bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbon isotopic composition and oxygen isotopic enrichment in phloem and total leaf organic matter of European beech (Fagus sylvatica L.) along a climate gradient
Authors: KEITEL CLAUDIA , MATZARAKIS ANDREAS , RENNENBERG HEINZ , GESSLER ARTHUR 
Published: April 2006

ABSTRACTThis study investigated the influence of climate on the carbon isotopic composition (δ13C) and oxygen isotopic enrichment (Δ18O) above the source water of different organic matter pools in European beech. In July and September 2002, δ13C and Δ18O were determined in phloem carbohydrates and in bulk foliage of adult beech trees along a transect from central Germany to southern France, where beech reaches its southernmost distributional limit. The data were related to meteorological and physiological parameters. The climate along the transect stretches from temperate [subcontinental (SC)] to submediterranean (SM). Both δ13Cleaf and Δ18Oleaf were representative of site‐specific long‐term environmental conditions. δ13C of leaves collected in September was indicative of stomatal conductance, vapour pressure deficit (VPD) and radiation availability of the current growing season. Δ18O was mainly correlated to mean growing season relative humidity (RH) and VPD. In contrast to the leaves, δ13Cphloem varied considerably between July and September and was well correlated with canopy stomatal conductance (Gs) in a 2 d integral prior to phloem sampling. The relationship between δ13C and Δ18O in both leaves and phloem sap points, however, to a combined influence of stomatal conductance and photosynthetic capacity on the variation of δ13C along the transect. Δ18Ophloem could be described by applying a model that included 18O fractionation associated with water exchange between the leaf and the atmosphere and with the production of organic matter. Hence, isotope signatures can be used as effective tools to assess the water balance of beech, and thus, help predict the effects of climatic change on one of the ecologically and economically most important tree species in Central Europe.
Translocation of Phosphorus‐32 in Sporophores of Collybia velutipes
Authors: Littlefield Larry J. 
Published: April 2006

AbstractPhosphorus‐32 was absorbed by the mycelium of Collybia velutipes and translocated to the pilei of intact sporophores within 1.5 hours. In the stipes upward translocation occurred first in the peripheral hyphac followed by movement of the isotoipe into the central hyphac. After 3.0 hours hyphae in the two regions were about equally labelled with the isotope. Except for very minor differences hyphal was the same in the peripheral and central portions of the stipe.
Adjustment to Light and Dark Rates of Coccolith Formation
Authors: Paasche E. 
Published: April 2006

AbstractCoccolith formation in Coccolithus huxleyi was investigated in a semiquantitative manner by microscopic enumeration of coccolith‐carrying cells appearing, after varying periods in normal growth medium, following an initial removal of all coccoliths by treatment with a decalcifying medium. Coccoliths were formed both in the light and in the dark, but the rate of coccolith formation was very much greater in the light.Time‐course experiments on the uptake of carbon‐14 in coccoliths demonstrated that after a period in darkness, the cells required half an hour of illumination in order to adjust to the light rate of coccolith formation. Coccoliths were produced at a maximum rate only as long as the illumination lasted, although about one hour in the dark was needed before the transition back to the original dark rate was complete.
Transpiration and Calcium Deposition by Unifoliate Leaves of Phaseolus vulgaris Differing in Maturity
Authors: Koontz H. V. , Foote Roberta E. 
Published: April 2006

AbstractUnifoliate leaves were individually enclosed in clear, plastic chambers for the 24 hour treatment periods and then sacrificed for Ca analysis. Two transpiration rates were obtained by passing dry air through the chambers tising flow rates of 160 and 260 cm3/min. A third rate was obtained by a combination of shade and the lower air flow rate.Neither the transpiration rate nor solution‐Ca concentration (0.5mM and 2.5 mM of 0.1, and 0.5 strength Hoagland solution) altered the amount of Ca deposited in the unifoliate leaves of 22 day old bean plants (Phaseolus vulgaris). The transpiration rate per unit area of leaf remained constant for all ages studied (1l–20 days) and was 1.8, 2.7, 3.6 g H2O per dm2 day for the three different imposed conditions.A definite pattern of Ca deposition occurred. With all the transpiration rates there was a maximum rate of calcium deposition at 13 days of growth and a gradual decrease thereafter. When the Ca concentration of the nutrient solution was 20 μg/ml the daily Ca deposition in terms of water transpired by the unifoliate leaves exceeded this amount, except for the oldest leaf tested, and, the maximum Ca to water ratios were 250, 320, and 430 (μg Ca/g) in order of decreasing transpiration rates.The uptake of Ca against a concentration gradient and approximately the same total uptake regardless of transpiration rates and solution concentrations used, firmly suggest that Ca secretion into root‐xylem elements from a surrounding low level Ca solution requires energy expenditure by the plant.A possible explanation was proposed for the decreased rate of Ca deposition by the unifoliate leaves subsequent to the 13th day.
Calcium Uptake by Potato Tuber Mitochondria
Authors: Grunwald C. 
Published: April 2006

