bluuebunny/crossref_metadata_2025_split huggingface dataset:
PHYSIOLOGICAL‐ENVIRONMENTAL INTERACTIONS IN LICHENS. VII. THE ENVIRONMENTAL CONTROL OF GLUCOSE MOVEMENT FROM ALGA TO FUNGUS IN PELTIGERA CANINA V. PRAETEXTATA HUE
Authors: TYSIACZNY M. J. , KERSHAW K. A. 
Published: May 2006

SummaryThe movement of labelled glucose from the phycobiont of the lichen Peltigera canina v. praetextata Hue., to the mycobiont, has been examined under contrasting environmental conditions of temperature and moisture. The ratio of labelled mannitol : labelled photosynthetic products is used as a relative measure of the rate of transport of glucose and its incorporation into mannitol.The relative amount of label appearing in mannitol remains fairly constant over a wide range of experimental temperatures, but there is a marked interaction with the level of thallus hydration. At 100% thallus water content by weight, when high rates of photosynthesis are still maintained, only a small proportion of the total label appears in mannitol. It is suggested that this retention of photosynthate at low levels of thallus saturation is essential to supply the basic metabolic requirements of the phycobiont. Conversely the requirements of the fungal partner are satisfied at higher levels of thallus saturation. Thus alternate wetting and drying cycles are essential to maintain the metabolic requirements of each of the bionts and hence the physical integrity of the lichen itself. The results are briefly discussed in terms of the facilitated diffusion of glucose proposed by Smith (1974).
LICHEN WATER RELATIONS UNDER DRYING CONDITIONS
Authors: LARSON D. W. 
Published: May 2006

SummaryThe loss of water by evaporation in various species of lichens has been examined under a range of controlled windspeed/radiation regimes. Temperate and arctic species both show a type of morphological control of evaporation. Such control varies, however, with the nature of the surrounding environment. Evaporation from those species which show a very low resistance to evaporative water loss such as Bryoria nitidula, Umbilicaria deusta and U. veiled appears to be relatively insensitive to increases in radiant flux. Conversely those species, or specific growth forms, which show a high resistance to evaporative water loss, such as Cladina stellaris and U. muhlenbergii, appear to be sensitive to increases in supply of radiant energy.These results suggest that the morphological control of evaporation in lichens is significant to the ecology of this group of plants.
APICAL INTRUSIVE GROWTH OF FIBRES FROM THE FLOWERING STEM OF LOLIUM TEMULENTUM L.
Authors: LAWTON J. R. , HARRIS P. J. , LOWRY K. H. , DHANOA M. S. 
Published: May 2006

SummaryExtension of the internode below the point of insertion of the flag leaf of Lolium temulentum L. takes place in the lower 10 to 15 mm. Extension of the long epidermal cells also takes place in this region. However, fibre cells show little extension in the lower 10 mm and maximum extension occurs at about 30 mm above the node. Thus, there is extension of fibre cells within that portion of the internode which has ceased extension and is bounded by an epidermis, the cells of which have also ceased elongation. This suggests the occurrence of intrusive growth of the fibres and evidence for this is shown from the measurement of macerated fibres and from electron micrographs.The walls of fibre cells measured in internodes of different lengths and ages thicken only very slightly in the lower 30 mm and most cell wall thickening occurs between 45 and 90 mm above the node. Thus most cell wall thickening occurs after the fibre cells have ceased to elongate.
CARBOHYDRATE METBOLISM IN AGARICUS BISPORUS: CHAGES IN NON‐STRUCTURAL CARBROHYDRATES DURING PERIODIC FRUITING (FLUSHING)
Authors: HAMMOND JOHN B. W. , NICHOLS ROYSTON 
Published: May 2006

SummaryMannitol, trehalose and glycogen contents of Agaricus bisporus fruit bodies were sampled throughout the 46 day period of production of two crops. Maximum trehalose and glycogen levels were consistently observed in the interflush periods, whilst mannitol production was greatest during the flushes. A correlation exists between the sum of the peak glycogen and trehalose values and the yield of the following flush in the first crop. The possible role of trehalose and glycogen as reserves for fruit body production and in the control of flushing is discussed.
CROSS INOCULATION GROUP SPECIFICITY IN CICER‐RHIZOBIUM SYMBIOSIS
Authors: GAUR Y. D. , SEN A. N. 
Published: May 2006

