bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECT OF GROWTH REGULATORS ON THE IN VITRO GERMINATION AND TUBE GROWTH OF MAIZE (ZEA MA YS L.) POLLEN FROM PLANTS RAISED UNDER SODIUM CHLORIDE SALINITY
Authors: DHINGRA H. R. , VARGHESE T. M. 
Published: May 2006

SummaryPollen grains, collected from maize plants raised under conditions of 0, 80, 120 and 160 meq l−1 salinity, were used to investigate the effect of various growth regulators on in vitro germination and tube growth. Indole‐3‐acetic acid had no effect on germination, irrespective of the source of pollen, whether derived from plants grown under saline or non saline conditions. However, its lower concentrations enhanced tube growth in pollen from salinized plants. Gibberellic acid at a concentration of 1 mg l−1 antagonized the depressive effects of 120 meq l−1 salinity on pollen germination. It stimulated tube growth of pollen from saline, as well as, non‐saline plants. However, pollen from salinized plants required a higher concentration of gibberellic acid. Benzylaminopurine ameliorated inhibitory effects of NaCl salinity both on germination and tube growth of pollen. Abscisic acid inhibited germination to a greater extent in pollen from nonsaline than saline plants; but stimulated tube growth in all cases. The present investigation suggests that pollen from salinized plants responds more to growth regulators than those from non‐salimzed plants.
ENZYMES OF AMMONIUM ASSIMILATION IN THE MYCORRHIZAL FUNGUS PEZIZELLA ERICAE READ
Authors: JOHN B. J. ST. , SMITH S. E. , NICHOLAS D. J. D. , SMITH F. A. 
Published: May 2006

SummaryGrowth of Pezizella ericae Read in solution culture with ammonium (NH4+) as the primary nitrogen source was accompanied by decrease in pH and ammonium concentration. Both glutamate dehydrogenase (GDH) and glutamine synthetase (GS) were involved in ammonium assimilation. Activities of these enzymes changed during the time course of the experiment (28 d). Maximum GDH activity [0.35 μol NAD(P)H oxidized min−1 mg protein−1] occurred when external NH4+ concentration was high (5 to 10 mM). Maximum GS activity (0.2 μol of γ‐glutamyl hydroxamate min−1 mg protein1) occurred when external NH4+ concentration was low (1 mM). L‐Methionine DL sulphoximine (MSX), a specific inhibitor of GS, inhibited uptake of 15NH4Cl in 13‐d‐old mycelium of P. ericae.The nitrogen nutrition of the fungus and the host in the soil environment is discussed.
INTERACTION OF SUBSTRATE C:N RATIO AND OSMOTIC POTENTIAL ON GROWTH AND OSMOREGULATION OF FOUR FILAMENTOUS FUNGI
Authors: LUARD ELIZABETH J. 
Published: May 2006

SummaryVariation in the carbon to nitrogen ratio in the range 10:1 to 1000:1 had only a small effect on the radial growth rate of four species of fungus on a basic nutrient agar medium. There was no obvious pattern to the differences observed, whether the nitrogen source was organic or inorganic or the medium osmotic potential high or low. The final fresh weight of the colonies was more sensitive to C: N ratio and was depressed by high C: N ratios by as much as 90 % in some treatments. Polyporus versicolor L. ex Fr. was the most efficient accumulator of biomass at C: N of 1000:1, but Penicillium chrysogenum Thorn had the highest mycelial N content. Colony yield did not show the same relationship to external osmotic potential as did the radial growth rate, and the ratio at which the maximum yield at each osmotic potential occurred varied with the different treatments.Turgor potential was reduced by high C:N in the majority of treatments in Polyporus versicolor, Poria vincta (Berk.) Cke. and Phytophthora cinnamomi Rands but not at all in Penicillium chrysogenum. Water content increased with the C: N ratio and decreased with external osmotic potential in all the species except Phytophthora cinnamomi. There was no clear effect of C:N ratio on any of the hyphal solutes measured, that is Na+, K+, Cl−, proline or glycerol. Lower concentrations of the organic solutes were present in Phytophthora cinnamomi and Penicillium chrysogenum in these conditions than when KCl and Czapek‐Dox with yeast extract medium was used; turgor potential of Penicillium chrysogenum also was 50% lower. Sodium chloride was used to adjust the external osmotic potential and Na+ and Cl− were taken up in increasing amounts as the osmotic potential decreased in all species. Potassium concentrations were similar between species and treatments. The hyphal osmotic potentials, calculated from these solutes alone, were lower (more negative) than the values measured in Poria vincta grown at –1 MPa and Penicillium chrysogenum grown at – 10MPa, but very close to those for Phytophthora cinnamomi grown at – 2.5 MPa.
FUNGAL POPULATION AND COMMUNITY DEVELOPMENT IN CUT BEECH LOGS
Authors: COATES D. , RAYNER A. D. M. 
Published: May 2006

