bluuebunny/crossref_metadata_2025_split huggingface dataset:
TERATOLOGY AND METAMERIC PLANT CONSTRUCTION
Authors: van GROENENDAEL J. M. 
Published: May 2006

SummaryThe growth of Plantago lanceolata L. has been described using metamers as construction units. The growth of each unit has been broken down into a sequence of four simple building instructions, two of which incorporate two or three alternatives. The resulting conceptual model has been tested against a variety of teratologies known to exist in Plantago lanceolata. All of these malformations could be explained in terms of either wrong steps, or wrong sequences, or both. There seems to be a certain hierarchy of control such that more malformations tend to occur at tertiary meristems than at primary meristems. For at least some of the teratologies, the nature of the control seems genetic.
EFFECT OF CATIONS ON UPTAKE, TRANSLOCATION AND REDUCTION OF NITRATE IN WHEAT SEEDLINGS
Authors: BARNEIX ATILIO J. , BRETELER HANS 
Published: May 2006

SummaryThe effect of Ca2+, K+ and Na+ on uptake, transport and reduction of NO3− was studied in 10‐day‐old plants of Triticum aestivum L. cv. Sicco grown in water culture in relation to the ion balance in plant, medium and xylem exudate.When Ca2+ (0.25 mM) was the only nutrient cation, NO3− uptake and accumulation of NO3− in the leaves were low as compared to treatments with K+ or Na+ (0.5 mM). With Na+, the uptake of NO3− was similar to that with K+, but virtually no Na+ and 75 % less NO3− accumulated in the leaves.Medium pH dropped initially with 0.5 mM KNO3 but rose immediately when Ca2+ was the only cation. The carboxylate content rose in roots and leaves of K+ plants and, to a lesser extent, in Na+ plants. Roots of Ca(NO3)2 plants showed negative ash alkalinity indicating the presence of acidity.The pH of the xylem exudate increased with the cation/NO3− ratio in the exudate and was about one unit higher with Ca(NO3)2 than with NaNO3 or KNO3.We conclude that roots of plants grown in the absence of monovalent cations have serious pH problems because of a high rate of alkalinity release to the medium in exchange for NO3− uptake, and the secretion of alkalinity into the xylem.
EFFECTS OF SO2 AND OTHER AIR POLLUTANTS ON THE MORPHOLOGY OF EPICUTICULAR WAXES ON NEEDLES OF PINUS STROBUS AND PINUS BANKSIANA
Authors: RIDING R. T. , PERCY K. E. 
Published: May 2006

SummaryExposure of elongating needles of Pinus strobus L. to SO2 and other unidentified air pollutants delayed wax deposition in the epistomatal chambers. Following completion of wax deposition, the wax rodlets fused, forming plate like sheets. Needle wettability appeared to be increased as a result of modification of the epicuticular waxes, potentially increasing their sensitivity to acid rain‐induced injury. This occurred without alteration of the structure of the stomatal complex itself. No alteration of wax form was evident on needles of P. banksiana Lamb., even under conditions which led to acute SO2 foliar injury.
ECTOMYCORRHIZAS AFFECT IONIC BALANCE DURING AMMONIUM UPTAKE BY DOUGLAS‐FIR ROOTS
Authors: BLEDSOE CAROLINE S. , RYGIEWICZ PAUL T. 
Published: May 2006

SUMMARYMycorrhizas have been shown to alter ion fluxes for many nutrients. Experiments were done to determine the extent to which ectomycorrhizas alter the ionic balance of roots of Douglas‐fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings mycorrhizal with Hebeloma crustuliniforme (Bull, ex St. Amans) Qúel. exposed to solutions containing either 16N ammonium sulphate or 16N ammonium chloride. Net fluxes of ammonium, hydrogen, potassium, calcium, sodium, bicarbonate, sulphate and chloride were measured. The mycorrhizal association altered ion fluxes, primarily decreasing sodium uptake and potassium release rates (both anion treatments) and increasing bicarbonate release during exposure to ammonium chloride. Rates of carboxylate accumulation in the tissue were inferred from the net flux data; mycorrhizal seedlings may produce more cation‐carboxylate complexes compared with nonmycorrhizal seedlings. When compared with agricultural plants exposed to ammonium, Douglas‐fir took up a considerably greater number of cations for each ammonium ion absorbed, which may account for the greater number of carboxylate anions also produced by Douglas‐fir. These findings were discussed in terms of ecological significance for growth of Douglas‐fir.
RESPONSE OF SO2‐SENSITIVE AND RESISTANT GENOTYPES OF RYEGRASS (LOLIUM PERENNE L.) TO PROLONGED EXPOSURE TO SO2
Authors: KOZIOŁ M. J. , SHELVEY J. D. , LOCKYER D. R. , WHATLEY F. R. 
Published: May 2006

