bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE INTERDEPENDENCE OF PHOTON IRRADIANCE AND FREE CARBON DIOXIDE OR BICARBONATE CONCENTRATION ON THE PHOTOSYNTHETIC COMPENSATION POINTS OF FRESHWATER PLANTS
Authors: MABERLY S. C. 
Published: May 2006

SummaryThe free CO2 (CO2*) and HCO3− compensation points of eight freshwater macrophytes and four phytoplankters were measured using a pH‐drift technique developed by Allen and Spence (1981). Below a critical photon irradiance, which was about that at which net photosynthesis was half‐maximal, CO2* and HCO3− compensation points increased with decreasing photon irradiance. However, the CO2* compensation point of two species that were able to use HCO3− were little or not affected by photon irradiance. The light compensation point increased at low CO2* or HCO3− concentrations. The simultaneous generation by phytoplankton of light and carbon depletion could have a large deterimental effect on macrophyte performance.
EFFECTS OF INSECT TRAPPING ON GROWTH AND NUTRIENT CONTENT OF PINGUICULA VULGARIS L. IN RELATION TO THE NUTRIENT CONTENT OF THE SUBSTRATE
Authors: ALDENIUS JOHAN , CARLSSON BENGT , KARLSSON STAFFAN 
Published: May 2006

SummaryThe significance of the carnivorous habit of Pinguicula vulgaris L. was studied when plants were fed with insects and/or supplied with complete nutrient solution in the substrate. In most cases, plants supplied with insects alone or in combination with fertilizer showed higher values for dry wt, number and length of leaves, and concentrations of nitrogen and phosphorus. The amount of nitrogen absorbed when insects were added to fertilized plants was larger than the insects contained. It is inferred that P. vulgaris uses both nitrogen and phosphorus from the insect. It is hypothetized that some other substance is also obtained from the insects and used for the uptake by roots or utilization of nitrogen. No major differences in response were found between plants from the two sites studied, i.e. one relatively rich and one relatively poor mire in the Torneträsk area, North Sweden.
EFFECT OF DROUGHT STRESS AND VESICULAR–ARBUSCULAR MYCORRHIZA ON CITRUS TRANSPIRATION AND HYDRAULIC CONDUCTIVITY OF ROOTS*
Authors: LEVY YOSEPH , SYVERTSEN J. P. , NEMEC S. 
Published: May 2006

SummaryInfection of rough lemon seedlings (Citrusjambhiri Lush) by the vesicular–arbuscular mycorrhizal (VAM) fungus, Glomus intraradices (Schenck and Smith), increased root growth and transpiration rate and reduced leaf water potentials relative to non‐infected control plants. Half of the VAM and control plants were subjected to three drying cycles each of 5 to 7 days. The hydraulic conductivity of previously drought stressed root systems was lower than that of the well‐watered plants and VAM infection further reduced root conductivity. These data suggest that the higher root densities and higher transpiration rates of VAM infected plants may have depleted soil water more quickly than the non‐infected seedlings and resulted in more severe water stress conditions during drought cycles.
ECOLOGICAL ROLES OF BASIDIOMYCETES FORMING DECAY COMMUNITIES IN ATTACHED OAK BRANCHES
Authors: BODDY LYNNE , RAYNER A. D. M. 
Published: May 2006

SummaryFrom sites in south‐west England attached oak (Quercus robur) branches bearing basidiomycete sporophores were cut down from mature trees, and the three‐dimensional structure of their decay communities analysed. Twelve basidiomycetes characterized the decay communities. These fungi varied in their ecology, particularly in relation to their ability to colonize living wood, and their interaction with each other and with animals. Phellinus ferreus, Stereum gausapatum and Vuilleminia comedens were pioneers actively growing in partially living branches and causing extensive white rot but little cambial loosening. Peniophora quercina behaved similarly but was often confined to the ends of branches. Exidia glandulosa appeared principally to cause cambial death and loosening leading to white rot in the wood. Phlebia rufa seemed to act as a pioneer causing white rot but only in obviously weakened branches. Coriolus versicoior and Phlebia radiata were secondary invaders only, readily replacing other fungi. Peniophora lycii and Stereum lursutum were each only obtained once. The roles of Hyphodertna setigerum and Schizopora paradoxa were less clear, but both were closely associated with insect activity.
COMPARATIVE GROWTH OF THE AUSTRALIAN TEMPERATE PASTURE GRASSES: PHALARIS TUBEROSA L., DACTYLIS GLOMERATAL. AND FESTUCA ARUNDINACEA SCHREB
Authors: SAMBO E. Y. 
Published: May 2006

