bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE EFFECT OF ABSCISIC ACID AND FUSICOCCIN ON MALIC ACID CONCENTRATION IN PULVINI OF PHASEOLUS COCCINEUS L.
Authors: BIAŁCZYK JAN , LECHOWSKI ZBIGNIEW 
Published: April 2006

SummaryFusicoccin and abscisic acid can modify the movements of some nyctinastic plants. This paper reports the effects of these two compounds on the concentrations of malic acid in pulvini of Phaseolus coccineus L. in the transition period of two phases of the circadian rhythm. The concentrations of malic acid in the two parts of the pulvinus, extensor and flexor, depend upon the phase of leaf movements. Abscisic acid and fusicoccin significantly affected the content of malic acid in leaves compared with the control. In the two phases of the diurnal cycle investigated, abscisic acid markedly reduced the production of malic acid in the flexor and extensor regions of the pulvinus, and treatment with fusicoccin produced small but distinct increases in the concentration of malic acid in the same regions. The results are discussed with particular reference to the effect of abscisic acid and fusicoccin on the activity of the H+ pump associated with the control of turgor in cells.
COMPARATIVE STUDIES OF PLANT GROWTH AND DISTRIBUTION IN RELATION TO WATERLOGGING
Authors: TALBOT RICHARD J. , ETHERINGTON JOHN R. , BRYANT JOHN A. 
Published: April 2006

SummaryRooted cuttings of Salix caprea L. and ‐S. cinerea ssp. oleifolia (Macreight) growing in soil were exposed to (a) intermittent, (b) partial and (c) complete waterlogging of the soil. Measurements of growth and other characteristics were compared with unflooded controls. Both species were harmed by waterlogging but S. caprea was more sensitive than 5. cinerea as shown by the greater reduction of height, internode number, dry weight of root, stem and leaf, specific leaf area and leaf area per plant. The waterlogging treatments did not differ amongst themselves in the degree of inhibition of growth which they caused. A single fully waterlogged treatment would thus have been quite adequate in screening for tolerance.The reduction in specific leaf area of S. caprea was probably mediated by reduced turgidity and failure of leaf tissue to expand fully. Leaf iron content increased in both species but less so in S. cinerea, which is able to immobilize more iron in, or on, its roots. 5. caprea leaves contained over 2000 μg g−1 iron, a concentration recorded as toxic in other plants; these leaves became brittle and some lower leaves were shed. Root iron content increased more in S. cinerea than in S. caprea, and this was accompanied by an increase in phosphorus content. Chlorophyll and magnesium content of leaves was significantly reduced in S caprea but not in S. cinerea. Photosynthetic potential was reduced in S. caprea but not in S. cinerea; this was probably unrelated to stomatal control of CO2 uptake. S. cinerea produced adventitious roots at the surface of flooded soil and when cuttings were immersed in water; S. caprea did not. These observations are compatible with the ecology of the two species, S. caprea normally inhabiting better drained soils than 51. cinerea.
THE EFFECT OF WATERLOGGING ON INFECTION OF EUCALYPTUS MARGIN AT A SEEDLINGS BY PHYTOPHTHORA CINNAMOMI
Authors: DAVISON E. M. , TAY F. C. S. 
Published: April 2006

SummaryThree‐ to four‐month‐old Eucalyptus marginata Donn ex Sm. (jarrah) were grown in the glasshouse in peat/sand at 20° C root temperature, infected with zoospores of Phytophthora cinnamomi Rands, added either 10 cm below the soil surface or flooded onto the soil, and various waterlogging regimes were imposed. When plants were infected but not waterlogged, the proportion of infected root length adjacent to the point where zoospores were added was low. More lesions were formed per metre root length on tap roots than on lateral roots, but lesions on lateral roots were longer than on tap roots. When plants were waterlogged for a 4 d period before the addition of zoospores, there was no increase in root infection. When plants were waterlogged at the same time or after the pots were inoculated, there was a significant increase in the proportion of root length infected. This was due to an increase in the number of lesions and not, in four of the five harvests, to an increase in lesion length.When inoculation and waterlogging were imposed at the same time, the increased number of infections was probably due both to the increased attraction of zoospores to anaerobically respiring roots and to increased zoospore motility in flooded soil. When waterlogging was imposed several days or weeks after the plants had been infected, the increased number of lesions was unlikely to have been due to residual zoospores in the soil, because their numbers declined exponentially. It was also unlikely to have been due to sporangia developing de novo on the roots after waterlogging had been imposed, because the O2 concentration of the soil solution was inadequate. It is probable, therefore, that the new infections originated from zoospores liberated from sporangia already formed on lesions before waterlogging was imposed.When plants were infected but not waterlogged, there was no effect on the leaf diffusive resistance, leaf relative water content and shoot xylem pressure potential between 1 and 28 d. When plants were flooded, the daily water loss decreased more rapidly and plants died more rapidly in the inoculated and waterlogged treatments than in the treatments which were only waterlogged. Infection by P. cinnamomi did not affect the proportion of xylem vessels occluded with tyloses in seven of the eight unflooded, and seven of the eight flooded, comparisons.
GROWTH AND REPRODUCTION OF SILENE CUCUBALUS WIB. INTERMITTENTLY EXPOSED TO LOW CONCENTRATIONS OF AIR POLLUTANTS, ZINC AND COPPER
Authors: DUECK TH. A. , WOLTING H. G. , MOET D. R. , PASMAN F. J. M. 
Published: April 2006