AbstractAn attempt was made to isolate from potato tuber mitochondria the reported calcium‐45 complex. Mitochondria fractionation results showed that the lipids were not involved in the calcium‐45 complex formation. Using hot water as an extracting solvent it was found that two calcium‐45 complexes occurred in the mitochondria fraction. One of the complexes was readily removable while the other complex was much less readily extractable with hot water. The readily removable calcinm‐45 complex was identified as calcium phosphate and the less readily extractable complex seemed to be directly related to mitochondrial RNA liberation, however, it was impossible to isolate a calcium‐45 ribonucleic acid complex. The extraction of the slowly removable calcium‐45 complex was not a simple liberation of the complex but rather a breakdown which was irreversible and could be inhibited partially by sodium arsenate.A possible explanation of these data is that the TCA soluble fraction represents the total calcium45 uptake by the mitochondria, that is, the calcium‐45 that has been accumulated plus that which is in the “calcium‐carrier complex”. It is suggested that the easily extractable hot water fraction is the accumulated calicum‐45 while the less readily extractable fraction is the “calcium‐carrier complex”.
Growth‐Promoting Effects of Fatty Acids on Excised Wheat Roots and Oat Coleoptiles
Authors: GUdjónsdóttir Sigŕan 
Published: April 2006

AbstractThe growth action of some fatty acids and alcohols with carbon number from 1 to 4 was tested on excised wheat roots in aseptic cultures. Growth, cell length, and dry weight were measured after seven days. The tested substances were: Formic acid, acetic acid, propionic acid, n‐Butyric acid, isobutyric acid, acelaldehyde, propionaldohyde, ethanol, n‐propanol, isopropanol, n‐butanoL and isobutanol. The primary alcohols and all of the acids, except formic acid, promoted the cell elongation and the total growth, but the meristematic activity was inhibited in the higher concentrations. The concentrations with maximal growth‐promoting activity were 10−2M to 10−3M for the alcohols and 10−4M for the acids. Propionic acid was applied in darkness, red light, and white light and proved to increase the cell length from 215 μ, 180 μ, and 120 μ up to 240 μ in all three treatments. The growth rate was not affected, but the duration of the cell elongation was extended. The presence of iron proved to be necessary for the stimulation. The chlorophyll content in the light grown roots was relatively unaffected when the cell length was increased and the dry weight was not increased as long the cell number was normal.The growth of Avena coleoptile segments was slightly promoted by propionic acid in the presence of IAA.
An Ion‐stimulated Adenosine Triphosphatase from Bean Roots
Authors: Gruener N. , Neumann J. 
Published: April 2006

AbstractA soluble ATP‐ase from bean roots was discovered. The enzyme was assayed by measuring the release of inorganic P from 32P‐labelled ATP. The enzyme is strongly stimulated by hoth sodium and potassium ions, in the alkaline pH range. Its characteristics are compared to that of the animal membrnnal ATP‐ase which is presumably involved in the transport of ions in animal tissues.
Quantitative Determination of Indole‐3‐Acetaldehyde. II.
Authors: Lahsen Poul 
Published: April 2006

