bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on Greening of Etiolated Seedlings II. Leaf Greening by Phytochrome Action in the Embryonic Axis
Authors: DE GREEF J. A. , CAUBERGS R. 
Published: April 2006

AbstractWe could demonstrate that greening of primary bean leaves in etiolated seedlings of Phaseolus vulgaris cv. Limburg can be controlled by a selective light‐pretreatment of the embryonic axis. This light‐induced interorgan synergism proved to be a phytochrome‐mediated process. The red/farred photoreversible effect on the embryonic axis seems to be primarily linked to changes in the energy metabolism of the primary leaves. Phototransformation of the protochlorophyll present and pigment synthesis are very dependent upon an adequate supply of biochemical energy. When the embryonic axis is selectively pre‐exposed to red light for a short time, respiration is markedly enhanced in the leaves and photosynthesis starts immediately upon illumination of the etiolated leaves after an incubation period of optimal length in the dark. The stimulatory effect of the red pretreatment on leaf respiration and photosynthetic capacity could be abolished to the level of the dark controls by a subsequent far‐red irradiation on the embryonic axis. It is therefore postulated that phytochrome plays a regulatory role in interorgan cooperation. The metabolic changes involved in photomorphogenesis of etiolated seedlings are closely related to changes in energy production. Our data indicate that the primary act of phytochrome becomes operative at the biochemical level by its directional influence on the energy balance of the cell and coordinates the use of metabolic energy within a tissue and between organs.
Induction of Thermosensitivity in Wheat Roots: Salt Sensitivity and Effects of Chloramphenicol and Ethanol
Authors: SKOGQVIST INGRID 
Published: April 2006

AbstractThermosensitivity was induced through a heat shock in wheat roots. Chloramphenicol and ethanol decreased the induced sensitivity to a degree where all roots were alive. The heat sensitized wheat roots were more sensitive to high salt concentrations than untreated roots.
Identification of a Cytokinin, 6‐(3 Methyl‐2‐butenylamino) purine, in Sea Water and the Effect of Cytokinins on Brown Algae
Authors: PEDERSEN MARIANNE 
Published: April 2006

AbstractUsing combined gas chromatography and mass spectrometry a growth‐promoting, organic component of sea water has been quantitatively estimated and identified as the cytokinin 6‐(3 methyl‐2‐butenylamino) purine. Additions of this cytokinin, kinetin or sea water from the Fucus‐Ascophyllum zone increased the growth of Ectocarpus confervoides and Pylaiella litoralis in artificial sea water. Additions of kinetin to bacteria‐free cultures of Ectocarpus fasciculatus also initiated the production of upright ectocarpoid filaments.
Effects of Daylenth on Endogenous Gibberellins in Solanum andigena
Authors: RAILTON I. D. , WAREING P. F. 
Published: April 2006

AbstractWhen tritiated gibberellin A1 was fed to intact potato plants growing under different daylength conditions it was converted to a more polar acidic metabolite. The rate of metabolism was the same under both long and short day conditions.Attempts were made to obtain information about the possible sites within the cell where gibberellin metabolism took place.
Cytochemical Localization of Peroxidase in Plant Cells
Authors: RAA J. 
Published: April 2006

AbstractPlant cells were stained for peroxidase by exposing them to a mixture of p‐phenylene diamine and hydrogen peroxide. Peroxidase activity is shown to be associated with chromosomes, nucleoli, cell walls and cytoplasm. Possible physiological roles of peroxidase bound to different structures are discussed.
Phase Shift Effects in the Kalanchoë Petal Rhythm due to Two or More Light Pulses
Authors: JOHNSSON A. , KARLSSON H. G. , ENGELMANN W. 
Published: April 2006

AbstractThe circadian petal rhythm of Kalanchoë blossfeldiana Poellniz was studied theoretically and experimentally. Results of experiments in which (i) two light pulses and (ii) repeated light pulses were given to the flowers are compared with predictions based on a previously published feedback model. In this model both the amplitude and the phase of the rhythm are affected by light pulses. Results from the present phase shift studies are shown to be in good agreement with the model.The results are also discussed in relation to a constant amplitude model like that suggested by Pittendrigh for the eclosion rhythm of Drosophila.
Trypsin Inhibitors during Germination of Vigna sinensis Seeds
Authors: FILHO JOSE XAVIER 
Published: April 2006

