bluuebunny/crossref_metadata_2025_split huggingface dataset:
PRELIMINARY INVESTIGATIONS INTO THE STRUCTURE OF THE ROOTS OF THE MANGROVES, AVICENNIA MARINA AND BRUGUIERA GYMNORRHIZA, IN RELATION TO ION UPTAKE
Authors: LAWTON JUNE R. , TODD ANN , NAIDOO D. K. 
Published: May 2006

SUMMARYThe structure of the roots of Avicennia marina (Forsk.) Vierh., a salt excretor, and Bruguiera gymnorrhiza (L.) Lam., an excluder (non‐excretor), differed in the length and thickness of the root cap, phenolic content, the development of the Casparian strip in the endodermis and in the differentation of the vascular tissues.The uptake and distribution of lanthanum, used as a marker for ion movement differed in the two species. Though both had similar root concentrations, the amount of lanthanum in the leaves of Avicennia marina was significantly higher than that in stem and root, whereas in Bruguiera gymnorrhiza it was significantly lower. The barrier to lanthanum transport, probably located in the hypocotyl, is discussed in relation to the anatomy of the root and the uptake of salt under natural conditions.
ABAXIAL AND ADAXIAL STOMATAL BEHAVIOUR AND RESPONSES TO FUSICOCCIN ON ISOLATED EPIDERMIS OFCOMMELINA COMMUNISL.
Authors: PEMADASA M.A. 
Published: May 2006

SummaryA comparative study was made of the behaviour of abaxial and adaxial stomata on isolated epidermis ofCommelina communisincubated under controlled conditions. The degree of opening and of K+accumulation, and the responsiveness to light, carbon dioxide, abscisic acid and KC1 concentration were substantially higher in abaxial than in adaxial stomata; thus their differential behaviour is mainly a result of inherent, rather than of environmental, differences between the two epidermes. The isolation of guard cells, by killing other epidermal cells, failed to annul the disparity, suggesting that any difference in subsidary cell resistance between the two epidermes is not responsible for this phenomenon. Fusicoccin was able to overcome the smaller opening of adaxial stomata, indicating that there is no fundamental difference in the potential opening ability between abaxial and adaxial stomata. Even in a medium free of KC1, fusicoccin stimulated exceptionally high K+accumulation in adaxial guard cells, demonstrating that endogenous K+available in the adaxial epidermis is sufficient for wide opening. Accordingly, an inherent metabolic condition of adaxial stomatal cells appears to prevent them opening as wide as abaxial stomata. The effectiveness of fusicoccin to produce exceptionally wide adaxial apertures suggests that, when necessary, the proton pump can operate as efficiently in adaxial as in abaxial guard cells.
COMPARATIVE INOCULUM POTENTIAL OF SPORES OF SIX VESICULAR‐ARBUSCULAR MYCORRHIZAL FUNGI
Authors: DANIELS B. A. , McCOOL P. M. , MENGE J. A. 
Published: May 2006

SummaryUsing the most probable number method, differences in inoculum potential between six vesicular‐arbuscular (VA) mycorrhizal fungal isolates were demonstrated. Inoculum of Glomus mosseae had the highest inoculum potential while G. constrictus, and G. fasciculatus isolate 92, and isolate 0–1 were approximately 1/5, 1/6 and 1/12 as effective. G. fasciculatus isolate 185 and G. epigaeus were approximately 1 /50 as effective. These differences were not correlated with differences in spore viability or germinability since approximately 75 % germination occurred in all species after 3 weeks. While G. mosseae has the largest spore size and had the highest inoculum potential, no further correlation between spore size and inoculum potential was observed. The rate of increase of infection by these six VA mycorrhizal fungi differed more when equal spore numbers were used as inoculum than when equalized inoculum potentials were used. The percentage root infection, subjected to the multiple infection correction, was regressed against log of inoculum density and yielded slopes of 063 to 070 for all VA mycorrhizal fungi tested. The inoculum density‐infection relationships of mycorrhizal fungi are discussed with respect to Baker's epidemiological models.
EFFECT OF PHYSICAL FACTORS ON GAMETANGIAL INDUCTION, FERTILIZATION AND SPOROPHYTE DEVELOPMENT IN THE MOSS BRYUM ARGENTEUM GROWN IN VITRO
Authors: CHOPRA R. N. , BHATLA S. C. 
Published: May 2006

