bluuebunny/crossref_metadata_2025_split huggingface dataset:
REPRODUCTIVE ECOLOGY OF BANKSIA GRANDIS (PROTEACEAE)
Authors: ABBOTT IAN 
Published: May 2006

SummaryThe reproductive characteristics of Banksia grandis Willd. were studied in the northern jarrah forest of Western Australia. Most flowering occurs in November, with maturation of fertile (seed‐bearing) infructescences taking about 12 to 14 months. Number of inflorescences produced by a tree is not closely related to its diameter at breast height (DBH). Trees become reproductive at mean DBH of 4–5 cm and fruit successfully at mean DBH of 6.7 cm. Trees of DBH < 10 cm produce fewer fertile infructescences than trees of larger DBH. Moderate‐intensity fire markedly reduces production of inflorescences for at least three flowering seasons.Less than 2% of flowers on an average inflorescence set fruit, and only 1 to 5% of inflorescences develop into fertile infructescences. The cause of the latter was investigated experimentally. Although insect larvae (Lepidoptera, Coleoptera) damage infructescences, inflorescences sprayed with insecticide do not develop differently from those not so treated. Insect damage is least in inflorescences produced in late November and early December but there is no corresponding increase in development of fertile infructescences. Ants do not protect inflorescences from insect damage and insects are of little significance as predators of seed within the follicle. Whether fruit development is limited by pollination could not be adequately assessed. Low fruit set in B. grandis may result from shortage of resources, with many flowers and inflorescences allowing B. grandis the option of setting large numbers of fruits should favourable conditions prevail.
SPEED OF DEVELOPMENT OF RADIATE AND NON‐RADIATE PLANTS OF SENECIO VULGARISL. FROM HABITATS SUBJECT TO DIFFERENT DEGREES OF WEEDING PRESSURE
Authors: KADEREIT J. W. , BRIGGS D. 
Published: May 2006

SummaryIn a cultivation experiment, plants of both radiate and non‐radiate Senecio vulgaris L. (S. vulgaris ssp. vulgaris var. hibernicus Syme and var. vulgaris) from intensively weeded habitats develop more quickly from sowing to first fruiting than plants from less intensively‐weeded habitats. Within the same habitat, non‐radiate plants are quicker from sowing to first fruiting than radiate plants. This shortening of the life‐cycle is achieved by a faster development from sowing to the formation of the first capitulum buds, resulting in shorter plants with fewer leaves on the main axis. In contrast, the development from anthesis to first fruiting takes longer in quick‐developing plants, and the number of achenes on the first fruiting capitulum as well as the potential reproductive output is smaller. This is explicable in terms of reduced availability of resources resulting from the smaller number of leaves in the quick‐developing plants.The possible origin of the two populations of radiate S. vulgaris is discussed.
SALT TOLERANCE IN SUAEDA MARITIMA (L.) DUM. FINE STRUCTURE AND ION CONCENTRATIONS IN THE APICAL REGION OF ROOTS
Authors: HAJIBAGHERI M. A. , YEO A. R. , FLOWERS T. J. 
Published: May 2006

SummaryAnatomy and ion concentrations have been studied in the roots of the halophyte Suaeda maritima (L.)Dum. growing in saline and non‐saline conditions. The roots were fine with only three layers of cortical cells. Salinization of the growth medium resulted in cellular vacuolation commencing closer to the apex than in non‐salinized plants and led to an increase in root dimensions through increased cell (vacuole) size but not increased cell numbers: the Casparian strip developed much closer to the apex and was twice as long in salt‐grown plants. Ion concentrations were determined in sections (1 mm) of root. The apical 1 mm was predominantly non‐vacuolate, with a K+ concentration greater than 100 mol m−3 and a Na: K ratio less than 2, even when growing in 340 mol m−3 NaCl. The adaptive value of the anatomical observations are discussed and the ion concentration data assessed in relation to current concepts of the haiophyte cell.
THE INFLUENCE OF SO2 AND NO2 ON THE GROWTH, DEVELOPMENT AND GAS EXCHANGE OF BETULA PENDULA ROTH
Authors: FREER‐SMITH P. H. 
Published: May 2006