AbstractThe trypsin inhibiting activity of cotyledonary extracts of serido beans (Vigna sinensis) falls continuously during germination to a value which represents 5 % of the value for the dry seed. The specific activity is constant over the first three days and then decreases, reaching a level at the seventh day of germination which represents 20 % of the initial value. It is also shown that the axial parts control the disappearance of the trypsin inhibiting activity of the cotyledons. The results presented here seem to indicate a role for these substances in the process of germination.
Movement of Amyloplasts in the Statocytes of Geotropically Stimulated Roots. The Pre‐Inversion Effect
Authors: IVERSEN TOR‐HENNING , LARSEN POUL 
Published: April 2006

AbstractPreviously inverted Lepidium roots were placed in a horizontal position and the amyloplasts in the statocytes of the root cap allowed to fall through their entire range of movement across the cell. Under these conditions the amyloplasts first follow a mainly downward course for 6 to 8 min at a speed between 0.5 and 0.8 μm per min. For the next 10 min they move slightly more slowly in a direction away from the apical end of the cell, still sinking somewhat, but without reaching the plasmalemma along the lower wall.Previous experiments have shown that conditions assumed to allow the amyloplasts to slide parallel to the longitudinal cell walls are those that give rise to the largest geotropic curvatures. Such conditions are for instance (1) stimulation at 135° (root tips pointing obliquely upward) and (2) inversion of roots for 16 min followed by stimulation at 45°. Treatments assumed not to permit extensive sliding of the amyloplasts produce smaller geotropic curvatures, namely (3) stimulation at 45° without pre‐inversion and (4) inversion followed by stimulation at 135°. The location of the amyloplasts after these four kinds of treatment has now been determined on photomicrographs and the assumptions concerning the paths and extent of sliding of the amyloplasts confirmed.Observations on electron micrographs showed that under all conditions the amyloplasts are separated from the plasmalemma by other organelles, such as ER, nucleus or vacuoles.In roots rotated for 15 min parallel to the horizontal axis of the klinostat at 2 rpm, the amyloplasts are not clumped together as densely as in normal, inverted or stimulated roots, but they are not scattered over the entire cell volume.The statolith function of the amyloplasts is discussed in view of these and other observations.
Translocation and Metabolism of Picloram and 2,4‐D in Populus tremula
Authors: ELIASSON LENNART , HALLMÉN ULF 
Published: April 2006

AbstractTranslocation and metabolism of 4‐amino‐3,5,6‐trichloropicolinic acid (picloram) and 2,4‐dichlorophenoxyacetic acid (2,4‐D) in small plants of aspen (Populus tremula L.) were studied. In most experiments 14C‐carboxyl‐labelled herbicides were used. Considerable quantities of both herbicides were retained in the treated leaf. Translocation was mainly upwards into the growing shoot tip. Only minute quantities were found in the roots. Injection of the herbicides through a cut stem surface increased the translocation into the roots very little. One of the reasons for the limited downward translocation is considered to be a ready transfer of the herbicides between the phloem and the xylem.Both herbicides were incorporated into complexes from which the active herbicides could be released. However, this complex formation can only partly account for the retention of the herbicides in the treated leaves. The differences in metabolism found between 2,4‐D and picloram cannot explain the considerable difference in toxicity between the compounds.
Growth Substances Isolated from Tubers of Cyperus esculentus var. aureus
Authors: TAMÉS R. SÁNCHEZ , GESTO M. D. V. , VIEITEZ E. 
Published: April 2006

AbstractA methanolic extract of tubers of Cyperus esculentus Ten. var. aureus Richt. contains compounds which inhibit growth of oat coleoptile sections and germination of Beta vulgaris L., Lotus corniculatus L., Lolium perenne L., Pisum sativum L., Trifolium repens L., Lactuca sativa L. and Lycopersicum esculentum Ludwig. p‐Hydroxybenzoic acid, vanillic acid, syringic acid, ferulic acid and p‐coumaric acid were identified. Four other active compounds which could not be identified were also isolated.
Rubidium and Potassium Absorption by Bean‐leaf Slices Compared to Sodium Absorption
Authors: JACOBY B. , ABAS S. , STEINITZ B. 
Published: April 2006

