bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbohydrate Availability and Shoot Formation in Tobacco Callus Cultures
Authors: THORPE TREVOR A. 
Published: April 2006

AbstractTobacco callus grown on a shoot‐forming medium containing sorbitol or no carbon source survived, but did not produce shoots. Transfer of tissue from a sucrose medium to carbohydrate‐deficient media and vice versa suggested that the growth of the tissue was a function of a total period in contact with available carbohydrate. Both starch and free sugars in the tissue were utilized during shoot initiation. Furthermore, it appeared that the continuous availability of carbohydrate was required for shoot primordium growth and/or their development into leafy vegetative shoots in dark‐grown cultures.
Carbohydrate Metabolism and Translocation in Healthy and Cocoa Swollen Shoot Virus‐Infected Cocoa Plants
Authors: ADOMAKO D. , HUTCHEON W. V. 
Published: April 2006

AbstractAnalyses of cocoa swollen shoot virus‐infected and healthy cocoa (Theobroma cacao L.) plant tissues were made to determine the effect of virus infection on the metabolism and transport of carbohydrates in affected plants. Starch, sucrose and reducing sugars were found to accumulate in infected tissues. Translocation of photosynthates (mainly as sucrose) to the stem and root system, as estimated by the overnight loss of carbohydrates from the leaves and by 14CO2 tracer experiments, was as efficient in the infected plants as in the healthy. Infected plants showed a higher diurnal turnover of carbohydrates in their leaves and, on unit leaf area basis, higher levels of 14C‐labelled assimilates suggesting that they have a greater photosynthetic capacity than the healthy plants. The rate of respiration, as determined by the proportions of organic acids, amino acids and other intermediary metabolites formed from translocated 14C‐labelled sugars, was generally higher in infected than in healthy plants. It is concluded from available data showing the presence in infected tissues of mineral nutrients, protein N and amino acids at the same concentrations as in healthy plants, and from the relatively high rates of photosynthesis and respiration that a high rate of metabolic activity is maintained in the host‐virus system. Some factors possibly contributing to the stunted growth of infected plants are discussed in the light of these findings.
Thermal Denaturation Properties of Deoxyribonucleic Acid and Chromatin during the Life Cycle of Spirogyra
Authors: SASAKI KIMIKO , TAKAYA KATSURO 
Published: April 2006

AbstractHalf melting temperature (Tm) of DNA prepared from the nuclear fraction of vegetatively growing cells of Spirogyra was 86°C in the standard saline‐citrate solution and 68°C in the dilute saline‐citrate solution, and the major Tm values of soluble chromatin were 68°C and 78–80°C in the dilute saline‐citrate solution. The Tm value of DNA prepared from the nuclear fractions of conjugating and zygote cells was 88°C in the standard saline‐citrate solution and 70°C in the dilute saline‐citrate solution, and the major Tm values of soluble chromatin were 72°C, 78–80°C, and 84°C in the dilute saline‐citrate solution. The Tm values of DNA prepared from cells arrested at different stages of the life cycle of Spirogyra were raised by combining with different fractions of histones. The results agreed with an altered structure of the nucleoprotein complex during the life cycle of Spirogyra.
Abscisic Acid Effects on Growth and Metabolism in the Roots ofLemna minor
Authors: NEWTON RONALD J. 
Published: April 2006

AbstractThe effects of abscisic acid (ABA) on individual plants of Lemna minor L. were studied. The effects on growth and metabolism of the roots were the most noticeable and the most desirable to measure. Two mg/1 of ABA inhibited the root growth rate by 60% and this was accompanied by a 60% deceleration in the rate of uridine incorporation. The uptake of uridine and leucine and the incorporation of leucine were not affected by ABA. The latent period of root growth inhibition was 1 hour, whereas the inhibition of ribonucleic acid (RNA) synthesis occurred 2 to 4 hours after application. The growth inhibition caused an accumulation of starch in the peripheral, differentiated cell layer of the cortex. Apparently, the growth inhibition by ABA was not entirely due to an inhibition of RNA synthesis, and other plausible mechanisms of growth inhibition are discussed.
Bulblet Formation in Achimenes longiflora
Authors: DEUTCH BENTE 
Published: April 2006

