bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE EFFECT OF GIBBERELLIG ACID ON A GENETIC DWARF IN LOLIUM PERENNE
Authors: COOPER J. P. 
Published: May 2006

summaryA genetic dwarf (dd) of Lolium perenne is described. Its effect is to reduce cell elongation in the leaf blade and sheath. As a result, successive leaves on the shoot, instead of increasing in length, as in the normal plant, remain short and broad, and a small dwarf rosette is formed. The rate of leaf appearance on the main shoot is unaffected.Gibberellic acid, at a weekly dose of 1 cc. of a 50 mgm./1 solution per plant, results in increased cell elongation in the leaf blade and sheath, and brings the genetic dwarf within the normal phenotype for both leaf and inflorescence development.Although many genes are known which influence developmental patterns in flowering plants, in few cases is any information available about the possible biochemical mechanisms involved. In certain genetic dwarfs, however, evidence is accumulating that the mutant form can be brought within the normal phenotypic range by treatment with gibberellic acid, a growth‐regulating substance derived from the fungus Gibberella fujikuroi (Saw) Wr. This substance increases the length of leaves and internodes in normal plants of many species (Brian et al., 1954), and Brian and Hemming (1955) report that in the pea (Pisum sativum), broad bean (Vicia faba) and French bean (Phaseolus vulgaris) the dwarf varieties show a greater response than the tall varieties, the different genotypes producing similar phenotypes after treatment. In maize, Phinney (1956) tested six non‐allelic dwarf mutants and found that four of them could be converted into phenotypic ally normal plants by treatment with gibberellic acid.The present note describes a similar example of this effect on a dwarf mutant of perennial ryegrass (Lolium perenne).
A NOTE ON TWO FRESHWATER DINOFLAGELLATES
Authors: CRIDLAND ARTHUR A. 
Published: May 2006

SummaryA new species of Dinoilagellate, Gymnodinium hippocastamm, is described. Its resting spore is compared with Dinastridium sexangulare Pascher. Tetradinium chiastospomm Harris is recombined as Gymnodinium chiastospomm (Harris).
THE UPTAKE OF PHOSPHATE BY EXCISED MYCOR‐RHIZAL ROOTS OF THE BEECH
Authors: HARLEY J. L. , McCREADY C. C. , BRIERLEY J. K. 
Published: May 2006

SummaryThe temperature coefficients of phosphate absorption by beech mycorrhizas for temperature intervals below 20°C. were found to be above 2 regardless of the external concentration applied. Similar Q1o values were obtained for their constituent fungal and host tissues when exposed separately to phosphate solutions. The proportion of absorbed phosphate passing to the host through the fungal sheath was unaffected by temperature in very high or very low phosphate concentrations and the Q1o values for absorption by both tissues were of the expected magnitude. By contrast the proportion of phosphate passing to the host from intermediate concentrations (3.2 mM) was increased by low temperatures so that the estimates of Q1o for the host were lower than expected.Similarly, the inhibitors sodium azide and iodoacetic acid diminished uptake by both fungus and host in high and low concentrations of phosphate but did not affect the amount absorbed into the host from 3.2 mM phosphate.In concentrations of 3.2 mM phosphate also, separation of the fungal and host tissue increased their absorption rates over short periods but not over long periods of time.In the discussion, these results are considered together with previous experiments and it is concluded that in ecologically probable conditions phosphate passes to the host through the living hyphae of the sheath.
STUDIES IN BRITISH PRIMULAS
Authors: CLIFFORD H. T. 
Published: May 2006

SummaryIn Britain the cowslip and primrose are widely distributed and often grow intermixed or in adjacent habitats. Their flowering times overlap and apparent F1 hybrids between them are well known in the field but are numerically rare; apparent backcross plants have also been reported but are extremely rare. Experimental studies have shown that the artificial F1 hybrid is difficult to obtain and is only partially fertile, but that both the back‐cross and the F2 generations are quite vigorous under garden conditions. This being so gene flow between the species is possible and data were collected to determine if it had occurred.As no obvious hybrid swarms were encountered, some method of classifying populations had to be devised so that those likely to contain unrecognized introgressed individuals were grouped together. To bring this about populations of either species growing in the absence of the other were regarded as pure populations, and those in which the species grew together or in the company of apparent F1 hybrids were regarded as mixed populations. It was assumed that the mixed populations would contain more introgressed plants than the pure populations.Since the species showed no sign of discordant variation in the mixed populations the usual method of comparing populations diagrammatically by means of radiate indicators was not applicable. Instead, biometrical methods were employed. Three floral dimensions were selected for investigation. The inheritance of these in artifical crosses was also studied so that their behaviour was known. The plants from each population were classified into one of three groups, primroses, cowslips and apparent F1 hybrids. Pure populations and mixed populations were then compared in respect of the means and variances of the three dimensions.
POPULATION DIFFERENTIATION IN AGROSTIS TENUIS SIBTH.
Authors: BRADSHAW A. D. 
Published: May 2006