AbstractThe method by Larsen and Klungsöyr (1964) for the quantitative determination of indole‐3‐acetaldehyde (IAAld) was modified for the purpose of eliminating the need for filtration after oxidation of the IAAld to indole‐3‐acetic acid (IAA).The essentials of the modified method are as follows: Samples of IAAld or IAA containing 0.015 to 0.15 μmol (ca. 2.5 to 25 μg) dissolved in peroxide‐free ether are evaporated to dryness and redissolved in 1.5 ml 0.02 M Ag2SO4. The oxidation is carried out in dim light by adding 0.5 ml 0.12 N NaOH. After 1.5 min, 2 ml of a modified Salkowski reagent are added. The optical density at 525 nm is read on a spectrophotometer after 75 min. The modified Salkowski reagent consists of 100 ml 0.05 M Fe2(SO4)3 in 1.5 N H2SO4; 240 ml H2O; and 160 ml cone. H2SO4 (sp. gr. 1.84). O.D. readings are identical for equal samples of IAAld and IAA (the latter used as a standard) up to 0.08 μmol (O.D. = 0.32). Larger quantities of IAAld may be determined when using pure IAAld as a standard, but at 0.20 μmol the O.D. for IAAld is lower than for IAA (0.69 as against 0.72).Indole‐3‐acetonitrile, tryptophol, indole‐3‐carboxylic acid, and indole‐3‐aldehyde all give O.D. values lower than 0.1 when tested at 0.20 μmol under the same conditions as described for IAAld and IAA.
Breaking of Dormancy in Xanthium Seeds by Kinetin Mediated by Light and DNA‐dependent RNA Synthesis
Authors: Khan A. A. 
Published: April 2006

AbstractKinetin was able to break the dormancy of the “upper seed” (in bur) of Xanthium by antagonizing the endogenous inhibitor present in the embryo. Other growth substances like indoleacetic acid, gibberellic acid and cycocel were without effect. Breaking of dormancy by kinetin was dependent on reversible phytochrome system and DNA‐dependent RNA synthesis. Protein synthesis is possibly not involved in the act of dormancy breaking. Endogenous inhibitor possibly participates in the mechanism of repression of genie site(s). It is suggested that an interplay of endogenous inhibitors, kinins and other factors (light, temperature, etc.) regulate dormancy, germination and differentiation by repression and derepression of DNA sites.
The Germination of Avena fatua under Different Gaseous Environments
Authors: Hart J. W. , Berrie Alex. M. M. 
Published: April 2006

AbstractThe atmosphere in which seeds germinate can profoundly affect the level of germination and dormancy. Seeds were germinated in atmospheres containing various concentrations of carbon dioxide and oxygen. At the same time the effect of light on these systems was examined.The germination of partially dormant populations of wild oat seed is inhibited by white light. This response to light is most apparent when the curyopsis is enclosed in the pales.Investigations into the effect of the ambient atmosphere on germination have indicated that, while oxygen is a necessary factor in the germination of tliis species, carbon dioxide also has an effect. A lack of carbon dioxide increases the degree of light inhibition of germination; 3 per cent carbon dioxide (by volume) allows germination in light; 20 per cent carbon dioxide inhibits germination in light and darkness at all tested oxygen concentrations.
Phytochrome Levels Assayed by in vivo Spectrophotometry in Modified Underground Stems and Storage Roots
Authors: Koukkari Willard L. , Hillman William S. 
Published: April 2006

Abstract In vivo spectrophotometric assays were conducted with sections of plant material cut from modified stems and storage roots. Phytochrome levels are highest in sections associated with growth such as buds and cambial regions. Interior tissues of tubers and the scale leaves of bulbs which are storage tissue contain low or no detectable phytochrome. However, in the storage root of Pastinaca saliva L. phytochrome is distributed in both the phloem and central regions, though it is highest in the cambial region. Total phytochrome in Gladiolus corm buds exposed to 5 minutes of red light followed by approximately 24 hours of darkness decreases more than 60 per cent. This rapid loss of detectable phytochrome in Gladiolus corm buds resembles phytochrome destruction in etiolated seedlings.
Spontaneous Movements in Plants Studied as a Random Walk Process
Authors: Johnsson Anders 
Published: April 2006

AbstractA theory to describe spontaneous curvatures performed by different plant materials on the clinostat is put forward. The movements are proposed to follow the assumptions of a random walk process (statistically randomly distributed movements) and thus to give curvatures following the equationsE(α) = 0V(α) = constant * timewhere α is the curvature from the starting direction, E(α) is the expectation of α and V(α) is the variance ofα. These equations are experimentally shown to be valid for Lepidium roots and Helianthus hypocotyls. Results for roots reported in the literature are recalculated and are shown to support the theory.
Effect of UV Light on Lettuce Seed Germination and on the Unfolding of Grass Leaves
Authors: Wagné Claes 
Published: April 2006