SummarySO2 and NOx are main primary pollutants which often occur together in Europe. In three experiments, Betula pendula Roth, was exposed to SO2 and NO2, at concentrations of between 30 and 90 nl l−1, in controlled conditions during the first year of growth. In addition, single plant chambers were used to examine the net fluxes of SO2 to the shoots.The effects of continuous exposure to this range of concentrations of SO2+ NO2 varied from a 20% increase to a 32% decrease in total dry weight. This contrast of responses came about because the doses of pollutant and light conditions were altered. Foliar injury and subsequent decreases of growth occurred when exposure concentrations exceeded 70 nl l−1 of both gases, although the onset of dormancy influenced the responses which were observed. Premature loss of leaves was the main symptom of chronic injury‐ in SO2 and the threshold concentration for this effect was about 50 nl l−1. When grown in conditions of poor light B. pendula made changes of partitioning so that leaf growth was favoured, and also showed greater phytotoxic effects as a result of exposure to SO2 and SO2+ NO2. In conditions of large PFD and longdays the toxic effects of SO2 were lost so that significant interactions in the effects of SO2 and photoen vironment were detected. SO2 also caused decreases in root–shoot ratio and increases in LAR but NO2 did not influence partitioning in this way. Stomatal conductance was influenced by fumigation with 40 nl l−1 SO2 and there were slight decreases of net photosynthesis in the presence of 55 nl l−1 SO2. The rates of deposition of SO2 were largely controlled by stomatal conductance and no emission of H2S was detected. Cuticular deposition of SO2 varied, making up between 11 and 25% of the total flux and becoming of greater importance as the stomata closed.
THE CHARACTERIZATION AND ESTIMATION OF POLYPHOSPHATES IN ENDOMYCORRHIZAS OF THE ERICACEAE
Authors: STRAKER C. J. , MITCHELL D. T. 
Published: May 2006

SummaryMetachromatic staining demonstrated the presence of polyphosphate granules in endophytes isolated from root systems of Vaccinium macrocarpon Ait., Rhododendron ponticum L., Calluna vulgaris (L.) Hull, Erica hispidula L. and E. mauritanica L. The granules accumulated in response to high concentrations of phosphorus in the external medium and during the lag phase of growth. Nucleic acid‐polyphosphate co‐precipitates prepared from endophytes were separated by means of polyacrylamide gel electrophoresis and the molecular weights of polyphosphate of three endophytes were between 3000 and 4700. Inoculated root systems of Vaccinium macrocarpon had significantly more acid‐labile polyphosphate than non‐mycorrhizal roots. The results are compared with studies of polyphosphate in ecto‐ and vesicular‐arbuscular mycorrhizas and are discussed in relation to ultrastructural analyses and the role of polyphosphate in the phosphorus nutrition of ericaceous plants in heathlands.
INTERACTIONS BETWEEN MATING AND SOMATIC INCOMPATIBILITY IN THE BASIDIOMYCETE STEREUM HIRSUTUM
Authors: COATES D. , RAYNER A. D. M. , BODDY LYNNE 
Published: May 2006

SummaryExperimental systems for studying the migration of nuclei into mating‐type compatible homokaryons across a pre‐existing or developing somatic incompatibility barrier are described. Using these systems with Stereum hirsutum Willd. ex Fr. it was found that different donor nuclei migrated from implants at more or less equal rates through acceptor homokaryons. However, access of nuclei across a somatic incompatibility barrier was subject to delay, selectively favouring those non‐sib‐related to the acceptor, as opposed to sib‐related nuclei. The selective delay was greater across a pre‐formect than a developing barrier, and in the latter case there was evidence of suppression of the somatic incompatibility reaction associated with passage of non‐sib nuclei.
PHOTOSYNTHESIS AND CARBOHYDRATE METABOLISM IN DETACHED LEAVES OF LOLIUM TEMULENTUM L.
Authors: HOUSLEY T. L. , POLLOCK C. J. 
Published: May 2006

SummaryMature leaves of Lolium temulentum L. remained photosynthetically competent for some days following excision. During this time, amounts of soluble carbohydrate rose markedly and there was substantial accumulation of sucrosyl‐fructans. Cell‐free extracts of excised leaves showed enhanced ability to synthesize oligofructosides from sucrose in vitro. Excised leaves were capable of the synthesis of fructans from exogenous sucrose applied in the dark. Exposure of leaves to 14CO2 immediately following excision led to movement of radioactivity from sucrose into higher oligosaccharides and the distribution of 14C suggested the presence of multiple pools of sucrose within the leaf. These results are discussed in relation to the control of reserve accumulation during periods of fluctuation in sink demand.
EVOLUTION OF XYLEM RESULTED IN A REQUIREMENT FOR BORON IN THE APICAL MERISTEMS OF VASCULAR PLANTS
Authors: LOVATT CAROL J. 
Published: May 2006