SummaryIn some of thirty‐seven populations of Agrostis tennis and A. stolonifera sampled by tillers and grown as spaced plants, the incidence of infection by the fungal parasite ‘Choke’, Epichloe typhina, has been found to be remarkably high. These populations are from environments in which vegetative growth is important owing to the incidence of heavy grazing, exposure, etc.A comparison of the growth of infected and non‐infected plants shows that infection, in preventing inflorescence production, causes a considerable increase in tiller density, without any other deleterious effects. These effects are of advantage to plants growing under conditions where vegetative growth is important.It is therefore concluded that infection of Agrostis sp. by Epichloe must be considered to be not an example of parasitism but of a curious form of symbiosis.
INCLINED POINT QUADRATS
Authors: WILSON J. WARREN 
Published: May 2006

Summary‘Relative frequency’ recorded by point quadrats measures not the actual area of foliage but the area projected in the direction in which the quadrat lies. Accordingly the relative frequency varies both with the slope of the foliage and also—when inclined quadrats are used—with the inclination of the quadrat. A theoretical study reveals that variation in relative frequency resulting from differences in foliage angle is greatest for vertical quadrats, is considerably reduced when (as suggested by Tinney, Aamodt and Ahlgren) quadrats are inclined at 45°, and is least when quadrat inclination is 32.5°. Accordingly the usual, vertical position for point quadrats is the worst possible one, since it results in the most erroneous estimates of percentage contribution (area basis); while with quadrats inclined at 32.5° errors are greatly reduced and are of an order acceptable in general survey work.
THE NATURE OF THE VARIATION IN FLOWER COLOUR IN THE GENUS LATHYRUS
Authors: PECKET R. C. 
Published: May 2006

SummaryAn examination of the flowers of nineteen species of the genus Lathyrus, which presented a considerable range in colour from red to blue, has revealed a marked uniformity in the anthocyanin pigments. Up to three closely related anthocyanidins were found in each species, namely, delphinidin, petunidin and malvidin. No other anthocyanidin was detected in any species. The pigments occurred as monoglycosides, not as diglycosides as reported by earlier workers, and behaved chromatographically as 3‐monoglucosides. L. sativus L. was exceptional, however, in that all the pigment was apparently present as free aglycone.Blueness of whole flowers or of wing petals was frequently correlated with, and is believed to be due to, the presence of the flavonols quercetin and kaempferol.
INTERGLACIAL DEPOSITS AT TRAFALGAR SQUARE, LONDON
Authors: FRANKS J. W. 
Published: May 2006

SummaryFossiliferous gravels were discovered during recent building operations on the south side of Trafalgar Square. At a later date organic deposits were exposed and an investigation of their plant remains was undertaken by the writer.A similar organic deposit had previously been described from the site of the Admiralty Offices (Abbott, 1892). In that work the following plants were recorded: Amblystegium ripanum Schimp., Hypninn stramineum Dicks., H. fluitans Hedw., Potamogeton sp., Lemna cf. polyrhiza, Ceratophyllum demersnm L., Polygonum sp., Rumex sp., Carex sp., Scirpus sp., and Betula nana L. With the exception of B. nana all the vascular plants recorded above have been also recognized in the present study. It seems probable that the record of B. nana was due to mis‐identification, since the general aspect of the flora is not one of cold or open conditions.The mammalian and molluscan remains from the present site have been studied by Dr. A. J. Sutcliffe and Mr. M. P. Kerney and will be published in detail later. The list of mammals forms an interesting counterpart to the plant determinations and is as follows: Panthera spelaea (Goldfuss), cave lion; Rhinoceros sp. indet., rhinoceros; Palaeoloxodon antiquas (Falconer), straight‐tusked elephant; Bos primigenius Bojanus, wild ox; Hippopotamus amphibius Linn., hippopotamus; Cervus elephas Linn., red deer; Dama cf. dama (Linn.), fallow deer. In addition a coprolite suggests that hyaenas may have been present and remains of bears not represented at this site have been found on two previous occasions during nearby excavations in other parts of the same terrace.
GARBOXYLASE IN CARROTS AND POTATOES
Authors: JAMES W. O. , RICHENS ANNE M. 
Published: May 2006