SummaryCultures of Bryutn argenteum, a dioecious moss, were raised aseptically from single spores. Normal gametophytes were formed at 25 ± 2 °C in 3500 to 4000 lx of continuous illumination. Gametangial formation in both male and female clones is affected by temperature, light intensity and photoperiod. Both sexes exhibit maximum gametangial formation at 25 ± 2 °C. Lowering of temperature to 10 ± 2 °C lowers the response. Light intensity within the range 1800 to 2000 lx is optimum for gametangial induction. Higher light intensities favour vegetative growth. Bryum behaves as a quantitative day‐neutral plant, since it becomes fertile even in an 8 h photoperiod. Gametangial induction increases with increasing day‐length, and the best response is observed with continuous illumination.Flooding of mixed cultures is necessary for fertilization. Although sporophytes appear in cultures maintained both at 18 ± 2 °C and at 25 ± 2 °C, the higher temperature is more favourable for the proper development of capsules.
DIATOM ANALYSES OF SEDIMENTS FROM LOUGH INE, CO. CORK, SOUTHWEST IRELAND
Authors: BUZER JENNY S. 
Published: May 2006

SummaryDiatom analyses of a sediment core from the marine Lough Ine are described. Diatom diagrams have been divided into four assemblage zones, LID 1 to 4, and these are used to interpret the post‐glacial history of the lough.The oldest diatom‐containing sediments recovered are attributable to Mitchell's pollen zone V, the Boreal Period. The lough was fresh water and very productive at this time, having a predominantly alkaliphilic, planktonic diatom flora, dominated by Cyclotella spp. During zones LID 1 and 2, Fragilaria spp. became dominant and productivity decreased. A slight tendency to more neutral or acid conditions is noted. Epiphytic diatoms increased in frequency. Zone LID 3 covers the marine transgression into Lough Ine, tentatively dated at c. 4000 B.P. The transgression appears to have been a gradual process. This is illustrated by successive peaks of diatoms indifferent to salt, halophilous, mesohalobous, estuarine and truly marine. Total numbers of diatoms in the sediments dropped dramatically during the marine transgression. This was partly a result of the change in sediment type. The marine transgression was completed in zone LID 4, where Paralia sulcata and other benthic marine species dominate the sediments.
CONTROL OF DEVELOPMENT IN CHENOPODIUM ALBUM L. BY SHADELIGHT
Authors: CHILD RICHARD , MORGAN D. C. , SMITH HARRY 
Published: May 2006

SummaryMany open‐habitat species are capable of perceiving and reacting to the reduced red: far‐red ratio of vegetational shade. A well‐documented example is the arable weed Chenopodium album, which responds most noticeably by a dramatic increase in height. Here this characteristic response is considered in greater detail, together with other morphogenic modifications elicited by shadelight quality. To enable such modifications to be interpreted in terms of differences in light quality, particular attention was paid to the minimization of fluence‐rate differences between simulated daylight and simulated shadelight treatments. It was found that the greater stem extension in simulated shadelight results mainly from an increase in cell elongation. Individual internodes also showed an acceleration of the extension growth phase, and a reduction in the time taken for completion of their growth, in simulated shadelight. There was no evidence to suggest that the rate of leaf formation was affected; however, apical dominance was enhanced resulting in the suppression of axillary outgrowth.Total leaf area was relatively unaffected by the different light quality regimes; however, leaves of higher insertion expanded more rapidly in simulated shadelight. Leaves which developed in this treatment had reduced stomatal frequencies on both surfaces, together with a reduction in photosynthetic pigment content on a leaf area basis. The possibility that these modifications are part of a coordinated response to shadelight, and the site of light quality perception, are discussed.
THE INFLUENCE OF VESICULAR‐ARBUSCULAR MYCORRHIZA ON GROWTH AND WATER RELATIONS OF RED CLOVER
Authors: HARDIE KAY , LEYTON L. 
Published: May 2006

