾࡞ࡊ࡙࠷ࡂࠊ
Nitrogen (N) is one of the essential macronutrients for plants, and plants take up
inorganic N (ammonium (NH4+-N) and nitrate (NO3--N)) from soil as major N sources.
Plant NO3--N uptake is an important process in the N cycle in forest ecosystems, since it is
one of the possible factors reducing the NO3--N loss from forest ecosystems, as NO3--N is
an anion that readily leaches from ecosystems. The ability of plants to take up andassimilate NO3--N as a source of N differs greatly among species. It is necessary toinvestigate the physiological properties of plant species concerning N use to understand N
cycling in ecosystems and its buffering functions in forests.
The physiological properties of NO3--N use in ferns will be investigated in thisresearch. Ferns (Pterophyta) are dominant in the understory in Japanese forests. However,their physiological characteristics have not been described in detail. This research will
provide information on the physiological characteristics of ferns concerning NO3--N use:
species differences in the ability to use NO3--N as a N source, seasonal changes of NO3--N
assimilation, and allocation patterns of NO3--N assimilation.
-1-1. ◂✪┘Ⓩᛮ࣬‭ᛮࡡ㜾ୖ∸࡛ࡊ࡙⏍ឺ⣌࡞౩⤝ ㎾ᖳࠉ㒌ᕰᇡ࡞࠽࠷࡙✽⣪㓗໩∸࡞ࡈࡿࡒ✽⣪ࡢࠉᅰቫ୯࡚᚜⏍∸ࡡ഼ࡀࡻࡾኬẴỗ᯹ࡢ῕็࡝≟Ἓ࠿⤾࠷࡙࠷࡞ࡻࡖ࡙ᙟឺ࠿ን໩ࡊࠉ᳔∸࡞ࡻࡖ࡙ࡾࠊኬẴỗ᯹∸㈻࡛ࡊ࡙ᵕࠍ࡝ᑊ➿࠿ྺ཭࣬ྜྷ໩ࡈࡿࠉ᭯ᶭឺ✽⣪࡛ࡊ්ཱི࡙ࡼࡿ࡙࠷ࡾ࡞ࡵ࠾࠾ࢂࡼࡍࠉྜྷࡋࡂࡦᅰቫ࡫࡛౩⤝ࡈࡿࡾࠊᅰቫ୯࡞Ꮛᅹỗ᯹∸㈻࡚࠵ࡾ◪㯜㓗໩∸࡞Ẓ㍉ࡊ࡙ࠉ ࡌࡾ✽⣪ࡡ࠹ࡔࠉ࣏࢕ࢻࢪ࢕࢛࡚ࣤ࠵ኬẴ୯ࡡ✽⣪㓗໩∸ࡡ⎌ሾᇱ‵ࡡ㐡ᠺࡾ◢㓗ឺ✽⣪࡞ࡢࠉ㏳ᖏ࣏࢕ࢻࢪ࡞ᖈ

≟Ἓࡢ఩࠷Ề‵ࡡࡱࡱ࡚࠵ࡾࠊ⮤ິ㌬

㞹ࡌࡾᅰቫ⢇Ꮔ࡞ྺ╌ࡈࡿࡍ⣌አ࡫࡛ᤴฝ࢝ࢪࡢ✽⣪ 㓗໩∸ Ⓠ⏍″ ධమࡡὮฝࡊࡷࡌ࠷ᛮ㈻࠿࠵ࡾࠊࡗࡱࡽࠉ⣌50㸚๑ᚃࢅ༥ࡴࡾ࡛ࡈࡿࠉᤴฝぞโ࡝ࢅᵋᠺࡌࡾ᳔∸ࡡ◢㓗ឺ✽⣪ࢅฺ⏕ࡌ

