bluuebunny/crossref_metadata_2025_split huggingface dataset:
INWASHED POLLEN SPECTRA AT LOCH FADA, ISLE OF SKYE
Authors: BIRKS H. J. B. 
Published: May 2006

SummaryPollen and macrofossil analyses of contiguous 1 cm samples have been made through a band of terrestrial bryophyte remains interstratified in Late‐Weichselian limnic silts. Various forms of pollen deterioration were distinguished and scored for the different sediment types. The fossil assemblage in the moss band suggests derivation by inwashing from a montane moss‐dominated spring. This is supported by comparison with a modern pollen spectrum from such a community in Scotland. Pollen in the bryophyte band is largely corroded, due to aerial oxidation and microbial attack, while pollen in the silts is broken and degraded, resulting from mechanical damage. The silts also contain pre‐Quaternary microfossils, largely of Jurassic origin. Two forms of redeposited microfossils are distinguished: secondary types redeposited from erosion of older strata, and inwashed types redeposited from contemporary materials.
POLLEN AND DIATOM ANALYSES OF LATE‐QUATERNARY DEPOSITS IN THE BLELHAM BASIN, NORTH LANCASHIRE
Authors: EVANS G. H. 
Published: May 2006

SummaryInvestigations have been made of Late‐Weichselian and Flandrian deposits in Blelham Tarn, Lancashire and other parts of its basin. Pollen and diatom analyses have been made of several cores and samples taken from the inflows. Pollen analysis has been used as a basis for chronology. The vegetational history of the region and past diatom flora of the tarn and ‘kettle‐hole’ are discussed. During the Late‐Weichselian, in pollen zones I and III, the vegetation was dominated by herbs of open habitats, whilst in pollen zone II birch woodland developed. The diatom flora consisted mainly of non‐planktonic forms with Fragilaria spp. dominant. In the Early‐Flandrian (pollen zones IV–VI) birch woodland developed and was succeeded by a mixed oak forest. Differences are shown in the pollen spectra from the ‘kettle‐hole’, marginal and open water regions of the tarn. The planktonic/non‐planktonic (P/NP) diatom ratio slowly increased in the tarn. However, dominance was retained by the non‐planktonic forms. This increase in P/NP ratio did not occur in the ‘kettle‐hole’ region. A new diatom variety Melosira distans var. blelhamensis appeared in the flora. At the opening of pollen zone VIIa Alnus rapidly increased, and for the first time planktonic diatoms became dominant in the open waters of the tarn. In littoral regions non‐planktonic forms, in particular Achnanthes minutissima var. cryptocephala, remained dominant. Sphagnum‐sedge peat accumulated in the ‘kettle‐hole’. Diatoms are scarce in this peat. During the Late‐Flandrian (pollen zone VIIb to the present day) the local vegetation was an older mixed oak forest. However, more open vegetational conditions gradually developed as shown by the increase in herbaceous pollen. Dominance was held in the open waters by the planktonic diatoms. The littoral regions favoured the growth of Achnanthes minutissima var. cryptocephala. Sphagnum‐sedge peat continued to accumulate in the ‘kettle‐hole’. Other limnological aspects considered include the tarn's trophic condition, productivity, alkalinity, the transparency of its waters and tarn level changes. In the past the tarn covered a much wider area. Field evidence shows that man has interfered with the drainage system.
THE USE OF COMPUTERS IN THE PRESENTATION OF POLLEN DATA
Authors: SQUIRES R. H. , HOLDER A. P. 
Published: May 2006

SummaryProblems associated with comparing pollen diagrams can be partly avoided by using a computer to draw diagrams in a standard form. A program which may be used to produce comparative diagrams is described. The input specifications and limitations and examples of the output are presented and discussed in the light of the increasing volume of pollen data which are available.
THE MECHANISM OF CHLORIDE TRANSPORT IN CHARACEAN CELLS
Authors: SMITH F. A. 
Published: May 2006

SummaryActive chloride uptake by cells of Chara corallina decreases as the pH of the bathing solution is increased, using a range of buffers. Superimposed on this effect, large stimulations of Cl− uptake can be obtained by the addition of imidazole and tris buffers or ammonium sulphate. ‘Stimulated’ or ‘normal’ Cl− influxes respond similarly to the presence of metabolic inhibitors.It is suggested that these effects are not due to changes in photosynthesis or respiration, but reflect the dependence of Cl− transport on the pH gradient across the plasmalemma. Possible ways in which Cl− transport might be linked to H+ or OH− fluxes are discussed. It is proposed that the pH gradient across the plasmalemma is controlled by charge‐separating reactions which produce an active H+ efflux, and that Cl− uptake is linked to OH− efflux by ion‐exchange reactions.The metabolic implications of this scheme are discussed in detail, with reference to previous work on Characean and other plant cells.
AUTORADIOGRAPHIC LOCALIZATION OF SOLUBLE AND INSOLUBLE 14C FROM [14C]INDOLYLACETIC ACID SUPPLIED TO ISOLATED COLEUS INTERNODES
Authors: WANGERMANN ELISABETH 
Published: May 2006