SummaryVesicular‐arbuscular (VA) mycorrhizal infection of red clover grown in phosphate deficient soils enhanced the concentration of P in the tissues, stimulated growth of root and shoot but reduced the root/shoot ratio. Addition of phosphate to well below the optimum level also stimulated growth and enhanced P status of non‐mycorrhizal plants, but their yields and P concentrations were much smaller than those of mycorrhizal plants and their root/shoot ratios were unaffected.The hydraulic conductivities of the root systems were very much higher in mycorrhizal than in uninfected plants. This could be partly attributed to the greater lengths and diameters and hence total surface areas of the mycorrhizal roots. Per unit length of root, the conductivities of the mycorrhizal roots were still two to three times higher, suggesting that this was mainly due to hyphal growth in the soil.When soil water was not limiting, the lower root resistances combined with larger leaf surface areas and possibly also lower leaf diffusion resistances resulted in very much higher transpiration rates and fluxes in mycorrhizal than in non‐mycorrhizal plants. Under conditions of water stress, however, the leaf diffusion resistances of mycorrhizal plants were higher and transpiration fluxes lower compared with uninfected plants but, because of their higher total water demands, they wilted more rapidly. Mycorrhizal plants were able to extract soil moisture down to lower water potentials than non‐mycorrhizal plants (difference about 1 MPa) but, possibly because of their lower leaf water potentials and higher root conductivities, they recovered turgor more rapidly than non‐mycorrhizal plants when soil water was restored. Thus, the mycorrhizal habit is an advantage to the host plant in times of moisture stress.
THE ASSESSMENT OF NITROGEN FIXATION AND THROUGHPUT BY LICHENS
Authors: MILLBANK J. W. 
Published: May 2006

SummaryUsing specially made controlled environment chambers, the rates of nitrogen fixed in the field by the lichens Peltigera membranacea, P. polydactyla and Lobaria pulmonaria have been estimated under simulated seasonal conditions. The chambers permitted direct comparisons between short term acetylene reduction estimates and long term incorporation of 15N2 labelled gas. Large thallus samples minimized variation, and the overall figures of N2 fixed integrated the effects of fluctuations in temperature, daylength, light intensity and thallus moisture content. Empirical factors have been derived to relate short term rates of acetylene reduction to long term rates of N2 incorporation. Under predominantly moist conditions, factors of 8 to 10 were found. Drier summer conditions can result in factors in excess of 20. Estimated rates of total nitrogen input were 4 to 6 kg ha−1 per year. In dry exposed situations rates can be approximately half this figure.
EFFECT OF SOME ORGANIC CARBON SOURCES ON THE DARK CALCIFICATION OF THE FRESHWATER GREEN ALGA GLOEOTAENIUM
Authors: PRASAD P. V. DEVI , CHOWDARY Y. B. K. 
Published: May 2006

SUMMARYThe effect of glucose, acetate or succinate on the dark calcification of Gloeotaenium, a freshwater green alga, was studied. Under normal conditions calcification does not occur in this alga in darkness but addition of acetate or succinate induced calcification whereas glucose failed to do so. The induction of calcification by acetate was inhibited by dinitrophenol and that by succinate was inhibited by malonate. It is concluded that no separate light‐dependent mechanism of calcification exists in Gloeotaenium and that oxidative phosphorylation may be supplying, at least partly, the energy required for calcification.
SALT UPTAKE AND RESPIRATION OF EXCISED BEECH MYCORRHIZAS
Authors: HARLEY J. L. 
Published: May 2006

SUMMARYWhen excised beech mycorrhizas aged in aerated water absorb ammonium from NH4C1 solutions in the presence of low concentrations of 32P‐labelled KH2PO4, the incorporation of 32P in the tissues during a 2‐min period was greater than when ammonium was not supplied. At the same time, the respiratory rate was also greatly increased. The destination of the phosphate incorporated was similar whether ammonium was present or not. The results are consistent with the view that the respiratory rate of aged beech mycorrhizas is limited by the rate of phosphate turnover and the availability of phosphate acceptors, and that the absorption of ammonium increases this turnover.
GROWTH RESPONSES OF ENDOMYCORRHIZAL ONIONS IN UNSTERILIZED COAL WASTE
Authors: Khan A. G. 
Published: May 2006

SummaryThe effects of the widespread vesicular‐arbuscular (VA) endophytes, namely Glomus macrocarpus var macrocarpus, Glomus mosseae, and Sclerocystis rubiformis and those of E3 (a strain of Endogone introduced from Rothamsted Experimental Station) on growth of onions were compared in unsterilized coal washery waste from the Coal‐Cliff Collieries in the Illawarra region of New South Wales. Mycorrhizal onions were significantly larger (P < 0.05), with respect to all the growth measurements than NM controls. Different VA endophytes had quantitatively different effects on the growth; the S. rubiformis was always poorest and E3 most consistently good. This is because S. rubiformis produced more localized infection, while the growth of E3 was more general producing, under similar conditions, more extramatrical hyphae than any other endophyte used. Among widespread species G. mosseae was the most efficient at stimulating plant growth. The possible role of VA mycorrhizas in plant colonization of coal spoil areas is discussed.
THE MYCORRHIZAL RELATIONSHIPS OF AUSTRALIAN ORCHIDS
Authors: WARCUP J. H. 
Published: May 2006

