bluuebunny/crossref_metadata_2025_split huggingface dataset:
A NOTE ON THE OCCURRENCE OF VITIS AND OTHER NEW PLANT RECORDS FROM THE PLEISTOCENE DEPOSITS AT HOXNE, SUFFOLK
Authors: TURNER C. 
Published: May 2006

SummaryA number of new plant records are described from the Pleistocene deposits at Hoxne, Suffolk. These include a seed of Vitis. The significance of Vitis records from Holstein interglacial deposits across north‐west Europe is discussed in the light of its present ecology and distribution.
THE EFFECT OF CERTAIN GROWTH SUBSTANCES ON ASYMBIOTIC GERMINATION AND DEVELOPMENT OF ORCHIS PURPURELLA
Authors: HADLEY G. , HARVAIS G. 
Published: May 2006

SummaryThe effect of some growth substances on gernnination and development of Orchis (Dactylorchis) purpurella seeds was studied in an attempt to simulate the developmental pattern observed in symbiotic cultures.Gibberellic acid enhanced protocorm survival and caused abnormal elongation of the emergent shoot but did not influence the growth and overall size of the protocorms. Indoleacetic acid impeded germination and caused some elongation of the protocorms. Kinetin, both alone and in conjunction with indoleacetic acid, had a pronounced effect on growth and development and the results suggested that the auxin/cytokinin ratio is important in controlling root and shoot initiation. Adenine appeared to have little effect.The growth factor mixtures used did not have as beneficial an effect on protocorm development as did the presence of either symbiotic fungi or undefined fractions such as potato extract and coconut milk, suggesting that symbiotic fungi also provide other growth substances.
TAPETAL ORIGIN OF POLLEN‐COAT SUBSTANCES IN LILIUM
Authors: HESLOP‐HARRISON J. 
Published: May 2006

SummaryAt maturity, the pollen of Lilium spp. is coated with an adhesive, pigmented material, the Pollenkitt of German authors. This material contains a lipid component and carotenoid pigments; in L. longiflorum the principal pigment is α‐carotene 5,6‐epoxide. Synthesis of the coat materials takes place in the tapetum. The pigments accumulate in osmiophilic globuli from the time of release of the spores from the tetrad until the dissolution of the tapetum as a tissue. The lipids and associated pigments are then discharged into the loculi, where they migrate between the spores, filling the recesses in the surface of the exine.
NITROGEN METABOLISM IN DEVELOPING SEEDS OF VICIA FABA
Authors: BOULTER D. , DAVIS O. J. 
Published: May 2006

SummaryFruits of Vicia faba L. were harvested from plants grown outdoors to provide a developmental series trom flower opening to maturity. Pod and seed were separated, extracted, and the changes in distribution of protein and non‐protein nitrogen determined. Amino acid content of pod and seed was determined and changes in albumin protein were characterized by acrylamide gel electrophoresis.The bulk of nitrogenous material accumulated by the seed was found to be globulin protein, and accumulation was found to coincide with the appearance of protein granules in the developing cotyledons. Similar protein bodies were observed in the maternal tissues of the young ovule, but not in pod tissues, and possible sources of nitrogenous material destined for globulin synthesis are discussed.
A COMPARISON OF SOME PROPERTIES OF VICILIN AND LEGUMIN ISOLATED FROM SEEDS OF PISUM SATIVUM, VICIA FABA AND CICER ARIETINUM
Authors: JACKSON P. , BOULTER D. , THURMAN D. A. 
Published: May 2006

SummaryA comparison has been made of the globulins, vicilin and legumin, prepared by isoelectric precipitation, of the seeds of three species of the Vicieae, namely Pisum sativum, Vicia faba and Cicer arietinum. Their amino acid composition, band patterns after electrophoresis upon polacrylamide‐urea gels, fingerprint patterns of their tryptic digests and N‐terminal amino acids were compared. Considerable portions of the amino acid sequences of vicilin and legumin of Pisum sativum are probably the same or very similar and both proteins consist of a number of sub‐units. Vicia faba and Cicer arietinum also contain two proteins homologous with the vicilin and legumin of Pisum sativum. The homologous proteins of the three species resemble each other more closely than do the vicilin and legumin of any one species.
THE ECTOTROPHIC MYCORRHIZAS OF ALNUS VIRIDIS (CHAIX) D.C. AND THEIR SIGNIFICANCE IN RESPECT TO PHOSPHORUS UPTAKE
Authors: MEJSTRIK V. , BENECKE U. 
Published: May 2006

