bluuebunny/crossref_metadata_2025_split huggingface dataset:
AN EXPERIMENTAL STUDY ON TWO POPULATIONS OF CHAMAENERION ANGUSTIFOLIUM (L.) SCOP. (=EPILOBIUM ANGUSTIFOLIUM L.) OCCURRING ON CONTRASTING SOILS, WITH PARTICULAR REFERENCE TO THE RESPONSE TO BICARBONATE
Authors: VAN ANDEL J. , BOS W. , ERNST W. 
Published: May 2006

SUMMARYTwo populations of Chamaenerion angustifolium occurring on contrasting soil types (alkaline v. acid) were studied with regard to mineral nutrition. Plants were grown from seeds of both populations on each of the soils and in culture solution with different levels of sodium bicarbonate.Differentiation between the populations in a strictly ecological sense was not established. The main effects on the growth and mineral nutrition of the populations were correlated with characteristics of the root medium rather than with the origin of the seeds. Neither chlorosis under alkaline, nor toxicity under acidic conditions occurred. There were, however, some differences between the nutritional behaviour (Ca, Fe, Na) of the natural populations and their seedlings so that the overall potential of the seeds might be much wider than that of the already‐selected, natural populations. This seemed to be confirmed by the high percentage mortality in water cultures. Amongst the plants which survived some slight physiological differences appeared but not ones which influenced dry‐weight production.It can be concluded that C. angustifolium is indifferent with regard to the soil factor pH, or better; that the species is adapted both to acid and alkaline soil. This was discussed with reference to Ca, Fe and HCO3+.
PROBLEMS OF INTERPRETING THE RELATIONSHIP BETWEEN THE AMOUNTS OF LEAD AND ZINC IN PLANTS AND SOIL ON METALLIFEROUS WASTES
Authors: BARRY S. A. S. , CLARK S. C. 
Published: May 2006

SUMMARYThe lead and zinc contents of shoot material of Agrostis tennis, Festuca ovina and Minuartia verna and of the soil in which they were growing at an abandoned lead‐mining area on Grassington Moor, Yorkshire, England were determined. The relationship between the zinc contents of shoot material and soil was broadly linear. There was little increase, however, in the lead content of the shoot material over the range 500‐20000 μg g−1 lead in the soil. Above this value the lead content of the shoot material increased markedly. There were large differences between samples in the metal contents of the shoot material collected from soils having the same metal contents. Possible reasons for this variation are discussed and specific suggestions for future comparative work are made.
SOME NEW PALAEOBOTANICAL RECORDS FOR THE BRITISH IPSWICHIAN INTERGLACIAL
Authors: HALL ALLAN 
Published: May 2006

SUMMARYDetails are given of four interesting new palaeobotanical records from an Ipswichian (last) Interglacial site in the East Midlands of England. The taxa are considered in the context of the site, and a brief review is presented of their Tertiary and Pleistocene history and present ecology, with some discussion of the phytogeographical implications.
LEAF RESISTANCES IN DIFFERENT POPULATIONS OF SESLERIA CAERULEA (L.) ARD.
Authors: LLOYD N. D. H. , WOOLHOUSE H. W. 
Published: May 2006

SUMMARYSix races of Sesleria caerulea from widely separated parts of the geographical range of the species exhibited different rates of photosynthesis and transpiration when grown under standard conditions. These can be traced to various attributes of the stomatal apparatus. The stomata differ in frequency, size and the depth to which they are sunk below the epidermal surface in the different races, but quantitative consideration of these parameters leads to the conclusion that the apertures to which the stomata can open, an attribute which correlates with the depth to which they are sunk, determines the maximum rates of photosynthesis and transpiration. Evidence is presented to suggest that, although this complex of stomatal modifications may be interpreted as representing xerophytic adaptations, they may have evolved not so much for conservation of water per se, but to conserve the energy balance of the leaves, thereby reducing evaporative heat loss and so maintaining leaf temperature. A leaf temperature of 1–2°C above ambient may increase the rate of photosynthesis by 10–20% in the range from 10–20°C.
THE OCCURRENCE OF SOME ACID PHOSPHATASES AND DEHYDROGENASES IN THE VESICULAR‐ARBUSCULAR MYCORRHIZAL FUNGUS GLOMUSMOSSEAE
Authors: MACDONALD R. M. , LEWIS M. 
Published: May 2006