SUMMARYThe symbiotic associations of Australian orchids have been examined by isolating Rhizoctonia endophytes from orchids growing in the field and by symbiotic germination of orchid seed. Many Rhizoctonia isolates fruited and were identified to their perfect states.The isolation studies showed considerable specificity in association between many orchids and their endophytes. In particular Sebacina vermifera was generally associated with Caladenia and several related genera. Tulasnella calospora was closely associated with Diuris and Orthoceras and it and other species of Tulasnella with Thelymitra and Dendrobium. Ceratobasidium cornigerum was associated with Prasophyllum and Pterostylis and, with other species of Ceratobasidium, with orchids of the subtribe Sarcanthinae. Specificity, however, was not absolute for different Rhizoctonias may occur in an orchid either alone or with the more usual endophyte. A few orchids had a wide range of endophytes commonly present.Symbiotic germination studies generally substantiated the field isolations but showed further levels of specificity in that isolates of a fungus often differed markedly in their ability to germinate seed of a host or of different hosts under the conditions used.With orchids specificity seemed to occur at different levels, from species to at least subtribe, though the data are imprecise. If there is specificity to subtribe then there are some anomalies in classification. For instance all Caladeniinae sampled were associated with Sebacina vermifera except Lyperanthus which was associated with a wide range of other fungi. Microtis and Prasophyllum, though not considered closely associated, are placed together in the Prasophyllinae; their endophytes are quite different.
A TECHNIQUE FOR THE ESTABLISHMENT OF MYCORRHIZAL INFECTION IN ORCHID TISSUE GROWN IN ASEPTIC CULTURE
Authors: BEARDMORE JANE , PEGG G. F. 
Published: May 2006

SUMMARYTwo techniques for producing large quantities of mycorrhizal and non‐mycorrhizal orchid tissue for experimental purposes are described.Protocorm‐like masses of Dactylorhiza purpurella (T. & T. A. Steph.) Soó, were grown axenically in darkness on 2 % sucrose mineral salts medium with growth supplements at 22 °C. These cultures, derived from seed, were substantially larger than the original protocorms.Mycorrhizal infection of this tissue was achieved successfully in 100 ml conical flasks in which the protocorm‐like tissue was suspended on water agar only and the fungus inoculated on an adjoining cellulose, mineral salts slope.Infection, using several Rhizoctonia strains in this double‐culture system gave consistent mycorrhizas characteristic of natural protocorms and with extensive colonization of cortical tissue. Alternative inoculation methods using a single aqueous or agar medium and with recognized mycorrhizal strains, gave variable infection, frequently resulting in pathogenicity and host death. The advantage of the double culture system in providing large quantities of orchid mycorrhizal tissue for experimental studies is discussed.
ANATOMY, HISTOCHEMISTRY AND CYTOLOGY OF DORMANT AND STRATIFIED APPLE EMBRYOS
Authors: DAWIDOWICZ‐GRZEGORZEWSKA A. 
Published: May 2006

SUMMARYThe following sequence of structural changes which are related to the utilization of storage materials have been shown to occur in the apple embryo: degradation of protein bodies, degradation of lipid bodies, appearance and degradation of starch. These processes take place in the embryonic axis during stratification and in the cotyledons during the germination of stratified embryos. Important differences were observed in the localization of these processes during the early post‐embryonic (up to 12 days) growth of dormant and stratified embryos. It is concluded that during the germination of dormant embryos the embryonic axis influences certain hydrolytic processes in cotyledons by delaying and inhibiting their progress, whereas in non‐dormant embryos these are stimulated by the embryonic axis.
THE SOLUTE AND WATER RELATIONS OF AGROSTIS STOLONIFERA ECOTYPES DIFFERING IN THEIR SALT TOLERANCE
Authors: AHMAD I. , WAINWRIGHT S. J. , STEWART G. R. 
Published: May 2006

