bluuebunny/crossref_metadata_2025_split huggingface dataset:
PLANT GROWTH RESPONSES TO VESICULAR‐ARBUSCULAR MYCORRHIZA V. PHOSPHATE UPTAKE BY THREE PLANT SPECIES FROM P‐DEFICIENT SOILS LABELLED WITH 32P
Authors: MOSSE B. , HAYMAN D. S. , ARNOLD D. J. 
Published: May 2006

SummaryThe uptake of phosphorus from 32P‐labelled soil solution by three plant species, with and without mycorrhiza, was measured. All soils contained very little CaCl2‐ and NaHCO3‐soluble phosphorus. In two soils the specific activity of phosphorus taken up by mycorrhizal and non‐mycorrhizal Melinis minutiflora was very similar, indicating that even in very P‐deficient soils mycorrhizal plants used the same source of phosphate as non‐mycorrhizal. In two other soils non‐mycorrhizal Paspalum notatum and Centrosema pebescens contained no 32P activity, suggesting that they had not taken up any soil phosphorus, whereas mycorrhizal plants of both species contained 32P activity and grew much better. It is suggested that non‐mycorrhizal roots of some plant species do not utilize phosphate present at extremely low concentrations in the soil solution, but that mycorrhizal roots or fungal hyphae do. The implications of this finding for the mechanism of phosphate uptake by VA mycorrhiza are discussed.
CYTOLOGICAL STUDIES IN THE GENUS SILENE L.
Authors: BARI E. ABDEL 
Published: May 2006

SummaryChromosome counts on twenty‐two taxa of Silene L. confirmed that the genus is dibasic with ×= 10 or 12. Most European species have 2n= 24, but species of Section Conomorpha have 2n= 20. No cytodemes were found in any annual taxa, but within the perennial S. vulgaris the Mediterranean subsp. macrocarpa is tetraploid with 2n= 48. Karyotype comparisons showed the frequent presence of a satellited chromosome, and a large variation in chromosome size between species.
HEAT SENSITIVITY OF ESTERASE ISOZYMES IN THE STYLES OF LILIUM AND NICOTIANA
Authors: PANDEY KAMLA KANT 
Published: May 2006

SummaryThe heat sensitivity of esterase isozymes in styles was studied by the method of acrylamide gel electrophoresis in nine clones of Lilium and fifteen species of Nicotiana. The material included both self‐incompatible and self‐compatible species, strains or clones, and the Nicotiana species comprised natives of South America, Australia and South Pacific islands.The heat response was highly specific to particular isozymes, the affected isozyme bands usually disappearing completely under treatment while the other bands usually remained unaffected. The remarkable specificity of isozymes to heat is thought to be significant in adaptation of plants to different temperature conditions. This discovery offers the possibility of using the gel electrophoretic technique for identifying heat resistant and heat sensitive genetic eco‐types for breeding high‐yielding varieties specifically suited to different environmental conditions.In Lilium, heat response occurred exclusively in self‐incompatible clones, all self‐compatible clones showing no response. Among the South American Nicotiana species most genotypes in all self‐incompatible species showed heat response and about two‐thirds of the material in self‐compatible species showed at least some response. However, all the examined Australian species and the one South Pacific islands species, which are all self‐compatible, showed no heat response.The heat response in the species of Australia and South Pacific islands is discussed with reference to Waddington's concept of ‘canalization’ and ‘genetic assimilation’. The possible significance of two other general characteristics of isozyme bands in these species, namely, the comparatively lower total number and their generally slower movement in the gel, is considered briefly.
A NUMERICAL ANALYSIS OF THE PAST AND PRESENT FLORA OF THE BRITISH ISLES
Authors: BIRKS H. J. B. , DEACON JOY 
Published: May 2006