AbstractA study of the factors controlling productivity (dry‐matter production) during early growth was made for the four perennial temperate pasture grasses: Phalaris tuberosa L. cvs. Australian and sirosa (Australian Phalaris and sirosa Phalaris, Festuca arundinacea Schreb. cv. derneter (demeter fescue) and Dactylis glomerata L. cv. currie (currie cocksfoot). A detailed analysis was made of the partitioning of dry matter into the separate leaf and sheath fractions on the main shoot and tillers.In the period covering early growth (up to 71 days from sowing), a high relative growth rate was associated with a high rate of leaf appearance in currie cocksfoot, enhanced by a high tillering capacity. As a result, currie cocksfoot, although initially the smallest in size, increased its productivity to outyield Australian phalaris and equal that of sirosa phalaris and demeter fescue. The last two cultivars consistently showed higher productivity than Australian phalaris and currie cocksfoot throughout most of early growth. This was attributed to high leaf growth rates resulting in bigger leaf areas. A high leaf extension rate was associated with higher productivity.
LEAF DEMOGRAPHY, FLOWER PRODUCTION AND BIOMASS OF DIPLOID AND TETRAPLOID POPULATIONS OF PHLOX DRUMMONDII HOOK. ON A SOIL MOISTURE GRADIENT
Authors: GARBUTT K. , BAZZAZ F. A. 
Published: May 2006

SummaryWe investigated the effects of chromosome doubling upon leaf demography, flower production, biomass and response breadth on a soil moisture gradient of three varieties of Phlox drummondii, each variety being represented by two cytotypes.Increased chromosome number produced slower growth rates, increased leaf and plant longevity, and a tendency to flower later, less synchronously and produce fewer flowers. The loss of the ability to reproduce in hydric environments was also observed in all tetraploids. Other factors such as degree of response breadth, overlap and increased vigour due to increased chromosome number were found to be genotype dependent. Level of polyploidy had no effect upon the number of pre‐reproductive deaths.
MORPHO‐ECOLOGICAL STUDIES OF LOWERING IN THE SEEDLING OF THE GEOPHYTE IXIOLIRION TATARICUM (PALL.) HERB.
Authors: GALIL J. 
Published: May 2006

SummaryThe structure and behaviour of seedlings of the geophyte Ixiolirion tataricum has been studied. Germination is hypogeal. The cotyledon consists of a haustorium, an elongated stalk and a basal sheath. Germination takes place at or near the soil surface. By a process of ‘lowering’ the plumular bud reaches its appropriate depth in the soil. Lowering occurs in three successive stages: preliminary lowering by downward growth of the basal sheath, followed by growth of the bud carrying first leaf into a tunnel formed within the outer cortex of the primary root. In the second enlargement of the tunnel is the result of growth contraction of the internal core of the root (core = inner cortex + central cylinder), while in the third stage a wide space is formed within the outer cortex by disintegration of parenchyma cells of the inner cortex. The remaining central cylinder is then pushed in front of the advancing first leaf within this root tunnel.
DEVELOPMENT OF INTERCELLULAR CONNECTIONS BETWEEN OPPOSING CELLS IN A GRAFT UNION
Authors: JEFFREE C. E. , YEOMAN M. M. 
Published: May 2006

SummaryA morphological and developmental framework is presented for the cellular events leading to graft formation in tomato autografts based on scanning and transmission electron microscopy. Initial adhesion in the pith of grafts is followed by confrontation of new cells generated from the peripheral tissue of stock and scion. Pectinaceous beads on the surfaces of these cells establish a mechanical union between the cell surfaces, forming the functional equivalent of a middle lamella, Plasmodesmata formed de novo at the point of contact between opposing cells link the cell membranes, forming a potential pathway of communication of high specificity. Subsequently, wound vessels differentiate within the ‘callus’ at the graft union, and are connected into the vascular system of stock and scion by wound vessels differentiating from vascular and cortical parenchyma. The significance of these cellular interactions is discussed.
ACID PHOSPHATASE ACTIVITY IN SPHAGNUM SPECIES IN RELATION TO PHOSPHATE NUTRITION
Authors: PRESS M. C. , LEE J. A. 
Published: May 2006