SUMMARYThe occurrence of acid phosphatase, glutamate dehydrogenase, succinate dehydrogenase, glyceraldehyde‐3‐phosphate dehydrogenase, glucose‐6‐phosphate dehydrogenase and NADH and NADPH diaphorases in Glomus mosseae (yellow vacuolate Endogone spore type) was demonstrated cytochemically. Acid phosphatase was found in lysing and growing fungal structures. It was inferred that the fungus possesses an Embden‐Meyerhof‐Parnas system, a tricarboxylic acid cycle and a hexose monophosphate shunt.
STUDIES ON MUCORALEAN MYCOPARASITES
Authors: CURTIS F. C. , EVANS G. H. , LILLIS V. , LEWIS D. H. , COOKE R. C. 
Published: May 2006

SUMMARYThe effects of nine species of Piptocephalis de Bary on the growth of four host fungi were studied. Depending on temperature and the mycoparasite‐host combination, host growth was either unaffected, inhibited or stimulated, In addition, mycoparasite‐induced abnormal morphology in the host often resulted. Hypotheses are presented to explain these phenomena and to act as a basis for investigations into the physiology of mycoparasitism.
WHOLE PLANT STUDIES ON PHOTOSYNTHESIS AND ACETYLENE REDUCTION IN ALNUS GLUTINOSA
Authors: GORDON J. C. , WHEELER C. T. 
Published: May 2006

SUMMARYRates of photosynthesis and acetylene reduction by whole plants were measured on (a) twelve Alnus glutinosa clones and (b) A. glutinosa seedlings grown in low and high irradiances. Both genetic and environmental manipulation of photosynthetic rates produced concomitant changes in rates of acetylene reduction. For the clonal material, growing under closely similar environmental conditions, mean rate of net photosynthesis was significantly positively correlated with both the mean fresh weight of nodules formed per plant and with the mean rate of acetylene reduction.
DINOFLAGELLATE CYSTS IN THE PLANKTON
Authors: REID PHILIP C. 
Published: May 2006

SUMMARYThe geographical and seasonal occurrences of dinoflagellate cysts at a depth of 10 m in the North Atlantic and North Sea are described from samples taken by the Continuous Plankton Recorder between June 1973 and December 1975. A special study was made of the large cyst of Polykrikos schwartzii Bütschli in the autumn of 1973 when CPR samples were supplemented by vertical sampling in the upper 500 m with a Longhurst‐Hardy Plankton Recorder at Ocean Weather Station, INDIA.Only ten isolated records of cysts were made in the western Atlantic. All others occurred to the east of 30° W in both oceanic and neritic waters and especially in the shallow waters of the North Sea. Cysts were found in the spring plankton but were most abundant in the autumn. They have been recorded down to 500 m but occur most frequently in the top 30 m of the water column. Large aggregations of cysts in bottom sediments probably reflect concentration over many years since they cannot be explained by the low numbers found in the plankton. Generally, the distribution of cysts in the plankton is reflected in bottom sediments but concentrations in sediments may be outside the centres of production, implying movement by currents or sediment transport.
STUDIES IN THE VEGETATIONAL HISTORY OF MID‐WALES
Authors: MOORE P. D. 
Published: May 2006

SUMMARYStratigraphic and pollen evidence is presented from a mire site on the eastern side of the main Cambrian watershed of central Wales. A complex basin contains Late Devensian lake sediments overlain by Flandrian organic detritus muds. Organic lake muds were replaced by swamp and carr vegetation on the north and west of the site, but the south‐east basin continued as a lake until relatively recent times (the last 200 years). Final colonization of the lake was by a floating raft of Carex rostrata, Menyanthes trifoliata and Sphagnum cuspidatum, on which the present sphagnum‐dominated vegetatiiin has developed. Such schwingmoor mire types are uncommon in Britain and this is a particularly good example.Pollen analysis of the Flandrian lake sediments provides information concerning vegetational history. Interesting early Flandrian records are of Hippophäe rhamnoides. Linum bienne and Fumaria. Pinus sylvestris has low pollen levels in the early Flandrian, unlike many western sites. It is suggested that sites having high values may have Pinus as a local mire colonist. The Ulmus decline is very marked and is accompanied by evidence of cultivation. This is the first evidence of cereal growing in early Neolithic times in Central Wales. Higher in the profile Cannabis saliva assumes importance, possibly as a result of Iron Age/Roman cultivation.
AMYLASE ENZYMES ISOLATED FROM INCUBATED DE‐EMBRYONATED MAIZE KERNELS
Authors: GOLDSTEIN L. D. , JENNINGS P. H. 
Published: May 2006