SummaryThree subtypes of mycorrhizas, sensu Dominik (1955), were found on roots of Alnus viridis growing in New Zealand. Roots with 60% of their rootlets mycorrhizal absorbed phosphate five times as rapidly as non‐mycorrhizal roots. Root nodules appear unable to absorb labelled phosphorus actively from externally supplied solution.
CYTOTAXONOMIC VARIATION IN POTENTILLA FRUTICOSA L.
Authors: ELKINGTON T. T. 
Published: May 2006

Summary Potentilla fruticosa is a widespread species for which chromosome numbers of 2n = 14 (diploid), 2n= 28 (tetraploid) and 2n = 42 (hexaploid) have been published from wild populations. These are listed together with a number of new counts. A morphological study of North American and European plants shows that the diploids are hermaphrodite and the tetraploids dioecious, and that the diploids have smaller pollen and stomata than the tetraploids. These distinguishing characters are used to show that the populations of P. fruticosa from northern Europe are tetraploid and those from southern Europe, western Asia and North America are diploid. Subspecific status is given to the tetraploids and diploids; the tetraploid cytotype is the type subspecies and the diploid is named ssp. floribunda (Pursh) Elkington.It is suggested that the centre of evolution of shrubby Potentillas is in eastern Asia and that westwards migration took place separately to the north and south by tetraploids and diploids respectively. The North American populations are most likely to have immigrated across the Bering Straits from north‐east Asia.
THE ASSESSMENT OF A METHOD FOR THE DETERMINATION OF ABSOLUTE POLLEN FREQUENCIES
Authors: MATTHEWS J. 
Published: May 2006

SummaryOne method for the estimation of absolute pollen frequencies involves the addition of a known amount of an exotic pollen to a known quantity of sediment. From the observed ratio of indigenous to exotic pollen, the absolute quantity of indigenous per unit volume of sediment can be calculated.The pollen of Nyssa sylvatica was considered to be a suitable exotic for addition to northwestern European Post‐glacial sediments to be measured by this method. A series of experiments was made to estimate the settling rate of fresh N. sylvatica pollen in pure glycerine, to determine the period of agitation required to produce an even suspension of N. sylvatica pollen in pure glycerine, to observe the effects of KOH treatment and acetolysis on a mixture of fresh N. sylvatica and Ailanthus eligantissima pollen and to estimate the experimental error of the method by using it to determine the quantity of pollen in a series of homogenized samples of gyttja.The value of the method for the estimation of absolute pollen frequencies is assessed.
STUDIES IN THE VEGETATIONAL HISTORY OF MID‐WALES
Authors: MOORE P. D. , CHATER E. H. 
Published: May 2006

SummaryPollen diagrams are presented from two sites in the uplands of mid‐Wales. One of these, the Elan Valley Bog, provides a continuous record of vegetational history during the Post‐glacial period. Many of the conclusions drawn from this pollen diagram are confirmed by reference to the other site at Llyn Gynon.
TWO POLLEN DIAGRAMS FROM THE MAINLAND, ORKNEY ISLANDS
Authors: MOAR N. T. 
Published: May 2006

SummaryTwo pollen diagrams, one through Late‐Weichselian and early Flandrian sediments and the other through Flandrian sediments from sites on the western side of the Mainland, Orkney Islands are discussed. The results provide an outline of vegetation development from Late‐Weichselian time and imply that at its best the dominant vegetation has a birch and hazel shrubland. On the basis of present evidence the Late‐Weichselian and Flandrian floras were impoverished and the presence of pollen derived from trees of mixed‐oak‐forest does not necessarily imply that these trees grew locally.
CHANGES IN ABSCISSION‐ACCELERATING SUBSTANCES WITH DEVELOPMENT OF COTTON FRUIT
Authors: SMITH O. E. 
Published: May 2006

SummaryCotton bolls of known ages from 2 to 50 days after anthesis were extracted with acetone. The chromatographed extracts were examined for abscission activity on the cotton explant test and gibberellin activity on the dwarf maize test. The abscission‐accelerating substances (ABA and gibberellins) were very high in young fruit, showing a peak at about 6 days, then declined to nil at 20 days. An unidentified abscission accelerator showed a marked peak at 15 days. Abscisic acid, GA3, another gibberellin which acts biologically like GA5 and GA9, and an abscission‐retarding substance were all extracted from 5‐day‐old bolls.
COMPARISONS OF FRUITING AND DEBLOSSOMED MAIDEN APPLE TREES, AND OF NON‐FRUITING TREES ON A DWARFING AND AN INVIGORATING ROOTSTOCK
Authors: AVERY D. J. 
Published: May 2006