AbstractAt salt concentrations of 0.1 mM as well as of 5.0 mM, the 22Na+ absorption capacity of bean (Phaseolus vulgaris L. cv. ‘Brittle Wax’) leaf tissue increased during the period of leaf expansion and decreased rapidly after leaf maturation. The absorption capacity for 86Rb+ and 42K+ was highest in very young leaves and decreased continuously in expanding and in mature leaves. The 86Rb+ absorption capacity of mature leaves was not increased by detopping the plants; this senescence‐retarding treatment more than doubled 2Na+ absorption.The absorption of 22Na+ by bean‐leaf slices was not enhanced by light, whereas 86Rb+ and 42K+ absorption was much affected.Previously absorbed 86Rb+ and 42K+ were more available for exchange than 22Na+.
Seasonal Changes in Auxin Effect on Rooting of Douglas‐Fir Stem Cuttings as Related to Bud Activity
Authors: ROBERTS A. N. , FUCHIGAMI L. H. 
Published: April 2006

AbstractThe relation of seasonal bud activity to the periodicity of rooting in Douglas‐fir, Pseudotsuga menziesii (Mirb.) Franco, stem cuttings was studied in combination with auxin and cold storage treatments. Cuttings were collected in all months except April and May, for 3 years.Rooting was least in September and October when bud dormancy was most pronounced, greatest in December and January if exogenous auxin was applied, or in February and March if no auxin was used. The buds contributed significantly to rooting from January to April, and were responsible for differences in rooting of terminal and lateral cuttings during this period. Auxin did not enhance rooting in September and October, but at other times it replaced or supplemented the role of vegetative buds in promoting rooting. Auxin also removed the differences in rooting between lateral and terminal cuttings. Cold treatment in October and November removed bud dormancy and enhanced rooting. After November the need for auxin or cold treatment diminished and rooting without either treatment reached a maximum in February and March. Auxin did not change the seasonal pattern of rooting but broadened and enhanced the rooting response in favor of earliness.These results are discussed in relation to the effect of bud activity on auxin response and root initiation. The hypotheses are proposed that cambial dormancy or auxin deficiency is not the limiting factor during bud dormancy, and that cold treatments have the effect of bringing inhibitors and promoters into proper balance for optimum rooting response.
Changes in Endogenous Cytokinins of Lettuce Seed during Germination
Authors: VAN STADEN J. 
Published: April 2006

AbstractUsing the soybean callus bioassay it has been shown that dormant lettuce seeds (Lactuca sativa L. cv. Grand Rapids) contain large amounts of water soluble cytokinins and small amounts of butanol soluble ones. When the seeds are irradiated with red light, or imbibed with 5 mg/1 gibberellic acid in the dark, the total cytokinin content of the seeds decreases, the level of water soluble cytokinins decreases, and the level of the butanol soluble cytokinins increases. Far‐red light does not reverse this effect completely although cytokinin activity in the butanol extracts decreases following such irradiation.It is proposed that the interconversion of cytokinins initiated by red light, or gibberellic acid in the dark, is one of the primary events leading to radicle elongation in light‐sensitive lettuce seed.
The Quantitative Yield in Purification of Cytokinins. Model‐experiments with Kinetin, 6‐Furfuryl‐amino‐purine
Authors: HEMBERG TORSTEN , WESTLIN PER ERIK 
Published: April 2006

AbstractModel‐experiments with kinetin, 6‐furfuryl‐amino‐purine, to determine the quantitative yield in purification of cytokinin extracts have been performed. If kinetin in acidic water solution is partitioned three times with equal volumes of ethyl ether, about 50 per cent of the kinetin passes into the ether phases. In similar experiments with ethyl acetate more than 90 per cent of the kinetin goes over to the ethyl acetate phases. Accordingly, use of these two solvents in purification of cytokinin extracts leads to very large losses. Use of petroleum ether or n‐hexane on the other hand leads to none or very small losses.Partitioning of alkaline kinetin solutions three times with equal volumes of 1‐butanol results in an almost quantitatitve extraction of the kinetin from the water solution.About 7 per cent of the original amount of kinetin follows the acid auxin, when a saturated ether solution of kinetin is extracted according to a common method for acid auxins. Kinetin may thus interfere in later analyses for auxins.The dangers involved when cytokinins are “purified” according to normal practice are pointed out.
The Relationship Between Rooting of Dahlia Cuttings and the Presence and Type of Bud
Authors: BIRAN I. , HALEVY A. H. 
Published: April 2006

AbstractDahlia cuttings with actively growing buds are relatively hard to root as compared with those having non‐growing or inhibited buds. In cuttings containing buds which sprouted during the rooting period, an inverse relationship was found between rooting percentage and growth rate of buds. Reproductive buds suppress rooting more than vegetative ones. Removing the growing terminal, parts of the cuttings (vegetative or reproductive) increased rooting percentage of cuttings. It is suggested that growing buds may affect rooting of cuttings in two opposed directions. The first is inhibition of rooting by competing with the roots for metabolites and the second is promotion of rooting by enhancing cambial activity.
Growth Retardants and the Germination of Light Sensitive Lettuce Seed
Authors: BERRIE ALEX M. M. , ROBERTSON JAMES 
Published: April 2006