SummaryAcid phosphatase activity in 11 Sphagnum species collected from one or more of 13 sites in the U.K. and Sweden was negatively correlated with tissue phosphorus concentration. The effects of phosphate supply on enzyme activity were investigated in both laboratory and field experiments. Phosphate enrichment reduced enzyme activity and phosphate starvation increased enzyme activity. The results are discussed in relation to the use of acid phosphatase as an indicator of phosphate supply in both natural and polluted ecosystems.
LEAF AND FLOWER DEMOGRAPHY OF TRIFOLIUM REPENS L.
Authors: TURKINGTON ROY 
Published: May 2006

SummaryTwo clones of Trifolium repens L., differentiated in response to their neighbours, the grasses Dactylis glomerata L. and Poa pratensis L., were grown as single ramets in mixture with these same two grasses. At weekly intervals for 59 weeks, births and deaths of leaves and flowers, and extension of stolons were recorded. These birth and death statistics were used to calculate life spans, natality and mortality rates, age class distributions and other demographic parameters of the populations of leaves and Bowers of T. repens L. For both individuals recruitment and death of leaves occurred throughout most of the year. Flowers were produced from early May to mid September by one individual and from late March to mid September by the other. The average life span of leaves does not vary significantly between the four treatments but the timing of birth has a strong influence on the expectation of life. For leaves and flowers from both white clover plants, the population flux was more rapid when growing with P. pratensis L. than with D. glomerata L., yet in both treatments the final population sizes were similar.
NITROGEN METABOLISM IN HALOPHYTES V. THE OCCURRENCE OF MULTIPLE FORMS OF GLUTAMINE SYNTHETASE IN LEAF TISSUE
Authors: McNALLY SHEILA F. , HIREL B. , STEWART G. R. 
Published: May 2006

SummaryIon‐exchange chromatography was used to examine the occurrence of glutamine synthetase (GS) isoforms in leaf tissue of 18 species of coastal plants. Two groups of species were recognizable on the basis of their complement of GS isoforms. One group comprised those species which exhibited two forms of GS, the properties of which were consistent with their being cytoplasmic and chloroplastic isoforms. In the second group were species which had only a single isoform, and exhibited properties similar to those of the chloroplastic isoform. Immunoprecipitation studies with antibody raised to the cytoplasmic isoenzyme of barley were carried out to identify the isoform present in species having only one peak of activity on ion‐exchange chromatography. No relationship was evident between either total GS activity or the occurrence of the cytoplasmic isoform and the photo respiratory capacity of different species.
EFFECT OF GLUCOSE AND ACTIVE CHARCOAL ON IN VITRO SYNTHESIS OF ERICOID MYCORRHIZA WITH VACCINIUM SPP.
Authors: DUCLOS J.L. , FORTIN J. A. 
Published: May 2006

SummaryThe addition of a small quantity of glucose (0.5 g 1−1) to the culture medium enhanced mycorrhiza formation on Vaccinium angustifolium Ait. and V. corymbosum L. with Pezizella ericae Read in vitro. Under these conditions, 15 isolates of ericoid mycorrhizal fungi obtained from diverse hosts and habitats demonstrated different abilities to colonize the root system of the two species of Vaccinium. Moreover, the addition of activated charcoal especially in presence of glucose or pectin greatly stimulated ericoid mycorrhiza formation by P. ericae on V. angustifolium. The possibility that active charcoal adsorbs toxic compounds from the rhizosphere is discussed.
PURIFIED PHYTOLECTIN FROM THE LICHEN PELTIGERACANINA VAR CANINA WHICH BINDS TO THE PHYCOBIONT CELL WALLS AND ITS USE AS CYTOCHEMICAL MARKER IN SITU
Authors: PETIT PATRICE , LALLEMANT R. , SAVOYE DOMINIQUE 
Published: May 2006

SummaryA purified phytolectin was isolated from the nitrogen‐fixing lichen Peltigera canina var canina. This lectin was thermostable, truly non‐specific and may have a molecular weight in its native form of the order of 80000 to 90000. It binds to the appropriate phycobiont cell walls and may be involved in some way in the recognition of, or interactions between, compatible lichen symbionts; it may be used in situ as a cytochemical marker of the free receptor sites in the lichen thalli. We advance a hypothesis that within the lichen the morphological and physiological state of the phycobiont is different in the various parts of the thallus; the capacity of the phycobiont to bind to lectins varies with fluctuations in the symbiotic relationship between partners.
TRANSLOCATION FROM LEAVES OF BARLEY INFECTED WITH BROWN RUST
Authors: OWERA S. A. P. , FARRAR J. F. , WHITBREAD R. 
Published: May 2006