SummaryPatterns of fungal colonization from the base of cut beech logs placed upright and partly buried in the ground at a mixed deciduous woodland site were fundamentally different from those from the aerial cut surface.Principal colonists resulting in decay, and mostly arriving within three months, were the ascomycete Xylaria hypoxylon (L. ex Hooker) Greville and various rhizomorph/mycelial cord‐forming basidiomycetes, including Armillaria bulbosa (Barla) Kile & Watling, Phallus impudicus (L.) Pers., Phanerochaete velutina (DC ex Pers.) Parmasto and Tricholomopsis platyphylla (Pers. ex Fr.) Sing. Apart from A. bulbosa, these generally readily formed mycelial mats on the basal surface, between which somatic incompatibility reactions were often observed. Most frequent reactions occurred with X. hypoxylon which almost invariably produced numerous individuals in discrete decay columns. By contrast, lack of somatic incompatibility reactions between isolates of A. bulbosa indicated that a single extensive mycelial type occurred throughout the site. The occurrence of somatic incompatibility between isolates off. velutina from different logs indicated independent establishment, presumably via basidiospores, and this was consistent with the unusually late arrival of this species at the site. In no cases were numerous somatically incompatible individuals isolated from small volumes of wood lacking demarcation into discrete columns, as had been observed near the aerial cut surface.Vertical penetration from the base was more rapid than from the aerial cut surface, with X. hypoxylon a major pioneer species, and there was no pronounced lag phase.
THE METABOLISM AND PHYSICAL STATE OF POLYPHOSPHATES IN ECTOMYCORRHIZAL FUNGI. A31P NUCLEAR MAGNETIC RESONANCE STUDY
Authors: MARTIN F. , MARCHAL J.‐P. , TIMINSKA A. , CANET D. 
Published: May 2006

SummaryPhosphorus‐31 nuclear magnetic resonance spectroscopy was used to estimate the levels of polyphosphates and to probe their intracellular environment in the ectomycorrhizal fungi Cenococcum graniforme Ferd. & Wing, and Hebeloma crustuliniforme (Bull.) Quel. Polyphosphate content was a function of the growth phase and nitrogen content in the medium, lowest in rapidly growing mycelia, highest in older and N‐starved cultures. During phosphorus depletion the polyphosphate store was mobilized; degradation of the polymer was rapid in H. crustuliniforme, whereas it was slower in C. graniforme. This difference between the two fungi might be related to differences in the intracellular physical state of polyphosphates.Measurements of nuclear magnetic relaxation parameters, such as resonance line widths and spin‐lattice relaxation times, T1, have been carried out in model systems and in intact mycelia with the aim of characterizing the physical state of polyphosphates. The intracellular T1 of inner P of polyphosphates was dramatically shorter than that in the culture medium. Polyphosphate relaxation may result from a combination of partial immobilization of the polymer by cellular components and interaction with paramagnetic ions.On the basis of these data, it is suggested that polyphosphates exist in ectomycorrhizal fungi as aggregates with reduced correlation time. A more fluid state of polyphosphates in H. crustuliniforme than in C. graniforme might allow their rapid degradation by polyphosphates.
GROWTH AND MINERAL NUTRIENT STATUS IN PEANUT AND SORGHUM IN RESPONSE TO ACID PRECIPITATION AND ALUMINIUM
Authors: OWNBY JAMES D. , DEES LYNDON 
Published: May 2006