SummaryMethods for localizing soluble label in Plant tissues using frozen sections and stripping film are discussed. After 24 hours' application, 14C derived from radioactive indolylacetic acid (IAA) is heavily concentrated in the phloem, less so in the xylem, and very weak in the cortex and pith. The 14C cannot be ‘chased’ out of the tissues by non‐radioactive IAA, but nearly all of it is removed by leaching sections in water or methanol. The small amount which remains after leaching is attached to the walls of vessel elements.Chromatograms of extracts of treated internodes show that very little of the label seen in the tissues remains attached to IAA, and that most of it is present associated with substances which remain near the origin.
STUDIES ON THE EFFECT OF CERTAIN ENZYMIC POISONS ON THE METABOLISM OF STORAGE ORGANS
Authors: YOUNIS M. E. , YOUNIS A. E. , GABR M. A. 
Published: May 2006

SummaryGlucose and fructose fed to radish slices were taken up at different relative rates with marked accumulation of carbohydrates; a possible working mechanism is presented to explain the differential rates of uptake. Addition of iodoacetate to the sugar media decreased both the uptake of sugars and the accumulation of carbohydrates.Although there was synthesis of proteins in the presence of iodoacetate, the synthesis both in iodoacetate and in iodoacetate plus sugar was less than in the absence of iodoacetate.Sugars and iodoacetate either alone or in combination increased the rates of CO2 output; a possible explanation of the different rates observed is given. Moreover, iodoacetate increased the permeability of the cell membranes as is evident from the increased leakage of nitrogen compounds from the tissues into the media.
SUBAQUEOUS TRANSPIRATION IN NEW PERSPECTIVE
Authors: POTTER A. W. , MILBURN J. A. 
Published: May 2006

SummaryDixon's original observation that the submerged shoots of terrestrial plants continue to take up water through the cut stems for considerable periods has been confirmed. His observations were not due to artifacts, as suggested by others. His interpretation, that the uptake was in response to a loss of water from the leaves, termed ‘subaqueous transpiration’, caused by metabolic activity of the mesophyll cells, was not supported by experiments with shoots of the same genus he used.The possibility that minute amounts of water can be actively excreted by shoots cannot be eliminated, but none could be detected under paraffin by microscopy. A more satisfactory explanation is that uptake was due to incorporation of water into cells during growth whilst ‘fully turgid’. This postulated growth uptake seems sufficiently large to explain all experimental observations to date and active water secretion need not be presumed.
THE PARTITIONING OF RESISTANCES TO PHOTOSYNTHETIC CO2 UPTAKE IN THE LEAF
Authors: KOLLER DOV 
Published: May 2006

SummaryA theoretical analysis is presented of the partitioning of overall resistance to photosynthetic CO2 uptake in the leaf. This is based on the existence of a resistance to gaseous diffusion between the upper and lower layers of the chlorenchyma (Ri). It takes into account the anisolaterality of the leaf with respect to resistance to diffusion (Rw) through the upper and lower surfaces, and with respect to the (residual) resistance to CO2 uptake and fixation (Rm, the ‘mesophyll resistance’) in the upper and lower chlorenchyma. When Ri exists in conjunction with epidermal anisolaterality, mesophyll resistance of the whole leaf (R¯m) is over‐estimated by subtracting the diffusion component resistance (R¯w) from the total resistance to CO2 uptake (R). This over‐estimation increases with epidermal and mesophyll anisolaterality, as well as with increase in Ri and R¯w, but decreases as R¯m becomes relatively greater. A method is presented and discussed, by which Ri and the Rm values of the two sides of the leaf can be simultaneously estimated, using simultaneous measurement of their transpiration and photosynthesis and of diffusion porometry through the leaf.
THE ACCUMULATION AND BINDING OF COPPER IN LEAF TISSUE OF BECIUM HOMBLEI (DE WILD.) DUVIGN. & PLANCKE
Authors: REILLY C. , ROWEL JANE , STONE JANE 
Published: May 2006