SummaryLists of all the taxa of vascular plants recorded from deposits of Late‐Devensian, mid‐Flandrian, and late‐Flandrian age in twelve geographical regions of Britain were compiled. From these lists coefficients of floristic dissimilarity between the regions were calculated, and two‐dimensional dispositions of points representing the regions were found for each time interval by non‐metric multidimensional scaling. Distributional data for the present day were analysed in a similar way. The method demonstrates a marked north‐south floristic gradient in the British Isles today, and analyses of the fossil data suggest that although a gradient was present in Late‐Devensian and mid‐Flandrian times it only became well developed in late‐Flandrian times. Phytogeographical analyses of the flora in each region at each time interval also demonstrate the existence of some west‐east floristic gradients, particularly in Late‐Devensian times. It is concluded that, despite the many limitations of the primary floristic data, the numerical methods have considerable potential for handling and synthesizing large amounts of historical biogeographical data.
UPTAKE OF GLUCOSE, TREHALOSE AND MANNITOL BY LEAF SLICES OF THE ORCHID BLETILLA HYACINTHINA
Authors: SMITH S. E. , SMITH F. A. 
Published: May 2006

SUMMARYGlucose, trehalose and mannitol were all absorbed by leaf slices of the orchid Bletilla hyacinthina. The rates of uptake of trehalose and mannitol were respectively 17.8% and 33.6% of the glucose uptake rate. Absorption of all three carbohydrates was reduced by low temperature or the presence of the inhibitor CCCP.Glucose and trehalose were extensively metabolized within the tissues and 14C appeared in both ionized and neutral compounds. Of the latter sucrose was the most heavily labelled. In contrast mannitol was scarcely metabolized at all.These results are compared with recently reported experiments on the germination of B. hyacinthina on glucose, trehalose or mannitol.
SOIL AERATION, NITRATE REDUCTION AND FLOODING TOLERANCE IN HIGHER PLANTS
Authors: GARCIA‐NOVO F. , CRAWFORD R. M. M. 
Published: May 2006

SUMMARYFlood‐tolerant species from natural habitats differ from flood‐intolerant species by being able to make more effective use of nitrate as an alternative electron acceptor to oxygen during periods of partial anaerobiosis. When flooded, tolerant species show marked increases in nitrate‐reductase activity in roots and leaves. A greater ability to synthesize amino‐acids under anoxia was also found in the tolerant species than in the intolerant. It is suggested that these properties enable the flood‐tolerant species to facilitate the re‐oxidation of NADH2 under conditions of anoxia and that this is associated with the greater ability of the species to withstand a reduction in the partial pressure of oxygen.
ZINC, LEAD AND COPPER TOLERANCE IN THE GRASS STEREOCHLAENA CAMERONII (STAPF) CLAYTON
Authors: REILLY ANN , REILLY C. 
Published: May 2006

SUMMARY Stereochlaena cameronii, a grass widely distributed in south central Africa, possesses tolerance towards heavy metals. Its tolerance and accumulation of zinc, lead, copper, iron, manganese and magnesium as well as sulphur have been studied and compared with similar phenomena in two other local metal‐tolerant grasses, Cynodon dactylon and Trachypogon spicatus, as well as in some herbs and trees. The grasses accumulate high levels of copper in their roots in contrast with the herbaceous plants which accumulate the metal in their leaves. Distribution of other metals between roots and leaves is variable and is related to soil composition. Heavy‐metal tolerance in Stereochlaena cameronii does not appear to be dependent directly on sulphur or nitrogen metabolism. In S. cameronii from zinc‐rich soil, the zinc is largely in insoluble form in the roots, but in plants from other soils about half of this metal is in soluble form.
MINERAL NUTRITION OF LYCHNIS VISCARIA
Authors: JARVIS S. C. , PIGOTT C. D. 
Published: May 2006

SUMMARYIn Britain, Lychnis viscaria is restricted to shallow soils on outcrops of basic igneous rocks and, in experiments, seedlings grow well on these soils but fail on soils from outcrops of sandstone, limestone and acid igneous rocks. The growth of seedlings in water‐culture with purified salts shows that the species does not require an unusual balance of ions and its response to trace‐elements is normal. Seedlings will only grow on acid soils (other than on basic igneous rocks) if calcium carbonate, nitrogen, potassium and phosphate are provided, and on calcareous soils if phosphate is provided. There is evidence that L. viscaria can obtain phosphate from soils on basic igneous rocks even though other species show severe deficiency.
LIMITING FACTORS IN PHOTOSYNTHESIS
Authors: JONES HAMLYN G. 
Published: May 2006

