bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metabolism of Maleic Hydrazide in Tea, Camellia sinensis
Authors: Biswas P. K. , Hall Oscar , Mayberry B. D. 
Published: April 2006

AbstractThe results obtained with tea plants treated with 14C‐maleic hydrazide indicate that tea plants can metabolize maleic hydrazide to some extent. According to autoradiographic studies, two radioactive spots were found on X‐ray films after exposure and development. Based on two‐dimensional paper chromatography, possible ring cleavage, and infrared spectroscopic techniques, the possible metabolic products are lactic acid, succinic acid, maleimide and hydrazine.The biological activity of the metabolic products was tested by utilizing the Avena first internode test. Based on this investigation, it was noted that each radioactive area contained compound(s) that possess(es) some growth promoting properties. However, the results obtained with unknown number one (U1) indicate that it possesses greater growth‐promoting properties than unknown two (U2). finally, the approximate concentrations of U1 and U2 were determined by comparison with known concentrations of IAA and in relation to the amount of growth produced during the 19½‐hour period of incubation.
Studies on Cellular Site of Calcium Action in Promoting Pollen Growth
Authors: Kwack Beyoung H. 
Published: April 2006

AbstractStudies were conducted to determine cellular site of Ca action in promoting pollen growth of Crinum asiaticum and a few other species.The following experimental results have strongly indicated that Ca binding takes place in pectins of the pollen tube walls. This appeared to increase the wall rigidity and to regulate permeability of the pollen cells thereby enhancing pollen growth.Radioactive Ca incorporation was observed exclusively in the pollen tube wall regions. The promoting action of Ca on pollen growth disappeared when pectinase was supplemented to the media. This was not the case with cellulase and other enzymes used. Methyl donors promoted pollen growth, and the promotion was more than doubled if Ca ions were present. Ethionine, on the other hand, inhibited tube elongation and exhibited no Ca effect.Growth of pollen tubes in oscillaled liquid media during elongation was poorer than growth in standing media. The Ca effect was also reduced when pollen was oscillated. The observations made of the reduced rate of 45Ca incorporation when pollen was washed in water, and the hydroxylamineferric chloride test, have indicated that a considerable portion of these pectins are cold‐water soluble.
Effects of Auxin and Kinetin on the Development and Differentiation of Potato Tissue Cultured in vitro
Authors: Okazawa Yozo , Katsura Naoki , Tagawa Takashi 
Published: April 2006

AbstractThe present investigation deals with the influence of auxin and kinetin on cultures of potato tuber tissue, and the effect of the size of the explants on the organ formation.Exogenous application of auxin is indispensable for initiating callus formation of the tissue, but kinetin is not necessarily required. Kinetin serves to maintain the callus development, indicating that the stimulation of callus growth due to exogenous auxin would presumably be mediated by the addition of kinetin to the medium.A relatively low concentration of auxin in the medium is required for root formation on the culture. In this case, IAA is markedly superior to any other auxin in root forming activity. NAA is somewhat less effective than IAA, and 2,4‐D shows no stimulation on root formation.The growth and organ formation of potato tissue are remarkably affected By the variation in sizes of the explants. Spontaneous formation of a sprout was observed on the large explant in the medium without auxin. Small explants form only callus or roots in the presence of auxin and kinetin irrespective of combination or concentration. It seems likely that a sufficient amount of stimulus for initiation of bud formation may be contained in the large sized explant itself.
The Auxin Level of Begonia Leaves in Relation to their Regeneration Ability
Authors: Heide O. M. 
Published: April 2006

AbstractThe level of endogenous growth substances in leaves of Begonia × cheimantha Everett plants grown under various temperature and day‐length regimes has been studied.In the acidic fraction of ether extracts two main growth promoting factors were present. Evidence is presented indicating that one of these is indole‐3‐aeetic acid (IAA), the other a gibberellin‐like factor. The level of both these factors was always higher in extracts of long day grown plants than in those from short days. Similarly, high temperature (20 and 25°C) caused an increase in the level of the auxin, whereas the gibberellin activity was not much affected by temperature. Several growth promoting factors were present also in the non‐acidic fraction, but their identity is not known.The results are discussed in relation to the effect of environment on the regeneration ability of the Begonia leaves. The results of these and previous investigations strongly support the hypothesis that short days and low temperature increase the budding ability and reduce the rooting ability of Begonia leaves through a lowering of the ratio of endogenous auxins to endogenous cytokinins in the leaves. The author wishes to thank professor Poul Larsen for advice and criticism. He also gratefully acknowledges financial support from the Agricultural Research Council of Norway.
Absorption of Iron by Enzymically Isolated Leaf Cells
Authors: Kannan S. , Wittwer S. H. 
Published: April 2006