SummaryCross‐inoculation group specificity in Cicer arietinum L. (chickpea) was studied. Seventy‐one strains of root nodule bacteria of C. arietinum were examined for nodulation on 87 species of legumes. These species represent all the known cross‐inoculation groups and were selected from various tribes and genera of family Fabaceae and Mimosaceae. In a reciprocal cross‐inoculation study, 287 strains of root nodule bacteria from 52 of the 87 species, were examined on various genotypes of C. arietinum. C. arietinum and its root nodule bacteria did not show cross inoculation affinity with any of the members of the known cross‐inoculation groups: alfalfa, clover, pea, bean, soybean, lupin‐lotus and cowpea miscellany; except for some loose non‐reciprocal kinship with Sesbania, which in its turn has strong affinity with the cowpea miscellany. However, under natural conditions in soil, even the loose non‐reciprocal kinship between Cicer and Sesbania was rare. For practical reasons, it is suggested that C. arietinum and its root nodule bacteria should be considered in a separate cross‐inoculation group.‘Cross‐inoculation host specificity’ appears to be of some help in the revision of the taxonomy of order Leguminosales and supports the placement of Cicer in a monogeneric tribe Cicereae.
THE DEVELOPMENT OF WATERLOGGING DAMAGE IN YOUNG BARLEY PLANTS IN RELATION TO PLANT NUTRIENT STATUS AND CHANGES IN SOIL PROPERTIES
Authors: Drew M. C. , Sisworo E. J. 
Published: May 2006

SummaryWhen the soil in which 13‐day‐old barley plants were growing was flooded, the concentration of dissolved oxygen in the waterlogged soil declined to < 2 % (in the equilibrium gaseous phase) within 48 h. Within the same time there was injury to seminal roots and a reduction in the rate of leaf extension. The net rates of uptake of nitrogen, phosphate and potassium in shoots were reduced shortly after the onset of waterlogging, and because dry matter accumulation by shoots was initially little affected, the average concentration of these nutrients showed a marked decline after 48 h compared with aerated controls. The concentration of nitrate in shoots was particularly sensitive to waterlogging and after 48 h was about one third of that in controls. Analysis of individual leaves and tillers showed that with waterlogging, nitrogen was accumulated by the younger tissues at the expense of the older leaves. This trend, which was not observed with plants in aerobic soil, preceded the premature breakdown of chlorophyll in the older leaves.With prolonged anaerobiosis, there were increases in the concentration of potentially inhibitory soil products (ethylene, organic acids, manganese) and a decline in nitrate in the soil solution, but these changes, which mostly occurred after the onset of the characteristic symptoms of waterlogging damage were relatively small and unlikely to have led to injury to shoots. The possible relations between the low concentration of oxygen around roots, the inhibition of ion uptake, the redistribution of nutrients within the shoot, and the premature senescence of leaves are discussed.
ROOT FORMATION IN CUTTINGS OF APPLE IN RELATION TO AUXIN APPLICATION AND TO ETIOLATION
Authors: DELARGY J. A. , WRIGHT C. E. 
Published: May 2006

SummaryThe inter‐relationship of auxin treatment and etiolation, in their effect on adventitious root formation, was investigated in stem cuttings of the difficult‐to‐root cultivar of apple ‘Bramley's Seedling’. Unetiolated cuttings of the scion variety rooted at a comparatively low level with a range of concentrations of each of six synthetic hormones. Localized etiolation of the shoot, on the other hand, stimulated root formation in proportion to the length of the stem segment treated. Indole butryric acid applied to etiolated cuttings promoted a comparatively small, but still significant, increase in root formation. The effect of etiolation is attributed to a change in the effective level of an active factor, as opposed to a direct stimulation of its synthesis.
SALT TOLERANCE IN THE WILD RELATIVES OF THE CULTIVATED TOMATO: PROLINE ACCUMULATION IN LYCOPERSICON ESCULENTUM MILL., L. PERUVIANUM MILL. AND SOLANUM PENNELLI COR. TREATED WITH NaCI AND POLYETHYLENE GLYCOLE
Authors: TAL M. , KATZ A. , HEIKIN H. , DEHAN K. 
Published: May 2006

