bluuebunny/crossref_metadata_2025_split huggingface dataset:
Auxin overproducer mutants of Hebeloma cylindrosporum Romagnesi have increased mycorrhizal activity
Authors: GAY G. , NORMAND L. , MARMEISSE R. , SOTTA B. , DEBAUD J. C. 
Published: April 2006

summaryThe ectomycorrhizal activity (expressed as the number of mycorrhizas per plant) of indole‐3‐acetic acid (IAA) overproducer mutants of Hebeloma cylindruspurum Rumagnesi and of their mono‐ and dikaryotic progenies has been studied in an attempt to clarify the role of fungal IAA in the establishment of ectomycorrhizal symbiosis, The original mutants obtained from the hi monokaryon produced a higher number of mycorrhizas than did the wild type. The study of the mycorrhizal activity of synthesized dikaryons heterozygous for the FIR (fluoroindoleresistant) mutations, which are responsible for IAA overproduction, showed that these mutations are recessive.The vitro fruiting of a dikaryon heterozygous for a FIR mutation allowed the isolation of IAA‐overproducing sib‐monokaryons. Their average mycorrhizal activity was higher than that of non‐overproducers. indicating that, although the mycorrhizal activity of sib‐monokaryons is under polygenic control, high IAA production gives an advantage in mycorrhiza formation. This was confirmed by the higher number of mycorrhizas formed by synthesized dikaryons homozygous for a FIR mutation than by wild type mycelia.The mycorrhizas formed by the mono‐ or dikaryotic wild types were characterized by a uniseriate Hartig net, whereas it was pluriseriate in the case of mycorrhizas formed by IAA overproducer mutants. The mutants stimulated the growth of the host plants to the same extent as did the wild types, indicating that growth stimulation is not a direct consequence of fungal auxin production. The usefulness of these mutants as a model to study the role of fungal IAA in mycorrhiza formation is discussed.
Influence of parental NaCl treatment on salinity tolerance of offspring in Sorghum bicolor (L.) Moench
Authors: AMZALLAG G. N. 
Published: April 2006

summaryAdaptation and resistance responses to NaCl salinity Have been expressed in Sorghum bicolor (L.) Moench (genotype MP610) by exposure to 150 mol m−3 NaCl respectively 8 of 21 d after germination. Offspring of the adapted or the resistant plants (respectively named Al and Rl) were compared with offspring of control plants (Cl). Eighteen days after germination in presence nr absence of 75 mol m−3 NaCl, the Al plants showed a large increase in vigour, and a reduction in Na+ accumulation into the shoot, compared with the Cl plants. The Rl plants were widely heterogeneous and presented intermediate characteristics between the Al and Cl plants. When first exposed to salinity 21 d after germination, the AI plants showed a significant increase in salinity tolerance, when compared with Cl plants. Conversely, the Rl plants remained very similar to the Cl plants after late exposure to salinity. These results indicate that the exposure of Sorghum plants to salinity induced an increase in vigour in the progeny. Moreover, an enhanced salinity‐tolerance is specifically observed for offspring of adapted plants, suggesting that this property is not a simple consequence of parents grown in a saline environment. The possible nature of the observed effects on offspring is discussed.
The effectiveness of ectomycorrhizal fungi in increasing the growth of Eucalyptus globulus Labill. in relation to root colonization and hyphal development in soil
Authors: THOMSON B. D. , GROVE T. S. , MALAJCZUK N. , HARDY G.E. St J. 
Published: April 2006

SUMMARYForty‐seven different isolates of ectomycorrhizal fungi, from the different genera, were screened for their effectiveness in increasing the growth of Eucalyptus globulin La hi 11. where supply of P is deficient. Plants were grown in a P‐delicient sand, in pots, in a temperature‐ control led glasshouse. Seedlings we re harvested 6‐S and K7 d after planting, and were assessed for dry matter production and mywirrhizal colonization. Selected treatments were also assessed for P concentrations in the plant and hyphal development in the soil.Dry weights of inoculated plants ranged from 50 to 350% of the dry Weights of uninoculated plants. Growth increases in response to ectorriycorrhizal inoculation corresponded with increased P uptake by the plant.‘Early’colonizing fungal species (Descolea maculata, Hebeloma westraliens, Laccaria laccata and Pisolithus tinctorius) were generally more effective in increasing plant growth than‘late’colonizing species (Cortinarius spp. and Hyutenmgium spp.), although there was also variation in effectiveness among isolates of the same fungal species. Plant dry weights were positively correlated (r2= 0·79‐0·84) with the length of colonized root, indicating that fungi which colonized roots extensively were The most effective in increasing plant growth. For some fungi, however, plant growth responses to inoculation were not related to colonized root length. These responses could not.be related to the development of hyphae in soil by the mycorrhizal fungi.
Fructan synthesis in oat
Authors: LIVINGSTON DAVID P. , KNIEVEL DANIEL P. , GILDOW FREDRICK E. 
Published: April 2006