AbstractIron uptake was studied using cells enzymically isolated from green tobacco leaves. Absorption was increased both by light and succinate as probable energy sources. Bicarbonate in the incubation mixture was inhibitory, and citrate also reduced absorption presumably by chelation with the metal. Absorption of iron was temperature sensitive and optimal at 25°C. Temperature coefficients and activation energies suggested that absorption was energy mediated. NaN3 and DNP inhibited uptake at concentrations of 10‐3M and 10−4M, respectively. The inhibition caused by DNP was not negated by an external supply of ATP. The results suggest that iron absorption is an active metabolic process in cells enzymically isolated from green tobacco leaves.Cells from Fe‐chlorotic leaves of PI 54619–5–1 soybean absorbed less iron than those derived from healthy leaves of the same variety, while leaf cells from the variety Hawkeye showed no such differences.
The Oxidising Activity of Roots in Waterlogged Soils
Authors: Armstrong W. 
Published: April 2006

AbstractRoot oxidising activity has been studied quantitatively in two species, Menyanthes trifoliata and Molinia coerulea, using a non‐specific dye technique, and an oxygen‐specific “polarographic” technique in conjunction with artificial roots constructed from silicone rubber tubing.Oxidising activity in these two species has been found to be up to nine times greater than can be accounted for by oxygen diffusing from the roots. Enzymatic oxidation is thought to be the cause of such high oxidising activity.The characteristic patterns of iron oxidation found on and around roots are discussed, and oxidation of iron at the rhizophere ‘boundary’ is illustrated.Earlier work on root oxidising activity is briefly reviewed.
Some Characteristics of Rapidly Labeled RNA in Jack Beau Leaves
Authors: Matsumoto H. , Kobayashi M. , Takahashi E. 
Published: April 2006

AbstractThe characteristics of rapidly labeled RNA in jack bean leaves were investigated. The RNA was prepared by the phenol method and fractionated with methylated serum albumin column. The composition of DNA and ribosomal RNA were also determined. The labeled RNA which appeared after 90 minutes' incubation could be differentiated clearly from the ribosomal RNA by means of the elution pattern and the nucleotide composition. The RNA labeled for 90 minutes disappeared completely after 210 minutes' incubation and the other three peaks appeared at almost the same position as ribosomal RNA.
Marine Plankton Algae Grown with Light‐Dark Cycles. I. Coccolithus huxleyi
Authors: Paasche E. 
Published: April 2006

AbstractA description is given of an apparatus for semi‐continuous cultivation of unicellular algae under various combinations of light intensity, temperature and daylength (photoperiod). In this apparatus growth of the coccolithophorid Coccolithus huxleyi was limited by light intensities below 0.05 cal/cm2 min regardless of daylength. Growth was retarded by daylengths shorter than 16 hours out of a total of 24 hours of light plus dark. The temperature optimum for growth was about 20 C and showed little variation with daylength. The content of chlorophyll a varied between 2 and 15 mg per ml cell volume and was greatest under low light intensities, short daylengths and high temperatures. Cultures were synchronised by four different combinations of light intensity and daylength. In all four cases, cell division was restricted to 6 out of 24 hours. Synchronised cell division took place in the dark but its timing bore no simple relationship to the onset or termination of illumination.
Metabolism of Indole‐3‐acetaldehyde.
Authors: Rajagopal R. 
Published: April 2006

