bluuebunny/crossref_metadata_2025_split huggingface dataset:
Constitutive Uptake of Choline Sulfate by Roots and Leaf Slices of Barley
Authors: NISSEN PER 
Published: April 2006

AbstractBarley roots take up choline sulfate constitutively via 3 separate, homogeneous mechanisms which obey Michaelis‐Menten kinetics and have, respectively, low, high, and very high affinity for the sulfate ester. Leaf slices possess only the low‐and the high‐affinity mechanism. These are both inhibited by dini‐trophenol and NaF but are differently affected by solute analogues. Uptake via the high‐affinity mechanism is active; the low‐affinity mechanism has also characteristics of facilitated diffusion.
Calcium Uptake by a Psychrophilic Achromobacter Strain
Authors: LEDEBO INGRID 
Published: April 2006

AbstractThe permeability of a psychrophilic Achromobacter strain to calcium ions was examined with the radioisotope 45Ca2+. The amount of radioactivity that remained associated with the cells after exposure to 5 to 200 mM solutions of radioactive calcium was determined. The concentration of 45Ca2+ of the cells compared to that of the surrounding medium gave a ratio larger than one, and this ratio increased with decreasing ambient calcium concentration. The same results showed that the higher the external calcium concentration was, the more calcium remained with the cells. The radioactivity of the cells had the following characteristics: 1. It was rapidly lost when the cells were washed with 40Ca‐solution. 2. Most of it was retained after water washings. 3. It was not affected by the presence of 2,4‐dinitrophenol. 4. It was only slightly affected by temperature. 5. It increased when the cells were treated with toluene or heat and reached a maximum of 2–3 times the value of untreated cells. The same treatment brought about a smaller increase of the uptake of 22Na+. 6. Approximately 60% of the radioactivity of whole cells was associated with isolated cell envelopes.
Evidence for Compartmentation of Tryptophan in Cultured Plant Tissues: Free Tryptophan Levels and Inhibition of Anthranilate Synthetase
Authors: WIDHOLM J. M. 
Published: April 2006

Abstract1. Anthranilate synthetase activity in crude extracts from tissue cultures of Daucus carota L. (carrot), Nicotiana tabacum L. (tobacco; cv. Wisconsin 38 and xanthi), Glycine max Merr. (soybean) and Oryza sativa L. (rice) was completely inhibited by l‐tryptophan (5 to 50 μM). Mutant carrot and tobacco lines, capable of growth in the presence of 5‐methyltryptophan, required 500 to more than 1000 μM tryptophan for complete inhibition of enzyme activity, respectively.2. Except for the mutant tobacco line, the concentrations of free tryptophan in all tissue cultures tested were greater than the levels necessary to completely inhibit the respective anthranilate synthetase activities in vitro. These findings would indicate that much of the free tryptophan is compartmentalized away from the regulatory enzyme, anthranilate synthetase. This could implicate compartmentalization of the inhibitor as a biosynthetic control mechanism.3. During the growth of normal and mutant carrot tissues the anthranilate synthetase enzyme must be at least 7.8 and 10.8% active, respectively, in order to accumulate the amount of tryptophan found in the tissues.4. Of the substrates and cofactors required for anthranilate synthetase activity in vitro, Mg2+ and glutamine were present at near optimal levels in the carrot and tobacco tissues, but chorismate was found to be significantly below the optimal concentrations.
Half‐Life of sRNA and its Consequence for the Formation of Cytokinins in Lactobacillus acidophilus‐A.TCC 4963 Grown in the Logarithmic and Stationary Phases
Authors: LEINEWEBER MICHAL , KLÄMBT DIETER 
Published: April 2006

AbstractCytokinin nucleotides are normal constituents of transfer RNAs. The formation of free cytokinins might be connected with the normal hydrolysis rate of those RNAs. To get an impression about the cytokinin production by this pathway, the half‐life of sRNA from Lactobacillus acidophilus grown in the logarithmic and in the stationary phases has been estimated. At the generation cycle of two hours the half‐life of sRNA is 3 to 4 hours during the logarithmic phase, and 10 to 12 hours during the stationary phase.
Effects of Carbon Source, Gibberellins and Ethylene on Wall‐Bound Invertase Activity in Callus of Convolvulus arvensis
Authors: KLIS F. M. , de GROOT C. , VERWER R. 
Published: April 2006