SummaryThe cultivated tomato Lycopersicon esculentum cv. Rhemlands Ruhm and the two wild species L. peruvianum and Solomon pelnnellii which originated in dry habitats were compared with respect to accumulation of free proline, chloride and succulence under NaCl stress, and accumulation of proline and succulence under water stress produced by polyethylene glycole.Proline accumulation increased in all three species under both types of stress. Increase under salinity stress, however, was smaller in the two wild species which accumulated more chloride and were more succulent. Under water stress, the increase of proline level was greatest in is. pennellii, in which succulence decreased drastically, and smallest in L. peruvianum.The possible role of salt tolerance in enabling wild tomato species to endure drought, and the difference between them with respect to proline accumulation, are discussed.
INDUCTION OF FLOWERING IN WILD LETTUCE (LACTUCA SERRIOLA L.). II. DEVERNALIZATION
Authors: Marks M. K. , Prince S. D. 
Published: May 2006

SummaryVernalized Lactuca serriola L. seeds (cypselae) are devernalized by 25 ° C for 24 h and complete reversal of the vernalization caused by 28 days at 2 to 4 ° C occurs after approximately 7 days. Seeds can only be devernalized before germination and in the absence of light. Plants cannot be devernalized. The significance of stabilization of the vernalized state by light is discussed in relation to seeds in the natural environment and it is concluded that seeds exposed on the soil surface are unlikely to be devernalized whereas those which do not germinate may pass through repeated cycles of vernalization and devernalization.
THE EFFECT OF TEMPERATURE, SOLAR RADIATION AND MOISTURE ON THE REDUCTION OF ACETYLENE BY EXCISED ROOT NODULES FROM ALNUS GLUTINOSA
Authors: MCNIEL R. E. , CARPENTER P. L. 
Published: May 2006

SummaryThis study describes the influence of light, temperature, and moisture on N2‐fixing ability of Alnus glutinosa. Diurnal and day by day variations in the rate of acetylene reduction by excised root nodules were observed.Field‐grown A. glutinosa responded in C2H2‐reducing ability due to fluctuation in solar radiation or temperature or both when the plants were not under moisture stress. When solar radiation and temperature increased during the day, the rate of C2H2 reduction increased. Ample soil moisture was needed for nodules of A. glutinosa to be responsive to solar radiation or temperature.
N2‐FIXATION (ACETYLENE REDUCTION) AND THE MICROBIAL COLONIZATION OF MANGROVE ROOTS
Authors: ZUBERER D. A. , SILVER W. S. 
Published: May 2006

SummaryScanning and transmission electron microscopy were employed to study the microbial colonization of roots of three Florida mangrove species (Rhizophora mangle, Avicennia germinans and Laguncularia racemosa). Observations of ultrathin sections revealed that all three species were colonized in the outer cortical cell layers and that colonization was primarily limited to the mucigel layer and sloughing cells. Interpretation of these observations in relation to biological nitrogen fixation associated with roots of these species of intertidal halophytes is presented.
INTERNAL SPREAD OF FUNGI INOCULATED INTO HARDWOOD STUMPS
Authors: RAYNER A. D. M. 
Published: May 2006

SummaryFreshly cut stumps of beech (Fagus sylvatica), birch (Betula pendula) and oak (Quercus robur) were inoculated with wooden plugs permeated by mycelium of wood‐decaying basidiomycetes and treated with 40%(w/v) aqueous ammonium sulphamate solution (AMS), 1.5 % (w/v) 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐T) in paraffin, or water. Successful establishment frequently occurred in water‐treated stumps but internal spread was usually limited. AMS prevented establishment of certain fungi (e.g. Daedaleopsis confragosa in birch and oak), but greatly stimulated internal spread of others especially in wood adjacent to the bark. Here some fungi (e.g. Hypholoma fasciculare, Phlebia meritmoides) were favoured because of their capacity for subcortical mycelial growth. 2,4,5‐T stimulated colonization in beech, but not birch or oak.Colonization patterns varied for different fungus‐tree species combinations, e.g. Chondrostereum purpureum spread faster initially than any other fungus tested in beech and birch, and was not stimulated by AMS treatment in the former. Longitudinal spread of fungi such as Bjerkandera adusta, Coriolus versicolor and Stereum hirsutum in birch was considerably less after 6 months than in oak, but subsequently accelerated, whilst spread in oak ceased.
SEASONAL EFFECTS OF WOUNDING AND GROWTH SUBSTANCES ON DEVELOPMENT OF TRAUMATIC RESIN DUCTS IN CEDRUS LIBANI
Authors: FAHN A. , WERKER E. , BEN‐TZUR P. 
Published: May 2006