SummaryThe carboxylase of carrots is extracted almost wholly in the clear supernatant solution after all particles have been centrifuged down at forces up to 100,000 × g. There is very little carboxylase in fresh potatoes kept in air; but their ability to decarboxylate pyruvic acid increases steadily with storage under nitrogen. The activity is again found in the soluble fraction; but is not certainly enzymatic. These results are discussed in relation to the known differences between the anaerobic respirations of carrots and potatoes.
AN AGEING PROCESS IN EXCISED ROOTS OF GROUNDSEL (SENECIO VULGARIS L.)
Authors: HANNAY J. W. , BUTCHER D. N. 
Published: May 2006

SummaryThe growth and ageing of individual meristems of excised groundsel roots is described. Their behaviour upon repeated subculture is basically similar to that described by other workers for excised tomato roots, although excised groundsel roots require a greater concentration of sucrose for optimal growth than do excised tomato roots. However, growth in low‐sugar media can be considerably improved by adding small amounts of 2‐naphthoxyacetic acid.When roots grow vigorously in media containing the optimal sucrose concentration, or in low‐sugar media supplemented with 2‐naphthoxyacetic acid, they show signs of ageing after a few passages and usually stop growing after about 10 weeks. Roots in low‐sugar media grow less vigorously but survive longer, 1‐naphthoxyacetic acid is a very effective ‘anti‐ageing’ substance in that it enhances survival of roots in high‐sugar media, or in media supplemented with 2‐naphthoxyacetic acid.The ageing process appears to be under the control of a hormonal factor which is not β‐indolylacetic acid.
THE DIATOMS OF A CORE FROM ESTHWAITE WATER
Authors: ROUND F. E. 
Published: May 2006

SummaryThe diatom flora of a core taken from the region of the central buoy in Esthwaite has been analysed quantitatively and qualitatively. The diatom flora of the sediments laid down from the early zones of the Late‐glacial to the present day can be subdivided into five periods characterized by indicator species and variations in diatom productivity. The zones in Esthwaite have been compared with those from Windermere and Kentmere and shown to agree in general features, indicating a similar historical development for all three lake basins. The diatom periods show good correlation with the zoning derived from pollen analysis; and the change at the Boreal‐Atlantic Transition from base‐rich to base‐poor status, which was first detected in Kentmere, has been substantiated in Esthwaite. Comparison with the present‐day diatom flora suggests that a transition to eutrophic conditions, detected in late Post‐glacial time, is still occurring.
PATTERN OF DISTRIBUTION OF CHEMICAL CONSTITUENTS IN FLUE‐CURED VIRGINIA TOBACCO LEAF
Authors: SASTRY A. S. , RAMAKRISHNAYYA B. V. 
Published: May 2006

SummaryIt has been observed that the yellowing in the flue‐cured tobacco leaf starts from tips and margins and progresses gradually towards the base and midrib. A study of the pattern of distribution of chemical constituents in the different regions of the leaf was undertaken to see how it tallied with the pattern of yellowing.Twenty leaves were cut into two halves each by removing the midrib and each half was again cut into six portions such as base, middle, tip, lower margin, middle margin and upper margin. The segments from corresponding regions were mixed. The twelve composite samples thus obtained were analysed for moisture, total nitrogen, protein nitrogen, nicotine, total sugars and starch.It was found that there was a gradient in these constituents and that the tips and margins which yellowed first contained more total nitrogen, protein nitrogen and nicotine and less moisture and starch than the areas near the base and midrib.
TYPES OF NECTAR IN ANGIOSPERMS
Authors: PERCIVAL MARY S. 
Published: May 2006

Summary

The nectar of 889 species and some fifty varieties of Angiosperms has been analysed by paper partition chromatography.
Ten different types of nectar are distinguished (with two or three very uncommon types in addition) and are broadly classified into:

Nectars with dominant sucrose.
Balanced nectars with about equal amounts of sucrose, fructose and glucose.
Nectars with dominant fructose + glucose.