SUMMARYAn enzyme extract prepared from incubated, de‐embryonated maize (Zea mays L.) kernels was resolved into three major amylase activities by ion‐exchange chromatography using DEAE‐cellulose. These activities, designated peak I, II and III in order of their elution, were further analysed utilizing isoelectric focusing. The pi values of peaks I and II were found to be 4.55 and 4.95 respectively. The activity contained in peak III was separated into two isoelectric components with pI's of 4.30 and 5.05. Each of the four isoelectric forms showed distinct electrophoretic properties on polyacrylamide gels. Peak I contained (β‐amylase on the basis of its inactivation by 10−5M HgCl2, lack of protection against heat inactivation by added Ca2+, stable activity after dialysis against 10−2 M EDTA, and its sole reaction product with starch being identified as maltose. Peak II activity appeared to be an a‐amylase as determined by its reaction products with starch and its stabilization against heat inactivation by added Ca2+, however, it was inactivated by HgCl2 treatment and dialysis against EDTA. The two isoelectric components of peak III were also characterized as a‐amylase using the same criteria, with the 5.05 component being more sensitive to HgCl2 inactivation than the 4.30 component. All four isoelectric forms exhibited broad pH activity profiles.
GENECOLOGICAL STUDIES OF SALT TOLERANCE IN GROUNDSEL (SENECIO VULGARIS L.) WITH PARTICULAR REFERENCE TO ROADSIDE HABITATS
Authors: BRIGGS D. 
Published: May 2006

SUMMARYSalt contamination of soils has been studied in a range of habitat types of groundsel (Senecio vulgaris L.). Evidence suggests that roadsides salted in winter and areas around salt dumps have high mean values of exchangeable sodium; lower values have been found for coastal areas, and inland sites not known to be salted.Salt tolerance tests‐both in Petri‐dish experiments and in soils irrigated with different salt solutions‐suggest that topodemes from sites subject to salting are, in general, more salt tolerant than those from non‐salted areas. This apparently simple relationship is critically examined. Genecological implications of salt tolerance patterns are fully discussed.
PROTANDRY AND THE SEQUENCE OF FLOWER OPENING IN THE ONION (ALLIUM CEP A L.)
Authors: CURRAH LESLEY , OCKENDON D. J. 
Published: May 2006

SUMMARYTo assess the importance of protandry in promoting outbreeding in onions, detailed observations were made of the sequence of flower opening in onion umbels. Six stages of flower development were defined, covering the period from flower opening to withering of the style. Regular counts were made in the 1976 season of the total number of flowers at each stage during the flowering of twenty‐nine umbels representing four cultivars and six inbred lines. The pattern of flowering was similar in all cases, although the number of flowers per head varied from 126 to 681. At first the number of flowers opening was small, but rapidly increased, giving a peak, which lasted for a mean of 4–10 days. During the middle of the peak flowering period the maximum number of flowers open at one time was often more than 50% of the total flowers on the head. A particular flower could not easily be pollinated with its own pollen because the stigma did not become receptive until about 2–3 days after the anthers had started to dehisce. Protandry was not considered to be effective in preventing pollination between flowers on a single umbel because there was abundant pollen available from the time the first stigmas became receptive, almost until the end of flowering. Other factors which may account for high out‐crossing rates in onions are discussed.
COMPARATIVE ASPECTS OF PHOTOSYNTHESIS, PHOTORESPIRATION AND TRANSPIRATION IN FOUR SPECIES OF THE CYPERACEAE FROM THE RELICT FLORA OF TEESDALE, NORTHERN ENGLAND
Authors: LLOYD N. D. H. , WOOLHOUSE H. W. 
Published: May 2006

SummaryPopulations of two continental‐northern species, Carex ericetorum Poll, and Eriophonim latifolium Hoppe and two arctic‐alpine species, Kobresia simpliduscula (Wahlenb.) Mackenzie and Carex capillaris L., from the flora of Teesdale were grown under controlled conditions and their rates of photosynthesis, photorespiration and transpiration were measured in an open gas‐analysis system over the leaf temperature range 5 to 30 °C over a range of irradiances. The maximum rates and the temperature optima for photosynthesis were similar for all the species. The rates of photosynthesis at low temperature and the light saturation characteristics of C. ericetorum and E. latifolium were significantly different from those of K. simpliciuscula and C. capillaris. The differences are discussed in relation to the habitats in which these species usually occur.
LEGUMIN OF PISUM SATIVUM AND VICIA FABA
Authors: CROY R. R. D. , DERBYSHIRE E. , KRISHNA T. G. , BOULTER D. 
Published: May 2006