AbstractThe effect of UV light on germination of lettuce seeds and on the unfolding of wheat leaves was studied.A small improvement in germination was noted on exposure lo light of 254, 265, 334, 405 nm, and in unfolding on exposure to light of 254, 265, 313, 334, 360 and 405 nm.The low germination rate at 238 nm shows, that light energy absorbed by the high‐absorbing protein part of the phylochrome (Siegelman and Butler 1965) cannot be used in the germination process.
Chemical and Physical Factors Influencing Growth of Phytophthora parasitica var. nicotianae on Vegetable Oils
Authors: Hendrix James W. , Norman Calvin , Appli J. L. 
Published: April 2006

AbstractFactors influencing the growth of Phytophthora parasition var. nicotiona on vegetable oil liquid media were studied. This fungus grew poorly on oleic acid, triolein, and tristearin. Cholesterol and α‐tocopherol reversed the toxicity of oleic acid. Growth was often stimulated by addition of mineral oil to a glucose medium, and sterols dissolved in mineral oil frequently stimulated grwoth.Shaking produced a 5‐fold or more increase in growth on either glucose or cottonseed oil media. Cholesterol (20 μ/ml further increased growth on glucose meidum in shake culture by at least 100%. Growth was usually better at pH 6.7 than at 5.4 or 7.7. Growth in shake culture on a glucose medium supplemented with cholesterol and α‐tocopherol approached that occuring on vegetable oil media.
Stem Internode Elongation in the Japanese Morning Glory (Pharbitis nil Choisy) in Relation to an Inhibitor System of Auxin Destruction
Authors: Stonier T. , Yoneda Y. 
Published: April 2006

AbstractFurther investigations on a wild‐type strain of the Japanese morning glory (Pharbitis nil Choisy) to ascertain the relationship between stem internode maturation, decreasing rate of internode elongation, and increasing auxin destruction, have established the following: There exists in young, elongating, internode tissue, substances which prevent the destruction of indoleacetic acid by enzymes normally found in stem tissue. Almost all of the protecting activity can be attributed to two substances, one of them possessing an apparent molecular weight in the 5000 to 10,000 g/mol range, the other, in the 1500–5000 g/mol range. Both are water soluble, and heat labile, at least in vitro. It is further suggested that associated with Japanese morning glory stem maturation, is the loss of these auxin‐protecting substances, and as a consequence of this loss, the loss of further endogenous auxin‐induced elongation.
Some Effects of Light on Excised Wheat Roots with Special Reference to Peroxide Metabolism
Authors: Björn L. O. 
Published: April 2006

AbstractWhen excised wheat roots are exposed to blue light, catalase activity changes in a way to he expected as a result of photodestruction with first order kinetics. Wheat root catalase in vivo is less light sensitive than animal catalase in vitro, possibly due to internal screening. Illumination of the roots with red light causes some increase in catalasc activity. Peroxidase activity is much less affected by light. No relation has been found between catalase destruction and chlorophyll formation.The ability of roots to oxidize pyrogallol to purpurogallin (by other workers interpreted as peroxide production) is decreased by light, especially blue light. On the contrary, one peroxide producing enzyme, glycolic acid oxidase, was detected only in roots grown in blue light.The total flavin content, or the fraction present as FAD, is not affected by light. The ascorbic acid content is low, but slightly increased by blue light.
Growth, Turgor, Water Potential, and Young's Modulus in Pea Internodes
Authors: Burström H. G. , Uhrström Inger , Wurscher R. 
Published: April 2006