SUMMARYTwo genotypes of perennial ryegrass (Loliutn perenne L.), one (S23) sensitive to SO2 and the other (BR) reported to be resistant, were exposed to 0, 50 or 150 ni SO2 1−1 (0, 133 or 398 μg SO2 m−3 at STP) for four weeks under conditions that gave ‘slow’, ‘medium’ or ‘fast’ rates of growth. These treatments allowed comparisons of the responses between genotypes over a range of conditions within which plants could be expected to exhibit maximum and minimum sensitivities to SO2. Significant effects on growth from exposure to SO2 were observed primarily when growth was slow, when the plants were expected to be most sensitive. Although exposure to 150 nl SO2 1−1 significantly increased stomatal resistance two‐fold in both genotypes during slow growth, there was no accompanying diminution in leaf sulphur content, implying that a two‐fold increase in stomatal resistance is not sufficient to be considered an avoidance mechanism to SO2.Compared with the sensitive S23 gentoype under control (SO2‐free conditions, the resistant BR genotype shows slightly greater stomatal resistance, reduced absorption of sulphate through the roots, and reduced dry matter production. Reduced dry matter production in BR may be attributed to its peculiar isoenzyme of ribulose‐1,5‐bisphosphate carboxylase, which shows a greater resistance to inhibition by sulphite but lower carboxylation rates than ribulose‐1,5‐bisphosphate carboxylase from S23.
PHOSPHOLIPID CATABOLISM AND SENESCENCE OF PEA FOLIAGE MEMBRANES: PARAMETERS OF Ca2+:CALMODULIN:PHOSPHOLIPASE A2−INDUCED CHANGES
Authors: SRIDHARA SAMPATH , LESHEM YA'ACOV Y. 
Published: May 2006

SUMMARYWith progress of normal senescence of pea (Pisum sativum) foliage membranes free fatty acid: sterol ratios increase, this reflecting increment of phospholipolytic activity. The effect is simulated by exogenous application of phospholipase A2 in the presence of Ca2+ and calmodulin and inhibited by the calmodulin inhibitor fluphenazine. This trend is accompanied by an increase in membrane microviscosity and transition temperatures and, as evidenced by wide angle X‐ray diffraction data, indicates a change from the liquid crystalline phase to a solid gel lipid bilayer configuration. Ethylene production, associated with plant senescence, closely follows the above biophysical changes. Membranes also manifest lipoxygenase activity, increasing with age and upon application of Ca2, calmodulin and phospholipase A2 the increment being inhibited by the more specific calmodulin inhibitor calmidazolium. Moreover, the polyunsatu‐rated linolenic acid enhanced phospholipase A2‐induced ethylene production, whereas the saturated stearic acid was ineffective. Results are interpreted as a Ca2+‐triggered and calmodulin mediated phospholipase A2 activation whereby membrane integrity is impaired by the release of the 2‐situated polyunsaturated fatty acids which in the freed form induce lipoxygenase and specific Ca2+ ionophoretic activity during the process of which an ethylene forming mechanism is activated.
CALCIUM ACCUMULATION BY TWO STRAINS, CALCICOLE AND CALCIFUGE, OF THE MYCORRHIZAL FUNGUS PAXILLUS INVOLUTUS
Authors: LAPEYRIE F. F. , BRUCHET G. 
Published: May 2006

SUMMARYPatterns of calcium accumulation have been compared between two strains of the ectomycorrhizal fungus Paxillus involutes (Batsch. ex Fr.) Fr. Calcium accumulation during a period of growth on a substrate containing calcium paralleled that found in higher plants, with the calcifuge strain accumulating higher levels of calcium than the calcicole strain, especially in the older parts of the mycelium. In short‐term uptake experiments, using mycelia grown on calcium free medium then placed for 3 h in various calcium solutions, this order was usually reversed with the calcicole strain accumulating higher levels than the calcifuge strain. Accumulation in relation to calcium concentration was biphasic, and was generally higher at 4 °C than at 24 °C. This is inconsistent with an equilibrium model based on passive mechanisms but is consistent with a model which has active calcium efflux balancing a large passive influx. The operation of this mechanism in mycorrhizal fungi could serve to protect calcifuge plants in calcareous situations.
FLOWERING BEHAVIOUR OF THE MONOCARPIC PERENNIAL CYNOGLOSSUM OFFICINALE L.
Authors: JONG TOM J. , KLINKHAMER PETER G. L. , PRINS ADRIANA H. 
Published: May 2006