SUMMARYThe water, ion, proline, amide, amino acid and quaternary onium contents of ecotypes of Agrostis stolonifera isolated from salt marsh, spray zone and inland habitats were determined over a range of external salt concentrations. When grown at high salinites the plants exhibited inhibition in the root water absorption and reduction in the shoot water content, these being most pronounced in the inland ecotype and least in the salt marsh ecotype. In the presence of salt the accumulation of Na+ and Cl− in both shoots and roots was accompanied by a decline in tissue potassium content. At high salinities the increase in tissue ion content was greatest in the inland ecotype and least in the salt marsh ecotype. Proline, asparagine, glutamine, serine and glycine betaine showed increases in response to salinity, these being most pronounced in the salt marsh ecotype. The inland and spray zone ecotypes exhibited marked decreases in the aspartate and glutamate contents when grown at high salinities.With polyethylene glycol or mannitol in culture solutions, the salt marsh ecotype exhibited a greater ability to resist losses in shoot water content and to increase shoot proline, asparagine, glutamine and serine contents, than the inland and spray zone ecotypes.Changes in the solute and water status are discussed in relation to salt tolerance of the ecotypes.
FREEZE‐ETCH ULTRASTRUCTURE OF A PROCHLORON SPECIES ‐ THE SYMBIONT OF DIDEMNUM MOLLE
Authors: COX GUY , DWARTE D. M. 
Published: May 2006

SUMMARYA species of Prochloron, a genus of photosynthetic prokaryotes containing chlorophylls a and b and lacking phycobilins, has been investigated by the freeze‐etch technique and thin sectioning. The thylakoids show a high level of stacking; particle distributions on fracture faces of the membranes resemble those of chloroplasts more than those of cyanophytes. Polyhedral bodies (carboxysomes?) are surrounded by a unit membrane which probably derives from the thylakoids. Vacuole‐like areas are seen in freeze‐etch replicas to contain a structured substance, probably a reserve material.
OVULE DEVELOPMENT INORNITHOGALUM CAUDATUM(LILIACEAE) WITH A REVIEW OF SELECTED PAPERS ON ANGIOSPERM REPRODUCTION
Authors: TILTON VARIEN R. , LERSTEN NELS R. 
Published: May 2006

SUMMARYOrnithogalumovules are bitegmic: the inner is initiated first, but both attain maturity at the same time. Both integuments are derived from the epidermal layer of the nucellus and are covered by a cuticle. Inner integument cells define the micropyle and those which line it are secretory. An outer integument is present only on the distal (non‐funicular) side of the ovule. Its proximal portion apparently is fused congenitally with the funiculus. A funiculus attaches the ovule (and seed) to placental tissue. Proliferation of cells at the base of the funiculus contributes to development of the obturator. Funicular curvature causes the ovules to assume an anatropous orientation. A procambial strand branches from a ventral vein of the carpels and differentiates acropetally in the funiculus. At ovule maturity, vascular tissue terminates in the chalaza a few cells removed from the hypostase. Terminal cells of the vascular bundle consist only of tracheary elements with annular thickenings.
SEEDLING SURVIVORSHIP IN NATURAL POPULATIONS OF NINE PERENNIAL CHALK GRASSLAND PLANTS
Authors: SILVERTOWN JONATHAN W. , DICKIE JOHN B. 
Published: May 2006

SUMMARYSeedling survivorship in cohorts of nine perennial species of chalk grassland is reported. Heavy (> 80%) mortality in the first year occurred in six of the species with still higher values of mortality expected before any individuals in a cohort flowered. The observations are compared with the results of previous studies.
NUMBER AND STRUCTURE OF ANTHERS IN FIG SYCONIA IN RELATION TO BEHAVIOUR OF THE POLLEN VECTORS
Authors: GALIL J. , MEIRI LIORA 
Published: May 2006

Structure and functioning of anthers have been studied in Ficus carica L., F. sycomorus L. and F. religiosa L. Polleniferous figs of F. carica produce numerous male flowers with plenty of pollen (multistaminate type). Mature anthers contain a normal fibrous layer and open spontaneously. On the other hand, figs of F. sycomorus produce a comparatively small number of male flowers, their anthers have a degenerated endothecium and do not dehisce normally.In pollination (pollen loading and unloading) the great differences occurring in the organization of the androecium of F. carica and F. sycomorus may be seen to be associated with different behaviour patterns of their specific pollen vectors, the agaonid wasps Blastophaga psenes and Ceratosolen arabicus, respectively. While the pollinators of F. carica become passively coated with pollen on their exit from the native fig (topocentric pollination), the pollen vectors of F. sycomorus help in opening of the anthers and load the pollen purposively, by direct lifting of the pollen from the anthers on to special pockets on the body of the insect (ethodynamic pollination). Thus, in the context of pollination, the complementary nature of the characteristics of the two participants of fig symbiosis is evident.