Three oligosaccharides occurring in nectar are identified and a fourth is named tentatively.
Eight hundred and twenty‐eight species appear to have nectar of constant composition: sixty‐one species have nectar which varies distinctly. The variation does not appear to be linked with locality or date of sampling.
The distribution of nectar types is traced through the Herbaceae.
Sucrose‐dominated nectars appear to be associated with long‐tubed flowers having protected nectar, and fructose +glucose‐dominated nectars with ‘open’flowers having unprotected nectars.
Many humble‐ and honey‐bee, butterfly and moth flowers have nectars with sucrose more or less strongly predominating over fructose and glucose.
The climax groups of the Cruciferae, Umbelliferae, a section of the Compositae, the Euphorbiales and the herbaceous Rosaceae have a completely broken‐down nectar of equal parts of fructose and glucose which is technically honey.
The preference of Apis mellifera for certain sugar mixtures and the types of nectar in some honey‐bee flowers are explored.
PLANT GROWTH AND THE AERIAL ENVIRONMENT
Authors: HUGHES A. P. , EVANS G. C. 
Published: May 2006

SummaryA detailed description is given of the growth of Impatiens parviflora DC in the laboratory at 15° C and saturation deficits of 1.5 or 2.0 mm Hg, illuminated for a 16‐hour day with light quantities of 11.2, 13.8, 20.6 and 26.2 cal./cm2/day. Growth under these conditions is compared with growth under artificial shades in the field, described in paper I of this series. The description and comparison cover growth in dry weight and leaf area, relative growth rate and relative leaf growth rate, unit leaf rate and leaf‐area ratio, specific leaf area, the distribution of dry matter between leaf, stem and root, and the dry weight/fresh weight ratios of leaf, stem and root. In all these account is taken of ontogenetic drifts up to dry weight of 500–600 mg (reached at an age of about 6 weeks) above which analysis is complicated by self‐shading.Nearly all the comparisons reveal closely similar plants, passing through similar ontogenetic drifts, and make it possible to use the laboratory studies, which in general reveal relationship with greater detail and precision, to help to interpret growth in the field.Observations are included on the effects of transferring plants from the lowest to the highest light and vice versa. The complications which this causes in the calculation of unit leaf rate are discussed. When they have been overcome it is shown that plants transferred to a given intensity have a unit leaf rate almost identical with that of plants grown in this intensity, differences in growth being due to differences in leaf‐area ratio (mainly reflecting differences in specific leaf area). In other respects adaption to a new light climate is largely complete within a week. The leaf growth of adapted and transferred plants is in harmony with the hypothesis that leaf expansion is controlled by a balance between extension due to water uptake by cells with high osmotic pressure and loss of cell wall plasticity by growth in wall thickness.Both field and cabinet observations yield a similar relationship between specific leaf area and unit leaf rate. It is shown that this relationship accounts for the relatively slight changes in relative growth rate with changing light at medium intensities. A comparison is also made of unit leaf rates in the field and in the cabinets, for equal mean daily quantities of visible radiation expressed in absolute units, problems of such measurements having been discussed. While closely similar at very low intensities, the curves rapidly diverge at higher intensities, unit leaf rate around 3.3 mg/cm2/week being reached at 26 cal./cm2/day in the cabinets and 51 cal./cm2/day in the field. Finally, the efficiency of conversion of visible radiation is shown to be about 15% for the lowest intensity in the cabinets, falling to 12.5% at the highest, and 3% in full daylight.
THE COMPARATIVE BIOLOGY OF CLOSELY RELATED SPECIES LIVING IN THE SAME AREA
Authors: HARPER JOHN L. , McNAUGHTON I. H. 
Published: May 2006

SummarySeeds of Papaver rhoeas, P. dubium, P. lecoqii, P. argemone and P. apulum were sown in garden plots at a range of densities in pure stands and mixtures of two species. The plants reacted to density by a reduced chance of establishment and a plastic reduction of plant weight and capsule numbers—the species did not differ in their reactions to density in pure stands.In mixed populations the chance of establishment of a species was reduced when its own density in the mixture was increased—the density of the associated species exerted a less significant influence.The species in lower proportion in a mixture gave the more successful establishment from seed—and it is argued that the persistence of mixed populations is therefore favoured in comparison with pure stands.
STUDIES ON CYSTOPHYLLUM MURICATUM (TURNER) J. AGARDH, 1848
Authors: NIZAMUDDIN MOHAMMED 
Published: May 2006