SummaryThe potential effects of acid rain on the availability of soil nutrients were examined by growing sorghum and peanut seedlings in a loamy sand/perlite mixture such that nutrient availability limited growth. Seedlings were watered with simulated acid precipitation at pH 5.5 (control), 4.5, 3.5, and 2.5 for 28 or 31 d. There was a significant increase in growth rate and plant dry weight for seedlings exposed to subambient (pH 2.5) watering regimes containing both SO42− and NO3− (6:1, mol/mol). When NO3− was omitted there was no enhancement of shoot growth, and root growth was approximately 50% of that in the control (pH 55) seedlings.Peanut and sorghum seedlings were also grown in soil amended with AlCl3 to simulate conditions where acid precipitation depresses soil pH to the Al neutralization range. Under these conditions there was a complete cessation of growth which was attributed primarily to inhibition of uptake and translocation of Ca rather than accumulation of Al in plant tissues.These experiments indicate that input of N but not S from acid precipitation may potentially benefit crop plants and forage grasses growing under low nutrient availability. Al mobilization in acidified soils may affect plant growth through the induction of Ca deficiency.
SEED MANGANESE CONTENT AND ITS RELATIONSHIP WITH THE GROWTH CHARACTERISTICS OF WHEAT CULTIVARS
Authors: SINGH DINESH KUMAR , BHARTI SUDHAKAR 
Published: May 2006

SummaryDry seeds of wheat (Triticum aestivum L.) subjected to electron spin resonance (ESR) spectroscopy show a characteristic sextet of Mn2+. Perchloric acid extracts of seeds also show a resolved hyperfine sextet of Mn2+. The Mna+ content of seeds show a direct linear relationship with the height of the wheat cultivars. The Mn2+ content of the seeds may be taken as a parameter to determine the height of the mature plant.
IMPROVED HYPHAL GROWTH OF TWO SPECIES OF VESICULAR‐ARBUSCULAR MYCORRHIZAL FUNGI IN THE PRESENCE OF SUSPENSION‐CULTURED PLANT CELLS
Authors: CARR G. R. , HINKLEY M. A. , LE TACON F. , HEPPER C. M. , JONES M. G. K. , THOMAS E. 
Published: May 2006

SummaryConditions required for the combined culture of either Glomus caledonium (Nicol. &Gerd.) Trappe &Gerdemann or Glomus mosseae (Nicol. &Gerd.) Gerdemann &Trappe with suspension‐cultured plant cells have been investigated. Sucrose levels (0.05 to 0.5%, w/v) lower than those used for growth of plant cells were optimal for hyphal growth of both G. caledonium and G. mosseae. In vitro hyphal growth from chlamydospores of G. caledonium was stimulated by addition of cells of wheat (Triticum aestivum L. cv. Maris Butler), lucerne (Medicago sativa L. cv. Europ) and potato (Solanum tuberosum L. cv. Maris Piper). The presence of wheat cells similarly stimulated hyphal growth from chlamydospores of G. mosseae. Further tests on the effect of lucerne cells on G. caledonium indicated that a volatile substance was involved in the improvement of hyphal growth.
THE EFFECTS OF SOIL TEMPERATURE ON PLANT GROWTH, NODULATION AND NITROGEN FIXATION IN CASUARINA CUNNINGHAMIANA MIQ.
Authors: REDDELL PAUL , BOWEN G. D. , ROBSON A. D. 
Published: May 2006