SummaryCritical review of the literature regarding the influence of boron on the metabolism of vascular plants shows that the cessation of cell division in the apical meristem is the earliest and most prevalent result of boron deficiency in vascular plants. Furthermore, the literature, in general, can be interpreted to support the view that perturbations in auxin metabolism, increased signification, phenol accumulation and reduced sucrose transport are probably secondary effects of boron deprivation resulting from the decrease or complete cessation of plant growth. It is proposed that the acquisition of a role for boron essential to the normal functioning of the apical meristem was a consequence of the evolution of xylem and the subsequent passive transport of boron in the transpiration stream. This resulted in the accumulation of boron at the transpiration terminus, i.e. the shoot apex of a primitive vascular plant. Thus, it was in the shoot apex that boron, for the first time in the evolution of life, reached a concentration sufficient to influence the metabolism of an organism. In support of this hypothesis, evidence is presented that demonstrates that boron probably was not available in the environment at a concentration great enough to result in its being a primordial essential nutrient. The accumulation of boron in the shoot apex resulted in the acquisition of an essential role for boron in vascular plants, thereby imparting the selective advantage of preventing boron toxicity. In addition, the accumulation of boron in the shoot apex to a concentration sufficient to influence the metabolism of a eucaryotic cell presents the possibility that boron may be required by vascular plants in a metabolic pathway that is not unique to them, but one which they may have in common with non‐vascular plants and, potentially, all living organisms. A possible role for boron in maintaining an adequate supply of one or more species of pyrimidine nucleotide or in facilitating their utilization is proposed.
COPPER TOLERANCE IN TWO LEGUME SPECIES FROM A COPPER MINE HABITAT
Authors: WU LIN , KRUCKEBERG A. L. 
Published: May 2006

SummaryLupinus bicolorLindl. andLotus purshianus(Benth.) Clem. & Clem, plants growing on copper mine waste in northern California exhibited considerably greater copper tolerance at 0.2 mg copper 1−1in nutrient solution than plants from an adjacent meadow. Effective nitrogen fixation in the copper‐enriched soils is suggested from acetylene reduction assays.
WHY DO PLANTS HAVE CYTOCHROME P‐450? DETOXIFICATION VERSUS DEFENCE
Authors: HENDRY GEORGE 
Published: May 2006

SUMMARYEvidence is presented which suggests that cytochrome P‐450, in plants, probably functions as in all other eukaryotic organisms, principally as a detoxification mechanism. In plants this function is largely suppressed during tissue maturation coinciding with cell vacuolation. The consequential accumulation and isolation of potential toxins within vacuoles provides higher plants with an anti‐herbivore defence of evolutionary significance.
MANNITOL DOES NOT INHIBIT GLYCOLYTIC ENZYMES IN ROOTS OF PINUS SYLVESTRIS AND FAGUS ORIENTALIS
Authors: JIRJIS RAIDA , RAMSTEDT MAURITZ , SÖDERHÄLL KENNETH 
Published: May 2006

SUMMARYGlucose‐6‐phosphate dehydrogenase, hexokinase and phosphoglucose‐isomerase extracted from roots of Pinus sylvestris L. or Fagus orientalis Lipsky were not inhibited by mannitol at concentrations up to 0.5 M in contrast to previous reports for these enzymes from Fagus sylvatica L. The Km‐values for the carbohydrate substrates were the same in the presence or absence of mannitol (50 mM).
THE EFFECT OF WINTER FIELD CONDITIONS ON THE DISTRIBUTION OF TWO SPECIES OF UMBILICARIA
Authors: SCOTT MARTHA G. , LARSON DOUGLAS W. 
Published: May 2006