SUMMARYThe limitations of present methods for describing the relative importance of different processes in controlling rates of photosynthesis are discussed, and a new method proposed. It is suggested that‘photosynthetic limitations’, instead of resistances, should be used to describe the relative importance of different component processes at normal ambient carbon dioxide concentrations. The limitation approach is particularly relevant if the photosynthetic rate is not limited entirely by the supply of carbon dioxide.
A CONSERVATION DATA BASE
Authors: RADFORD G. L. , PANKHURST R. J. 
Published: May 2006

SUMMARYThere is an urgent need to examine the range of ecosystems that is currently protected in national parks and reserves, to point out those examples that are unprotected and to establish a rational programme of priorities for protecting as complete a series as possible. The International Biological Programme has pioneered the field of large‐scale survey work for the collection of data of relevance to this need and has contributed to the development of information retrieval techniques for handling the data. The first part of the paper discusses the rationale of the development of the data base and its modus operandi. The system is illustrated by two examples of retrieval and analysis for specific enquiries; the distribution of four species of Pinus, and the occurrence of grazing, logging and burning in national parks and equivalent reserves in the United States. The second part of the paper deals with system design, details of programming for the data base, and retrieval strategy. It is intended as an independent section which may be skipped if the reader has no interest in the finer points of the data base itself.
GROWTH FACTORS PRODUCED BY GAMETOPHYTES OF POLYPODIUM VULGARE L. GROWN UNDER RED AND BLUE LIGHT
Authors: SMITH D. L. , ROBINSON P. M. , GOVIER R. N. 
Published: May 2006

SUMMARYFiltrates from gametophyte cultures of Polypodium vulgare L. grown under red or blue light contain several substances affecting gametophyte development. Chromatograms prepared from red‐light‐grown cultures show two separate zones of inhibition while those from blue‐light‐grown cultures show a broad zone of promotive activity and a zone of inhibition. All the zones of activity affect spore germination, cell division and the transition to two‐dimensional growth. None affects cell length but the inhibitors cause a reduction in cell width. Most of the known effects of red and blue light on gametophyte morphogenesis can be interpreted in terms of the activity of these substances.
TRANSLOCATION AND DISTANCE I. THE GROWTH OF THE FRUIT OF THE SAUSAGE TREE, KIGELIA PINNATA
Authors: CANNY M. J. 
Published: May 2006

SUMMARYThe dependence of rate of translocation on the distance between source and sink was investigated. The relationship previously predicted was tested by measuring the rate of growth of sausage fruits on different lengths of stalk. It was shown that the measured rates of translocation were not at variance with the predictions, and that the spectacular fruit growth can be accounted for by the massive development of secondary phloem in the fruit stalk which need function at a level that is quite moderate compared with other known systems. The parameters of the theoretical curve needed to fit the data are fully consistent with those measured by independent techniques in other translocating systems.
THE ASSAY OF NITRATE REDUCTASE IN WHOLE CELLS OF CHLORELLA: STRAIN DIFFERENCES AND THE EFFECT OF CELL WALLS
Authors: SYRETT P. J. , THOMAS E. M. 
Published: May 2006

SUMMARYStrains of Chlorella with a sporopollenin‐like layer in their cell‐walls differ from strains without this layer in that their chlorophyll is extracted poorly by ethanol and they fail to stain with aniline blue. Exogenous NADH is not used as an election donor for nitrate reduction by frozen/thawed organisms having this layer and it is concluded that the layer impedes the passage of NADH; malate, which presumably reduces NADH held within the cell walls, is an effective electron donor for nitrate reduction. Frozen/thawed organisms of strains without this layer in their walls reduce nitrate when NADH is added. All the tested strains with this layer and the associated properties have been classified on other criteria as belonging to C. fusca var. vacuolata; the other strains examined have been classified as C. vulgaris or C. saccharophila.
BIOCHEMICAL AND PHYSIOLOGICAL ASPECTS OF LEAF DEVELOPMENT IN COCOA (THEOBROMA CACAO) I. DEVELOPMENT OF CHLOROPHYLL AND PHOTOSYNTHETIC ACTIVITY
Authors: BAKER N. R. , HARDWICK K. 
Published: May 2006