AbstractThe effect of the dwarfing compounds chlormequat, B995, and Phosphon D on the germination of lettuce seed in darkness was found to be a depression which could be overcome in part by red light, GA, and kinetin. There was a marked statistical interaction between the growth retardants and all the mitigating treatments except B995 and GA, and light, at 30°C and GA and Phosphon D at 20°C and this implies a biological interaction at the site of action of the growth retardant. It is suggested that the action of the compounds considered is in the establishment of an ordered system since it is unlikely that there would be a common binding site for kinetin and GA.
Étude par électrophorèse en gel de polyacrylamide de I'évolution enzymatique des tissus de Poire Passe‐Crassane pendant la maturation du fruit cueilli
Authors: HARTMANN C. , DROUET A. 
Published: April 2006

AbstractEvolution of different enzymes (glucose 6‐phosphate dehydrogenase EC 1.1.1.49, fructose 1–6 diphosphate aldolase EC 4.1.2.1.3, malic enzyme EC 1.1.1.40, pyruvic decarboxylase EC 4.1.1.1) was followed by polyacrylamide gel electrophoresis and specific staining during the maturation of the pear (cv. Passe‐Crassane) harvested and stored at +15°C. During the increase of the respiration rate, the glucose 6 P dehydrogenase activity declines while the three other enzymes activity increases. Results obtained are discussed.
On the Nature of the Heat Stabilizing Effect of Inorganic Ions on Escherichia coli
Authors: LJUNGER CLAES , LARSSON KERSTIN 
Published: April 2006

AbstractThe growth lag of Escherichia coli at 45°C was reduced by the addition of sodium, potassium, magnesium and calcium ions to the growth medium. A method to quantitatively determine the lag‐reducing effect of these ions was developed. The results obtained showed that equivalent amounts of the ions produced the same reduction of the growth lag. According to the results of plasmolysis experiments cells of E. coli suspended in peptone broth were permeable to all four ions. The course of plasmolysis and subsequent deplasmolysis was registered as changes in the cells' ability to scatter light. The heat stability of catalase from E. coli was increased by addition of the four ions. This was observed in experiments with intact cells and with a crude cell‐free preparation of catalase. The results of our experiments are most easily explained by assuming a stabilizing effect of the ions tested on the intracellular bacterial proteins.
Pool Control of Uracil Uptake by Synchronous Chlorella
Authors: KNUTSEN GJERT 
Published: April 2006

AbstractExperiments with autospores of Chlorella fusca showed that the uptake rate of uracil was reduced as much as 40 % as the result of formation of soluble pools of uracil and its metabolites from exogenous uracil.Using synchronous cultures similar results were obtained with cells at other developmental stages.
Lipid Metabolism in Dehydrating Peanut Kernels
Authors: MOHAPATRA SUBHAS C. , PATTEE HAROLD E. 
Published: April 2006

AbstractMetabolism of radioactive lipids in kernels from peant plants subjected to 14C2 under field conditions was studied during dehydration (curing) of the seeds at 22°C or 50°C. Synthesis of lipid was predominant during the first 6 to 12 hours of dehydration whereas degradation dominated between 12 to 24 hours of curing. These changes were related to the moisture content of the dehydrating kernels; a moisture range of 42 to 47% was found to be an important factor influencing the observed pattern of lipid metabolism. The results from the present study also indicate compartmentalization of lipid metabolism in dehydrating peanut kernels.
Oscillatory Transpiration and Water Uptake of Avena Plants
Authors: BROGÄRDH T. , JOHNSSON A. 
Published: April 2006

AbstractXylem vessels in the lower part of the leaf of young Avena plants have been exposed to deformation by application of an external pressure. In this way a resistance to the water flow at the deformation site has been achieved, inducing undamped oscillations in transpiration and water uptake, even after removal of the root system.
The Light Induced Protochlorophyll–Chlorophyll a‐Transformation and the Succeeding Interconversions of the Different Forms of Chlorophyll
Authors: VIRGIN HEMMING I. , FRENCH C. STACY 
Published: April 2006