SummaryPopulations of Silene cucubalus Wib. which were sensitive or tolerant to heavy metals or sulphur dioxide, were grown in zinc‐ or copper‐supplemented soil and were exposed to mixtures of SO2, O3 and NO2 in low concentrations for a period of 12 weeks. Fumigations were applied only during elevated ambient concentrations of ozone. Growth during fumigations was reduced, but flower production was significantly higher in metal‐tolerant populations when grown in soil supplemented with their specific metal. Flowers were hand‐pollinated when plants were exposed to at least 60 μg m3 O3, 40 μg m3 SO2 and 60 μg m−3 NO2. Although the number of seeds and individual seed weight were significantly influenced by heavy metals and/or air pollutants, it appeared that flower production has the greatest effect on potential sexual reproduction. Plants which have evolved resistance to pollution express optimal reproductive capacity when grown in soil most resembling their native soil. The interpretation and comparison of results gained under experimental conditions are discussed with respect to field observations and effects of pollutant/species combinations.
ABSENCE OF ASPECIALIZED INTERFACE BETWEEN INTRACELLULAR HYPHAE Of COLLETOTRICHUM LINDEMUTHIANUM AND CELLS OF PHASEOLUS VULGARIS
Authors: O'CONNELL R. J. 
Published: April 2006

SummaryThe intracellular infection vesicles and primary hyphae of Colletotrichum lindemuthianum (Sacc. & Magn.) Briosi & Cav. invaginate protoplasts of cells of Phaseolus vulgaris L. A matrix composed partly of polysaccharide or glycoconjugates containing vicinal hydroxyl groups separates the fungal wall from the host plasmalemma. Coated vesicles appear to release host material into the matrix by exocytosis. The invaginated region of the host plasmalemma stains normally with phosphotungstic acid, retains adenosine triphosphatase activity and appears normal when freeze‐fractured. This contrasts with the highly modified host plasmalemma surrounding haustoria of many obligately biotrophic fungi. The absence of a specialized host‐parasite interface is discussed in relation to the transient nature of biotrophy in the bean anthracnose disease.
SOMATIC INCOMPATIBILITY AND FIELD DISTRIBUTION OF THE ECTOMYCORRHIZAL FUNGUS SUILLUS LUTEUS (BOLETACEAE)
Authors: FRIES NILS 
Published: April 2006

SummaryTissue isolates were collected from 25 basidiocarps of Suillus luteus (L. ex Fr.) S. F. Gray under pine trees (Pinus sylvestris L.) at nine sites in a small forest area (approximately 1 km2) and tested for somatic incompatibility. Eleven distinct clones were detected, none of which was found in more than one site. This ectomycorrhizal fungus therefore possesses a population structure similar to that of many wood‐decomposing basidiomycetes.
HYDROXYLAMINE METABOLISM IN MONORAPHIDIUM BRAUNII
Authors: BALANDIN TERESA , APARICIO PEDRO J. 
Published: April 2006

SummaryThe utilization of nitrate by cells of Monoraphidium braunii Legnerová was immediately impaired by low concentrations of hydroxylamine. The consumption of NO3− resumed when almost no hydroxylamine was left in the culture medium but resumption took place only under illumination with blue light. The addition of hydroxylamine to cell suspensions caused the rapid inactivation of nitrate reductase. The inactivation was largely prevented by the previous incubation of the cells with menadione, a rinding which suggests that hydroxylamine inactivates the reduced form of nitrate reductase. Illumination of cells previously treated with hydroxylamine promoted the in situ reactivation of the enzyme.
ULTRASTRUCTURAL DISTRIBUTION OF GLUTAMATE DEHYDROGENASES DURING FRUIT BODY DEVELOPMENT IN COPRINUS CINEREUS
Authors: ELHITI MAYSOON M. Y. , MOORE DAVID , BUTLER R. D. 
Published: April 2006