࡜ࡡἪⓏ࡝ᑊฌ࠿⾔ࢂࡿ࡙࠷ࡾ࠿ࠉ⌟ࡾ⬗ງࡢࠉ⣌ࡡᣚࡗὯ໩࣬⥾⾢ᶭ⬗ࢅ᫤Ⅴ࡚ࡢ㢟ⴥ࡝ຝᯕ࠿⌟ࡿࡒ࡛ࡢゕ࠷ᵋᠺࡌࡾ㔔さ࡝さ⣪࡚࠵ࡾ࡛ゕ࠻ࡾࠊ㞬࠷ࠊࡆࡡࡻ࠹࡝≟Ἓ࡞࠽࠷࡙ࡢࠉአ ࢨࢱ㢦ࡢ᪝ᮇᅗහࡡ᲻ᯐࡡୖᒒ࡞ᗀ㒂࠾ࡼ౩⤝ࡈࡿࡾ✽⣪㓗໩∸ࢅ⏍ឺ⣌ࡂฦᕱࡊࠉ᲻ᯐධమࡡࣁ࢕࢛࣏ࢪ࡞༥࠿✽⣪″࡛ࡊ࡙ྺ཭ฺ࣬⏕ࡌࡾ⬗ງࢅࡴࡾẒ⋙ࡢ௙ࡡୖᒒ⛸࡞Ẓ㍉ࡊ࡙㧏࠷ᢍᥩࡌࡾࡆ࡛ࡢࠉ᪜࡞ᤴฝࡈࡿࡒ✽⣪ሔྙ࠿ኣ࠷ࠊࡈࡼ࡞ࠉ‭₮࡝⎌ሾࢅይ㓗໩∸ࡡ⾔᪁ࢅᢍᥩࡊࠉᑊฌࡊ࡙࠷ࡂࡳࢨࢱ㢦ࡢࠉἑ⏹ᇡ࡝࡜Ề㎰࡞ኣࡂ⏍୕࡚㔔さ࡝ㄚ㢗ࡡୌࡗ࡚࠵ࡾࠊ⫩ࡊࠉ⏍ឺ⣌አ࡫Ὦฝࡌࡾ㣬ฦࢅ᭩ᚃ ᲻ᯐ࡝࡜ࡡ⮤↓ࡡ⏍ឺ⣌࠿ᣚࡗ࡛ࡈ࡞ྺ཭ฺ࣬⏕ࡌࡾ⛸࡛࡝ࡾሔྙ࠿ኣ࠷ࠊࡿࡾࠉ✽⣪㓗໩∸ࢅྱࡳኬẴỗ᯹∸㈻

ࡆࡡࡆ࡛࠾ࡼࠉࢨࢱ㢦࠿◢㓗ឺ✽⣪ࢅ࡞ᑊࡌࡾὯ໩࣬⥾⾢ᶭ⬗ࡢᅒ 1 ࡡࡻ࠹ฺ⏕ࡌࡾ⬗ງࢅᢍᥩࡌࡾࡆ࡛ࡢ⏍ឺ⣌࡝ᚘ⎌㐛⛤ࡡ୯ ഼࡚ࡂ ࠊኬẴ ࠾ࡼஜࡡᣚࡗᶭ⬗ࢅよ᪺ࡌࡾ୕࡚ࡵ㔔さ࡚࠵ࡾ࡛⩻࠻ࡼࡿࡾࠊࡊ࠾ࡊࠉࡐࡡ✽⣪ฺ⏕࡞㛭ࡌࡾ⏍⌦≁ᛮࡢ࡮࡛ࢆ࡜ᮅよ᪺࡚ࠉ✽⣪ࡡ
ྺ཭″࡛ࡊ࡙ࡡふⅤ࠾ࡼࡡ◂✪ౚࡢ࡮࡛ࢆ࡜࡝࠷ࠊᮇ◂✪࡚ࡢࠉ✽⣪㓗໩∸ྺ཭″࡛ࡊ࡙ࡡࢨࢱ㢦ࡡᙲ๪ࢅフ౮ࡌࡾࡒࡴ࡞ࠉࢨ
ࢱ㢦ࡡ✽⣪ฺ⏕࡞㛭ࡌࡾ⏍⌦≁ᛮࢅ᪺ࡼᅒ  㝛୕⏍ឺ⣌࡞࠽ࡄࡾ✽⣪ࡡᚘ⎌
-2-