AbstractAerobic infiltration of synthetic indoleacetaldehyde (IAAld) in buffered medium of pH 4.55, into living tissues of lower and higher plants, leads in the majority of cases to the formation of both indoleacetic acid and tryptophol. This activity is evinced by etiolated as well as green tissues. Besides, all parts of higher plants tested — roots, cotyledons, hypocotyls and leaves possess this activity. Abolishment of this activity by boiling indicates its enzymic nature. Coupled with the established occurrence of indoleacetaldehyde, the widespread distribution of such activity, strengthens the probability that indoleacetaldehyde may be the normal and natural precursor in the biosynthesis of indoleacetic acid.
The Salt Absorption Isotherm
Authors: Oertli J. J. 
Published: April 2006

AbstractIt is shown that the absorption isotherm of rubidium by excised barley roots can be explained either by two uptake mechanisms following Michaelis‐Menten kinetics or by two mechanisms, one actively transporting salts into the tissue (the pump), the other one being more passive in nature (the leak), operating in either direction, depending on external and internal substrate concentration. Kinetic data are thus consistent with more than one transport model.It was further demonstrated for the pair K‐Na, that a competitor not only reduces salt uptake but can also reverse the direction of net flux. This observation cannot be explained by classical enzyme kinetics, it is, however, consistent with the pump and leak system.Just as Michaelis‐Menten kinetics, the pump and leak system can explain ion competition, in addition it offers a possible explanation of the Viets' effect and it can explain the time curve of absorption.
Effect of Protein Synthesis Inhibitors, Auxin, and Gibberellic Acid on Abscission
Authors: Valdovinos Jack G. , Ernest Leland C. 
Published: April 2006

AbstractChloramphenicol, actinomycin D, and other inhibitors of protein synthesis promote abscission in several plant genera. Abscission is accelerated in species where an abscission layer is present, as well as in tissue where no abscission layer develops prior to abscission. The inhibitors promote abscission in species where cell division is reported to precede the separation processes as well as in tissues where no cell division is associated with the initiation of abscission. Indoleacetic acid (IAA) or auxin precursors, when applied with chloramphenicol and aclinomycin D, overcome the promotive effects of the inhibitors on abscission. These inhibitors apparently do not promote abscission through their effects on auxin precursor conversion, IAA transport, and IAA destruction in the petiole. IAA increases the incorporation of leucine‐1‐14C into a trichloroacetic acid precipitable fraction of the abscission zone under conditions where abscission is retarded. A low concentration of IAA which accelerates abscission, decreases incorporation of leucine into protein. Other promoters of abscission — chloramphenicol, d‐aspartic acid, and gibberellic acid —also decrease the incorporation of leucine into the protein of the abscission zone. The data indicate that enzymes required for the degradative processes associated with abscission are already present in the abscission zone whereas a continuous synthesis of protein is required for the retention of the leaf.
Respiratory Patterns in Fruit of Pineapple, Ananas comosus, Detached at Different Stages of Development
Authors: Dull Gerald G. , Young Roy E. , Biale Jacob B. 
Published: April 2006

AbstractThe postharvest respiratory drifts for six stages of development of pineapple fruit (Ananas comosus cv. Cayenne) ranging from dry flower to senescence are presented. Based upon these data, pineapple is a non‐climacteric fruit. Pineapple does produce ethylene gas hut when levels ranging from 0.01 to 1000 μl/l were applied to stage 4 fruits (fruit just at the start of ripening) no respiration or chemical changes were induced which could he interpreted as affecting the ripening processes. A decrease in the oxygen concentration (to 2.5 per cent) resulted in a decrease in the respiration rate. An increased carbon dioxide concentration (up to 10 per cent) had not detectable effect on the respiration rate.
Methods for Measuring Phototaxis of Cell Populations and Individual Cells
Authors: Feinleib Mary Ella Harman , Curry George M. 
Published: April 2006