SummaryTechniques based on a copper ferricyanide method were developed for the cytochemical localization at the ultra structural level of NAD‐ and NADP‐linked glutamate dehydrogenases (NAD‐GDH, NADP‐GDH), the latter enzyme being specifically involved in mushroom cap development. These techniques were validated using malate, lactate and succinate dehydrogenases (MDH, LDH, SDH). Tests were applied to unfixed and formaldehyde‐fixed material from three developmental stages of fruit bodies of Coprinus cinereus (Schaeff.: Fr.) S.F. Gray sensu Konr. (1) before spore formation (stage 2), (2) with young spores (stage 3), and (3) with mature spores (stage 4). Spectrophotometric assay showed that NADP‐GDH was still detectable after 15 min formaldehyde fixation and approximately 9 and 80% activity of NAD‐GDH and MDH, respectively, was preserved. At all stages of development MDH, LDH and SDH activities were localized in mitochondria or mitochondrion‐like bodies. In contrast, both NAD‐GDH and, especially NADP‐GDH, were localized in cytoplasmic vesicles, mainly in basidia and very young spores, sometimes being found adjacent to the cell walls, suggesting that these enzymes are transported to the vicinity of the plasma membrane. Such a location would be consistent with enzymological data, indicating that NADP‐GDH contributes to an ammonium scavenging system. Ultra structural localization of this system at the peripheral region of basidia suggests it may be linked to the synthesis and/or assembly of cell wall components and may protect the meiotic apparatus against ammonium inhibition.
INTERACTIONS BETWEEN INTERNAL AND EXTERNAL CO2 POOLS IN THE PHOTOSYNTHESIS OF THE AQUATIC CAM PLANTS LITTORELLA UNIFLORA (L.) ASCHERS AND ISOETES LACUSTRIS L.
Authors: MADSEN TOM VINDBÆK 
Published: April 2006

SummaryThe significance of CAM as a carbon‐conserving mechanism in two submerged aquatics, Littorella uniflora (L.) Aschers and hoetes lacustris L., was evaluated by determining (1) the loss of previously fixed CO2, released through decarboxylation of malic acid and (2) the quantitative importance of CAM relative to external CO2 uptake in photosynthesis.Using a 14C‐labelling technique it was found that the loss of CO2 derived from decarboxylation of malic acid constituted less than 2 % of nocturnal carbon uptake, confirming that the diurnal rhythm of acidity provides a good measure of the incorporation of carbon via CAM.The exchange pattern of inorganic carbon and oxygen was measured for plants incubated in open flow‐through systems. The contribution of internal and external CO2 to photosynthesis was determined as the difference in CO, uptake and oxygen release, where excess oxygen release reflected the assimilation of CO2 released from deacidification of malic acid. Despite a rapid deacidification, uptake of external CO2 was stimulated by 15 to 30% at intermediate external CO2 concentrations. It is suggested that this effect was due to a reduced photorespiratory activity caused by an enhanced internal CO2 concentration generated from malic acid. The simultaneous uptake of inorganic carbon from high internal and low external CO2 concentrations can only be explained by assuming a non‐linear CO, gradient from the lacunal air to the bulk medium, with the CO2 concentration in the outermost cell layers being lower than both the bulk medium and the lacunal air.The relative contribution of CAM to the total uptake of CO2 in daytime declined from 95% (both species) at an external CO2 concentration of 30μ CO2 to 38% (Littorella) and 34% (Isoetes) at 200μ CO2. This resulted from increased uptake of external CO2 at high external CO2 concentrations and a parallel suppression of internal decarboxylation of malic acid.The observed suppression of decarboxylation was confirmed by following the time course in the content of titratable acidity of the leaves. A reversible inhibition of daytime deacidification was seen for external CO2 concentrations higher than 3.0 to 5.4 mM CO2 in both Littorella and Isoetes.The functional significance of CAM for aquatics rests in the enhanced capacity for obtaining inorganic carbon resulting from the extension of the diel period in which inorganic carbon can be accumulated and in the high reassimilation efficiency of nocturnal respiratory CO2.
NITROGEN FIXATION (ACETYLENE REDUCTION) BY FOREST LEGUMES: SENSITIVITY TO PRE‐HARVEST AND ASSAY CONDITIONS
Authors: GROVE T. S. , MALAJCZUK N. 
Published: April 2006