SummaryThe effects of soil temperatures between 15 and 30°C on plant growth, nodulation and nitrogen fixation in seedlings of Casuarina cunninghamiana Miq. inoculated with Frankia from two different sources were examined. The optimum soil temperature for the growth of plants dependent on symbiotic nitrogen fixation was 25°C. Decreasing the soil temperature below 25°C markedly decreased plant growth that was reliant on symbiotically fixed nitrogen; effects on the growth of plants supplied with mineral nitrogen were much smaller. At 15°C there was no response in plant growth to inoculation after 148 d, whereas plants supplied with nitrogenous fertilizer were 10 times the weight of uninoculated plants.Nodulation was delayed at 15 and 20°C with nodules formed at 15°C fixing no nitrogen in these studies. The production of fewer nodules at 20°C than at 25°C was partly compensated by the production of larger nodules. Nodule growth at 20 to 30°C was a prime determinant of nitrogen fixed, with the exception of one Frankia at 20°C.The amount of nitrogen‐fixed g−1 nodule was the same for the two Frankia sources at 25 and 30°C, differences in effectiveness being due to nodule development. However, differences in the effectiveness of the two Frankia sources at 20°C were related to differences both in nodule development and in nitrogen‐fixing ability.The absence of nitrogen fixation at 15°C would be expected to limit the natural distribution of Casuarina species reliant on symbiotically fixed nitrogen to areas where soil temperatures exceed 15°C for a major part of the potential growing season.
THE BIOLOGY OF MYCORRHIZA IN THE RICACEAE
Authors: BAJWA R. , READ D. J. 
Published: May 2006

SummaryThe ericoid mycorrhizal endophyte Hymenoscyphus ericae (Read) Korf &Kernan was grown both in pure culture and in mycorrhizal association with the host plant Vaccinium corymbosum L. on media containing peptides of differing chain length as sole nitrogen sources. The ability to utilize the peptide nitrogen was assessed in terms of growth of the fungus and of growth and nitrogen content of the plants.The tripeptide, glutathione, and alanine units of 1–6 amino acid residues in length were all readily utilized by the endophyte, though assimilation was less rapid in the case of the longer chain lengths. Mycorrhizal seedlings showed significantly higher yields and had higher nitrogen contents than non‐mycorrhizal seedlings in almost all cases.The physiological and ecological implications of these results are discussed.
THE BIOLOGY OF MYCORRHIZA IN THE ERICACEAE
Authors: BAJWA R. , ABUARGHUB S. , READ D. J. 
Published: May 2006

SummaryThe ability of the ericoid mycorrhizal endophyte to utilize a range of proteins as substrates for growth is assessed in liquid culture and in mycorrhizal association with host plants. Some aspects of proteolytic enzyme production are also investigated.The fungus readily utilizes the soluble protein bovine serum albumin (BSA) as sole nitrogen and carbon source, and produces lower yields on less soluble plant and animal proteins. Maximum yields of endophyte on all substrates were obtained in the pH range 3 to 5. Infection provides a significant enhancement of plant growth on agar over this pH range on most of the proteins. Yields and nitrogen contents of mycorrhizal plants grown on cellulose sheets with BSA as sole N source were significantly higher than those of the uninfected controls, which were unable to use protein.Using a chromogenic substrate it was shown that the pH optimum for enzyme activity is comparable with that for utilization of protein in pure culture and in mycorrhizal association. Non‐mycorrhizal plants produced negligible proteolytic activity.The significance of these observations is discussed in relation to the nutrition of both host and fungus in the natural environment, and the broader ecological implications of the results are assessed.
PHOTOSENSITIVITY OF HYPOCOTYL HOOK OF CAESIUM‐TREATED TOMATO SEEDLINGS
Authors: KORDAN H. A. 
Published: May 2006