50cm50cm ࡡࣈࣞࢴࢹࢅスᏽࡊࠉࡐࡡ

࠾࡞ࡌࡾࡆ࡛ࢅモࡲࡒࠊ୯࡞⏍⫩ࡌࡾᙔル⛸ࡡ಴మධ࡙ࢅᤸࡽ
2. ◂✪⤊㐛ཱིࡽࠉⴝ࣬ⴝᯮ࣬ᆀୖⱴ᰷࣬࡞ฦࡄ࡙ ᮇ◂✪࡚ࡢࢨࢱ㢦ࡡ✽⣪ฺ⏕࡞㛭ࡊஜ㔔ࢅῼᏽࡊࡒࠊ

࡙✽⣪ࡡᙟឺื࡞ㄢᰕࢅ⾔࠹ࠊ᳔∸ࡢᚪ㡪ඔ⣪ࡡୌࡗ࡚࠵ࡾ✽⣪ࢅ࢓࣓ࣤࢼ

3. ◂✪ᠺᯕ࢓ឺ✽⣪࡛◢㓗ឺ✽⣪ࡡ஦⛸ࡡᙟឺ࡚ NRA ࡢධ⯙࡞ࢗࣚࢩࣞ࡞࠽࠷࡙ࢤࢨ

ྺ཭ࡌࡾ࠿ࠉࡐࡡᚃࡡྜྷ໩㐛⛤ࡢྺ཭ࢱࡻࡽࡵ㧏࠷ലྡྷ࠿ヾࡴࡼࡿࡒ㸝ᅒ 2㸞ࠊࡈࡿࡒ✽⣪ࡡᙟឺ࡞ࡻࡽኬࡀࡂ␏࡝ࡾࠊ ࢗࣚࢩࣞ࡞ࡢ 10 ࡛᭮ 2 ᭮࡞ࠉࢤࢨࢱ࡚࢓࣓ࣤࢼ࢓ឺ✽⣪ࡢ├᥃᭯ᶭឺ✽⣪࡫

ࡢ 2 ᭮࡞㧏࠷ NRA ࠿᳠ฝࡈࡿࡒࠊ୦⛸࡛ྜྷ໩ࡈࡿࡾࡡ࡞ᑊࡊ࡙ࠉ◢㓗ឺ✽⣪࡛ࡵ࠷ࡍࡿࡡᏒ⟿࡞࠽࠷࡙ࡵⴝ࡚㧏࠷ࡢ◢㓗㑇ඔ㓕⣪➴ࡡ㓕⣪ࡡ഼ࡀ࡞ࡻࡾ

NRA ࠿᳠ฝࡈࡿࠉ◢㓗ឺ✽⣪ྜྷ໩࡞࠽ல◢㓗ឺ✽⣪ࠉࡈࡼ࡞࢓࣓ࣤࢼ࢓ឺ✽ࡄࡾⴝࡡᐞ୙࠿㧏࠷ࡆ࡛࠿♟ࡈࡿࡒࠊ⣪࡫ࡡ㑇ඔ㐛⛤ࢅ⤊ࡒᚃࠉ᭯ᶭឺ✽⣪✽⣪⃨ᗐࡢࢗࣚࢩ࡚ࣞࡢⴝ࡚≁࡞ 5 ᭮࡫࡛ྜྷ໩ࡈࡿࡾࠊࡆࡡᛮ㈻ࢅฺ⏕ࡊࠉ࡞㧏࠾ࡖࡒ࠿ࠉྜྷ᫤᭿࡞ࢤࢨࢱࡢࡱࡓᮇ◂✪࡚ࡢࠉ◢㓗㑇ඔ㓕⣪Ὡᛮ㸝NRA:ᒈⴝ࠿㉫ࡆࡖ࡙࠽ࡼࡍࠉⰾ࡚✽⣪⃨ᗐ