SUMMARYThe accumulation of fructan oligomers in cold hardened oat stems was compared to oligomer synthesis in a crude enzyme extract. Water‐soluble carbohydrates were quantified at specified time intervals in three oat cultivars which had been hardened for a total of 5 wk at 2 °C. A crude enzyme extract was prepared from stems of one cultivar hardened for 6 d at 2 °C and incubated at 30 °C with 200 mM sucrose. 1‐Kestose was the first oligomer to accumulate in vitro but neokestose rapidly increased after 3 h of incubation and eventually surpassed the level of 1 ‐kestose. Neokestose and 1‐kestose accumulated at similar rates in vivo in the first week of hardening but after 1 week, 1‐kestose began to decrease while neokestose remained relatively constant. The same phenomenon was observed in vitro but after only 3 h. 6‐Kestose was not observed in vivo or in vitro, except for a trace before hardening began. The first tetramer to increase was 1&6G‐kestotetraose but it subsequently decreased and its concentration was surpassed by that of 6G,6‐kestotetraose. Similarities and differences between in vivo and in vitro patterns of fructan synthesis are discussed.
Identification of glycoproteins specific to biotrophic intracellular hyphae formed in the Colletotrichum lindemuthianum‐bean interaction
Authors: PAIN NAOMI A. , O'CONNELL RICHARD J. , MENDGEN KURT , GREEN JONATHAN R. 
Published: April 2006

SUMMARYMonoclonal antibodies (MAbs) specific for intracellular for hyphae (IH, i.e. infection vesicles and primary hyphae). Appressoria/germ tubes and conidia of Colletotrichum lindemuthianum (Sace, & Magn.) Briosi & Cav. isolated from infected leaves of Phaseolus vulgoria L. were obtained using a co‐immunization procedure. One of the MAhs; UB25, bound specifically to IH in immunofluorescence immunogold and Western blot assays: it showed no affinity for conidia, conidial germ tubes, appressoria or appressorial germ tubes growing in vitro, of for any plant components. Immunogold labeling of infected tissue prepared by high pressure freezing, freeze‐substitution and low temperature embedding showed that the UB25 antigen was present in the interfacial matri surrounding IH and in the fungal wall. The antigen was confined to infection vesicles and primary hyphae in contact with host protoplast and could not be detected in primary hyphae growing in intercellular spaces. UB25 recognizes a protein epitope present in a set of N‐linked glycoproteins. These glycoproteins are expressed at an early stage of intracellular development, suggesting a possible role in biotrophy or recognition.
Purification and characterization of fructans with β‐2, 1‐ and β‐2, 6‐glycosidic linkages suitable for enzyme studies
Authors: BONNETT G. D. , SIMS I. M. , ST. JOHN J. A. , SIMPSON R. J. 
Published: April 2006

SUMMARYFructan pentasaccharides were purified, in quantities suitable for use as substrates for enzyme assays, from Neosugar‐p‐(Meijj Seika Kaisha Ltd. Japan), tubers of Helianthus tuberosus L., L., and stems and leaf sheaths of Triticum aestivum L by a combination of gel‐filtration and RP‐HPLC. Fructan of higher molecular mass (mean DP = 30) was purified from Leaves of Lolium rigidum Gaud, that had been induced to accumulate fructan and characterized along; with the commercially available fructan from Cichorium intybus L. (Sigma, St Louis, USA) (mean DP = 33). The fructan pentasaccharide purified from H. tuberosus was found to contain exclusively 2, 1‐linked fructose and terminal fructose and terminal glucose, and was identified as (1, 1, 1)‐kestopentatise. The fructan pentasaccharide purified from Neosugar‐P also contained (1,1,1)‐kestopentaose. although the presence of fructan Klinked glucose and 1 % 2, 6‐linked fructose indicated that a small proportion of other kestopentaoses were present, The fructan pentasaccharide purified from T aestivum consisted of almost exclusively 2,6‐linked fructose and terminal glucose and terminal fructose and was considered to contain predominantly (6,6,6)‐kestopentaose. The presence of 1 % 2,1,6)‐linked fructose indicated the sample also contained a small proportion of branched kestopentanse. The high molecular mass fructan from C. intybus was found to comprise linear molecules containing only 2,1‐linked fructose, terminal glucose and terminal fructose‐ High molecular mass fructan from L. rigidum contained predominantly 2. h‐linked fructose, had predominantly internal glucose, indicated by 2 %, 1.6‐linked glucose, low levels of branching, indicated 2 % 2,1,6‐linked fructose residues; and 1% of the residues were 2,1 ‐linked fructose.
Stimulation by auxin and sucrose of bulbil formation in vitro by single leaf cultures of Narcissus
Authors: STAIKIDOU I. , SELBY C. , ARVEY B. M. R. 
Published: April 2006