SummaryThe effects of environmental and methodological factors on acetylene reduction by nodules of Acacia pulchella R.Br., Kennedia coccinea Vent, and K. prostrata R.Br. grown in pots were studied.The time course of acetylene reduction, measured for each species during assays lasting up to 3 h, showed that there was an initial lag phase before maximum rates were reached and that rates then declined rapidly. This decline in activity was less marked for K. prostrata than for the other two species. Rates of acetylene reduction did not differ significantly between detached nodules, roots with attached nodules and whole plants.Delaying the introduction of acetylene into assay vessels indicated that the decline in nitrogenase activity during assays at higher temperatures was only partly caused by the acetylene substrate. As weights of nodules were small in relation to the volume of assay vessels, the decline in activity is unlikely to result from changes in pO2. The initial lag phase was shorter and the decline in activity with time more marked with increasing temperature. This finding has important implications for conducting and interpreting field assays, and in determining optimum temperatures for nitrogenase activity.Calibration factors relating acetylene reduction to nitrogen fixation were estimated from measurements of nitrogen accumulation and acetylene reduction during growth of young plants in a nitrogen‐free sand. Ratios for A. pulchella (2·5:1) and K. coccinea (2·4:1) were lower than theoretical ratios (3 to 4:1), probably because of the decline in rates of acetylene reduction during assays. Lowering of irradiance to about 4 % of full sunlight over 2 d depressed acetylene reduction rates by 58% for A. pulchella and by 36% for K. coccinea.
DIAZOTROPHIC REGULATION OF AKINETE DEVELOPMENT IN THE CYANOBACTERIUM ANABAENA DOLIOLUM
Authors: RAO V. V. , GHOSH RITA , SINGH H. N. 
Published: April 2006

SummaryCessation of growth with N2, NO3− or NH4+ as nitrogen source marked the beginning of akinete differentiation in Anabaena doliolum. The primary trigger of the differentiation process during diazotrophic growth conditions appeared to be the generation of a nitrogen starvation signal resulting from progressive loss of the activities of nitrogenase and glutamine synthetase. Persistence of a substantial level of oxygenic photosynthetic activity long after the cessation of diazotrophic growth and the initiation of akinete development suggests a role for oxygenic photosynthesis in the process of akinete development subsequent to its initiation. The loss of diazotrophy much earlier than that of oxygenic photosynthesis explains the observed increase in the C/N ratio occurring during initiation and the middle phase of akinete formation. Both the initiation of akinete development subsequent to cessation of diazotrophic growth and the rise in the C/N ratio during the early and middle stages of akinete formation appear to be regulated by a developmental mechanism similar to the one that functions in the control of nitrogenase and glutamine synthetase activities during diazotrophic cyanobacterial growth.
EFFECT OF NODULATION ON THE EXPRESSION OF NITRATE REDUCTASE ACTIVITY IN PEA CULTIVARS
Authors: LIGERO F. , LLUCH C. , HERVAS A. , OLIVARES J. , BEDMAR E.J. 
Published: April 2006

SummaryNitrate reductase activity (NRA) was measured in leaves, stems, roots and nodules of four cultivars of Pisum sativum L. supplied with 2 mM KNO3 and nodulated by selected Rhizobium leguminosarum strains. As a control, non‐nodulated (uninoculated) plants were grown in the same nutrient medium. NRA was determined by an in vitro assay; it varied widely among strains and cultivars. Although differences in tissue NRA in nodulated plants were mainly related to cultivar genotype, nodulation much affected the distribution of NRA within the plant. There was also some cultivar x bacteria strain effect. Non‐nodulated plants had higher leaf and root NRA than nodulated cultivars, but nodulated plants had twice as high stem NRA as non‐nodulated plants. These differences correlated with nitrate concentrations which were depressed in leaves and roots, and increased in stems, of nodulated plants Nitrate accumulation was increased in leaves, stems and roots of nodulated plants in comparison with non‐nodulated ones. There were no differences in the root to shoot ratio between nodulated and non‐nodulated plants. The relationships between tissue nitrate reduction and nodulation are discussed.
RESPIRATION OF LEAVES OF BARLEY INFECTED WITH POWDERY MILDEW: INCREASED ENGAGEMENT OF THE ALTERNATIVE OXIDASE
Authors: FARRAR J. F. , RAYNS F. W. 
Published: April 2006

SummaryLeaves of barley cv. Maris Otter, susceptible to powdery mildew, show a large increase in respiration rate when infected with this fungus. About half of the increase is due to increased electron flow through the cytochrome chain and half through the alternative pathway. The alternative pathway shows increased engagement following infection but no increase in capacity. Respiration is not limited either by substrate or supply of inorganic phosphate. While the increase in activity of the cytochrome path may be due to adenylate regulation, that of the alternative path is not understood. The more resistant cvs Athos and Atem do not show alternative path activity following infection with mildew.
EFFECT OF MEDIA ON GROWTH AND INTERACTIONS BETWEEN A RANGE OF SOIL‐BORNE GLASSHOUSE PATHOGENS AND ANTAGONISTIC FUNGI
Authors: WHIPPS JOHN M. 
Published: April 2006