SummaryThe legumins of Pisum and Vicia have been compared and the proteins have been shown to differ in molecular weight, subunit molecular weights and amino acid composition. Legumin of Pisum however has a similar disulphide bridged subunit construction to that of Vicia and consists of basic (pI's greater than 7) and acidic subunits (pI's less than 7). Of the two molecules, Pisum legumin was shown to be more acidic at pH values of neutral and above. The protein from Pisum has all the antigenic determinants of Vicia legumin and one or more determinant groups in addition.Tryptic peptide maps indicate that legumin is an homologous protein in Vicia and Pisum.
MECHANISMS FOR UREA UPTAKE BY THE DIATOM PHAEODACTYLUM TRICORNUTUM: THE UPTAKE OF THIOUREA
Authors: REES T. A. V. , SYRETT P. J. 
Published: May 2006

SummaryThiourea inhibited competitively the uptake of urea by urea‐grown cells of Phaeodactylum with a Kt of 180 μM. Urea‐grown cells also absorbed and accumulated thiourea. Uptake of thiourea resembled that of urea in that (i) uptake by ammonium‐grown cells was slow, (ii) uptake was much increased by a period of nitrogen starvation, (iii) uptake was stimulated by light and (iv) at low substrate concentrations uptake was inhibited almost completely by 0.1 mM CCCP (carbonyl cyanide m‐chlorophenylhydrazone). It is concluded that thiourea and urea are taken up by the same active mechanism. With nitrogen‐depleted cells, the relationship between rate of thiourea uptake and thiourea concentration was hyperbolic with a half‐saturation constant of 170± 33 μM and a Vmaxof 580 nmol thiourea 108 cells−1 h−1. This half‐saturation constant is about 200 times greater than the value for urea uptake by nitrogen‐depleted cells although the Vmaxvalue is about the same. The relationship between passive and active uptake is discussed. Because of the low affinity of the active uptake mechanism for thiourea, passive uptake is quantitatively important at low thiourea concentrations; this is particularly so with nitrogen‐replete cells in which the capacity of the active mechanism is less well developed. As much of the urea taken up by Phaeodactylum remains in the cells as free urea, it is preferable to study the urea uptake mechanism by measuring the uptake of urea directly. In contrast, organisms like Chlorella metabolize [14C]urea rapidly and conclusions may be ambiguous if measurement of 14C within the cells is used as a measure of uptake. With Chlorella, it may be preferable to use the analogue, (14C)thiourea, to study the uptake mechanism and, in this organism, the difference in affinities of the active uptake mechanism for urea and thiourea is not so great as it is in Phaeodactylum.
THE APOPLASTIC CONDUCTION OF WATER IN POLYTRICHUM JUNIPERINUM WILLD. GAMETOPHYTES
Authors: TRACHTENBERG S. , ZAMSKI E. 
Published: May 2006

SummaryApoplastic water movement on the electron microscopic level was studied by means of PbS particles produced in situ after exposing gametophytes which were immersed in Pb‐EDTA to H2S. The presence of PbS particles in the tissue is used to evaluate the apoplastic conduction of water. All cell walls of all the tissues appear to conduct water. The heavy mass of cell‐wall material contributes to the radial conduction of water to the hadrom. Absorption of water through the aerial surface of the gametophyte is more efficient than through the rhizome.
COBALT AND NITROGEN FIXATION IN LUPINUS ANGUSTIFOLIUS L. I. GROWTH, NITROGEN CONCENTRATIONS AND COBALT DISTRIBUTION
Authors: ROBSON A. D. , DILWORTH M. J. , CHATEL D. L. 
Published: May 2006

SummaryCobalt application markedly increased the growth of and nitrogen concentrations in tops of Lupinus angustifolius irrespective of inoculation with an effective strain of Rhizobium. Cobalt‐deficient plants produced a greater weight of lateral nodules and total nodule weight than cobalt‐adequate plants. Cobalt‐sufficient plants produced more crown nodule weight than cobalt‐deficient plants.Cobalt concentrations were higher in roots and nodules than in tops irrespective of cobalt application. In plant tops cobalt concentrations in young leaves were considerably lower than those in old leaves at both cobalt levels. Cobalt concentrations and contents increased in old leaves throughout the experiment.Under cobalt deficiency cobalt appeared to be preferentially distributed to nodules. Six weeks after sowing cobalt contents of nodules of cobalt‐deficient plants were similar to those in whole tops. By contrast at this time cobalt contents of nodules of cobalt‐adequate plants were only approximately one‐third those of whole tops.
COBALT AND NITROGEN FIXATION IN LUPINUS ANGUSTIFOLIUS L. II. NODULE FORMATION AND FUNCTION
Authors: DILWORTH M. J. , ROBSON A. D. , CHATEL D. L. 
Published: May 2006