SummaryThe flowering plant Beciutn homblei is able to accumulate copper and other heavy metals to a relatively high level in its leaves. Approximately 17% of the total copper is concentrated in cell walls where it is bound as an organic complex. Copper in water extracts of leaf tissue is not in free ionic form but is complexed with amino acids or peptides. In vitro experiments indicate the strong complexing powers with copper of certain substances in leaf tissue.
NON‐SPECIFICITY OF SYMBOTIC INFECTION IN ORCHID MYCORRHIZA
Authors: HADLEY G. 
Published: May 2006

SummarySymbiosis tests carried out between orchids from several geographical localities and thirty‐two Rhizoctonias isolated from orchids, non‐orchid hosts and soils of worldwide distribution, showed no evidence of any species‐to‐species relationship between orchid and fungus. Dactylorhiza purpurella established a symbiotic relationship with most fungi tested while Coeloglossum wide, Goodyera repens and Cymbidium canaliculatum, although less frequently symbiotic, established compatible infections with many isolates. Among orchids with photo‐synthetic protocorms, Epidendrum radicans was compatible with several fungi but three other species of Epidendrum together with Spathoglottis plicata and a Laeliocattleya cultivar were symbiotic only with Tulasnella calospora and certain Ceratobasidium isolates. Tulasnella calospora may be a universal orchid symbiont. Ceratobasidium cornigerum and Thanatephorus orchidicola commonly occur as root endophytes but are doubtfully symbiotic with most orchids. T. cucumeris is frequently symbiotic with Dactylorhiza purpurella but less commonly so with other orchids tested.
THE EFFECTS OF POPULATION DENSITY ON GAMETOPHYTE MORPHOGENESIS IN POLYPODIUM VULGARE L.
Authors: SMITH D. L. , ROGAN P. G. 
Published: May 2006

SummaryGrowth and development of gametophytes of Polypodium vulgare L. in culture are affected by population density. Increasing population density leads to an increase in gametophyte length and a delay in the transition to two‐dimensional growth. Cell number is at a maximum at an intermediate density. On the evidence presented it is concluded that the inhibition of development associated with high population density is attributable to the presence in the medium of a substance (or substances) secreted by the gametophytes. Although other explanations are possible, all the effects could be caused by a single, diffusible, volatile factor. It is suggested that the promotive effect of blue light on gametophyte development is due to the suppression of this factor by blue light.
SPECIES DIFFERENTIATION IN PAPAVER DUBIUM
Authors: KOOPMANS ALIE 
Published: May 2006

Summary Papaver dubium seeds were obtained from several European countries. Two different chromosome numbers were found: 2n= 42 and 2n= 28. The forty‐two chromosome races are most widespread. Four races with 2n= 28 chromosomes can be distinguished.From results of cytological investigation especially of chromosome pairing behaviour during meiosis, it is suggested that the two 2n= 28 chromosome races, Alb and Upps II, may be considered as subspecies whereas the other two (Cors II and Ca Sw) are best regarded as chromosome races of P. dubium L.
THE IMMEDIATE RESPONSE OF THE QUIESCENT CENTRE TO X‐RAYS
Authors: CLOWES F. A. L. 
Published: May 2006

SUMMARYRoots of Allium sativum and Zea mays were given 150 rads and 1800 rads of X‐rays respectively. Cells of the quiescent centre respond at once by coining into mitosis although most are at G, before irradiation. There is a stimulation of DNA synthesis in the quiescent centre, but not elsewhere, immediately after irradiation.Some cells, however, undergo mitosis without having synthesized DNA and this results in prophase and metaphase nuclei without the normal 4C complement of DNA.
LIGHT‐INDUCED CHANGES IN SUCCINYL‐CoA SYNTHETASE IN BARLEY SEEDLINGS
Authors: STOBART A. K. , PINFIELD N. J. 
Published: May 2006

SUMMARYSuccinyl‐CoA synthetase activity increased with chlorophyll synthesis in etiolated barley seedlings exposed to light. The increased enzyme activity did not reside in the developing chloroplasts but appeared to be cytoplasmic in origin.
MOVEMENT OF14C‐PHOTOSYNTHATE INTO THE ROOTS OF WHEAT SEEDLINGS AND EXUDATION OF14C FROM INTACT ROOTS
Authors: McDOUGALL BARBARA M. 
Published: May 2006