SummaryHypocotyls of etiolated caesium‐treated tomato seedlings were morphologically similar to, but shorter than, those of the etiolated water control seedlings. Chlorophyll development became manifest in the cotyledons of both the caesium‐treated and control seedlings when exposed to white or red light but brown discolouration, reduction in diameter, and subsequent deterioration of the hypocotyl hook were evident in the caesium‐treated seedlings exposed to white or red light. It is suggested that the hypocotyl hook is the primary site of caesium‐induced photosensitivity of tomato seedlings.
CHROMOPLASTS IN SOME CYCADS
Authors: WHATLEY J. M. 
Published: May 2006

SummaryThe ripe seeds of some species of cycads are red in colour and contain chromoplasts: those in seeds of Cycas revoluta Thurb. and Macrozamia lucida L. A. S. Johnson belong to the tubulous class of chromoplast whereas those of Zamia purpurea sp.nov. contain large globules, some packed thylakoids linked by electron‐dense bridges, and other unusual structures. The Zamia plastids do not fall clearly into any of the generally recognized chromoplast categories. Some features of the chromoplasts of cycads closely resemble those found in angiosperms; other features appear more typical of plastids in lower plants.
LOCALIZATION OF AMYLOSE AND AN AMYLOSE‐BINDING LIPOPROTEIN IN NEUROSPORA CRASSA HYPHAE BY CYTOCHEMISTRY AND IMMUNOELECTRON MICROSCOPY
Authors: VARKEY JACOB P. , NADAKAVUKAREN MATHEW J. , McCRACKEN DEREK A. 
Published: May 2006

SummaryThe presence of amylose was demonstrated in hyphal walls of Neurospora crassa Shen and Dodge by silver proteinate staining for carbohydrates and differential digestion with β‐amylase. The amylose was found to be localized in the innermost layer of the wall. Similarly, amylose‐precipitating factor (APF) was also found to be localized in the same wall layer using ferritin‐tagged antibodies to APF. Lipase‐digestion of the isolated hyphal wall resulted in considerable reduction of the silver grain deposition in the innermost wall layer, suggesting the removal of amylose from this layer. Because lipid‐free APF cannot bind to amylose, these observations indicate that APF and amylose in Neurospora are in a complexed form in the innermost layer of the hyphal wall as a structural component.
CARBON MOVEMENT BETWEEN HOST AND MYCORRHIZAL ENDOPHYTE DURING THE DEVELOPMENT OF THE ORCHID GOODYERA REPENS Br
Authors: ALEXANDER CLARE , HADLEY G. 
Published: May 2006

Summary Goodyera repens Br. was either grown from seed and infected with its natural mycorrhizal endophyte, Ceratobasidium cornigerum (Bourd.) Rogers, or obtained as natural mycorrhizal plants from the field. Insoluble [14C]carbohydrate was provided at a point source available only to the external mycorrhizal mycelium of protocorms, plantlets (up to 50 mg w wt) or plants. Protocorms and plantlets obtained 14C via their external mycelium but plants did not, even when stressed for carbon by being kept in darkness for two weeks. There was no enhancement of growth of mycorrhizal plants when a carbon source was present in the substrate over an eight‐week period. When 14CO2 was fed to plant shoots to monitor movement of carbon from plant to endophyte, there was no evidence of such movement over a 7 d period.These results suggest that carbon moves only from fungus to orchid and that this movement ceases when the host reaches a certain stage of development. With respect to carbon, mature green plants of G. repens appear to be independent of their mycorrhizal association.
RELATIVE CHANGES IN LEVELS OF POLYAMINES AND ACTIVITIES OF THEIR BIOSYNTHETIC ENZYMES IN BARLEY INFECTED WITH THE POWDERY MILDEW FUNGUS, ERYSIPHE GRAMINIS D.C. ex MERAT f.sp. HORDEI MARCHAL
Authors: WALTERS D. R. , WILSON P. W. F. , SHUTTLETON M. A. 
Published: May 2006

