bluuebunny/crossref_metadata_2025_split huggingface dataset:
Germination Promotion of Loblolly Pine and Baldcypress Seeds by Stratification and Chemical Treatments
Authors: BISWAS P. K. , BONAMY P. A. , PAUL K. B. 
Published: April 2006

AbstractThe effects of 4 chemicals on the germination promotion of stratified and unstratified seeds of loblolly pine (Pinus taeda) and baldcypress (Taxodium distichum) were studied. The chemicals used were gibberellic acid, kinetin, potassium nitrate and thiourea, each at 3 different concentrations.Stratification promoted the germination of both seed species. Certain concentrations of gibberellic acid, potassium nitrate and thiourea improved the germination of unstratified loblolly pine and baldcypress seeds while kinetin had no stimulatory effect.All 4 chemicals at specific concentrations promoted the germination of loblolly pine seeds stratified for a short period of time. Considering both speed and completeness of germination, best results were obtained when 21‐day stratified seeds were treated with either gibberellic acid (100 mg/1) or kinetin (10 mg/1). In baldcypress, on the other hand, none of these chemicals had any stimulatory effect on the germination of stratified seeds. Germination of both species of seeds was either partially or completely inhibited by the highest concentration of thiourea (30,000 mg/1) used.
Ion Relations, Chlorophyll Synthesis and the Question of ‘Bulk’ Phytochrome in Pisum sativum
Authors: KENDRICK RICHARD E. , HILLMAN WILLIAM S. 
Published: April 2006

AbstractLack of correlation between spectrophotometric phytochrome assays and physiological experiments has led to the concept of a ‘bulk’ phytochrome that is measurable but inactive, in contrast to an active form that is not measured in the standard assay. Because of suggestions that phytochrome action involves changes in membrane permeability, particularly to potassium ions, we investigated potassium and sodium uptake and efflux in Pisum sativum epicotyl sections which were equally de‐etiolated yet differed three‐fold in their phytochrome contents. Although dependent on the metabolic integrity of cell membranes (as shown by respiratory inhibitors) the selective uptake of potassium in this tissue is not under phytochrome control. Experiments were also conducted to see whether a three‐fold difference in phytochrome content affects chlorophyll synthesis in Pisum. Differences in chlorophyll synthesis observed can be related to the effectiveness of the pretreatments in eliminating the lag phase, not to their differences in phytochrome; Pfr decay rate has no effect on chlorophyll synthesis. The failure to find any correlation with the amount or state of ‘bulk’ phytochrome in these and previous experiments indicates that no function of this material is yet known.
Effect of 2,4‐Dichlorophenoxyacetic Acid on Growth and on β‐Glucan Synthetases of Peroxyacetyl Nitrate Pretreated Avena Coleoptile Sections
Authors: ORDIN LAWRENCE , GARBER MORRIS J. , KINDINGER JUANITA I. 
Published: April 2006

AbstractColeoptile sections from Avena sativa L. were exposed to non‐lethal concentrations of peroxyacetyl nitrate (PAN). The sections were then incubated in solutions of 50 mM glucose plus 2.5 mM potassium phosphate with various concentrations of 2,4‐dichlorophenoxyacetic acid (2,4‐D). Growth after 4 hours was measured. A corresponding series of experiments was carried out and the effect of the 2,4‐D treatments on enzymes utilizing uridine diphosphate glucose (14C‐glucose) to form glucolipid and β‐glucans including cellulose was determined. Growth in the PAN‐treated sections was inhibited less at optimal and superoptimal auxin levels than at low auxin levels. Glucolipid synthetase activity was only slightly inhibited by PAN pretreatment and was reduced by increasing levels of auxin. Responses of alkali‐soluble glucan and cellulose synthetases were similar to growth in both control and PAN treated tissues. It was concluded that the earlier reported response of cell wall metabolism in vivo probably is due to effects on these enzyme levels.
Entrainment of Geotropic Oscillations in Hypocotyls of Helianthus annuus– An Experimental and Theoretical Investigation
Authors: ANDERSEN H. , JOHNSSON A. 
Published: April 2006