SUMMARYFlowering in Cynoglossum officinale L. is strongly size‐dependent. The probability of flowering increases with the size of the plant. Also, a critical size exists below which the plants do not flower. Plants above this size develop flower primordia during a cold period. During winter it is determined which plants will flower in the following spring and which plants will not. The probability of flowering is not affected by nitrogen concentration in the plant or light intensity, when these factors are separated from their effects on the dry weight of the plant. Delay of flowering is a common phenomenon in natural populations of Cynoglossum officinale on coastal sand‐dunes at Meijendel (near The Hague, The Netherlands). Over a seven‐year period the percentage flowering of rosettes varied between 2 and 25 %. The proportion of rosettes flowering was positively correlated with rainfall in the previous year and was reduced after a very cold winter.
EXPERIMENTAL ANALYSIS OF FLUORIDE SUSCEPTIBILITY OF GRAPEVINE (VITIS VINIFERA L.): LEAF DEVELOPMENT DURING FOUR SUCCESSIVE SEASONS OF FUMIGATION
Authors: DOLEY D. 
Published: May 2006

SUMMARYLeaf development was studied in potted specimens of grape vine (Vitis vinifera L., varieties Chardonnay, Gordo and Traminer) that were exposed to hydrogen fluoride in controlled environment cabinets during four successive growing seasons. The duration of exposures varied from 54 d in the second season to 159 d in the fourth. There was no significant or consistent effect of fluoride on the numbers of leaves produced on major or lateral shoots in any variety. Leaf size during the first growth flush of a season was not influenced by the present or previous exposure of plants to ambient fluoride concentrations up to 1.5μm F m−3. Mature leaf size during the middle or latter portion of the fourth season of fumigation was significantly reduced in the Chardonnay and Traminer varieties as a result of exposure to fluoride concentrations of 0.64μg m−3 or more. Leaf size in the variety Gordo was not affected by ambient fluoride concentrations up to 1.5μg F m−3. Stomatal frequency and size in the variety Chardonnay, and leaf water vapour conductance in all varieties were not affected by ambient fluoride concentrations up to 1.05μg F m−3. The work demonstrates variations in response of grape vine leaves to ambient conditions at different stages of the growing season.
A PAPER‐SANDWICH TECHNIQUE FOR RAPID SYNTHESIS OF ECTOMYCORRHIZAS
Authors: CHILVERS G. A. , DOUGLASS P. A. , LAPEYRIE F. F. 
Published: May 2006

SUMMARYIn the basic pure‐culture technique, fungus for inoculum is grown on stiff absorbent paper card over Potato Dextrose Agar, then this paper is removed aseptically and laid, fungus‐side down, on to a two‐dimensional array of roots of seedlings grown axenically on filter paper over a mineral salts agar medium. With the high inoculum potential achieved by this technique, ectomycorrhizas have been formed within one week of inoculating Pisolithus tinctorius Coker & Couch or Paxillus involutus (Batsch. ex Fr.) Fr. on to Eucalyptus globulins Subsp. bicostata (Maid, et al.) Kirkp., and over 50% of root apices were converted to ectomycorrhizas within two weeks. The paper‐based inoculum has also been applied successfully to convert peripheral roots of seedlings grown in peat‐moss within clay pots.
CELLULAR READJUSTMENT OF BARLEY SEEDLINGS TO SIMULATED ACID RAIN
Authors: WOLFENDEN JENNIFER , WELLBURN A. R. 
Published: May 2006

SUMMARYNo changes in buffer capacity at any range of pH were detected in either the shoots or roots of 9 d old hydroponically‐grown barley seedlings which had been grown in dilute acid (pH 3 or 4) for the last 4 days of growth. Similar lack of change in buffer capacity was observed in barley which had been intermittently sprayed with acidic mists (pH 3 or 4) as compared to those sprayed with pH 56 media for the last 2 or 4 d of growth. Acidic treatments, especially growth in acidic media or 2 d of occasional spraying, caused significant increases in the levels of plastidic sulphate, as measured by high performance ion chromatography but no changes in the plastidic concentrations of other anions occurred. High field 31P‐NMR spectroscopy of barley shoot tissue showed that the vacuolar pH levels (as revealed by the pH‐dependent orthophosphate signals) of those tissues which had been sprayed with acidic solutions (pH 3 or 4) for 2 d were significantly lower than in those similarly sprayed with pH 5.6 solutions. This may mean that ATP‐dependent H+‐pumps in the tonoplast are involved in cellular readjustments to the imposed acidity. No growth reductions or visible injury were detected over these short term treatments but these changes of vacuolar pH and plastidic sulphate content may indicate that homeostatic adjustments have an energetic cost which may ultimately account for reductions in plant growth attributed elsewhere to acidic precipitation.
THE NAME OF THE ROSE: A REVIEW OF IDEAS ON THE EUROPEAN BIAS IN ANGIOSPERM CLASSIFICATION
Authors: WALTERS S. M. 
Published: May 2006