SummaryThe dry weight increment of all parts, especially the rootstock, was less in fruiting than in non‐fruiting maiden Worcester Pearmain apple trees; the fruit accounted for one‐third of the total increment on M.IX. Fewer shoots grew out, and they had decreased rates of extension from the end of June, especially the later‐formed shoots. The leaves were smaller and this was the earliest observed difference between fruiting and deblossomed trees. The rate of leaf production was lower after late July. While fruiting affected the shoots on the tree as a whole, the proximity of fruit affected individual shoots. The influence of fruit was less in August and growth of the trees increased relative to deblossomed trees.Growth rates of leaves and shoots were similar until late June on deblossomed trees on dwarfing M.IX and on non‐fruiting trees on invigorating M.XVI, but many more shoots extended on M.XVI in June. Shoots on M.IX extended at a much decreased rate in July and early August and the internodes were shorter but thicker than on M.XVI. In trees on M.IX a smaller proportion of the dry weight increment was in the rootstoek. The efficiency of leaves on M.XVI was greater than of leaves of deblossomed trees on M.IX, but less than on fruiting trees. These data, and additional facts published by other workers, have been integrated in an attempt to explain the dwarfing mechanism of M.IX.Trees on M.IX are smaller because they are restricted to fewer growing points which continue extension for a shorter period. It is believed that the even smaller rate of growth of the root system limits the trees so that they are unable fully to utilize the products of photosynthesis in growth.
VESICULAR INVOLVEMENT IN DIFFERENTIATING PLANT VASCULAR CELLS
Authors: ROBARDS A. W. , KIDWAI PARVEEN 
Published: May 2006

SummaryIn differentiating xylem cells a prima facie case is made for the following cytoplasmic events to occur:

Production of vesicles from dictyosomes and endoplasmic reticulum, and probable guidance of these vesicles to the wall by microtubules.
Secondary formation of multivesicular bodies from dictyosome‐derived vesicles, which also move to the plasmalemma and fuse with it.
Passage of single vesicles across the plasmalemma to form lomasomes.
Evagination of the plasmalemma to form plasmalemmasomes.
Formation of myelin‐like bodies by the endoplasmic reticulum.
The fusion of vesicles and vacuoles with each other.

These processes are thought to be associated in general with the formation and separate transport of different wall precursors and enzymes to their appropriate sites and, possibly, with the management of synthetic by‐products.
THE MAINTENANCE OF STRUCTURE AND SHAPE IN THREE MALLEE EUCALYPTS
Authors: HOLLAND P. G. 
Published: May 2006

SummaryTo estimate the tissue production of stands of large woody plants a simple morphological analysis on a sample of the plants must be attempted if a rational clipping routine is to be established. It is shown that such an analysis reveals much about the maintenance of stem structure and shape by three species of mallee Eucalyptus. The species have a branching system which can be described by the geomorphologist's law of stream numbers and their shape is explicable in terms of this system and the effects of apical dominance on new twig growth.
GENECOLOGICAL DIFFERENTIATION OF LEAF MORPHOLOGY IN GERANIUM SANGUINEUM L.
Authors: LEWIS MARTIN C. 
Published: May 2006

SummaryGenecological differentiation of leaf dissection and size in European samples of Geranium sanguineum L. is considered against a background of the ecological behaviour of this species. The differentiation is analysed using Variance Analysis and shown to be closely correlated with a community classification based on eco‐geographical indicator species; leaf dissection is correlated with the ‘continentality’ and leaf size with the ‘openness’ of the original community. The variation in both cases is ecoclinal. The importance of morphological differentiation to studies of adaptation is discussed in the light of current knowledge.
AN INTERGLACIAL PEAT AT FUGLA NESS, SHETLAND
Authors: BIRKS H. J. B. , RANSOM MAREE E. 
Published: May 2006

SummaryThe stratigraphy of a peat bed about 1.5 m thick lying between boulder clays at Fugla Ness on North Roe of Shetland Mainland is described, and the results of analyses of pollen, spores, seeds, leaves and wood remains are presented. These analyses indicate wooded conditions, and the assemblage is considered to be of interglacial character. On the basis of floristic affinities it is equated with the closing phases of the Gortian Interglacial stage of Ireland. The most notable taxa represented include Abies, Chamaepericlymenum suecicuni, Daboecia canlabrica. Erica mackaiana, E. scoparia var. macrosperma and Picea. The phytogeographical significance of the fossil flora is briefly considered.
CONTRIBUTIONS TO THE ECOLOGY OF BRACKEN (PTERIDIUM AQUILINUM)
Authors: WATT A. S. 
Published: May 2006