AbstractThe effects of periodically repeated geotropic stimulations (geotropic pulses) on sunflower hypocotyls are studied. The experimental results agree with predictions from a theory for geotropic movements of the hypocotyl.A sunflower hypocotyl performs circumnutations around or across the plumb line with a period of about 2.5 hours. These oscillations can be entrained to periodically repeated geotropic pulses with a period in a region around 2.5 hours. The limits of this “region of entrainment’ for geotropic pulses are studied. In the region of entrainment resonance curves, i.e., the amplitude of the oscillations plotted as a function of the period of the geotropic pulses, are obtained. The phase differences (measured as time differences) between the geotropic pulse rhythms and the resulting oscillations are also studied. Beat phenomena are predicted and recorded outside the region in which the plants can be entrained.The results are discussed in relation to oscillating phenomena of circadian type (i.e., with a period close to 24 hours), and many similarities are pointed out.
Oxygen Evolution and Oxygen Uptake by Isolated Chloroplasts of Wheat Irradiated with Monochromatic Light, without the Addition of an Oxidant
Authors: EGNÉUS HANS 
Published: April 2006

AbstractThe oxygen exchange obtained when isolated chloroplasts of wheat are irradiated, without the addition of a Hill oxidant, has been investigated. Depending on the wavelength, two types of oxygen exchange are obtained. In light absorbed by both photosystems an oxygen gush appears directly upon irradiation. This oxygen evolving reaction is soon replaced by an oxygen uptake which is present until the end of the irradiation period. In light absorbed mainly in photosystem I, no oxygen gush can be observed, instead an oxygen uptake appears directly upon irradiation. An oxygen evolving process can also be observed in irradiations performed with photo‐system I light, but this process appears after 10–15 seconds of irradiation. The influence of various external factors on the oxygen gush and the oxygen uptake, e.g. different wavelengths, light intensity, length of the dark periods between irradiations, was studied.The results show that the oxygen evolving reaction appearing upon irradiation with light absorbed by photosystem II and I, reflect the reduction of an oxidant, probably plasto‐quinone, in the electron transport chain between the two photosystems. The reoxidation of this oxidant can be brought about after irradiating with light absorbed in photosystem I, or by prolonging the dark period between irradiations, or through some unknown process connected to photosystem II.The oxygen uptake which consists of two components, one appearing directly upon irradiation and the other one appearing after about 10 seconds of irradiation, confirms earlier observations that oxygen can be reduced in photosystem I. The electrons for the oxygen uptake appearing directly upon irradiation, are obtained from the reduced intermediates in the electron transport chain between the two photosystems. The electrons for the other oxygen uptake process are obtained from a reductant in the chloroplasts with access to the carrier chain between the photosystems. Whether the two oxygen uptake reactions reflect two sites of interaction of oxygen with the electron transport chain or only one site is discussed.
Growth Regulators in Picea abies
Authors: STEEN INGA 
Published: April 2006

AbstractThe occurrence of growth regulators active in the Avena coleoptile straight‐growth test in sprouting buds and seedlings of Norway spruce (Picea abies Karst.) was investigated.The acid ether fraction contained a growth stimulator, the Rf of which in isopropanol: ammonia: water was 0.2–0.4. This substance behaved as indole‐3‐acetic acid (IAA) in elec‐trophoresis, in chromatography in various solvent systems on paper and on a Sephadex column. It gave the colour typical of IAA when sprayed with Ehrlich reagent and its fluorescence characteristics corresponded to IAA. Acid ether‐soluble inhibitors showed most activity at Rf 0.4–0.7, but due to tailing they interfered with the determination of the stimulator at the Rf of IAA in the bioassay. They also masked the activity of other stimulators. Colour reactions were obtained with Ehrlich reagent in the inhibiting chromatogram zone. When eluates from this zone were tested in high dilutions or after gel filtration growth stimulation was obtained. The acid fraction of seedling shoots also contained a stimulator with Rf 0.7–0.8. In the neutral‐basic ether‐soluble fraction growth stimulation was obtained at Rf 0.5–0.7. The extracts also contained stimulatory substances insoluble in ether but soluble in n‐butanol and partly in ethyl acetate. When the butanol fraction was hydrolyzed in 1 M NaOH a substance behaving as IAA when chromatographed was released.
Transpiration and Water Uptake in the Fruit Bodies of Some Hymenomycetes
Authors: ZOBERI M. H. 
Published: April 2006