SUMMARYThis paper describes the effects of transplantation on the ultrastructure and storage body distribution patterns in two saxicolous lichens which show a mutually exclusive distribution pattern. Umbilicaria vellea (L.) Ach., which grows in a snow‐free microhabitat, was transplanted into an adjacent habitat which received a deep winter snow cover and which supported populations of Umbilicaria deusta (L.) Baum. The reverse was done for U. deusta m the U. vellea habitat.Effects of transplantation on storage body distribution were evident for U. vellea, but not for U. deusta. At the ultrastructural level, thalli of U. vellea showed clear signs of disruption including senescence of the algal cells and an increase in the amount of stored starch which was negatively correlated with a decline in photosynthesis in the same replicates. Lipid deposits in U, vellea were initially few in number and did not change as a result of transplantation. Changes were not observed for either species in the number of pyrenoglobuli in the pyrenoid body. Algal cells of U. deusta contained significantly larger amounts of starch and lipid than those of U. vellea and no overwintering treatment disrupted the fine structure of the plant. However, numbers of starch grains declined seasonally while thalli were under snow. Storage body distribution was found to be a stable feature of the algal cells and not dependent on short‐term fluctuations in net photosynthesis. It is possible that U. deusta accumulates large amounts of photosynthetic products in the autumn and uses these to maintain low metabolic levels during the winter. It may be that U. vellea is excluded from snow‐covered habitats because its thalli lack the ability to store photosynthetic products and have a pattern of gas exchange unsuited to overwintering under deep snow.
PHYTOALEXINS, WATER‐STRESS AND STOMATA
Authors: PLUMBE ALISON M. , WILLMER C. M. 
Published: May 2006

SUMMARYThe effects of several phenolic compounds, some of which accumulate in tissues under the stress of microbial attack, and of some‘water‐stress’ compounds (those which accumulate in leaf tissue under water‐stress and may cause stomata to close) on stomatal behaviour in epidermal strips of Commelina communis L. were studied.The phenolics, p‐coumaric acid, caffeic acid, chlorogenic acid, salicylic acid and particularly sinapic acid, were strong inhibitors of stomatal opening. The effects on open stomata were less marked but sinapic acid brought about considerable closure while ferulic acid stimulated wider opening.All the ‘water‐stress’ compounds except proline and glutamine, which had no effect on stomatal behaviour, inhibited opening and caused some closure of initially open stomata; ABA, farnesol, undecanoic acid, linoleic acid and a‐linolenic acid were all particularly effective.
FACTORS DETERMINING ANTHOCYANIN YIELD IN CELL CULTURES OF CATHARANTHUSROSEUS (L.)G. DON.
Authors: HALL R. D. , YEOMAN M. M. 
Published: May 2006

SUMMARYThe intense colour of anthocyanins has made it possible to identify the individual cells accumulating these compounds within cultures of Catharanthus roseus. Furthermore, the amount of anthocyanin per cell could be measured directly by microdensitometry thus revealing the degree of heterogeneity within the cell populations at any interval during the growth cycle. In this way the contribution to overall product yield of individual cells in the culture was assessed. It has been found using this approach that although some inter‐experiment variation occurs, intracellular anthocyanin concentration varies very little and is therefore likely to be controlled by a feedback inhibition mechanism. In general, attempts to enhance the mean intracellular concentration of the pigment through the manipulation of culture conditions have failed. A possible mechanism of metabolic control of intracellular anthocyanin accumulation is discussed. The proportion of cells accumulating anthocyanins, however, varied considerably in cultures grown under different conditions but nevertheless always remained low, never exceeding 20% of the total cell population. The cause of this poor response is unclear but it is suggested that a close metabolic interaction may exist between the cells in the culture to bring about this effect. The possible relevance of these observations to other culture systems accumulating secondary metabolites is discussed.
PLANT GROWTH RESPONSES TO VESICULAR‐ARBUSCULAR MYCORRHIZA
Authors: SCHUBERT A. , HAYMAN D. S. 
Published: May 2006

SUMMARYSeveral vesicular‐arbuscular mycorrhizal endophytes were inoculated separately on to onion plants in soils of low P status amended with five rates of Ca(H2PO4)2. H2O. Mycorrhizal infection was usually decreased by increasing additions of P, but the rate of root colonization and the infection plateau varied with different endophytes. Plant growth responses to mycorrhiza were large at low and medium P with Glomus mosseae and Glomus epigaeum and at medium P with Glomus macrocarpum and Gigaspora margarita. Glomus caledonium and Glomus sp.‘E3’were generally effective at low, medium and high P. Glomus clarum was ineffective at low P. The correlation between infection and growth response was higher for some endophytes than others. It was concluded that analysis of the VA symbiosis with any single endophyte cannot always be used as a basis for generalization about VA mycorrhizal fungi, and that the selection of field inoculants should take special account of endophyte behaviour in soils given extra phosphate.
THE EFFECT OF HIGH NUTRIENT ADDITION UPON SEASONAL PATTERNS OF MYCORRHIZAL DEVELOPMENT, HOST GROWTH, AND ROOT PHOSPHORUS AND CARBOHYDRATE CONTENT IN FRAXINUS PENNSYLVANICA MARSH
Authors: Douds D. D. , Chaney W. R. 
Published: May 2006