AbstractTwo quantitative methods have been devised for studying the phototactic response of Chlamydomonas. In the first procedure, the movement of a cell population is continuously monitored photometrically, yielding a permanent record of the time course of the response. The monitoring system consists of a pair of photovoltaic cells connected in a comparison circuit, and a dim red light which passes through the swimming chamber and strikes the photocells. A stimulus beam enters the chamber at right angles to the monitoring light. The movement of algae towards the stimulus light produces a difference in output between the photocells. With a continuous stimulus, this difference increases in a nearly linear fashion for several ninutes. The slope of the linear portion depends on such factors as stimulus ntensity and wavelength and is used as the index of the response.In the second procedure, a photomicrographic method is used to resolve the population response into its components; i.e., the number of cells responding, the directness of the swimming path, and the rate of swimming. The photographs are taken with a fixed exposure time, during which each cell in the field describes a swimming track on the film. Swimming rate is determined by measuring the length of the photographed track, while directness of path is indicated by the angle between the track and the stimulus light beam. The number of cells going towards the light is calculated from counts made while observing the culture through the microscope.These methods have been used to investigate the dependence of phototaxis on stimulus intensity and wavelength, age of culture, and pre‐illumination.This work formed a portion of a doctoral thesis submitted by one of the authors (M. E. Feinleib) to Harvard University, Cambridge, Mass. The work was supported in part by a U.S. Public Health Fellowship, No. FI‐GM‐17, 305–04, and by a National Science Foundation research grant, No. G14266.
14C‐Studies on Apple Trees III. The Influence of Season on Storage and Mobilization of Labelled Compounds
Authors: Hansen Poul 
Published: April 2006

AbstractThe present paper reports an attempt to elucidate the storage and mobilization processes in 1‐year‐old apple rootstocks by studying the 14C content of different parts of the tree following application of 14CO2. The translocation of the 14C taken up from the leaves to other parts proceeds at the highest rate during the first few days after the application of 14C. The distribution in shoots, trunk and roots after application of 14C during May, July, August, and in part of September depends in particular upon the intensity of growth in the various parts. From the lime of the application of 14C until leaf‐fall, 40–50 per cent of the 14C initially absorbed disappears from the tree.After exposure to 14C during October, and in part of September, a relatively large part of the 14C applied goes to the root. In this case there is a considerable reduction in the 14C‐conlent from leaf‐fall to the following spring after leafing, especially in the root, although relatively speaking reduction is also considerable in the bark of the parts above ground, and it is most pronounced in the methanol (80 %) soluble fraction. The reduction takes place primarily during spring, and comprises, after application during October, for the whole tree 20–25 per cent of the 14C initially absorbed. Only 13–17 per cent of this amount was recovered in the newly developed shoots and leaves in the following June.
The Minimum Growth Temperature of Obligately Thermophilic Bacteria as Influenced by Inhibitors in Complex Growth Media
Authors: Ljunger Claes 
Published: April 2006

AbstractThe inability of several obligately thermophilic bacteria to grow at or below 37°C in common laboratory media was shown to be caused by inhibitors present in these media. The inhibitors could be removed by extraction with chloroform and by adsorption on ion exchange resins or starch. It was concluded that they were of organic nature, probably bile acids. Four laboratory strains of Bacillus stearothcrtno‐philus grew readily at 37°C in detoxified media. With one of them (NCA 1503) growth was obtained at 34–35°C. A fresh soil isolate having a minimum growth temperature of 40°C in glucose nutrient broth grew at 30°C in this medium after the inhibitors had been removed.
Hydrolysis of Inorganic Pyrophosphate in Dictyostelium discoideum
Authors: Gezelius Kerstin 
Published: April 2006

AbstractThe hydrolysis of inorganic pyrophosphate has been studied in cell‐free extracts prepared at different stages of development of Dictyostelium discoideum. Two enzyme reactions, pH optima 7.25 and 9.0, appear specific for inorganic pyrophosphate and have an absolute requirement for a divalent cation, preferably Mg2+. The enzyme specific activities do not change significantly during differentiation. Neither enzyme reaction is inhibited by orthophosphate and the presence of exogenous potassium phosphate does not affect the levels of pyrophosphalase at any stage. Exogenous glucose raises the pyrophosphatase levels in the sorocarps.
Effects of Various Concentrations of Carbon Dioxide on Respiration and Potassium Uptake in Barley Roots
Authors: Jacobson L. , Schaedle M. , Cooper B. , Young L. C. T. 
Published: April 2006