SUMMARYThis ‘Tansley Review’ paper takes as its starting point a paper of mine published in 1961, which explored the shape and size of modern Angiosperm families and genera as a product of taxonomic practice over centuries. It considers how far the conclusion ‐ that our existing scientific classification, based on Linnaeus' masterly standardization in the eighteenth century, is very markedly ‘Eurocentric’– has been criticized, accepted or modified by subsequent writers. In particular, it assesses the important contribution made in recent years by ethnobiologists using expert knowledge from social anthropology, linguistics and other disciplines. Finally, the paper considers briefly the broader aspects of current controversies about the nature and purpose of taxonomic activity, including the argument about its relevance to evolutionary knowledge and speculation. It concludes that, to a remarkable degree, practising taxonomists ignore conceptual or philosophical difficulties and are able to co‐operate, although their leisurely and arcane procedures may not measure up to the‘information explosion’.

Contents

Summary
527

I.
Introduction
528

II.
The age and size of Angiosperm families and genera
530

III.
Recognition of the European bias in classification
539

IV.
Conclusions
542

References
544
THE APPARENT WIDTH OF THE RHIZOSPHERE OF TRIFOLIUM SUBTERRANEUM L. FOR VESICULAR‐ARBUSCULAR MYCORRHIZAL NFECTION: EFFECTS OF TIME AND OTHER FACTORS
Authors: SMITH S. E. , WALKER N. A. , TESTER M. 
Published: May 2006

SUMMARYWe use the mathematical model developed by Ferriss (1981) for the study of plant pathogens to calculate the apparent width of the rhizosphere (W) of Trifolium subterraneum L. for infection by propagules of vesicular‐arbuscular mycorrhizal fungi in soil, examining the effects of wetting the soil for different times before planting and of harvesting at different times. The reasons for choosing this model rather than that of Gilligan (1979) are given. Propagule densities were determined by the most probable number (MPN) method at 28 d using the same host species as the test plant, thus including a factor in the calculations which is the product of the efficiency of the propagules to infect and the susceptibility of the roots.Values for W at 10 to 12 d were between 2.5 and 6.5 mm for mixed soil inoculum and between 8.9 and 13.2 mm for Glomus mosseae (Nicol & Gerd.) Gerdeman & Trappe. W increased with time, associated with an increase in the number of infections formed. Factors contributing to this include progressive germination of propagules following wetting the soil, growth of hyphae from greater distances to the root and formation of secondary infections. Wetting the soil before planting had the greatest effect on W in 4 d old plants. By 10 d, there was no effect, supporting the idea that most propagules are likely to have germinated by that time. The contribution of secondary infections is harder to determine, but is likely to be important from about 10 d onwards, resulting in overestimation of W. By 12 to 16 d, in experiments in which six plants were grown in 210 or 222 cm3 soil, the apparent volume of the rhizosphere plus root exceeded the volume of soil. Values of the apparent width of the rhizosphere in our experiments are therefore most reliable before the plants are 10 d old.If the MPN method is used to determine propagule densities at the same harvest times and under the same conditions as those used to collect other data, then the equations can be used to compare different fungi and environmental conditions with respect to infection of young plants.
WATER RELATIONS OF XERIC GRASSES IN THE FIELD: INTERACTIONS OF MYCORRHIZAS AND COMPETITION
Authors: ALLEN E. B. , ALLEN M. F. 
Published: May 2006

SUMMARYThe effects of vesicular‐arbuscular mycorrhizal inoculum and competition from non‐mycorrhizal annual plants were tested on Agropyron smithii Rydb. and Agropyron dasystachyum (Hook.) Scribn. growing in an inoculum‐poor soil. Mycorrhizal A. smithii decreased stomatal resistance (rs) and increased leaf water potential compared to the non‐inoculated plants, but only during the driest portion of the growing season. The presence of annuals caused increased rs of A. smithii, but only of non‐inoculated plants. Mycorrhizal plants had the same rs with or without annuals, indicating that mycorrhizas may alleviate the detrimental effects of competition on rs of A. smithii. By contrast, neither inoculation nor annuals significantly affected water relations of A. dasystachyum. Mycorrhizas also did not increase N and P concentrations or percentage cover of either grass, but both had delayed phenology when mycorrhizal. This research was done during a wet year when the effects of mycorrhizas may be subtle. Long‐term observations are necessary to determine the importance of mycorrhizas under field conditions.
THE EFFECT OF A PHYTOTOXIN FROM ALTERNARIA BRASSICICOLA ON BRASSICA POLLEN
Authors: HODGKIN T. , MACDONALD M. V. 
Published: May 2006