AbstractThe relationship between relative humidity and transpiration was studied in the basidiocarps of Coprinus, Amanita, Agaricus, Tricholoma, Collybia and Polyporus. Transpiration decreases with an increase in the humidity and there is virtually no transpiration in nearly saturated air.To determine the relationship between uptake and transpiration, stipes were immersed in solutions of various osmotic ally active substances and inhibitors. Results showed that uptake has no influence on the transpiration.Additional data suggested that uptake in a detached basi‐diocarp proceeds as long as the fruit body is young and healthy. Studies with fluorescein dye and mannitol showed that most transpiration occurs at the surface and edges of the hymenium.
Extracellular Lytic Enzymes of Myxococcus virescens II. Purification of Three Bacteriolytic Enzymes and Determination of their Molecular Weights and Isoelectric Points
Authors: HASKA GUNO 
Published: April 2006

AbstractThe bacteriolytic enzymes produced by Myxococcus virescens and previously concentrated and separated from most of the non‐bacteriolytic proteins have been further separated and purified.The bacteriolytic enzyme solution was concentrated by lyo‐philization. When applied to a Sephadex G‐100 column, three peaks of bacteriolytic activity were eluted. Polyacrylamide gel electrophoresis showed that all the three enzyme fractions were contaminated with at least four non‐bacteriolytic proteins. In the first enzyme fraction the bacteriolytic enzymes could be freed from the contaminating proteolytic activity by adsorption on a hydroxylapatite column. The bacteriolytic enzymes could then be adsorbed on a CM‐cellulose column. The remaining contaminating proteins passed the column un‐adsorbed while the bacteriolytic enzymes could be eluted with a gradient of 0.02–0.10 M ammonium hydrogen carbonate solution. The second enzyme fraction was adsorbed on a CM‐cellulose column and then eluted with 0.03–0.15 M NH4 HCO3. After rechromatography on a new column under the same conditions, all of the contaminating proteins had disappeared. For purification of the third enzyme fraction chro‐matography on one single CM‐cellulose column was sufficient. The elution of the adsorbed enzymes was performed with a gradient of 0.15–0.30 M NH4HCO3. The recovery of activity for each of the ion‐exchange chromatography separations was at least 90%. The purity of the enzymes was tested by polyacrylamid gel electrophoresis. Each of the purified enzymes gave only one coloured band which coincided with the enzyme activity assayed in sliced gels. The molecular weights of the enzymes were determined by electrophoresis on acryl‐amide gels containing sodiumdodecylsulphate. The molecular weights determined in this way (about 40,000, 30,000 and 20,000, respectively) were about 10,000 daltons higher than those obtained by gel chromatography on Sephadex G‐100. This discrepancy seems to depend on interactions between the enzymes and the dextran molecules probably caused by the strongly basic nature of the enzymes or by formation of enzyme‐substrate complexes.
Changes in Endogenous Growth Regulators in the Gladiolus Corm during Dormancy
Authors: TSUKAMOTO YOTARO , KONOSHIMA HARUO 
Published: April 2006

AbstractChanges in endogenous growth regulators in gladiolus corms during dormancy were studied using paper and column chromatography followed by a bioassay with the test for straight growth of Avena coleoptile. Corms were grown in the field or in a glass room of a phytotron at 20°C in the light. Another lot was grown in a dark room at 20°C in the dark. Half of the daughter corms in each lot were cold‐treated for about one month and the other half were stored at room temperature after harvest. The earliest sprouting was seen in dark grown corms with cold treatment, and the latest sprouting in light grown corms without cold. This pattern was similar in each cultivar over a period of three years. Corms from both lots contained considerable amounts of inhibiting substance just after harvest. However, dark grown corms treated with cold showed a rapid decrease in inhibitor activity and an increase in promoter activity. On the other hand, in light grown corms without cold treatment there was inhibitor activity found consistently even after two months. —There appear to be two inhibiting zones in the chromato‐grams. One of these contains two inhibitory substances, one of which was assumed to be abscisic acid.
3‐Methyleneoxindole and Plant Growth Regulation
Authors: ANDERSEN A. SKYTT , MØLLER IB , HANSEN JÜRGEN 
Published: April 2006

AbstractThe campound 3‐methyleneoxindole was synthesized and tested in three “biological systems for auxin activity: Root initarion in pea stem currings, extension growth of etiolated pea stem segments and Avena first internodes. In none of the systems was found any effect — positive or negative of methyleneoxindole. It thus seems improbable that the compound participates in the growth regulation of these plants.
Gibberellin‐like Activity in the Developing Avocado Fruit
Authors: BLUMENFELD A. , GAZIT S. 
Published: April 2006