SUMMARYWhen 8‐day seedlings were exposed to14CO2in light, approximately 2 hours were required for14C to reach the apices of the roots. One method used to detect the progress of14C down the root was to scan the root with a radiochromatogram strip scanner. At this stage most14C in aqueous ethanol extracts of roots was present as sucrose, equally labelled in glucose and fructose. This was converted only slowly to other components of the soluble fraction so that after 12 hours almost 50% of14C was still retained in sucrose.14C exuded from intact roots into surrounding solutions was present in both volatile and non‐volatile compounds. In the non‐volatile fraction glutamine, glutamic and aspartic acids were the main14C‐amino acids. Exudation of14C was not affected by changing the inorganic composition of the collecting solution. A change in pH of collecting solution from 6.4 to 5.9 increased exudation. Exudation also increased markedly when 2,4‐dinitrophenol or potassium cyanide was present in the collecting solution.
A COLORIMETRIC METHOD FOR THE ESTIMATION OF CERTAIN INDOLES
Authors: ANTHONY A. , STREET H. E. 
Published: May 2006

SUMMARYThe Ehrich reaction can, under standardized conditions, form the basis of a sensitive method of estimating certain indoles down to 1–2 μg/5 ml. An appropriate concentration of HCl in the Ehrich's reagent is essential. The concentration of trichloroacetic acid to give maximum sensitivity compatible with linearity between concentration of indole and absorbance must be experimentally determined. Absorbance should be measured between 530 and 580 mμ after a precisely measured time for colour development. Specificity can be increased by extraction of the colour complex into chloroform. The method has proved satisfactory for estimating the recovery of indoles from paper and thin‐layer chromatograms and from silica gel columns.
ETHER‐SOLUBLE INDOLES FROM SEEDLING ROOTS OF WHEAT
Authors: WOODRUFFE PATRICIA , ANTHONY A. , STREET H. E. 
Published: May 2006

SUMMARYTechniques are described for the extraction, chemical detection, separation and purification of acidic, ether‐soluble Ehrlich reactive substances present in young seedling roots of wheat. The value of DEAE cellulose chromatography as a purification step is demonstrated. The presence of at least four Ehrlich reactors whose properties point to their being indole compounds can be demonstrated by paper and thin‐layer chromatography. The reactors detected did not coincide in their properties with any of the twenty‐six natural and synthetic indole compounds (these included indol‐3yl‐acetic acid and its nitrile, indole acetaldehyde and indole aldehyde) available as reference compounds.To test the value of the isolation procedures adopted one of the reactors was purified as far as possible. Its chromatographic and chromogenic properties, its ultraviolet (uv) spectrum, its behaviour on gas chromatography, its hydrolysis and its activity in an auxin bioassay are described.
THE EFFECT OF LEAF HAIRS OF VERBASCUM THAPSUS ON LEAF ENERGY EXCHANGE
Authors: WUENSCHER JAMES E. 
Published: May 2006

SUMMARYEnergy budgets were determined for normal and hairless leaves of Verbascum thapsus L. in a wind tunnel. Leaves with the dense hair present were warmer than hairless leaves. This was shown to be due to a thicker boundary layer over normal leaves. Boundary layer resistance to heat and water vapour loss was higher for normal than for hairless leaves, resulting in lower convection and transpiration from normal hair‐covered leaves. Differences in transpiration resistance were correctly predicted by heat transfer theory. The hairs had little effect on radiation absorption by the leaves.
SPECIFICITY OF MYCORRHIZAL ASSOCIATION IN SOME AUSTRALIAN TERRESTRIAL ORCHIDS
Authors: WARCUP J. H. 
Published: May 2006

SummaryMany isolations from roots of Caladenia and allied genera (Glossodia, Elythranthera and Eriochilus) from southern Australia show that these orchids are closely associated with the endophytic fungus Sebacina vermifera, and that species of Diuris are associated with Tulasnella calospora (Rhisoctonia repens). Back‐inoculation experiments with sterilized orchid seed on a medium with cellulose as the carbon source showed that Tulasnella calospora greatly stimulated germination of species of Diuris, whereas Sebacina vermifera and other species of Tulasnella from orchids had little effect. Results with Sebacina vermifera and seed of species of Caladenia have generally been less successful, but in one test the fungus greatly stimulated germination of seed of C. cornea.Mycelium of Tulasnella calospora was commonly found on and in tubers, growing or dormant, of the species of Diuris examined.
POPLAR MOSAIC VIRUS IN GREAT BRITAIN
Authors: BIDDLE P. G. , TINSLEY T. W. 
Published: May 2006