SUMMARYBulbil formation in vitro by single leaf explains from shoot clump cultures was investigated for Narcissus cultivars St Keverne and Havera. Single leaf explants (30–50 mm leaf with attached basal plate tissue) formed bulbils very infrequently unless cultured on media containing both auxin and a high concentration of sucrose whereas auxin was not necessary for bulbil formation by shoot dump cultures. As well as showing much stronger stimulation by auxin, bulbil initiation and development were more strongly inhibited In BA in single leaf cultures than in shoot dump cultures. Partitioning of dry matter into bulbils was generally lower in single lent cultures than in shoot clump cultures but was more sensitive to growth regulators.Optimal sucrose and auxin concentrations for bulbil development by single leaf cultures were investigated. Bulbil formation in the presence of NAA was strongly stimulated by 176 mM sucrose for both cultivars but there were genotypie differences in auxin responses, St Keverne showing good bulbil development with 0.54 μM NAA, 5.4 μ 1AA and 5.4 μM 1BA und Hawera responding only to 27 μM LAA.It is concluded that single leaf cultures could provide a simple system for investigation of the regulation of the regulation of Narcissus bulb initiation and development.
Influence of episodes of summer O3 on δ5and δ9 fatty acids in autumnal lipids of Norway spruce [Picea abies (L.) Karst]
Authors: WELLBLRN ALAN R. , ROBINSON DEBORAH C. , THOMSON ALAN , LEITH IAN D. 
Published: April 2006

SUMMARYCurrent year needles from 5 yr‐old Norway spruce trees, which had been exposed to either episodes of atmospheric O3, or periodic mistings with simulated acid rainwater throughout three summer periods, were‐analyzed for changes in molar percentages and ratios of fatty acids isolated from different lipids at the time of maximum winter hardening. No significant changes due to acidic misting were detected but significant decreases in the degree of unsaturation off both C 16 and C18, fatty acids, the molar percentage of δ5,9,12,15, and the molar ratio δ5,918: 2 to δ9,1218:2 in monogalactosyl diglyceride (MGDG) due to summer 03 exposures were found. Molar percentages and ratios of fatty acids did not change much in other lipids bur these changes in plastidie MGDG could be traced to a significant effect of summer O3 on the δ4‐ and δ12 ‐desaturases acting upon phosphatidyl choline (PC) in the endoplasmic reticulum. The replacement of the δ6‐subset of C18 fatty acids by an equivalent δ5‐series throughout was confirmed by Gas chromatography and mass spectrometry Molecular modelling also showed that the δ5 forms, which resembled the δ5‐isomers, are very different in shape to the δ5‐series and this may account, in part, for the extremely low winter temperatures from which Norway spruce needles may recover.
Fructan biosynthesis in excised leaves of Lolium temulentum L.
Authors: CAIRNS ANDREW J. , ASHTON JENNIFER E. 
Published: April 2006