AbstractCurve resolution into Gaussian components of the absorption spectra during the varying stages of the Shibata shift in dark grown, irradiated leaves of barley indicates that the chlorophyll a forms formed after irradiation consist of the same main components which have been reported to be present in all hitherto investigated plant materials (peak values in the red region 662, 670, 677 and 683 nm, respectively) but in varying proportions. The spectra during the Shibata shift proper can be satisfied by a mixture of two single components gradually changing their proportions, although a four component system gives a still better fit to the measured absorption curves. It is also shown that curves taken before and after the shift and added together in the appropriate proportions will match the absorption spectrum measured with peak at the isosbestic point (after ca. 15 min at room temperature).
Nucleotide Metabolism during Pine Pollen Germination
Authors: NYGAARD PER 
Published: April 2006

AbstractThe metabolism of purine‐ and pyrimidine nucleotides in pine pollen (Pinus mugo) grown in suspension cultures have been examined.In the ungerminated dehydrated pollen, the presence of ATP has been demonstrated. Incubation of the pollen in a germination medium leads to an exhaustion of the ATP pool, which is restored with the onset of oxygen uptake.By labelling pollen cultures with 32P‐orthophosphate, it has been possible to quantitate the nucleotide components of the pollen, and thereby to measure changes in the nucleotide pattern at various growth stages. The most marked changes occur during the initial phase of tube growth when a large increase in the ribonucleoside triphosphate and the sugar nucleotide pools is observed. The contents of ATP and UDP‐glucose are further increased if starch synthesis is initiated by the addition of sucrose to the culture medium.In order to determine whether nucleotides in pine pollen are synthesized from de novo pathways or via reutilization pathways, from breakdown products of nucleic acids, pollen was incubated with 14C‐labelled precursors of both the de novo and the reutilization pathways. Incorporation experiments established de novo synthesis of ATP and GTP from glycine, and de novo synthesis of CTP and UTP from orotic acid. The operation of pathways for the utilization of exogenous nucleosides was also demonstrated. While uridine, cytidine and adenosine are incorporated into nucleoside triphosphate to a great extent, only minor incorporation of inosine and guanosine is observed. These reutilization pathways might be of importance for the synthesis of nucleotides during tube growth in situ.Addition of inhibitors of glycolysis and oxidative phosphorylation drastically reduces the level of ribonucleoside triphosphates, indicating a rapid turnover of the nucleotide pool.
Subcellular Distribution of Picloram
Authors: BAUR J. R. , BOWMAN J. J. 
Published: April 2006

AbstractGas chromatographic and radioisotopic analyses were made of cell wall, chloroplast, mitochondria and the remaining cytoplasm fractions of cowpea (Vigna sinensis Endl. cv. Southern Blackeye) trifoliates acropetal to primary leaves treated with the growth regulator 4‐amino‐3,5,6‐trichloro‐picolinic acid (picloram). The majority of picloram was recovered from the remaining cytoplasm. Concentrations in chloroplasts and mitochondria were consistently low.
Characteristics of the Uptake Mechanism of Chloride Ions in Excised Roots of a Woody Plant (Citrus)
Authors: ALTMAN A. , MENDEL K. 
Published: April 2006

AbstractThe characteristics of the uptake mechanism of chloride ions in citrus (Citrus spp.) were studied in excised, high‐salt, roots as to the nature of the isotherm at a wide range of uptake durations and Cl− concentrations. In addition, the effects of metabolic inhibitors, low temperature and various treatments were studied, and compared with Cl− uptake in excised roots of wheat (Triticum vlgare) under the same conditions.It was found that the uptake mechanism in excised roots of citrus differs considerably from that in wheat: (1) the rate of active uptake from 10 mM NaCl in citrus is 2.0 to 4.3 umol Cl− per g dry weight and h (vs. 35.5 umol in wheat); (2) there is no saturation of the system even at high external concentrations (up to 90 mM), and uptake is continuous; (3) uptake in citrus is less sensitive to KCN and dinitro‐phenol. In addition, it was noted that the age of citrus seedlings and the initial chloride content of both citrus and wheat roots markedly affected Cl− uptake.The data were analyzed in the light of the dual mechanism hypothesis of ion uptake, and it was concluded that only system 2 (high Km), is operating in the excised citrus roots studied. This is in accordance with the conditions prevailing in the field (whence the plant material was collected): high concentration of the soil solution in contact with the roots, and high salt status of the tissue. It is further suggested that the uptake of ions in citrus (and presumably in other perennial woody plants), is related to its growth habits and to the size and morphology of the root systems.