Nitrate Reductase Activity㸞ࢅῼᏽࡌࡾࡆ

࠿㧏࠷ᵕᏄ࠿♟ࡈࡿࡒࠊ࡛࡞ࡻࡽ⮤↓᮪௲ୖ࡞࠽ࡄࡾࢨࢱ㢦ࡡ ࢨࢱ㢦ࡡ༟నᆀ⾪㟻✒࠵ࡒࡽࡡࣁ࢕◢㓗ឺ✽⣪ฺ⏕ࡡフ౮ࢅ⾔ࡖࡒࠊ࢛࣏ࢪࢅ୕ᒒᮄࡡࣃࢿ࡛࢞Ẓ㍉ࡌࡾ࡛ࠉ ㄢᰕࡢ⌿⍀ʻ㸝⁘㈙┬㸞ࡡ༞᮶㒂࡞న⨠ࡌࡾ᱊⏍Ềᩝモ㥺ᆀ㸝34˚58’, 136˚00’㸞࡚⾔ࡖࡒࠊㄢᰕ
ᆀ࡞࠽࠷࡙᭩ࡵඁ༥ࡊ࡙࠷ࡒࢨࢱ
2 ⛸ࠉࢗࣚࢩࣞ㸝Gleichenia japonica
Spr. 㸞 ࡛ ࢤ ࢨ ࢱ 㸝 Dicranopteris
linearis (Burm. f.) Und.㸞ࢅᑊ㇗࡛ࡊ࡙⏕࠷ࡒࠊ2005 ᖳ 5 ᭮࣬8 ᭮࣬10᭮࣬2006 ᖳ 2 ᭮࡞ࡐࡿࡑࡿ 5 ಴మࢅᤸࡽཱིࡽࠉⴝ࣬ⴝᯮ࣬ᆀୖⱴ᰷࣬࡞ฦࡄ࡙ჹᏻẎࡡ NRAࠉ⥪✽⣪⃨ᗐࠉ◢㓗ឺ✽⣪⃨ᗐࢅῼᏽࡊࡒࠊࡱࡒࠉ྘ࠍࡡ⛸ࡡ⏍⫩ᐠᗐ࡛ࣁ࢕࢛࣏ࢪ࡞ࡗ࠷࡙ࡵㄢᰕࢅ⾔ࡖࡒࠊ2⛸࠿྘ࠍඁ༥ࡊ࡙࠷ࡾሔᡜ࡞

ᅒ 2 ࢗࣚࢩࣞ࣬ࢤࢨࢱࡡჹᏻẎࡡ NRA ࠽ࡻࡦ✽⣪⃨ᗐࡡᏒ⟿ን໩
-3-ࡄࡾࢨࢱ㢦ࡡᙲ๪࣬ᐞ୙ᗐࢅᏽ㔖Ⓩ࡞フ౮ࡊࡻ࠹࡛ࡌࡾ࡛ࡀࠉࣁ࢕࢛࣏ࢪ
ࡡẒ㍉࡞࠽࠷࡙ࡢ୕ᒒᮄ
ࣃࢿ࢞࡞ᑊࡊ࡙ࢨࢱ㢦ࡢ㟸ᖏ࡞ᑚࡈ࠷ࠊࡊ࠾ࡊࠉ༟నᆀ⾪㟻✒࠵ࡒࡽ࡞ಕᣚࡈࡿࡾ✽⣪⌟Ꮛ㔖ࢅẒ㍉ࡌࡾ࡛ࠉࢨࢱ㢦ࡡಕᣚࡌࡾ✽⣪㔖ࡢ୕ᒒࡡࣃࢿ
࢞ࡡ 20%⛤ᗐ࡚࠵ࡽࠉࣁ
ᅒ 3 ༟నᆀ⾪㟻✒࠵ࡒࡽࡡჹᏻẎࡡࣁ࢕࢛࣏ࢪ࣬✽⣪⌟Ꮛ㔖࣬◢㓗ឺ✽⣪⌟Ꮛ㔖㸝ࣃࢿ࢞ࡡࢸ࣭ࢰࡢ
ᮿᮟ(2004)࡞ࡻࡾ㸞ࢗࣚࢩࣞ࣬ࢤࢨ ࢱ୦⛸ ࡛ࡵࣃ ࢿ࢞ࡡ࢕࢛࣏ࢪ࡞Ẓࡊ࡙ኣ㔖ࡡ✽⣪ࢅಕᣚࡊ࡙࠷ࡾ࡛ゕ࠻ࠉࡐࡡᐞ୙ࡢ↋っ࡚ࡀ࡝࠷ࡆ࡛࠿♟ࡈࡿࡒࠊ㸪㸚⛤ᗐ࡚࠵ࡖࡒ㸝ᅒ 3㸞ࠊࡐࡿ࡞ᑊࡊ࡙༟నᆀ⾪㟻✒࠵ࡒࡽࡡ᳔∸మ୯ࡡ✽4. ௑ᚃࡡㄚ㢗࡛Ⓠᒈ