SummaryTranslocation of14C from first leaves of barley is reduced by rust infection. Infection of the leaf base alone results in enhanced loss of14C from the leaf tip, whilst infected leaf tips show greatly reduced loss. Concentrations of soluble sugar are lower and those of storage polysaccharide higher in rusted leaves. Their amounts and the kinetics of flux of14C through them are used to validate a compartmental model of translocatory carbon flux derived from the pattern of14C‐effiux from the leaf. This model suggests that the major consequences of infection are reduced size of the sucrose transport pool and elimination of a phase of efflux with a half‐life of 2h.
THE STRUCTURE OF THE CUTICLE IN RELATION TO CUTICULAR TRANSPIRATION IN LEAVES OF THE HALOPHYTE SUAEDA MARITIMA (L.) DUM.
Authors: Hajibagheri M. A. , Hall J. L. , Flowers T. J. 
Published: May 2006

SummaryBoth cuticle and cell wall of the epidermal cells of leaves of Suaeda maritima showed a considerable increase in thickness (Cedeximately 1.8 times) in plants grown in the presence of 0.34 M sodium chloride when compared with plants grown without added sodium chloride. Differences in the structure of the cuticle were also observed. The rate of transpiration in the dark was markedly reduced with increasing concentrations of salt in the external medium. Cuticular transpiration appears to be related to cuticular thickness and to fall with increasing salinity.
ISOPOLLEN MAPS FOR POLAND: 0–11000 YEARS B.P.
Authors: RALSKA‐JASIEWICZOWA MAGDALENA 
Published: May 2006

SummaryIsopollen maps were first constructed by Szafer (1935) to illustrate the post‐glacial history of Picea and Fagus in Poland. New more detailed isopollen maps for 1000‐ or 500‐year intervals based on 64 pollen diagrams, many with good radiocarbon‐dating control, are presented for Picea abtes, Ulmus, Corylus avellana, Quercus, Tilia, Alnus, Carpinus betulus, Fagus sylvatica, and Abies alba. These maps illustrate the changing relative importance of these pollen taxa over the last 11000 years and suggest the possible routes of migration of the tree taxa concerned. The complex and diverse migrational history of these major Polish forest trees is demonstrated. The major migration routes appear to have been from the south‐east, south, south‐west and across the middle European lowlands from the west, north‐west and north‐east.
ADAPTATION OF UNICELLULAR ALGAE TO IRRADIANCE: AN ANALYSIS OF STRATEGIES
Authors: RICHARDSON K. , BEARDALL J. , RAVEN J. A. 
Published: May 2006

SUMMARYAnalysis of data in the literature relating to microalgal adaptations to different photon flux densities indicates that different algal classes have significantly different light requirements for growth and photosynthesis. Although there is some variability within each class, dinoflagellates and blue‐green algae generally photosynthesize and grow best at low photon flux densities. Diatoms also tend to be able to grow at very low photon flux densities (growth for some species has been reported at less than 1 μE m−1 s−2). Comparison of the photon flux densities at which photoinhibition occurs in dainoflagellates and diatoms suggests that the former often experience photoinhibition at comparatively low irradiances. In contrast, diatoms often can tolerate relatively high light environments. This tolerance of a large absolute range of photon flux densities may, in part, explain why diatoms are often associated with spring blooms. Green algae
OSMOREGULATION IN HIGHER PLANTS: EFFECTS OF NaCl SALINITY ON NON‐NODULATED PHASEOLUS AUREUS L. I. GROWTH AND MINERAL CONTENT
Authors: IMAMUL HUQ S. M. , LARHER F. 
Published: May 2006

SUMMARYThe adaptation, growth and changes in mineral composition of Phaseolus aureus L. were studied at six levels of NaCl, ranging from 10 to 200 mM. Plants tolerated up to 150 mM NaCl in the growth medium although their growth and mineral composition were adversely affected. Accumulation of Na+ in plant tissue increased with increasing NaClext reaching toxic concentrations and inhibited transport of different inorganic ions. K+ constituted only about 10 % of the total mineral content of plants grown in 150 mM NaCl as against 55 % in the controls. The principal balancing anion to counter Na+ accumulation was Cl−. ‘Ion excess’ in the plant is suggested to be the cause of reduced growth. The behaviour of P. aureus under condition of salt stress is discussed.
INCREASED UPTAKE OF BROMIDE AND CHLORIDE BY PLANTS INFECTED WITH VESICULAR‐ARBUSCULAR MYCORRHIZAS
Authors: BUWALDA J. G. , STRIBLEY D. P. , TINKER P. B. 
Published: May 2006