AbstractThe bulblet formation in Achimenes longiflora D.C. cv. Major was investigated under controlled conditions in growth chambers. The bulblet formation in Achimenes longiflora cuttings was found to be inhibited by long‐day treatment such as continuous illumination. The degree of inhibition depended, however, on the quality of the light. High intensity far red and especially infrared emission was needed to effectively suppress the bulbing. As opposed to this, red light was found to be stimulatory. When red light (660 nm) was substituted for 20% of the white light, the bulbing was promoted over 400%.Gibberellic acid was totally inhibitory in all cases. The cytokinins benzyladenine and 6‐γ,γ‐dimethylallylaminopurine were strongly promotive and even inductive under inhibitory light conditions. The growth inhibitor N‐dimethylamino succinamic acid also stimulated bulblet formation. α‐Naphthyl‐acetic acid was strongly inhibitory, an effect which could not be overcome by benzyladenine.
Organogenesis in Callus from Shoot Apices of Pisum sativum
Authors: GAMBORG O. L. , CONSTABEL F. , SHYLUK J. P. 
Published: April 2006

AbstractShoot formation was observed in callus from apical cells of pea (Pisum sativum L. cv. Century). Shoot apices from 4‐day‐old plants were macerated and the resulting cell masses grown on agar media. The callus formation and shoot production occurred within 4 to 6 weeks in defined media containing 0.2 to 5.0 μM benzyladenine and 1 μM naphthaleneacetic acid. While most callus produced one or more shoots at high frequency, root formation did not occur regularly. Plants obtained by these procedures were grown to maturity producing flowers and pods.
Induction of Biplanar Growth in Fern Gametophytes
Authors: RAGHAVAN V. 
Published: April 2006

AbstractThe inhibition of biplanar growth in the protonemata of different ages of Asplenium nidus by the pyrimidine analog, 5‐fluorouracil has been investigated. Under favorable light conditions, older protonemata become biplanar in concentrations of 5‐fluorouracil which inhibit biplanar growth in younger ones. Treatment of 4‐ or 5‐celled protonemata with a high concentration of 5‐fluorouracil or transfer of germinated spores to progressively higher concentrations of the inhibitor lead to their continued filamentous growth. It is suggested that the age of the protonemata and the counteracting effects of light should be taken into account in evaluating the effect of metabolic inhibitors on the inhibition of biplanar growth in fern gametophytes.
The Pool Size of Protochlorophyllide during Different Stages of Greening of Dark Grown Wheat Leaves
Authors: SUNDQVIST CHRISTER 
Published: April 2006

AbstractThe pool size of protochlorophyllide in wheat leaves irradiated for 5 minutes to 6 hours was studied. Protochlorophyllide then accumulated in the dark, but the pool size of regenerated protochlorophyllide was considerably smaller in leaves irradiated for six hours than in leaves irradiated for 5 minutes. The decrease in pool size of regenerated protochlorophyllide was found to take place at the time when the chlorophyll formation had accelerated and reached the linear phase. The protochlorophyllide accumulated is the form with absorption maximum at 650 nm, which is phototransformed to chlorophyllide with maximum absorption at 684 nm. This species goes through the Shibata shift when formed even after 6 hours of irradiation.If leaves, irradiated for 1 or 6 hours, were fed with δ‐amino‐levulinic acid the protochlorophyllide synthesis was only 1.2 times faster in the leaves irradiated for 6 hours than in those irradiated for 1 hour. In the case of leaves fed with δ‐amino‐levulinic acid the absorption maximum of protochlorophyllide is at 636 nm and the absorption maximum of the chlorophyllide formed is at 672 nm.
Interaction between 2,4‐Dichlorophenoxyacetic Acid and Vitamin K in Datura stramonium
Authors: JANSSON OWE 
Published: April 2006

AbstractPlants of the cross Datura stramonium L. var. stramonium×Datura stramonium L. var. inermis (Juss. ex Jacq.) Timm. were sprayed either with a water solution of the sodium salt of 2,4‐dichlorophenoxyacetic acid (2,4‐D) or with a combination of 2,4‐D (sodium salt) and the vitamin K compound menadione sodium bisulfite in water solution. The plants were found to differ in one of their responses to the treatments, namely the development of necrotic spots on the leaf blades. Many necroses appeared on the plants treated with 2,4‐D plus menadione sodium bisulfite while only a few necroses or none at all developed on the plants treated with 2,4‐D alone. Furthermore, 2,4‐D in combination with menadione sodium bisulfite induced much larger necrotic spots than did 2,4‐D by itself. Spraying with menadione sodium bisulfite in water solution did not produce any observable effects upon Datura plants. The great increase in necrotic lesion formation was probably due to an interaction between 2,4‐D and menadione sodium bisulfite (or a metabolite of this compound) within leaf cells.
Relative Activities of Some Cytokinin Fractions of Developing Cotton Fruit
Authors: SANDSTEDT ROBERT 
Published: April 2006