SUMMARYA methanol‐soluble extract from the culture filtrate of Alternaria brassicicola (Schw.) Wilts., grey leaf spot, markedly inhibited pollen germination and pollen tube growth of Brassica napus L., Brassica campestris L. and Brassica oleracea L. in hanging drop culture at concentrations comparable to those causing death of B. napus secondary embryoids. The extract was partially purified by Sephadex column chromatography, and the fractions obtained were tested for their inhibitory capacity. Two fractions which killed secondary embryoids also inhibited pollen germination. The methanol‐soluble extract and inhibitory fractions from Sephadex chromatography were further tested using a thin‐layer chromatographic bioassay which showed that the original extract could be separated into at least four inhibitory compounds.The potential of the techniques used for screening and selection for resistance to compounds toxic to plants is briefly outlined.
PHYTOALEXINS, WATER‐STRESS AND STOMATA
Authors: PLUMBE ALISON M. , WILLMER C. M. 
Published: May 2006

SummaryThe effects of the phytoalexins, rishitin, pisatin, wyerone acid and phaseollin, (all at 0.1 mol m−3) were tested on stomatal responses in epidermal strips of Commelina communis L. and Vicia faba L. Additionally, the effects of the phytoalexins on guard cell protoplasts of C. communis were examined and compared with those of several‘water‐stress' compounds namely abscisic acid (ABA), farnesol, nonanoic and undecanoic acids, and α‐linolenic acid. Phytoalexins may be loosely defined as‘microbial stress' compounds while‘water‐stress' compounds are denned as those which accumulate in leaf tissue under water‐stress and close stomata or act as osmotic adjusters.Wyerone acid and phaseollin inhibited stomatal opening in C. communis to the same extent as ABA, while rishitin had no significant effect and pisatin had an intermediate effect. When stomata were open, treatments with phaseollin and ABA brought about a marked closing response, while those with pisatin and rishitin were not statistically significant from the controls; wyerone acid initially opened stomata further but after 5 h exposure stomatal apertures were similar to those of the controls.Stomatal opening in epidermis of V. faba was greatly inhibited by ABA, while all phytoalexin treatments resulted in intermediate inhibitory effects between those obtained with the control and ABA treatments, wyerone acid being the most inhibitory.Pisatin and rishitin (at 0.1 mol m−3) had no discernible effects on guard cell protoplasts, while phaseollin and wyerone acid (at 0.1 mol m−3) caused loss of protoplast viability. The‘water‐stress' compounds, nonanoic, undecanoic and α‐linolenic acids, also caused gradual loss of protoplast viability and farnesol caused lysis of protoplasts. Only ABA caused protoplasts to contract without loss of vitality. Thus phaseollin and, to a lesser extent, wyerone acid have similar properties to ABA in that they inhibit stomatal opening and promote closure. However, unlike ABA but like farnesol, nonanoic, undecanoic and α‐linolenic acids, their effects are likely to be associated with phytotoxicity, their phytotoxicity depending on duration of exposure and on concentration.
COMPARTMENTATION AND FLUXES OF SUCROSE IN INTACT LEAF BLADES OF BARLEY
Authors: FARRAR S. C. , FARRAR J. F. 
Published: May 2006

SummarySucrose in barley leaf blades can be considered as being compartmented between two types of pool: transport (including mesophyll cytosol and apoplast, and vascular tissue) and vacuolar. The relative sizes of these pools, and their changes over a light/dark cycle, have been estimated using 14C labelling of the intact leaf and washout of 14C from leaf discs. Both types of pool increase during the photoperiod, the proportional distribution between them remaining the same; roughly one‐fifth of the sucrose is in the transport pool. The rate‐constants describing translocation, and loading and unloading of the vacuole, show diel changes, and fluxes of sucrose across the tonoplast are likely to be critical in controlling fluxes of photosynthetically fixed carbon within and out of barley leaves. The unloading of sucrose from vacuoles is probably the site where control is exercised; this conclusion is supported by a simple simulation model.