AbstractBarley roots contain a CO2 sensitive respiratory fraction which is inhibited in 50 per cent CO2 and is partially restored upon subsequent exposure to air. The residual O2 consumption occurring at CO2 concentrations between 50 per cent and 95 per cent amounts to about 40 per cent of the O2 uptake in air and can support K+ uptake for a limited time at a rate equal to or higher than occurs in air. Above 95 per cent CO2 both O2 and K+ uptakes decrease rapidly. 2,4‐dinitrophenol (DNP), in the range of 10−6 to 10−5M, stimulates O2 uptake by the roots in air. The stimulation is absent when roots are treated with DNP in 80 per cent CO2, presumably because of the reduced demand for inorganic phosphate and phosphate acceptor at the lower respiratory level in high CO2. In either air or CO2, K+ uptake is strongly inhibited by DNP. A comparison of the respiratory and K+ uptake data indicates that O2 consumption is a necessary requirement for the uptake process in high CO2.Protoplasmic streaming in the root cells is rapidly stopped by high CO2 although K+ uptake and O2 consumption continue. The cation uptake mechanism in high CO2 appears to be limited to the stationary cytoplasm. It is also possible that a similar mechanism may be involved in cation uptake in air.
Multiple Forms of Polyglucoside‐Branching Enzyme in the Algae
Authors: Fredrick Jerome F. 
Published: April 2006

AbstractThree isozymes specifically concerned with the “branching” of linear polyglucosides have been delected in algae. These enzymes were detected using two‐dimensional polyacrylamide gel electrophoresis, and were found to be present in blue‐green, red and in green algae. Two isozynies were found in Oscillatoria princeps; three enzymes were present in Spirogyra setiformis, and two and three such enzymes were detected in red algae of the Rhodymenia type. The significance of the multiple forms of this branching enzyme was assessed in light of the type of storage poly‐glucosides formed by these plants. The “degree of branching” of the storage sugar appeared to be related to the evolutionary status of these algae.
Isocitric Lyase and Isocitric Dehydrogenase in Germinating Lettuce
Authors: Mayer A. M. , Krishmaro N. , Poljakoff‐Mayber A. 
Published: April 2006

AbstractA soluble isocitric lyase is shown to occur in lettuce seeds. Its activity increases during germination till 72 hours and then falls again. No particulate lyase could be detected. In addition both a soluble and a particulate isocitric dehydrogenase is present in the seeds. Both enzymes react with NAD as well as with NADP. The soluble enzyme drops sharply in activity during germination, while the particulate enzyme remains at a more or less constant level of activity. By gel electrophoresis the isocitric lyase and the isocitric dehydrogenase were shown to consist of what appear to be several isozymes. The interrelation between the enzymes and their relation to fat metabolism during germination is discussed. Evidence is brought for an enzymic reaction by which isocitric acid is converted to pyruvic acid. The nature of this reaction is not clear.
Reversal of (±) ‐Abscisin II Induced Inhibition of Lettuce Seed Germination and Seedling Growth by Kinetin
Authors: Sankhla N. , Sankhla D. 
Published: April 2006

AbstractObservations have been made on the effect of synthetic, (±)‐abscisin II (dormin), alone and in combination with gibberellin, kinetin and indoleacetic acid, on seed germination and seedling growth of two strains of lettuce, cv. Attraktion and cv. Hohlblättriger Butter. (±)‐Abscisin II inhibited seed germination and seedling growth in both strains. The inhibitory effect of abscisin II on seed germination as well as seedling growth was completely overcome by kinetin in both dark and light. Gibberellic acid, on the other hand, proved ineffective in exerting its influence on seed germination in presence of abscisin II but affected subsequent seedling growth as usual. Indoleacetic acid was found to be least potent in reversing abscisin II caused inhibition of seed germination and seedling growtb. It is concluded, that like its effect on certain other naturally occurring inhibitors of seed germination, kinetin can effectively undo the inhibitory effects of abscisin II in these growth processes.
The Distribution of Mineral Elements Following Leaf and Root Uptake
Authors: Levi E. 
Published: April 2006

AbstractThe initial and subsequent distribution of 22Na, 43K, 86Rb, 134Cs, 32P, 35S, 45Ca, 65Zn and 85Sr in bean plants, following leaf and root uptake was studied under controlled environmental conditions. Autoradiographic and counting methods reveal vascular connections between leaves and roots and two patterns of distribution in the leaves following root uptake are reported. Distribution following treatment of specific parts of the leaves or roots points to a morphological unity in the bean plant. A possible circulation pattern for some ions is discussed.