SUMMARYA crude enzyme preparation from excised illuminated leaves of Lolium temulentum L. catalyzed the de novo synthesis of fructan of apparent degree of polymerization 3–20.In the absence of sucrose, the fructan synthetic activity (FSA) was labile at temperatures above 10 °C, but could be stored at 5 °C for 6 h with the loss of only 20% of the initial activity. Sucrose stabilized the FSA such that high rates of fructan synthesis continued for at least 6 h at 30 °C. By comparison, in the absence of sucrose 80% of the FSA was lost in 2 h at 30 °C.The FSA was maximal at pH 6·0 in citrate‐phosphate buffer and at 43 °C. It was not possible to saturate the FSA even at 1500 mol m−3 sucrose, or to calculate meaningful kinetic parameters for enzymatic fructan synthesis. 150 mill m−3 sucrose was the highest substrate concentration practically feasible and imposed an arbitrary maximum concentration for use in enzyme assays. Pyridoxal‐hydrochloride was found to reduce invertase activity by 40%, but also inhibited FSA by 20% at 1500 mol −3 sucrose and pH 6.0.
Flow cytometric probing of chromatin condensation in maize diploid nuclei
Authors: BIRADAR D. P. , RAYBURN A. LANE 
Published: April 2006

SUMMARYNuclei were isolated from stems, mesocotyls, nodal roots and root tips of two maize hybrids. The fluorochrome, propidium iodide (PI), was used to stain the nuclei that were passed through a flow cytometer‐cell sorter. Significant differences in fluorescence intensities were observed among the diploid nuclei from the different plant organs. These observations, in conjunction with previously reported DAPI fluorescence data, reflect the state of chromatin condensation in diploid nuclei isolated from meristematic and differentiating tissues. Nuclei from root meristematic tissues showed no or very little chromatin condensation. Mesocotyls and nodal roots, 1‐wk‐old, appeared to contain chromatin in a more diffuse state owing to completed differentiation which allows more DNA to be accessible to PI. Mesocotyls, 2‐wk‐old owing to senescence, contained degraded chromatin in which DNA was more accessible to PI because it lacked associated proteins. The diploid nuclei from stems had the highest amount of chromatin condensation. The results show the usefulness of flow cytometry for analyzing chromatin condensation in plant nuclei. The study also shows the importance of selecting a particular type of fluorochrome in the analysis of nuclear chromatin.
Ultrastructure of the endophyte and localization of nifH transcripts in root nodules of Coriaria nepalensis Wall, by in situ hybridization
Authors: MIRZA M. SAJJAD , PAWLOWSKI K. , HAFEEZ F. Y. , CHAUDHARY A. H. , AKKERMANS A. D. L. 
Published: April 2006

SUMMARYStudies on the root nodules of Coriaria nepalensis Wall. using light and electron microscopy revealed that infected cortical cells are enlarged and form a compact kidney‐shaped region with an acentric stele. Within a single cell, the actinomycetous endophyte has branched hyphae and elongate vesicles. Hyphae penetrate the host cell wall in different directions. Inside the host ceil, the hyphae are located in the peripheral region of the cytoplasm near the host cell whilst the vesicles are positioned towards the centre of the cell around the central vacuole. No septa formation was observed in the microsymbiont vesicles. Host cell mitochondria were aggregated near the hyphal/vesicular junction of the endophyte. In situ hybridization studies demonstrated that the nifH transcripts are unequally distributed over the infected cortical cells. In infected cells, nifH mRNA was located in the region occupied by the elongate vesicles of the endophyte near the host cell central vacuole. The results indicate that the elongate vesicles of the nodule endophyte of C. nepalensis are functionally identical to the spherical vesicles of the nodule endophyte of Alnus.
A palaeobotanical study of paludifying pine forest on the island of Hailuoto, northern Finland
Authors: HULME P. D. 
Published: April 2006

SUMMARYSoil profile, macrofossil and pollen analysis investigations were carried out at two sites within paludifying pint forest to determine the vegetation succession and paludification history of the area. Isostatic uplift raised the area above sea level less than 500 y ago. Before the land emerged from the sea, Phragmites and Schoenoplectus beds grew in shallow water close to the shore. As the area emerged, shore meadows dominated by grasses, sedges and forbs became established and were in turn replaced by alder woods. Mixed birth and alder woods then developed and the formation of an organic layer started with the accumulation of humus. Birch then largely replaced alder but both were superseded by pine forest about 50 y before the start of the investigation. After pine forest establishment, Sphagnum invaded, peat accumulation started and paludification was under way. Soil waterlogging necessary for paludification to proceed was a result of a low hydraulic head and shallow hydraulic gradient between the study area and the sea. The vegetation succession is comparable with contemporary succession around the present coastline of Hailuoto and on other Finnish islands. Paludification of the area was an autogenic process; no anthropogenic influences were detected. The relevance of this to the origin of blanket mire in Britain during prehistoric times is discussed. It is suggested that more evidence is required to clarify the roles of forest clearance and climate in the inception of blanket mire in Britain.
Salt tolerance and ion relations of Salsola kali L.: differences between ssp. tragus (L.) Nyman and ssp. ruthenica (Iljin) Soó
Authors: REIMANN CHRISTINE , BRECKLE SIEGMAR‐W. 
Published: April 2006