AbstractIon‐exchange fractionization, paper chromatography, and soybean callus bioassay have partly resolved an apparent discrepancy in the sequence of cytokinin appearance in developing cotton (Gossypium hirsutum L.) fruit compared to the sequence reported in corn (Zea mays L.).Cotton fruit cytokinins were separated into three fractions: A combined n‐butanol and ethylacetate extractable fraction comprisedc. 10% of the cytokinin activity, a fraction not retained by a polymethacrylate weakly acidic cation‐exchange resin comprised c. 45%, and a fraction that was retained by the resin, c. 45%. The latter fraction differs from cytokinin fractions reported in corn. However, like cytokinin ribonucleotides, its cytokinin activity remains below Rf 0.3 on paper chromatograms developed with water‐saturated sec‐butanol, thus complicating studies of sequential cytokinin appearance in cotton. An anion‐exchange resin did not retain the cytokinin activity of this fraction.
Tryptophan Decarboxylase Activity in Developing Cucumber Seedlings
Authors: ELKINAWY MAHASEN , RAA JAN 
Published: April 2006

AbstractThe rate of decarboxylation of DL‐tryptophan‐carboxyl‐14C in homogenates of cotyledons, hypocotyls and roots of sterile and non‐sterile cucumber seedlings of 4, 8 and 11 days was measured. Tryptophan decarboxylating activity is highest in hypocotyls, lowest in cotyledons. In all organs the activity decreases with age. This enzyme activity does not parallel the IAA level in the organs during ageing.
Shock Pulse Effects on Wheat Growth
Authors: MURRAY SYLVIA A. 
Published: April 2006

AbstractWheat seedlings (Triticum aestivum cv. Pacific Blue Stem) grown under continuous low‐level illumination were used to study the effects of pressure variation and its duration. Growth was determined by dry weights, leaf length, and types of secondary roots produced. Two sublethal shock pulses (1.41 and 2.82 kg cm −2) and three pressure duration intervals (0.1, 1.0 and 10.0 seconds) were studied. The results indicated a general overall reduction in growth associated with the shock pulse and that the pressure duration interval influenced the shock‐ growth response. The long pressure duration interval was found to be the most influential on shock pulse response. Present knowledge indicates that a pulse rise‐time of 1 ms and a pressure duration interval of at least 1.0 second affect plant growth at sublethal shock pulses, such that the growth response is linear or bi‐directional, depending on the magnitude of the shock pulses, and either linear or complex with respect to pressure duration interval for any shock pulse level.
Evidence for the Presence of Cytokinins in Malt and Yeast Extracts
Authors: VAN STADEN J. 
Published: April 2006

AbstractCompounds that bring about growth in soybean callus were extracted from yeast and malt extracts. In the former most of the activity is due to a compound that co‐chromatographed with zeatinriboside. This substance is also present in malt extract and coconut milk, together with a component which has the same elution volume as zeatin. Partition chromatography on Sephadex LH‐20 revealed the presence of an extremely active unidentified substance in both malt extract and coconut milk. Indications are that this compound is not diphenylurea.
The Role of Cellulase and Polygalacturonase in Abscission of Young and Mature Shamouti Orange Fruits
Authors: GREENBERG J. , GOREN R. , RIOV J. 
Published: April 2006

AbstractDuring the first eight weeks after setting young citrus fruits gradually lose their ability to abscise at the abscission zone between the stem and the pedicel; in fruits older than eight weeks abscission occurs at the calyx area. The activity of cellulase and polygalacturonase in the two abscission zones was markedly increased before and during abscission, and was localized mainly in the abscission zone. Ethylene accelerated the increase in enzymic activity after an 8‐ to 10‐h lag period; 2,4‐D delayed abscission and enzymic activity when applied during the first 24 h after excision. During this period 2,4‐D also partly suppressed the enhancing effect of ethylene. Early application of cyclo‐heximide inhibited the formation of the enzymes and thus abscission was delayed to a certain extent.Although there are some indications that the relationship between enzymic activity and abscission is a complex one, the data presented indicate that cellulase and polygalacturonase play a significant role in abscission of citrus fruits at various developmental stages. Both enzymes act almost simultaneously and are equally controlled by ethylene and 2,4‐D.
Glutamate Dehydrogenase Activity in Roots: Distribution in a Seedling and Storage Root, and the Effects of Red and Far‐red Illuminations
Authors: DUKE STANLEY H. , KOUKKARI WELLARD L. , SOULEN THOMAS K. 
Published: April 2006