⣪㔖ࢅẒ㍉ࡌࡾ࡛ࠉ୦⛸࡛ࡵ࡞ࣃࢿ࢞ ௑ᚃࡡㄚ㢗࡛ࡊ࡙ࠉ᲻ᯐ⏍ឺ⣌හࡡࡡ 20㸚⛤ᗐ࡚࠵ࡖࡒࠊࡱࡒ༟నᆀ⾪㟻✽⣪ᚘ⎌ࠉ࠽ࡻࡦ⣌ࡡᣚࡗ࡛ࡈࡿࡾ✽✒࠵ࡒࡽࡡ◢㓗ឺ✽⣪ࡡಕᣚ㔖ࡢࠉࢤ⣪ಕᣚ࡛Ề㈻Ὧ໩ࡡᶭ⬗࡞࠽ࡄࡾࢨࢱࢨࢱ࡚ࢗࣚࢩࣞࡻࡽࡵኣࡂࠉࣃࢿ࢞ࡡ

㢦ࡡᐞ୙ࢅࡻࡽᏽ㔖Ⓩ࡞フ౮ࡌࡾࡆ࡛

ಕᣚ㔖ࡡ 10㸚⛤ᗐ࡚࠵ࡖࡒࠊ࠿࠵ࡅࡼࡿࡾࠊࡐࡡࡒࡴ࡞ࡢࠉ⣌አ࠾ ௧୕ࡡ⤎ᯕ࠾ࡼࠉࢗࣚࢩࣞ࣬ࢤࢨࢱ

ࡼࡡ✽⣪ຊථ㔖ࠉᅰቫࡡ↋ᶭឺ✽⣪⏍ࡡ 2 ⛸࠿◢㓗ឺ✽⣪ࢅ✽⣪″࡛ࡊฺ࡙ᠺ࡛ࡐࡡ⛛ິ࡝࡜ࡡ✽⣪ᚘ⎌࡞㛭ࡌࡾ⏕࡚ࡀࡾࡆ࡛ࠉࡱࡒࠉ෢Ꮢ࡞◢㓗ឺ✽ࡻࡽレ⣵࡝ࢸ࣭ࢰࠉ࠽ࡻࡦࣁ࢕࢛࣏ࢪ⣪ࢅྜྷ໩ࡊ࡙࠷ࡾࡆ࡛࠿♟ࡈࡿࡒࠊࡗࡡᏒ⟿ንິ࡞㛭ࡌࡾ▩ぜࠉࡱࡒ௙ࡡඁ

ࡱࡽࠉࡆࡿࡼ 2 ⛸ࡢ᲻ᯐ⏍ឺ⣌࠿ᣚࡗ༥⛸࡞㛭ࡌࡾ᝗ሒ࡝࡜࠿ᚪさ࡚࠵ࡾ࡛࡛ࡈࡿࡾ◢㓗ឺ✽⣪ࡡὮஷࢅ㜭ࡃᶭ⬗⩻࠻ࡼࡿࡾࠊ࡞࠽࠷࡙ୌᏽࡡᙲ๪ࢅᯕࡒࡊ࡙࠷ࡾ࡛ゕ࠻ࡾࠊ≁࡞ࠉⴘⴝᶖᯐ࡞࠽࠷࡙ࡢ෢5. Ⓠ⾪ㄵᩝࣛࢪࢹ

Ꮢ࡞ࡢ㧏ᮄᒒ࡞ࡻࡾ✽⣪ࡡྺ཭ฺ࣬⏕ᑚᒜ㔓ዄ࣬ኬᡥಘெ࣬୕⏛ᐁᕵ࣬ᚠᆀ࠿㉫ࡆࡖ࡙࠷࡝࠷࡛⩻࠻ࡼࡿࡾࡒࡴࠉ├Ꮔ㸝2006㸞ࣃࢿ࢞ᯐୖᒒ࡞⏍⫩ࡌࡾ෢Ꮢ࡞ࢨࢱ㢦࠿◢㓗ឺ✽⣪ࢅฺ⏕ࡌࡾࢦࢦ㹺ࢨࢱ㢦ࡡ◢㓗ឺ✽⣪ฺ⏕࡞㛭ࡌࡆ࡛ࡡណ⩇ࡢኬࡀ࠷ࡆ࡛࠿஢ῼࡈࡿࡾࠊ ࡾ⏍⌦≁ᛮ㸡➠ 53 ᅂ᪝ᮇ⏍ឺᏕఌኬఌ
ㅦⁿさ᪠㞗, 322, 2006ࡈࡼ࡞ࠉ᲻ᯐ⏍ឺ⣌හࡡ✽⣪ᚘ⎌࡞࠽
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