SummaryThe crown forms of bracken in the marginal belts of areas D and E are examined in relation to the changing age‐structure of the frond population and damage by frost.In both areas there is a rise in height to a maximum followed in area D by a slight fall and then a levelling off in the distal part. In area E there is a uniform fall from the maximum to about half that height.The rise in the proximal part in both is regarded as an expression of inherent potentialities, and the fall in the distal of the influence chiefly of the ecological factors of frost and drought.Data of frost mortality from permanent transects (1936–40) show similar and parallel values in the proximal parts hut in the distal the values in area D are low, in area E high. These not only differentiate area D from area E hut the distal from the proximal in each.Frost mortality is related to the date of emergence, this in turn to the amount and continuity of the litter and this to the density, height and distribution of the fronds. As the thickness of the litter is about the same at maximum height and mortality only slightly greater in area E at this point, it is argued that some other factor is primarily beginning to operate just behind the region of maximum height. Frost, though important, does not initiate the fall although it contributes largely to it.Various observations (including the high correlation between the length of the petiole, which is fed exclusively from reserves, and the length of the lamina of the previous year, as a rough measure of the capacity to add to reserves) suggest the limited movement of reserves within the plant; and a hypothesis is formulated based on a hypothetical breakdown of food transport in the main and lateral axes at an age (approximately 30–35 years) in consequence of which the physical unitary system is differentiated into a large apical (proximal) physiological unit, and a distal part bearing lateral branch systems which are physiologically independent of the parent plant and of each other. As in the parent plant, so in the lateral branch systems, transport in the axes fails on attaining the appropriate age. Thus while the branch systems increase in size distally (though at a diminishing rate, because of competition from neighbours), the physiological units decrease. Smaller plants carry smaller fronds and the reduced litter‐cover means less protection from winter frost, earlier emergence and a higher spring frost mortality.The hypothesis applies to area D, but the physiological units there are on deeper soil and provide enough litter to delay emergence, reduce spring frost mortality and winter frost damage to zero.Because of the deeper soil and ahundant litter in area D the frond population is much more self‐protective and self‐regulatory and much less under the direct influence of the hahitat factors drought and frost.
AN APPLICATION OF ORDINATION TO GENECOLOGY
Authors: WILKINS D. A. , LEWIS M. C. 
Published: May 2006

SummaryGenecological differences in leaf size and dissection were known in Geranium sanguineum from uniform garden trials. Floristic data from the original habitats were used to construct a principal components ordination of the sites, and the first four axes were examined for correlations with the genecological data.The first axis was found to be associated with leaf size and the second and third with leaf dissection. An ecological interpretation of the axes was attempted from the occurrence of indicator species of known ecological tolerance. This showed that position along the second and third axes was highly correlated with the representation of steppe perennial species. No such interpretation was found for the first axis.The value of this approach for the identification of ecological gradients in genecology is discussed.
EFFECT OF ENDOGONE MYCORRHIZA ON PLANT GROWTH
Authors: DAFT M. J. , NICOLSON T. H. 
Published: May 2006

SummaryVarying amounts of soluble phosphate were applied over different periods during the growth of mycorrhizal maize. The amount of the endophyte produced within the root system and the growth of the host were related inversely. Repeated small doses of soluble phosphate over long periods depressed the production of the fungus more than when given over shorter periods. Large single applications of soluble phosphate applied early in the growth of the host also reduced the amount of the endophyte more than when given later. The role of mycorrhiza in relation to phosphate nutrition is discussed.
EFFECT OF ENDOGONE MYCORRHIZA ON PLANT GROWTH
Authors: DAFT M. J. , NICOLSON T. H. 
Published: May 2006

SummaryThe effects of concentration of the inoculum on growth of the host and level of infection were investigated in mycorrhizal tomatoes. All concentrations of the endophyte, ranging between 225 and three chlamydospores per plant, led to significant stimulation of growth. Measurements of height of plants and length of leaves during growth indicated that inocula containing low numbers of spores stimulated the host less than more concentrated inocula. Plants inoculated with high numbers of spores produced more upper and retained more lower leaves whereas plants inoculated with low numbers retained more lower leaves than uninfected control plants. Dry weight determinations of the foliage made at the end of the experiment showed that all inoculated treatments were larger than the control treatments. The concentration of spores in the inoculum did not appear to influence the final level of infection.
EFFECTS OF INHIBITORS ON PHOTOSYNTHESIS AND THE ACTIVE INFLUXES OF K AND CL IN HYDRODICTYON AFRICANUM
Authors: RAVEN J. A. 
Published: May 2006