AbstractThe relations between longitudinal growth, Young's modulus, turgor, water potential, and tissue tensions have been studied on growing internodes of etiolated pea seedlings in an attempt to apply some physical concepts to the growth of a well‐known plant material. The modulus has been determined by the resonance frequency method and expressed as Etissue It increases nearly proportional to the turgor pressure and is at water saturation more than 50 times higher than at plasmolysis. Etissue is higher in the epidermis than in the ground parenchyma. Indoleacetic acid causes a decrease in Etissue Other properties have been studied on intact and split segments of internodes in solutions of graded mannitol additions. — The following tentative picture of the normal course of the growth has been obtained. Auxin induces growth both in the periphery (epidermis) and in the central core (parenchyma) under a decrease in Etissue This is followed by an increase of Etissue which is independent of auxin but depending upon the turgor pressure. It is assumed to involve internal structural changes of the cell walls of the type of creep. The rapid growth takes place in a dynamic system with a low water potential despite favourable water conditions. Epidermis and parenchyma grow equally rapid without tissue tensions. — Such can be produced artificially by splitting of segments and water uptake. The parenchyma thereby loses its sensitivity to auxin. This is the background of the split stem test for auxin. — Etissue increases when growth is slowing down, probably owing to both synthesis of wall substance and structural changes within the wall. The cells attain a more static condition with Etissue higher in epidermis than in parenchyma. This leads to the normal tissue tensions. — The result agrees with growth according to the multi‐net‐principle. The cause of the low water potential and low turgor is discussed with reference to the dynamic nature of both growth and water transport and a probably low matric potential of the streaming water. The decrease in Etissue following auxin addition is small but is the net difference between an auxin‐induced decrease and an increase through the assumed creep.
The Nutrition of Excised Wheat Roots
Authors: Ferguson J. D. 
Published: April 2006

AbstractFrom an investigation of the nutrient requirements of Hilgendorf wheat roots, glucose emerged as the only suitable source of carbon and energy, and thiamine as the only vitamin necessary. The roots had the ability to utilise nitrogen from calcium nitrate, urea, alanine, glutamine, allantoin, and hydrolyzed casein.
The Promotion of the Immobilization of Auxin in Avena Coleoptiles by Triiodobenzoie Acid
Authors: Winter Alan 
Published: April 2006

AbstractA study was made of the inhibition of auxin transport in Avena coleopliles by 2, 3, 5‐triiodobenzoic acid (TIBA), using carboxyl labelled 14C indole‐3‐acetic acid (IAA). A transport period of 1 hour followed by an export period of 2 hours was used routinely. Treatment with TIBA resulted in increased radioactivity remaining in the coleoptile sections after the export period. This radioactivity was distributed throughout the length of the coleoptile. The increase in radioactivity was shown to be due to an increase in the amount of IAA immobilized. The action of TIBA in inhibiting auxin transport is achieved by the promotion of the immobilization of IAA.
Respiration Rate, Adenosine Diphosphate and Triphosphate Concentrations of Leaves Showing Necrotic Local Lesions Following Infection by Tobacco Mosaic Virus
Authors: Sunderland D. W. , Merrett M. J. 
Published: April 2006

AbstractThe respiration rate of TMV‐infected leaves of Nicotiana tabacum L. variety Xanthi has been shown to be greater than the respiration rate of healthy leaves. 10−5M DNP gave maximum stimulation of the respiration rate of the healthy leaf but had no effect on the respiration of the virus‐infected leaf with dense lesion cover. The concentration of ATP increased with greater lesion density while the ADP concentration decreased. The increase in ATP concentration was greater than could be accounted for by the decrease in ADP concentration. Thus, increased respiration in the virus‐infected leaf is accompanied by a decrease in the ADP/ATP ratio. Illumination of the virus infected leaf increased the ADP/ATP ratio.
Primary Photosynthetic Induction Phenomena in Wheat
Authors: Egnéus Hans 
Published: April 2006

AbstractThe induction phenomena of photosynthesis in leaves of wheat were studied with a Beckman oxygen sensor. By special treatment prior to illumination, e.g. long dark and anaerobic periods the oxygen evolution could be divided into two parts, one consisting of two or three transients appearing under the first minute of illumination and one consisting of the main oxygen evolution. One or two transients could be observed when the plant was placed in darkness after an illumination period. The oxygen evolution had the same appearance in monochromatic as in white light. KCN‐treatment inhibited only the main oxygen evolution.The transients are interpreted as being manifestations of the primary processes connected with the start of photosynthesis. The main oxygen evolution is assumed to be closely related to the processes connected to the Calvin‐cycle.Experiments were also performed to ascertain that the observed induction phenomena were not connected with the stomatal movements in the leaves.