SUMMARYPeriodicity of leaf origin, rapid leaf expansion and lack, of significant chlorophyll synthesis in expanding leaves of cocoa (Theobroma cacao) are unusual features of leaf development. Changes in chlorophyll content, photosynthetic activity and ribulose‐i1,5‐diP carboxylase activity were determined during flush leaf development. Chlorophyll synthesis was found to be closely related to leaf expansion. Photosynthesis per unit area, photosynthesis per unit chlorophyll and ribulose‐i,5‐diP carboxylase activity all developed in parallel with chlorophyll. The significance of these findings is evaluated with regard to current concepts of photosynthetic unit development. Particular features of flush leaf development suggest that cocoa is a useful plant in which to examine the role of hormones and other factors in the control of chloroplast development.
OXYGEN—POSITIVE CHEMOTROPIC FACTOR FOR FUNGI?
Authors: ROBINSON PETER M. 
Published: May 2006

SUMMARYTropisms related to the point of emergence of germ‐tubes and to the subsequent direction of growth of germ‐tubes have been considered to be due to labile negative chemotropic factors produced by germinating spore populations. In many assay systems used to demonstrate chemotropic responses of germinating spores the oxygen concentration in the system would be the factor most likely to inhibit growth and evidence is presented which indicates that some of these responses could be caused by a positive chemotropism to oxygen. It is suggested that marked tropic responses to oxygen occur when the oxygen concentration begins to limit spore germination and extension‐growth of the emergent germ‐tubes and a hypothesis is presented to explain the mechanism of these effects.
THE GEOMETRY OF PLANT EPIDERMAL CELLS
Authors: KORN ROBERT W. , SPALDING RICHARD M. 
Published: May 2006

SUMMARYSix monolayer tissues from various plants were studied for the number of anticlinal walls of non‐marginal, unspecialized cells. One class of tissues, including the abaxial epidermis of the scale of Allium cepa, the adaxial epidermis of the leaf of Euonymus fortunei var. vegetus, gametophytic cells of Dryopteris filix‐mas, and the surface cells of the bud of Anacharis demo, is characterized by (a) a probability distribution curve with a peak at six walls having a frequency of around 0.40, and (b) tissue growth in two directions. A second class of tissues has the distribution peak of six walls at an approximate frequency of 0.58 and is formed by growth in either one dimension or with regular alternation in two directions, as in the leaf of Anacharis densa and for the colony of Volvox aureus.Models for both classes of tissues were constructed in order to identify those features associated with tissue proliferation that contribute to the variability of cell geometry. Geometric models give a pictorial representation of cell arrangement and are useful in ascertaining cell division patterns whereas algebraic models aid in clarifying spatial relationships between cells. The distinction between packing types and developmental types of models is discussed in the light of the concept of form in plant morphology.
PLANT GROWTH RESPONSES TO VESICULAR‐ARBUSCULAR MYCORRHIZA VII. GROWTH AND MODULATION OF SOME HERBAGE LEGUMES
Authors: CRUSH J. R. 
Published: May 2006

SummaryIn phosphate‐deficient soils, VA mycorrhizas strongly stimulated nodulation and growth of Centrosema pubescent, Stylosanthes guyanensis, Trifolium repens and Lotus pedunculatus. The tropical legumes were much more dependent on mycorrhizas for growth than the temperate species and this difference seems to be related to the degree of root hair development. When Trifolium repens and Lolium perenne were grown together, mycorrhizas preferentially stimulated growth of the legume.
CARBOHYDRATE METABOLISM IN HEALTHY AND RUSTED LEAVES OF COLTSFOOT
Authors: HOLLIGAN P. M. , CHEN C. , McGEE E. E. M. , LEWIS D. H. 
Published: May 2006

SummaryInfection of leaves of Tussilago by Puccinia poarum results in decreased export of photosynthetic products and, when infection is severe, in increased import. Photosynthetic products move to infection sites where host metabolites are converted to specific fungal products, including mannitol, arabitol, trehalose, glycogen, glucomannan and lipids. More previously fixed 14C is translocated to the fungus in the dark than in the light since, in the dark, degradation of starch contributes to net movement of 14C.
THE THREE‐DIMENSIONAL SHAPE OF PLANT CELLS AND ITS RELATIONSHIP TO PATTERN OF TISSUE GROWTH
Authors: KORN ROBERT W. 
Published: May 2006