SUMMARYConcentrations of bromide in shoot tissue of field‐grown spring wheat and winter barley on sites both with and without methyl bromide fumigation were significantly higher in plants given mycorrhizal inoculum. In a pot experiment with spring wheat under controlled conditions, mycorrhizal inoculation increased bromide and chloride concentrations in plant tissue, but effects on iodide concentrations were small and inconsistent.A specific ability of mycorrhizal plants for increased uptake of chloride and bromide through mycorrhizal hyphae seems unlikely because both ions are highly mobile in the soil and readily absorbed by roots. An analysis of the cation–anion balance of shoot tissue from a field trial of spring wheat showed that mycorrhizal inoculation increased concentrations of inorganic anions, whilst cation concentrations were little altered. A possible explanation of the increased uptake of halides by mycorrhizal plants may be that the production of organic anions is restricted by the drain of carbon from the host by mycorrhizal fungi.
PHYSIOLOGICAL–ENVIRONMENTAL INTERACTIONS IN LICHENS
Authors: BROWN D. , MACFARLANE J. D. , KERSHAW K. A. 
Published: May 2006

SUMMARYThe wetting burst, resaturation respiration and basal respiration in Peltigera polydactyla, P. praetextata and Nostoc commune has been examined using both infrared gas analysis and oxygen electrodes. The physical nature of the wetting burst is further confirmed by drying replicates in CO2‐free air, after which the burst is eliminated. The data also shows that resaturation respiration is very dependent on prior events in the field. A prior fast drying rate produces higher resaturation respiration rates than does slow drying. However the length of time a lichen remains fully saturated is largely responsible for the amplitude of resaturation respiration and induces a very evident seasonal component in P. polydactyla. The extent of carbon loss and its potential ecological impact is questioned.
THE INTERACTION BETWEEN CO2 DIFFUSION AND THE DEGREE OF THALLUS HYDRATION IN LICHENS: SOME FURTHER COMMENTS
Authors: COXSON D. S. , BROWN D. , KERSHAW K. A. 
Published: May 2006

SUMMARYThe pattern of gas exchange in response to changing levels of thallus hydration is presented for several lichen species, together with the effects of high or low CO2 levels on net photosynthesis. The data shows that there is no discernible generalized relationship. Some species achieve very high optimum rates of net photosynthesis at full thallus hydration, while other species have optimum rates at lower levels of thallus hydration with CO2 diffusive resistance either remaining high or decreasing to a minimum coincident with the photosynthetic optimum. Where the diffusive resistance remains high, the phycobiont appears to be continuously CO2 limited even at optimum levels of thallus hydration. There can also be a strong interaction between temperature and the pattern of the CO2 limitation curve due to the high rate of respiration at full thallus moisture and a high thallus temperature. It is concluded that the discrete infra red gas analyser sampling method will slightly underestimate net photosynthetic rates in some species, particularly at full thallus water content, but the same errors will also be equally inherent in flow systems. Accordingly the traditional flow system without the replication advantages of the discrete sampling system, has little to recommend it for comparative seasonal or ecological work. The traditional correlation between the mesic requirements of a lichen and its net photosynthetic response pattern to the degree of thallus hydration is also questioned.
DECOMPOSITION OF SUPPRESSED OAK TREES IN EVEN‐AGED PLANTATIONS
Authors: BODDY LYNNE , THOMPSON WENDY 
Published: May 2006

SUMMARYThree oak stands in the Forest of Dean and one in Savernake Forest, planted between 1929 and 1957, were studied (as was a single beech stand in Savernake forest). On the basis of these surveys and other observations, a general pattern of death and decay of the aerial parts of suppressed trees is described. The major agents of decomposition of above ground parts consisted of both basidiomycetes capable of invading living wood and those which act solely saprophytically. Numerous non‐wood‐rotting fungi were also isolated. Most of the basidiomycetes were found to be those which characteristically colonize attached branches on mature oak trees that are not suppressed. These presumably colonize aerially as spores whereas the other basidiomycetes, which were generally found lower down in the trunk, colonized from below ground parts and often produced cords or rhizomorphs growing sub‐cortically.The consequences of close planting are discussed and a brief comparison is made between beech and oak stands.