summaryThe effect of increasing salt concentrations (up to 200 mmol l−1 Cl−1 on growth, succulence and mineral composition has been studied in some accessions of Saltola kali L. ssp. tragus (L.) Nyman and ssp. ruthenica (Iljin) Soó Differences between accessions corresponded to the taxonomic distinction of subspecies. Dry weight was increased by 50 mmol l−1 NaCl in ssp. tragus, but not in ssp. ruthenica. Rising salinity increased shoot water content in both subspecies, but ssp. tragus was more succulent than ssp. ruthenica. ssp. tragus potassium content decreased after NaCl treatment, and the accumulation of sodium was significantly higher than in ssp. ruthenica. Chloride content and total cation concentration were similar in all accessions. The results indicate a positive correlation between salt tolerance, succulence and low K/Na‐ratios in leaves.
Physical injury, re‐crystallization of wax tubes and artefacts: identifying some causes of structural alteration to spruce needle wax
Authors: BERMADINGER‐STABENTHEINER EDITH 
Published: April 2006

summaryThe study presents investigations of epicuticular wax morphology on spruce needles (Picea abies (L.) Karst.) performed by ambient temperature scanning electron microscopy. To use alterations to epicuticular wax morphology as a successful tool in forest damage research, it is necessary to distinguish environmental influences and artefacts from common pollution effects, The present paper summarizes observations of alterations to epicuticular waxes independent of pollution effects, recorded in various field studies. These observations are supplemented by controlled experiments to investigate wax alterations owing to solvents and mechanical injury. Fissures in the antechamber wax were the result of needle shrinkage during drying. Wax alterations, where only the antechamber wax was affected by a continuous loss of the structural integrity of wax tubes, were classified as storage artefacts since they occurred exclusively on needles stored in air‐tight glass vials and were unrelated to needle age, sampling site or pollution influence. Such wax alterations were never observed in needles stored in air‐permeable paper bags. Mechanical injury also resulted in severe morphological alterations to epicuticular wax structures. The wax tubes on the surface as well as in the antechamber were squashed and flattened. On smoothed and squashed wax layers a significant regrowth of wax tubes was occasionally observed, unrelated to needle age. Though the tubular form of the re‐crystallized waxes was similar to those originally present on the surface, the tube diameters were much wider. Since redeveloped wax tubes also occurred on dead needles which had been artificially injured, this process could be classified as re‐crystallization analogous to wax re‐crystallization out of solvent extracts. The re‐crystallization took place within 48 h after the mechanical injury occurred. The implications of the reported wax alterations for a successful use of epicuticular wax morphology as a bioindicator are discussed.
Plant growth and cell division in Pisum sativum L. and Picea sitchensis (Bong.) Carr. exposed to ozone
Authors: BAMBRIDGE LORRAINE , MACLEOD RONALD , HARMER RALPH 
Published: April 2006

summaryPea (Pisum sativum L. cv. Feltham First) and clonal Sitka spruce plants (Picea sitchensis (Bong.) Carr.) were exposed to ozone concentrations of 0–90 ppb to investigate effects on both shoot and root growth and also cell division in the apical mm of roots. P. sativum plants were maintained under these conditions for 3 wk whilst P. sitchensis were left for 3 months. After 3 wk in the presence of 90 ppb ozone the mitotic index in the root apical mm of P. sativum was reduced compared with control plants (0 ppb ozone), whereas the number of primordia along the length of the main root in P. sativum plants increased at 90 ppb ozone. The smallest concentration of ozone (30 ppb) had no effect on leaf area, shoot dry weight and number of leaves of P. sativum. However, the number of second order lateral roots and total root dry weight were reduced at concentrations of 60 ppb and above while leaf size, plant height and shoot dry weight were only reduced in the presence of 90 ppb ozone. Cell doubling time in the root apical mm of P. sitchensis increased in plants which had been grown in the presence of 30 ppb ozone and decreased in those plants grown in chambers containing 90 ppb ozone. Ozone did not appear to have any other effects on those aspects of the cell cycle examined in either P. sativum or P. sitchensis.