AbstractGibberellin‐like activity in avocado (Persea americana) fruit extracts was measured by the barley endosperm bioassay. Fruit tissues were anlyzed separately during fruit growth. The level of the activity found was very high in the endosperm and in the seed coats, but decreased in the latter during fruit growth. No measurable gibberellin‐like activity was detected in the mesocarp or in the embryo. It is assumed that the seed coats are a site of production of gibberellin‐like substances in the avocado fruit.
Physiological Responses of Apple Trees to Supraoptimal Root Temperature
Authors: GUR A. , BRAVDO B. , MIZRAHI Y. 
Published: April 2006

AbstractUngrafted apple rootstocks were grown in sand cultures at constant root temperatures between 20°C to 40°C. Temperatures of 30°C and above reduced root and shoot growth. Serious damage to the leaves occurred at 35°C and above.The O2 consumption, CO2 evolution and respiratory quotient (RQ) of the roots showed maximum values at 35°C.Different rootstock cultivars varied greatly in their susceptibility to damage by supraoptimal root temperatures apparently due to anaerobic respiration. The more susceptible ones differed from resistant types in the larger amount of ethanol they accumulated in their roots at supraoptimal root temperature, and the more severe reduction in the malic acid content of the roots at such temperature. Acetaldehyde was also found in roots and leaves at supraoptimal root temperatures, whereas the organic acid content of the leaves tended to decrease.Supraoptimal root temperature also caused a reduction of cytokinins in both roots and leaves accompanied by a reduction in the leaf chlorophyll content. This could be prevented by the application of kinetin or benzyladenine to the leaves.In a short experiment a rise in root temperature up to 40°C caused an increase in transpiration and a decrease in the resistance of the leaves to the passage of water vapor, whereas in prolonged experiments transpiration reached a maximum and leaf resistance a minimum at 30°C. The leaf water potential increased also with increasing root temperature. Leaf temperature increased with increasing root temperature, irrespective of increasing or decreasing transpiration rates.
Influence de la carence hydrique sur la repartition cellulaire de l'acide ribonucleique foliaire chez le cotonnier
Authors: MARIN BERNARD , DA SILVA JORGE VIEIRA 
Published: April 2006

AbstractWater stress, induced by addition of polyethyleneglycol 600 to the nutrient solution, reduces the ribonucleic acid content of cotton leaves. The chloroplastic compartment, especially its ribosomal fraction, was most affected, even losing ribonucleic acid to the cytoplasmic compartment. Decrease of ribonucleic acid content on dehydration of leaf tissue is linked with an increase of ribonuclease.
Photosynthesis, Transpiration, Leaf Stomatal and Mesophyll Resistance Measurements by the Use of a Ventilated Diffusion Porometer
Authors: BRAVDO BEN‐AMI 
Published: April 2006

AbstractA ventilated diffusion porometer was modified and adapted for simultaneous measurements of leaf resistance and photosynthesis (using 14C). The system enables measurements to be made under field and laboratory conditions with different concentrations of CO2 and vapor pressure gradients between the evaporating surfaces inside the leaf and the external atmosphere. The leaf is subjected to the porometer's atmosphere only for short periods (up to 30 seconds) and it is assumed that stomata are not affected. Establishing the linear regression of the effect of CO2 concentration on net photosynthesis makes it possible to extrapolate for CO2 compensation point, to calculate the overall resistance to CO2 and the mesophyll resistance to CO2.
Changes of the Protein Synthesis System during the Maturation of Potato Tubers
Authors: COCUCCI S. M. , GARLASCHI F. M. , BIANCHI E. , MARRÈ E. 
Published: April 2006

AbstractRespiratory activity, RNA contents and protein synthesis capacity of isolated ribosomes of tubers of Solanum tuberosum, cv. Tonda di Berlino, at progressive stages of development have been determined. In the immature, still growing tubers, respiration steadily decreases with the increase of fresh weight. The entering into dormancy of the tubers collected when immature corresponds to a rapid drop of respiration to the values characteristic of mature tubers. The RNA contents per tuber increase progressively during maturation. A decrease of the RNA contents per tuber (ca. 50 %) is observed in the period between the moment of harvesting and the end of dormancy. The endogenous capacity of isolated ribosomes to carry on amino acid polymerization strongly decreases during tuber development, while the activity supported by polyuridilic acid remains almost unchanged when measured at optimum Mg2+ concentrations, and becomes larger for the more mature tubers at superoptimum Mg2+ concentrations. These changes of the protein synthesis system during tuber development are compared with those occurring during seed maturation.
Conversion of Indole‐3‐acetaldehyde Oxime to 3‐Indolylmethylglucosinolate in Sinapis alba
Authors: JOSEFSSON EGON 
Published: April 2006