SummaryThe concentrations of three amines (putrescine, spermidine and spermine) were much increased in first leaves of barley infected with powdery mildew, whilst the concentrations of putrescine and spermidine in roots of mildewed barley were significantly decreased. Although no significant change in the activities of three polyamine biosynthetic enzymes (ADC, arginine decarboxylase; ODC, ornithine decarboxylase; and SAMDC, S‐adenosyl methionine decarboxylase) could be detected in roots of mildewed barley, the activities of ADC, ODC and SAMDC were increased in infected first leaves. The significance of these alterations in polyamines and their biosynthetic enzymes in mildewed barley is discussed.
PHOTOSYNTHETIC RESPONSES TO LIGHT OF AUSTRALIAN AND CHILEAN SPECIES OFNOTHOFAGUSAND THEIR RELEVANCE TO THE RAINFOREST DYNAMICS
Authors: READ JENNIFER , HILL ROBERT S. 
Published: May 2006

SummaryPhotosynthetic responses to light have been examined in nine temperate rainforest species, includingNothofagusspecies from Australia and Chile, in order to correlate comparative light requirements with regeneration patterns and forest dynamics.Nothofagus gunnii(Hook. f.) Oerst. has the highest light requirements of the AustralianNothofagusspecies and this correlates with its failure to regenerate in closed forest.N. alpina(Poepp. et Endl.) Oerst. is the most shade‐tolerant of theNothofagusspecies examined in this study, and this result conforms with regeneration patterns observed in Chilean rainforest. The Australian species,N. cunninghamii(Hook.) Oerst. andN. moorei(F. Muell.) Krasser, and the Chilean species,N. obliqua(Mirbel) Oerst. andN. dombeyi(Mirbel) Oerst., have similar photosynthetic characteristics. Consequently, the comparative light requirements of theNothofagusspecies described here do not explain differences in the dynamics of rainforests dominated by these species. Differences in the regeneration characteristics of co‐occuring understorey and shade‐tolerant canopy species appear to be more important determinants of the dynamics of these forests.
EVIDENCE FOR A REVERSIBLE ACTION OF METHIONINE SULPHOXIMINE DURING GROWTH OF THE CYANOBACTERIUM, GLOEOTRICHIA GHOSEI SINGH
Authors: TIWARI D. N. , SINGH L. J. , MISHRA A. K. 
Published: May 2006

SummaryInhibition by l‐methionine‐dl‐sulphoximine (MSX) of growth, nitrate and ammonia uptake in Gloeotrichia ghosei Singh disappeared after a lag period of 6 to 8 d. The ability of the organism to resume growth or nitrogen uptake following a lag period was not due to decay of the inhibitor. Amino acids such as glutamine or methionine, which function as nitrogen sources, abolished the inhibitory action of MSX.
NITRATE REDUCTASE ACTIVITY IN SPHAGNUM FUSCUM IN RELATION TO WET DEPOSITION OF NITRATE FROM THE ATMOSPHERE
Authors: WOODIN S. , PRESS M. C. , LEE J. A. 
Published: May 2006

SummaryNitrate reductase activity has been measured in Sphagnum fuscum (Schimp.) Klinggr. growing on an ombrotrophic mire in subarctic Sweden, remote from urban and industrial sources of atmospheric pollution.Perturbation experiments in the field demonstrated nitrate induction of nitrate reductase activity which was both rapid and concentration dependent. Cumulative nitrate reductase activity after repeated treatments with 1 mM nitrate declined with each successive treatment. It is suggested that this may be a result of intracellular ammonium accumulation. Nitrate reductase activity in plants subjected solely to wet and dry deposition from the atmosphere showed little diurnal change, and watering of Sphagnum fuscum hummocks with distilled water had no effect on the enzyme activity. Nitrate reductase activity was, however, shown to be induced by natural precipitation events, the cumulative induced activity being proportional to nitrate deposition.The data suggest that the wet deposition of nitrate represents an important source of nitrogen for ombrotrophic Sphagnum species, and that there is a close coupling of the physiology of S. fuscum plants with their atmospheric environment. Such a relationship would be readily perturbed by atmospheric pollution.