Abstract Pisum seedling and Pastinaca storage roots contained high glutanrate dehydrogenase (GDH) activity in areas of reported rapid growth and high phytoctrome content. A similar distribution was observed for malate dehydrogenase. Freeze‐thawings of mitochondrial preparations from Pisum roots always resulted in increases of GDH specific activity; however, the observed increases were much larger with basal than apical sections. Both intact and freeze‐thawed mitochondrial preparations from seedling roots exhibited increases in GDH activity with time after isolation. In intact mitochondrial preparations from roots of etiolated seedlings, an increase in malate dehydrogenase activity was observed similar to that of GDH activity; however, no increased malate dehydrogenase activity was noted in preparations from light‐grown seedlings.Illuminating Pisum seedlings with far‐red light slowly increased GDH activity in roots over a period of two weeks. Since these observed increases were not due to direct exposure of roots to light, other factors were likely involved.
Inter‐organ Control of Chlorophyll Synthesis in Primary Leaves of Dark‐grown Phaseolus aureus
Authors: HOLE C. C. , DODGE A. D. 
Published: April 2006

AbstractThe changing roles of the cotyledons and hypocotyl in the development of dark‐grown Phaseolus aureus seedlings are described. The effect of the cotyledons on total chlorophyll synthesis declined with age, but on a chlorophyll per gram fresh weight basis this was less pronounced. In five‐day‐old plants the hypocotyl was more effective than the cotyledons in increasing the chlorophyll level, and together their effect was less than additive. The promoting factors in the cotyledons were at a saturating level at this stage. The relationship between the effects of the two organs is discussed with particular reference to the components which they supply to the leaves.
Effect on the Progeny of Applying Different Day Length and Hormone Treatments to Parent Plants of Lactuca scariola
Authors: GUTTERMAN Y. , THOMAS T. H. , HEYDECKER W. 
Published: April 2006

AbstractSeedlings of the self‐fertilizing species Lactuca scariola L. grown continuously in 8 h days did not flower even one year from sowing. Seedlings grown in 16 h days uatil flower buds appeared 96 days after germination were either transferred to 8 h days or treated weekly with gibberellic acid (GA3), abscisic acid (ABA) or chlormequat (CCC) and retained, together with untreated control plants, in 16 h days. Each growth regulator caused characteristic morphological changes in the treated plants. All these plants flowered and produced seeds but the seeds showed distinct differences in weight, in their time to germination and in the seedlings which they produced. Germination and seedling characters depended on the light regime during germination as well as on the chemical applied to the parent plant and the rate of application. The parental treatment also affected the shape and size of the seedlings on a given day after germination, and certain treatments of the parent plant (transfer from long to short days and treatment with CCC in long days) advanced the flowering date of the seedlings. The gibberellin level in the seeds was raised, in increasing order, by treatment of the parent plant with 100 mg/1 GA3, transfer from long to short days, 10 mg/1 GA3, and 5000 mg/l CCC. It is suggested that the effect of day length on plant performance is mediated by the level of growth regelating substances within the plant and that the behaviour of seeds can be modified by the parental environment via the accumulation of different levels of certain growth factors in the seeds. A rise of one growth substance in the parent plant can result in the accumulation of a different one in the seeds.
Scopoletin: Kinetic Nature of Isoperoxidase A3 Catalyzed Oxidation and Its Possible Relation to the Physiological Action of This Naturally‐occurring Growth Effector
Authors: REIGH DARRYEL L. , WENDER SIMON H. , SMITH EDDIE C. 
Published: April 2006

AbstractIsoperoxidase A3 from tobacco tissue culture, Nicotiana tabacam W‐38, apparently does not have a subunit structure. Its molecular weight is approximately 54,000.The oxidation of scopoletin appears to occur in more than a single step since a blue intermediate is first formed. This is followed by the production of the final yellow product. A plausible explanation for this observation is the coupling of free radicals generated by the primary enzyme catalyzed reaction.
Action of Cordycepin on Gibberellic Acid Stimulated Cell Elongation in Coleoptiles from Gamma‐Plantlets of Wheat
Authors: KERN HARTMUT 
Published: April 2006