Abstract dl‐Tryptophan(methylene)‐14C and indole‐3‐acetaldehyde oxime(methylene)‐14C were supplied to cut shoots of 7‐day‐old plants of Sinapis alba L. Although both compounds were effective as precursors of 3‐indolylmethylglucosinolate, the incorporation of the aldoxime radioactivity was more effective than the incorporation of the amino acid radioactivity. This, together with other information, suggests that indole‐3‐acetaldehyde oxime is an intermediate in the biosynthesis of 3‐indolylmethylglucosinolate from tryptophan.
On the Nature of the Proteinases Secreted by the Aleurone Layer of Barley Grain
Authors: SUNDBLOM NILS‐OLOF , MIKOLA JUHANI 
Published: April 2006

AbstractThe nature of the proteinases which are secreted by barley aleurone layers in response to gibberellic acid was studied by constructing pH vs. activity curves for the hydrolysis of gelatin by incubation media and aleurone layer extracts. The results indicate that the aleurone layers release several different proteinases. The main component is a labile sulphydryl enzyme with an optimum pH of 3.9. The other enzymes include two sulphydryl proteinases with pH optima between pH 5 and 6.5 and a metal‐activated enzyme active at pH 7.0. No differences could be demonstrated between the proteinases released by and retained in the aleurone layers.
Effect of Wind on Plant Respiration
Authors: TODD GLENN W. , CHADWICK DON L. , TSAI SING‐DAO 
Published: April 2006

AbstractVarious plant species were placed in a 13.5 liter belljar equipped with a motor‐driven fan directly above the plants. Air was continually circulated from the belljar through an infrared CO2 analyzer at the rate of 1.5 1/min. Species tested included Triticum aestivum, Hordeum vulgare, Avena sativa, Zea mays, Sorghum vulgare, Phaseolus vulgaris, Glycine max, Pisum sativum, and Magnolia grandiflora. Increases in respiration of shoots or intact plants were detected at windspeeds of 3.6 m/s and above. All species responded in a similar fashion with increases in respiration of 20 to 40% being typical at a windspeed of 7.2 m/s which is similar to windspeeds under many natural conditions. The respiration rate returned to the initial rate within a short time after the wind had stopped. In Magnolia a sustained elevated respiration rate was measured over an exposure period of 3 hours to a wind velocity of 7.1 m/s. In some experiments flutter of the leaves was prevented but the respiration rate of bean and Magnolia was still elevated in the wind. This would suggest that the response is subcellular and not due to gross movement of the leaf itself. It is suggested that such an elevated respiration rate (maximum increase measured was 56%) might be expected to interfere with net assimilation and may be responsible for lower yields obtained in windy regions.
Oxindole‐3‐acetic Acid: Physical Properties and Lack of Influence on Growth
Authors: HENDERSON J. H. M. , PATEL C. S. 
Published: April 2006

AbstractThe auxin activity of OAA was studied.The assays used were the Avena coleoptile curvature and section tests, and the first internode test.OAA was completely inactive to these assays.Physical tests indicated no color reaction with modified Salkowski reagent (Gordon‐Weber) and no activity of any of the biochromatograms run with OAA.These data indicate that OAA is inactive as an auxin due to its characteristics of structural difference from IAA and further lends some speculation as to the site of activity of IAA as an auxin.
Studies on the Nitrogen Metabolism in Ectomycorrhizae
Authors: KRUPA SAGAR , FONTANA ANNA , PALENZONA MARIO 
Published: April 2006

AbstractFree and bound amino acids in the mycorrhizal and nonmycorrhizal root systems of Pinus nigra Arnold and Corylus avellna L. grown under semi‐natural conditions were analyzed through automatic amino acid analyzers. Tuber brumale Vitt. and T. melanosporum Vitt. were the respective fungal symbionts. Arginine and citrulline were found to accumulate in large quantities in the free pool of the uninoculated P. nigra and C. avellana root systems respectively. In the mycorrhizal root systems these substances decreased in their levels with a parallel increase in the concentrations of glutamine and asparagine. Implications of these changes are discussed with reference to ectomycorrhizae. In general the majority of the identified free amino acids were found in larger concentrations in both the types of mycorrhizal root systems. Results obtained suggested that this may not be due to proteolysis but due to increased biosynthesis. Possible interrelationships in ectomycorrhizal root systems with reference to nitrogen metabolism are presented in the form of a scheme.