SummaryThe structure, growth and life history of Cystophyllum muricatum has been studied. Growth is initiated by a single 3‐sided apical cell in the axis and in the receptacle. Three tissues— the meristoderm, the cortex and the medulla—are formed. The surface growth is initiated by the meristematic activity of the meristoderm cells. Cortical cells in the basal parts of the axis function as storage cells for they contain dense chromatophores. Hyphae function as mechanical as well as storage tissues. The initial cell of a conceptacle develops a tongue filament of three cells. Oogonia are embedded on the wall of the conceptacle and simultaneous oogonial discharge occurs. Four primary rhizoids are produced on the embryo. Paraphyses appear to be haploid and the apical cell diploid. Vesicle character is suggested as diagnostic character on the generic level.
THE STRATIGRAPHY AND POLLEN ANALYSIS OF LAKE DEPOSITS NEAR TADGASTER, YORKSHIRE
Authors: BARTLEY DAVID D. 
Published: May 2006

SummaryThe stratigraphy and pollen analysis of the deposits show that this is a lake basin which during the Late‐glacial period was partially filled by lake clays and muds. One of the main interests of the pollen diagrams lies in the division of zone I into three sub‐zones showing a minor climatic oscillation which seems to be comparable with the Bölling oscillation of northern Europe. During Post‐glacial time the greater part of the deposits has been muds but on one side a fen developed which in early zone VI was sufficiently dry to support birch and pine wood. Later in zone VI the water table must have risen slightly because the fen peats were gradually covered by a rather oxidized mud suggesting that the fen became replaced by a shallow swamp with a widely fluctuating water table. In the Atlantic period the basin was reflooded and the more central deposits were covered by a layer of mud. Later in the central region, swamp and eventually Sphagnum bog communities developed. The whole area is now covered by a silty soil and forms a flat meadowland.
POLLEN‐ANALYTICAL DATA FROM URSWICKTARN AND ELLERSIDE MOSS, NORTH LANCASHIRE
Authors: OLDFIELD FRANK , STATHAM D. C. 
Published: May 2006

SummaryStratigraphic and pollen‐analytical data from the margin of Urswick Tarn and from the centre of Ellerside Moss are presented and discussed. The diagrams record episodes in the local ecological history from the early part of Post‐glacial pollen zone VI almost up to the present day. It is suggested that at Urswick Tarn there was a phase of lowered lake level during zone VI contemporary with that recorded at Hawes Water in Lonsdale (Oldfield, 1960a). The Ellerside Moss record begins early in pollen zone Vila and at the end of this zone, both diagrams show a clearly marked ‘Elm Decline’separated from a subsequent ‘Landnam’phase (cf. Iversen, 1941; Morrison, 1959; etc.). Above this horizon, most of the pollen‐analytical changes in the diagrams seem to be mainly the result of successive periods of human interference with the local vegetation; the final episode at Urswick Tarn records nineteenth‐century land‐use in the area.
STUDIES IN THE PHYSIOLOGY OF LICHENS
Authors: SMITH D. C. 
Published: May 2006

SummaryThe main carbohydrates soluble in 80% alcohol in Peltigera polydactyla are mannitol and a galactose‐mannitol glycoside. The main carbohydrates obtained by mild acid hydrolysis of the insoluble residue are galactose and mannose, together with smaller amounts of glucose and a pentose provisionally identified as xylose. The utilization of the glucose absorbed by Peltigera discs in 24 hours is of the following approximate pattern: 20% is released as carbon dioxide, 20% is converted to an ‘insoluble’ glucose polysaccharide, and the remaining 60% is retained in the ‘soluble’extract—about 45% to 50% as mannitol, about 5% as the glycoside, and the remainder as unidentified substances. No free glucose could be detected in extracts of discs fed with labelled glucose. Dissection experiments did not reveal any qualitative differences between the carbohydrates of the ‘algal zone’ and medulla. The medulla contained more insoluble carbohydrate than the‘algal zone’. The ‘algal zone’ was the only region in which synthesis of the glucose polysaccharide and the galactose‐mannitol glycoside from absorbed glucose could be detected. There is as yet insufficient evidence to indicate the role of mannitol in the metabolism of P. polydactyla, but it is possible that it is a storage carbohydrate.