AbstractThe inhibitory effect of cordycepin (3′‐deoxyadenosine) on transcriptional processes has been used to follow the kinetics in the action of gibberellic acid on cell elongation in the coleoptiles from gamma‐planilets. It has been shown that, after a Sag period of 1 h, a high response to the phytohormone within a limited time is detectable.
Photosynthesis of Desiccating Leaves of Poplar
Authors: PIETERS G. A. , ZIMA M. 
Published: April 2006

AbstractThe relation between photosynthesis and water content was investigated using detached leaves of Populus euramericana (Dode) Guinier cv. Robusta.The time course of photosynthesis was measured at different light intensities, at different CO2 contents of the air and at constant temperature during the desiccation of the leaves. The time course of decreasing water content was obtained from continuous measurement of water transpired from the leaves.A large reduction of light saturated (400 W × m−2) photosynthetic rates was observed with decreasing water contents between 78 and 64% (water potential between −14 and −24 atm (bar)). This reduction was much greater in air with 0.3 % CO2 than in air with 5 % CO2, indicating a significant influence of CO2 diffusion resistance on rate of photosynthesis. The reduction of the rate of light and CO2 saturated photosynthesis (at 400 W × m–2 and 5% CO2 in the air) is a measure of the inactivation of the photosynthetic enzyme system by desiccation. A proportional reduction of the light saturated and light limited rate of photosynthesis (for different H2O contents) was found, when measured in air containing a saturating amount of CO2 (5 %). The reduction of the light limited rate of photosynthesis (at 20 W × m−2) was the same at both CO2 levels.
The Relation between Photosynthesis and Stomatal Resistance of Each Leaf Surface in Cotton Leaves
Authors: NAGARAJAH S. 
Published: April 2006

AbstractThe relation between photosynthesis and stomatal resistance of each leaf surface in cotton leaves (Gossypium hirsutum) was studied during ageing and with increase in light intensity.During ageing of leaves the stomatal resistance of the upper surface increases before that of the lower surface. This observation would suggest that the stomata of the upper leaf surface commence to age before those of the lower leaf surface. The earlier commencement of the increase in upper stomatal resistance results in the decline in photosynthesis at an early stage of ageing being negatively correlated with the upper stomatal resistance and not related to the lower stomatal resistance. The results indicate that in this initial phase of ageing the decrease in photosynthesis and increase in stomatal resistance of the upper surface are not causally related but occur simultaneously. At a more advanced stage of ageing the lower stomatal resistance also increases and then the decline in photosynthesis becomes related to the increase in stomatal resistance of both leaf surfaces.When illumination of leaves is increased stepwise, the resultant increase in photosynthesis is related to the reduction in stomatal resistance of each leaf surface. At low light intensities the stomatal resistance of the lower surface is low while that of the upper surface is relatively high. The difference between them decreases with increase in light intensity. This would indicate that the upper stomata require a higher light intensity to open than the lower stomata.The stormatal resistance of the two leaf surfaces is not related to the stomatal frequencey.
The Effect of Benzimidazole and Red Light on the Senescence of Detached Leaves of Oryza sativa cv. Ratna
Authors: SINGH N. , MISHRA D. 
Published: April 2006

AbstractExcised rice leaves (Oryza sativa L. cv. Ratna) werefloated on a 10–3M solution of benzirnidazole under dark or continuous red light. Compared to the water control a degradation of chlorophyll, protein, RNA, DNA and a decrease in the activity of alkaline inorganic pyrophosphatase was delayed at the same time as an increase of α‐amino nitrogen and the activity of acid inorganic pyrophosphatase occurred, Benzimidazole was more effective under red light than in the dark in retarding senescence. The possible role of inorganic pyrophosphatases is discussed with respect to biosynthesis during leaf senescence.
Endogenous Cytokinins in Solanum tuberosum as Influenced by Photoperiod and Temperature
Authors: FORSLINE P. L. , LANGILLE A. R. 
Published: April 2006

AbstractUsing the cucumber cotyledon bioassay, in combination with paper and column chromatographic techniques, 4 compounds exhibiting cytokinin activity were detected in extracts of Katahdin potato plant tissues. Two of these compounds were significantly higher in plants grown under inducing conditions (26°C day and 12°C night with an 8‐h photoperiod) than those grown under non‐inducing conditions (28°C day and 25°C night with a 16‐h photoperiod). One compound increased 10‐fold in above‐ground tissue after only 2 Inductive cycles. Both compounds reached their maximum values in below‐ground tissue after 6 days under inducing conditions, with tuber initiation observed after 8 to 10 days.