SummaryThe development of traumatic resin ducts, in response to wounding and to hormone [napthalene acetic acid (NAA) and gibberellic acid (GA)] application at various times of the year was studied in the secondary xylem of Cedrus libani Loud. Resin duct formation was associated with enhanced cambial activity. As a result of wounding or of application of NAA or NAA together with GA3, a system of longitudinally oriented ducts developed around the treated area. In most cases the ducts reached their greatest length above the treated area. Application of GA3 alone did not normally cause the formation of ducts. Wounding and auxin application, at the time of highest cambial activity, led to duct formation shortly after treatment. Ducts did not develop during the period of cambial dormancy. When auxin was applied during dormancy, duct systems developed in the following season of cambial activity, but wounding during the same period produced no ducts or only short ones in the following season.
SECONDARY METABOLISM IN TISSUE CULTURES OF THEOBROMA CACAO
Authors: JALAL M. A. F. , COLLIN H. A. 
Published: May 2006

SummaryA synthetic medium was developed for the routine subculture of callus and cell suspensions of cocoa. All growth hormones and the coconut milk (CM) supplement of previous media were replaced by indole butyric acid (IBA) and zeatin, at concentrations of 1 mg 1−1 IBA and 0·05 mg 1−1 zeatin for callus and 10 mg 1−1 IBA and 0·5 mg 1−1 zeatin for cell suspension cultures. During the exponential phase of the growth cycle on this medium, the total phenolics in the callus and cell suspensions declined but then increased at onset of the stationary phase and finally declined again with cell senescence. The flavonoid compositions of the callus and cell suspension were similar and much less varied than that of the original intact cotyledon. Both tissue cultures contained epicatechin, leucocyanidins, caffeic and coumaric acids, all of which are thought to act as flavour precursors when in the intact fermented cotyledon. The methylated purines, theobromine and caffeine, could not be detected in the tissue cultures even in the presence of high nitrate levels in the medium. When precursors of theobromine synthesis such as xanthine, hypoxanthine and 7‐methyl‐xanthosine, were fed to the cells, theobromine was formed only when the cells were incubated with 7‐methyl‐xanthosine and a methyl donor, methionine, suggesting that part of the biosynthetic route to theobromine synthesis is still functional in the tissue culture.
INCORPORATION OF 14C‐LABBLLED SUBSTRATES BY UNINFETED AND VA MYCORRHIZAL ROOTS OF ONION
Authors: LÖSEL DOROTHY M. , COOPER KAREN M. 
Published: May 2006

SummaryVA mycorrhizal infection of onion roots with Glomus masseae increases their ability to incorporate carbon from external sources, such as sucrose, acetate and glycerol, as well as from photosynthetic assimilate. Within 20 min of photosynthesis in 14CO2, radioactivity was present in lipid and non‐lipid, soluble and insoluble compounds of roots. After a chase period of 18 h, c.30 % of the radioactivity in mycorrhizal and non‐mycorrhizal roots supplied with [2‐14C]‐acetate and [14C]glycerol and 12 to 20% of that from [14C]sucrose was in the lipid fraction, while c. 5% of the 14C‐labelled photosynthate received by the roots appeared in lipids. Mycorrhizal roots differed from uninfected roots in their significantly higher incorporation of carbon from photosynthate, sucrose and acetate into ethanol‐soluble compounds and insoluble materials, from sucrose into water‐soluble compounds and from acetate into lipids.
BREEDING BEHAVIOUR AND POPULATION DIFFERENTIATION IN THE HEXAPLOID GRASS KOELERIA VALLESIANA (HONCK.) BERTOL.
Authors: CALLOW R. S. , Parker J. S. 
Published: May 2006

SummaryIn Britain, the hexaploid perennial grass Koeleria vallesiana (Honck.) Bertol. is confined to the western end of the Mendip Hills but is widespread in western Europe. Comparisons of the marginal British populations with continental populations from France indicate that there are no differences in breeding behaviour or genetic variability. There are, however, greater geneti differences in morphological characters between British and French material than between British populations. In addition, the Mendip populations, which are topographically isolated, show significant differences in morphology which are genetic in origin.Comparisons of floret fertility under different systems of mating indicate that K. vallesiana is a self‐incompatible outbreeder. Florets collected from the wild show low fertility (c. 5%) in common with other outbreeding perennial grasses.
FACTORS INVOLVED IN BREAKING BUD DORMANCY IN VIRUS‐INFECTED STEM CUTTINGS OF EUPHORBIA PULCHERRIMA
Authors: MANDAHAR C. L. , GULATI A. , NATH S. 
Published: May 2006