SummaryThe effects of cobalt deficiency on nodule formation and function in sweet lupin (Lupinus angustifotius L. cv. Unicrop) were studied in cobalt‐deficient Lancelin sand in the glasshouse.Bacteroid densities in cobalt‐deficient nodules were lower than in normal nodules. Recovery from cobalt deficiency in inoculated treatments was associated with increases in bacteroid density and cobalt accumulation in lateral nodules. Such changes did not occur in treatments infected with rhizobia from the soil.Acetylene‐reducing activity of cobalt‐deficient plants was not initiated until plants were nearly 6 weeks old, at which time cobalt‐treated plants were at their peak of activity. Specific activities of cobalt‐deficient nodules remained very low even when nitrogenase did develop. Their large mass of nodules allowed cobalt‐deficient plants to reach 20 to 50 % of the normal activity per plant, but specific activities were only 5 to 13 % of peak activities in cobalt‐treated nodules.Nodule bacteroid content and leghaemoglobin content were linearly related to cobalamin content, each with a single relationship. Plotting acetylene‐reducing activity against cobalamin content or leghaemoglobin content generated two different linear response curves in each case; the slopes of the lines were different, depending on the presence or absence of cobalt. It is suggested that there may be a function in N, fixation in legume nodules for a non‐cobalamin form of cobalt.
FAVOLASCHIA DYBOWSKYANA (SINGER) SINGER (APHYLLOPHORALES), A NEW ORCHID MYCORRHIZAL FUNGUS FROM TROPICAL AFRICA
Authors: JONSSON L. , NYLUND J. E. 
Published: May 2006

SummaryMycorrhiza of the ptyophagous type was formed by Favolaschia dybowskyana (Singer) Singer in axenic culture with protocorms of the terrestrial Japanese orchid, Bletilla striata (Thunb.) Rchb. f. The growth of inoculated protocorms was much greater than uninoculated material, which was unable to develop on cellulose agar. The growth rate of the inoculated material on this medium was almost the same as that of material in sterile culture on full nutrient medium. Infected Bletilla material was studied by light and transmission electron microscopy and information obtained, together with previously published data, support a non‐specific relationship between the symbionts.
VITAMINS AND NITROGEN REQUIREMENTS OF ORCHIS LAXIFLORA LAMK.
Authors: MEAD J. W. , BULARD C. 
Published: May 2006

Summary Orchis laxiflora Lamk. grown from seeds in asymbiotic cultures has a special need for thiamine which is necessary for its development; riboflavin though it has a favourable influence on germination is unable to replace it.The requirement of this orchid for a nitrogen source can be satisfied with casamino acids; no mineral nitrogen source can play the same role, but in presence of the organic source, the addition of ammonium nitrogen is an improving factor while nitric nitrogen is unfavourable.
THE ULTRASTRUCTURE OF POLLEN‐GRAIN DEVELOPMENT IN THE OLIVE(OLEA EUROPAEA). 2. SECRETION BY THE TAPETAL CELLS*
Authors: PACINI E. , JUNIPER B. E. 
Published: May 2006

SummaryThe parietal tapetal cells in the olive can, through their greater ribosome density, be distinguished from the pollen mother cells by about the leptotene stage. The organelles of these two cell types remain similar up to the tetrad stage. At this stage the tapetal and microspore cytoplasm are separated by four walls; the tapetal cell wall, the pollen mother cell wall, the tetrad callosic wall and the primexine. Microtubules are prominent against the radial walls of the tapetal cells. The cytoplasm of the tapetal cells is orientated around a central vacuole in a form suggesting cyclosis. Cytoplasmic vesicles generated from various sources within the tapetal cytoplasm appear to migrate towards the plasmalemma adjacent to the loculus or adjacent to the intercellular spaces. These vesicles, which are of at least three different types, fuse with the plasmalemma, apparently to discharge their contents.The points of contact between the plasmalemma of the tapetal cells and the exine sculptures leave a transitory layer, the ‘tapetal printing’, on the pollen surface. Fibrillar material, probably protein, accumulates in the tapetal intercellular spaces and eventually comes to rest on the pollen poral surfaces. Granular electron dense bodies also accumulate in the tapetal intercellular spaces and finally come to lie between the pollen bacula. Orbicules are also produced by the tapetal cells and, at maturity, cluster around the degenerate lipoidal mass which is the final state of the tapetal cells.