SummaryThe growth of and interactions between the glasshouse pathogens,Rhizoctonia solaniKühn,Fusarium oxysporumSchlect.,Pyrenochaeta lycopersiciSchneider & Gerlach,Phomopsis sclerotioidesvan Kesteren,Sclerotinia sclerotiorum(Lib.) de Bary andBotrytis cinereaPers. and the antagonistic fungi,Trichoderma harzianumRifai,Trichoderma viridePers.,Coniothyrium minitansCampbell,Gliocladium roseum(Link.) Bain andPythium oligandrumDreschler were examined on tap water agar, soil extract agar and potato dextrose agar. The medium had a significant effect on the growth rates of the fungi as well as the production of, and response to, volatile and non‐volatile antibiotic compounds and hyphal interactions. Responses to the media appeared to be related both to inherent properties of the fungi and to their natural ecological behaviour. The significance ofin vitroassays in screening systems for biological control agents of soil‐borne plant pathogens is discussed.
THE NATURE OF THE VEGETATIONAL CHANGES AT ABOUT 5000 b.p. WITH PARTICULAR REFERENCE TO THE ELM DECLINE: FRESH EVIDENCE FROM CONNEMARA, WESTERN IRELAND
Authors: MOLLOY KAREN , O'CONNELL MICHAEL 
Published: April 2006

SummaryResults of palaeoecological investigations on a core from Lough Sheeauns, N.W. Connemara, a small lake sited in an area with a dense concentration of megaliths datable to the Neolithic, are reported. Pollen analysis, involving continuous sampling over a 41 cm interval spanning the elm decline (c. 5000 B.P.), permitted a detailed reconstruction of the vegetational changes and the nature of human impact. The pollen data are supplemented by chemical analysis and a chronology is provided by radiocarbon dating.Farming, including cereal cultivation, in the century prior to the elm decline is demonstrated. The elm decline emerges as a distinct feature in both percentage and concentration pollen diagrams. It is argued that neither an anthropogenic nor a climatic explanation for that event is sustainable in the light of the available evidence; a disease hypothesis is favoured. In the immediate post‐elm decline period, Landnam, involving major woodland clearance in the context of a pastoral‐based Neolithic economy, is recorded as a distinctive feature in the pollen record.
Recent advances in palaeomycology
Authors: STUBBLEFIELD SARA P. , TAYLOR THOMAS N. 
Published: April 2006

summaryThe fossil record is a long‐neglected source of valuable information concerning the diversity, structure, evolution and activities of ancient fungi. However, interest in these organisms has increased in recent years as their importance in a wide variety of interactions with plants, animals and the geological environment has been recognized. Evidence from the fossil record now implicates fungi in such processes as the establishment of terrestrial plants, degradation of lignin in Devonian forests, parasitic relationships with plants and animals, and the development of ancient soils. Although fossil fungi remain difficult to study, their geological record is rich and rewarding. Recent advances in the study of fungi from the Palaeozoic and early Mesozoic (exclusive of palynological research) are presented in this review.

CONTENTS

Summary

I.
Introduction
3

II.
Fungal diversity
4

III.
Interactions between fungi and their environment
7

IV.
Evolution of fungi
12

V.
Special problems in studying fossil fungi
14

VI.
Future research in palaeomycology
16

Acknowledgements
17

References
17
The effects of root treatments on growth of the primary leaves of Phaseolus vulgaris L.: General features
Authors: MILLIGAN S. P. , DALE J. E. 
Published: April 2006

summarySeedlings of Phaseolus vulgaris, grown at 22.5 °C in moist vermiculite for 7 days, were transferred to nutrient solution held either at ambient temperature or at 10 °C, or subjected to a root–pruning treatment which removed all lateral roots and part of the main root. The effect of both treatments was to reduce primary leaf growth rate, within 3–6 h in the one case and 12 h in the other. The lower growth rate was maintained for the whole of the expansion period so that the final size of primary leaves on treated plants was only 35–40% of the controls. The smaller leaf size was caused by a reduction in average cell size judged from epidermal cell surface area and anatomical studies. Cell number per leaf was not affected by treatment. Root cooling caused an ephemeral initial fall in bulk leaf water potential, estimated by pressure chamber, but water stress was not thought to be the cause of the inhibition of leaf growth.