SUMMARYThe effects of Glomus macrocarpum and a high rate of nutrient addition upon growth, root carbohydrate and P content, and mycorrhizal development in green ash (Fraxinus pennsylvanica) seedlings were studied over two growing seasons. Mycorrhizal and simitaly growing non‐mycorrhizal seedlings had similar seasonal patterns in growth and in root carbohydrate and P content. No clear difference in mycorrhizal development as as result of nutrient treatment occurred until the middle of the second growing season when the percent root infection of seedlings that received low nutrient increased and that of seedlings that received high nutrient decreased. A seasonal cycle with two phases in the interaction of the VA mycorrhiza and host growth, root shoot ratios, root infection, root content of soluble sugars, starch and P, arbuscule and vesicle numbers, and spore population is proposed.
THE DEVELOPMENT OF MYCORRHIZAL ROOT SYSTEMS IN TRIFOLIUM SUBTERRANEUM L.: GROWTH OF ROOTS AND THE UNIFORMITY OF SPATIAL DISTRIBUTION OF MYCORRHIZAL INFECTION UNITS IN YOUNG PLANTS
Authors: SMITH S. E. , TESTER M. , WALKER N. A. 
Published: May 2006

SUMMARYThe development of young mycorrhizal root systems (up to 28 d) has been studied by growing Trifolium subterraneum L. in soil/sand mixtures with mycorrhizal inoculum mixed throughout the pots. Rates of initiation and of apical extension of main and first‐ and second‐order lateral roots were calculated by fitting spline functions to data collected from daily harvests. The average instantaneous rates of apical extension were found to be about 0.77, 0.2 and 0.06 cm d−1 respectively. These values were used, together with the size and distance from the root apex of the most apical mycorrhizal infection unit, to calculate the frequency of mycorrhizal infection close to the root apex (At) at 16 d. Values of At were found to be similar to average values for the whole main or lateral root system (A). We used plots of the size of infection units and their distances from the root apex, together with values of average rate of extension of roots (v) and rate of growth of infection units (B), to calculate the distances between entry points and the root apices at the time the entry points were formed. The results indicate that infection can occur not only immediately behind the root apex, but also to considerable distances (up to 55 mm) behind the apex in 16‐d‐old plants.
RACE‐SPECIFIC RESISTANCE IN GROUNDSEL (SENECIO VULGARIS) TO THE POWDERY MILDEW ERYSIPHE FISCHERI
Authors: HARRY I. B. , CLARKE D. D. 
Published: May 2006

SUMMARYTwo‐hundred‐and‐fifty lines of groundsel (Senecio vulgaris L.) were tested for their reactions to five different isolates of the powdery mildew fungus Erysiphe fischeri Blumer. Fifty‐one of the lines were also tested for their reactions to three further isolates. All the lines were tested using detached leaves but a number of them were also tested using seedlings. The seedling tests gave esentially the same results as the detached leaf tests. Over 50 % of the host lines were highly resistant (gave low infection types) to one or more of the mildew isolates and this resistance was isolate‐ or race‐specific. Eight specific resistance factors were differentiated by the eight mildew isolates used in the tests. Some of the resistance factors appear to be present in species of Senecio other than S. vulgaris. All eight mildew isolates were complex races with virulence for all but one of the specific resistance factors, the isolates differing from each other in the possession of avirulence for a unique specific resistance factor. The interactions between the host lines and mildew isolates are indicative of a gene‐for‐gene interaction but the genetic analysis required to establish this was not attempted. The majority of lines which were susceptible to each isolate developed the highest or most susceptible infection type. It is considered that tolerance of the parasite may operate together with race‐specific resistance in an overall survival strategy which has evolved to enable groundsel to cope with mildew attack.