SummaryTwo geometric models were devised for the shape of plant cells, one for those cells undergoing three‐dimensional expansion and the other for cells enlarging in one dimension (elongation). Probability distributions for the number and shape of wall facets were generated from the models and compared favourably with those found for real cells by other investigators. The i‐D growth model gave averages for the facet number and geometry of cells at interphase, division and daughter cell formation that closely approximated the averages from data collected by previous workers. These two types of developmental models, that is, ones following the quantitative relationships between cells over several generations, have two advantages over the standard interpretation of cell shape as the expression of packing forces. First, shape is explicitly explained from defined positions of cell plates during divisions. Second, subtle features of cell shape have morphogenetic importance in revealing the recent history of a cell with respect to its growth and its ontogenetic relationship to neighbouring cells.
REGENERATION OF THE CAP OF PRIMARY ROOTS OF ZEA MAYS
Authors: BARLOW PETER 
Published: May 2006

SummaryThe entire cap can be removed from the apex of the primary root of Zea mays. When this is done the nuclei of cells of the quiescent centre are stimulated to synthesize DNA and subsequently enter mitosis; the labelling and mitotic indices reach maximum values 12 and 18 h, respectively, after decapping. Division of cells of the quiescent centre and their descendants leads to the regeneration of a new cap which is completed about 3‐4 days after decapping. At this time a new quiescent centre is also established. The development of a new cap is a consequence of the changes in the polarity of growth and division of cells at the apex. Quantitative data are presented of the changes in rates and planes of division of the cells involved in cap regeneration. The data suggest that cells of the quiescent centre, stimulated to divide by de‐capping, complete about four mitotic cycles before a new quiescent centre forms. Experiments in which decapped roots were grown in a solution of colchicine, to induce polyploid nuclei, also showed that cells of the quiescent centre have the potential to enter four or five successive mitotic cycles as, in the quiescent centre of roots so treated, nuclei with up to 64C DNA content were found after 4 days.Mature cells of the cap of intact roots contain nuclei with an 8‐16C DNA content. In regenerating caps nuclei with an 8C DNA content were frequent on the fourth day after decapping. The pattern of [3H]glucose incorporation, as judged by quantitative autoradiography, by regenerating caps was compared with that by normal caps. On the fourth day of cap regeneration the patterns were similar. These two sets of results suggest that differentiation of the regenerating cap proceeds normally at the levels of both nucleus and cytoplasm.It is suggested that the initials of the cap collumella constrain the growth of the cells that constitute the quiescent centre and this in some way slows their rate of mitosis. Removing the cap relieves the constraint to cell growth and allows cell division, thus providing the trigger for regeneration. The changes in the pattern of cells in the regenerating apex, that accompany the reorganization of a new cap and quiescent centre, are explained in terms of the stresses that the cells impose upon each other.
PACHYCAULY, VESSEL‐ELEMENTS, ISLANDS AND THE EVOLUTION OF ARBORESCENCE IN ‘HERBACEOUS’ FAMILIES
Authors: MABBERLEY D. J. 
Published: May 2006

SummaryThe literature on pachycaul wood anatomy is reviewed. A simple mathematical proof discrediting Carlquist's ‘Theory of paedomorphosis in dicotyledonous woods’ is presented. In contrast to Carlquist's notion of juvenile wood patterns in mature pachycaul plants, it is shown that the narrow‐pithed leptocauls have wood patterns much like those of the juvenile stages of pachycauls. Leptocauls do not become pachycaul on islands; arborescent plants in ‘herbaceous’ families on islands are more easily explained as derived from pachycaul microspermous ancestors undergoing tree‐building in isolation from competition on the continents.
RESPONSE OF TWO VERONICA SPECIES TO A SIMULATED WOODLAND LIGHT CLIMATE
Authors: FITTER A. H. , ASHMORE C. J. 
Published: May 2006

SummaryTwo species of Veronica, V. montana and V. persica, respectively a woodland perennial and an annual weed of disturbed ground, were grown in unshaded, neutral shaded, and far‐red light. The only effect on V. montana was on root growth and was similar in shaded and far‐red treatments, but V. persica showed a far‐red specific reduction in leaf area, as well as shading effects on several other parameters. When grown in deeper shade under a leaf canopy, the growth of V. persica was drastically reduced and its developmental pattern radically altered, whilst that of V. montana was much more stable. It is suggested that the adaptation of V. montana to growth in woods involves resistance to both low light intensity and enhanced far‐red light stresses.