SummaryThe effects of the inhibitors HOQNO, salicylaldoxime, DSPD, NaCN, DNP, desaspidin, antimycin A and CCCP on photosynthesis and active K and Cl influxes in the light and the dark in Hydrodictyon africanum are reported. It is concluded (1) that active K influx in the dark is powered by oxidative phosphorylation; (2) that ATP produced by oxidative phosphorylation is not required for the full light‐stimulation of K influx; (3) that either cyclic or pseudocyclic photophosphorylation can power K influx in the light; (4) that Cl influx in the dark requires the operation of the mitochondrial electron transport chain; (5) that Cl influx in the light requires both photosystem one and photosystem two; (6) that cyclic photophosphorylation is not required for steady‐state photosynthesis in aerobic conditions at high light intensity.
SOME EFFECTS OF TEMPERATURE AND PHOTOPERIOD ON GROWTH AND FLORAL DEVELOPMENT IN THREE WINTER ANNUALS
Authors: CLARK S. C. 
Published: May 2006

SummaryAn experiment on the effects of temperature and day length on the vegetative and reproductive growth of populations of the winter annuals, Catapodium rigidum, Erophila verna and Saxifraga tridactylites from the west of Ireland, is described. The results are used to show the potentialities of subjecting plants at different stages of development to the same treatments, as a method of assessing the role of environmental factors under natural conditions. Catapodium rigidum was found to have an absolute vernalization requirement and long days were required for suhsequent development of inflorescences up to the flowering stage. Short days given after inflorescences had begun to develop resulted in the formation of secondary tillers at the extremities of primary tillers (‘mops’) and proliferations. Any vernalization requirement of Erophila verna and Saxifraga tridactylites was satisfied by mid‐November. The development of flower buds in winter was more rapid in Erophila verna than in Saxifraga tridactylites. Day length did not effect the number of flower buds produced by either species but they differed in their ability to mature fruits in short days.
SOME ASPECTS OF THE MORPHOLOGY, EMBRYOLOGY AND BIOLOGY OF TERNIOLA ZEYLANICA (GARDNER) TULASNE
Authors: MUKKADA ANTONY J. 
Published: May 2006

SummaryThe plant body in Terniola zeylanica (Gardner) Tulasne, a member of the Podostemaceae, consists of a creeping thallus. The flowers are bisexual, hypogynous and trimerous. The anthers are dithecous and all the microsporangia are arranged on the inner side of the anther and parallel to each other. The anther wall consists of four layers. The tapetum is of the secretory type. Quadripartition of the mother cells is simultaneous and the tetrads are isobilateral or tetrahedral. The microspore nucleus divides by an asymmetric spindle and the pollen grains are shed at the two‐celled stage. The ovules are anatropous, tenuinucellar and bitegminal with the micropyle formed solely by the outer integument. Both the integuments differentiate simultaneously. The embryo sac is bisporic, five‐nucleate and follows the reduced Allium type. A pseudo‐embryo sac is formed during early embryogeny. Both entomophily and anemophily are prevalent. Syngamy takes place normally. Previous reports of double fertilization are not confirmed. A primary endosperm nucleus is not formed and there is no endosperm. The development of the embryo follows the Solanad type and the embryo possesses a large, coeno‐cytic, haustorial cell. The development and maturation of the seed coat and pericarp have been studied. The cells of the inner epidermis of the ovary wall become binucleate and at times even multinucleate.
THE UPTAKE OF 32P BY DIFFERENT KINDS OF ECTOTROPHIC MYCORRHIZA OF PINUS
Authors: MEJSTŘIK V. 
Published: May 2006

SummaryThe rates of uptake of phosphate by two different kinds of mycorrhiza of Pinus radiata (Fa and Ca) were both greater than that of uninfected roots at all temperatures studied. Over periods of 160 minutes the optimum temperature for both mycorrhizal and uninfected roots was about 25° C, but the uptake rate of type Fa fell off more steeply above this optimum than that of Ca over the same time‐period. Uninfected roots showed, at all temperatures, a more rapid rate of absorption over the first 60 minutes of the experimental period than later.