SummaryPoplar mosaic virus occurs widely throughout the commercially important poplar clones grown in Great Britain. Symptoms develop from initial fine interveinal chlorotic spots to either a mosaic or veinal chlorosis, depending on the clone. The flexuous virus particle, length 679 ran, is very liable to aggregate during purification, but can be purified by precipitation with ammonium sulphate followed by density gradient centrifugation in sucrose or by gel filtration. The host range and in vitro properties of the virus are described. Infectivity and longevity in vitro of inoculum prepared from poplar leaves can be increased by the addition of insoluble poly‐vinylpyrollidone.
SOME EFFECTS OF POPLAR MOSAIC VIRUS ON THE GROWTH OF POPLAR TREES
Authors: BIDDLE P. G. , TINSLEY T. W. 
Published: May 2006

SummaryMeasurements have demonstrated severe growth losses in virus‐infected poplars, particularly during the first 2 years in the nursery. There is considerable clonal variation. Losses in height growth frequently exceed 10%, which in combination with a reduction in diameter of the stem, can result in a 25% reduction in the dry matter production of virus‐infected trees. These growth reductions were only apparent in the nursery, as no additional effects were noted on trees up to 11 years old in the plantations.Quantitative measurements are presented for the first time showing effects of virus infection on wood properties, particularly specific gravity and compressive strength. These effects are most apparent in wood produced during the first 2 years in the nursery, but there was also a significant increase in strength of branchwood from older trees.
STUDIES ON THE DISTRIBUTION OF OXYGEN AROUND THE ROOTS OF MUSTARD SEEDLINGS (SINAPIS ALBA I.)
Authors: GREENWOOD D. J. 
Published: May 2006

SummaryEvidence was obtained that oxygen transport through the plant greatly influenced the oxygen partial pressures in the medium surrounding the roots. Seedlings with their leaves in air had their roots embedded in agar gel that had been saturated with nitrogen, air or oxygen and after a 5‐hour period of incubation the distribution of oxygen in the gel was determined. When the gel had been saturated with nitrogen gas, oxygen partial pressures increased towards the surfaces of the roots of whole plants but not towards the surfaces of severed roots. When the gel had been saturated with air or oxygen, however, oxygen partial pressures always decreased towards the root surfaces irrespective of whether the roots had been severed or not. In oxygenated gel, the decreases were much greater towards intact roots than towards those that had been severed but in aerated gel the converse held. The results were in agreement with those expected if substantial amounts of oxygen moved from stem to root or in the opposite direction depending on the sign and magnitude of the oxygen partial pressure/distance gradients.
EVALUATION OF MENDOK AND DALAPON AS MALE GAMETOCIDES AND THEIR EFFECTS ON GROWTH AND YIELD OF LINSEED
Authors: RUSTAGI P. N. , RAM H. Y. MOHAN 
Published: May 2006

SummaryLinseed plants were sprayed with aqueous solutions of Mendok (sodium 2,3‐dichloroiso‐butyrate) and Dalapon (sodium 2,2‐dichloropropionate) at 250, 500 and 1000 ppm with a view to inducing male sterility. Both compounds produced more or less similar responses except that Mendok was slightly more effective than Dalapon. Toxicity symptoms consisted of hypo‐nasty, chlorosis and slight to severe burning of young leaves and flower buds. Treated plants showed profuse branching, enhanced vegetative growth and heavy flower production. However, flowers became progressively smaller and gradually closed. Production and germination of seeds were both considerably reduced in the treated plants. Gamete fertility was reduced by almost all treatments. Female sterility was caused by decrease in size and abnormal morphology of pistils, and non‐separation of styles and stigmas. Male sterility was induced in two forms: developmental and functional. The former was characterized by fully or partially barren anthers and non‐viable pollen. Rhythms of pollen non‐viability interspersed with periods of restoration of viability were noted. Functional male sterility resulted from lack of anthesis, fusion and non‐dehiscence of fertile anthers and agglutination of pollen.The tapetal cells in the anthers of undersized flowers were highly vacuolate, radially stretched and they persisted up to the mature pollen grain stage. Another feature of morphological interest was the differentiation of microsporangia on petals.It is concluded that neither Mendok nor Dalapon can be used as a specific male sterilizing agent in linseed.
INTRASPECIFIC VARIATION IN CALT HA PALUSTRIS
Authors: WOODELL S. R. J. , KOOTIN‐SANWU M. 
Published: May 2006

SummaryA biometric study of herbarium, wild and cultivated specimens of Caltha palustris L. s.l. in the British Isles indicates that most of the variation in the wild is environmentally determined. Further, there is no correlation of morphology with cytological differentiation. All taxa previously described within C. palustris L. are consequently regarded as untenable, with the exception of plants which differ by the single character of rooting at the nodes, and which show partial geographical differentiation. They are reduced to varietal status.