Summary Euphorbia pulcherrima, a vegetatively propagated ornamental plant, normally grows vegetatively in summer and is dormant in winter. Buds on virus‐infected rooted stem cuttings of this plant grew into leafy branches during the normal dormant period while the buds on similar stem cuttings obtained from healthy stocks remained quiescent or sometimes gave rise to cyathia. Estimations of seasonal variations in the endogenous levels of growth inhibitors (abscisic acid and phenols) and of a growth promoter (gibberellin) together with treatment of stem cuttings with GA3, indicated that the dormancy in virus‐infected stem cuttings may be broken because of their low abscisic acid and phenol levels and high gibberellin levels.
REPRODUCTIVE AND VEGETATIVE PERFORMANCE IN TWO WINTER ANNUAL GRASSES, CATAPODIUM RIGIDUM (L.) C. E. HUBBARD AND C. MARINUM (L.) C. E. HUBBARD
Authors: CLARK S. C. 
Published: May 2006

SummaryA combined field and growth‐room experiment was carried out using three populations of Catapodium rigidutn and one of C. marinum grown reciprocally on the soils and at the sites where they occurred and also at sites where neither species occurred naturally. The effect of late emergence on vegetative and reproductive production was also investigated. No plants survived to mature seed on either of the acidic soils in the field and on only one in the growth‐room.The coastal site was most favourable with least mortality, more vegetative growth in winter, most production and earlier maturation of caryopses. At two of the three sites when there were indigenous and artificially established colonies of the same populations, the indigenous plants were the most productive. Significant differences in productivity between sites were correlated with differences in the level of nutrients at the various sites. No differences between the populations at any one site were detected. There were, however, significant differences in the components of yield between the populations when all the sites were taken together. There were significant differences in the production of caryopses between the replicate colonies of each population at a particular site. The marked heterogeneity within sites indicated by this was probably the reason for failure to obtain evidence for adaptation to a particular site by its indigenous population. Constraints on the production of caryopses in the field operated through caryopsis number and not weight and probably early in the life cycle, since the number of tillers and the number of spikelets per inflorescence were the components of yield most reduced in the field compared with the equivalent treatments in the growth‐room. The results of the growth‐room experiment showed that soil factors and not genetic differences between populations were the main determinants of differences in reproductive performance between sites. There were, however, some significant differences in phenology, vegetative growth and yield of caryopses, between the populations of Crigidutn and between these and the one of C. marinum. The effect of late sowing in the growth room was to shorten the life‐cycle, to reduce the production of caryopses slightly, to increase the variation within treatments and to reduce the effect of soil type on performance.
THE INDUCTION OF A LIGHT REQUIREMENT IN BIDENS PILOSA SEEDS BY LEAF CANOPY SHADE
Authors: FENNER M. 
Published: May 2006

SummaryThe aim of these experiments was to determine whether exposure to leaf‐canopy shade induces a light requirement for germination in Bidens pilosa seeds.Seeds of this species were pretreated by placing them in the shade of a natural canopy for 12 days and then setting half of them to germinate in full light and the other half in darkness.Canopy‐treated seeds acquired a marked light requirement. The pretreatment was more effective if the seeds were imbibed during it. Fresh and old seeds gave similar results.In a second experiment the effect of time of exposure to canopy shade on the induction of a light requirement was investigated. It was found that only 1 h exposure to leaf‐transmitted light is required to induce an almost complete light requirement in this species. The ecological implications of the results are discussed.
HAWKMOTH BEHAVIOUR AND FLOWER ADAPTATION REDUCING SELF POLLINATION IN TWO LILIIFLORAE
Authors: BRANTJES N. B. M. , BOS J. J. 
Published: May 2006

SummaryIn experiments with models and a Petunia cultivar a hawkmoth makes its initial approach at about the same level as the flower. In Lilium martagon L., after flower opening, the style curves towards the direction of maximum light intensity. A hawkmoth comes into contact with the stigma at the beginning of its visit. Thereafter, while drinking from the individual nectaries on each petal, the visitor picks up pollen from the anther in front of the petals. During the initial approach to Crinum jagns (Thomp.). Dandy flowers a hawkmoth touches only the stigma, which is in front of the anthers. Anthers contact the visitor's body only during drinking. Then the moth leaves the flower by flying upwards and does not touch the stigma again. Thus there is evidence that in two Lilüflorae, the combination of the moth‐behaviour with the flower structure might reduce self‐pollination.