AbstractThe growth rate of Convolvulus callus on a sucrose‐containing medium appeared to be largely independent of the activity of cell wall invertase. The increase of this enzyme activity which occurs upon subculturing was unaffected within the first 24 h by the presence of the substrate sucrose. Neither substitution by glucose or fructose, nor complete deletion of the carbon source had any effect.Gibberellins apparently were not involved in the initiation and/or control of the increase of wall‐bound invertase activity occurring upon subculturing. Exogenous ethylene was unable to mimick this effect of subculturing but when applied immediately after subculturing it had a synergistic effect on the increase of invertase. Inhibition occurred, however, when exposure to ethylene was delayed until after 24 h of incubation. These findings suggest a role of ethylene in the control of wall‐bound invertase activity.
Comparative Studies on Water Uptake and Water Permeability of Potato Tissue under the Effect of Indoleacetic Acid, Chloramphenicol and Actinomycin D
Authors: ÖNDER NURTEN 
Published: April 2006

AbstractThe water uptake of potato tuber tissue under the influence of chloramphenicol and actinomycin D was compared with that of indoleacetic acid. Both antibiotics decreased the water absorption as compared to the effect of indoleacetic acid. This decrease, in the early hours (3 to 6 h), is due to diminished water permeability. In the later period (6 to 48 h), it is instead a result of a reduction in wall extensibility.
The Uptake of 2‐Deoxy‐dGlucose by Isolated Ricinus Cotyledons
Authors: GUY MICHA , REINHOLD LEONORA 
Published: April 2006

AbstractThe uptake of the non‐metabolizable glucose analogue, 2‐deoxy‐d‐glucose (DOG) has been followed in isolated cotyledons of Ricinus communis L. Within 2 min of immersion in a labelled DOG medium, DOG phosphate (DOG‐P) was detectable in the tissue. DOG uptake was relatively rapid for 30 min after which it slowed down but nevertheless continued for many hours; DOG was eventually accumulated against a concentration gradient. Internal DOG‐P concentration also rose for the first 30 min, but then reached a plateau. The relationship between uptake and external concentration was close to linear during the first hour, and subsequently curvilinear.Analysis of “wash‐out” curves indicated that after very rapid exit from the surface and free space of the tissue, the half‐time for exit of the remaining 85% of the absorbed DOG was approximately 250 min. By comparison, the half‐time for exit of sorbitol was 30 min. No DOG‐P could be detected in the wash‐out solutions.When cotyledons were transferred to labelled medium after preloading in non‐labelled DOG, the specific activity of the internal DOG pool rose faster than that of the DOG‐P. Both curves flattened out when their specific activity was less than half that of the external medium. Addition of d‐glucose to the medium depressed DOG‐P formation, but only when the incubation period was less than 45 min.Arguments are presented for concluding (a) that DOG uptake is mediated by a specific uptake mechanism; (b) that more than one internal DOG pool is involved; and (c) that the observed phosphorylation is not a necessary step in the entry process into either of the pools, whether the latter are in series or in parallel.
The Effect of Hadacidin on Bud Development and its Implications for Apical Dominance
Authors: LEE PETER KUNG‐WOO , KESSLER BEZELAL , THIMANN KENNETH V. 
Published: April 2006

AbstractHadacidin, which is known to inhibit the enzyme adenylo‐succinate synthetase, was applied locally to lateral buds on decapitated Pisum sativum L. plants. In controls the buds grew out normally, but the treated buds were almost completely inhibited. After a delay, the buds overcame the inhibition, and their subsequent outgrowth could be further hastened by the local application of a cytokinin. The inhibition, unlike that due to IAA, was not transported to a second bud, and it could be largely reversed by kinetin or dimethylallylaminopurine. Adenine itself produces little or no reversal, however. There was some reversal by aspartic acid, which is known to reverse, at least partially, the hadacidin inhibition of the isolated enzyme. It is deduced that lateral bud development is dependent on the synthesis of a cytokinin, which may take place by a biochemical route similar, but probably not identical, to that for adenine. It follows that this synthesis takes place locally in the bud itself.
Aspects of the Effect of ABA on the Water Status of Barley and Wheat Seedlings
Authors: MIZRAHI Y. , SCHERINGS S. G. , ARAD S. MALIS , RICHMOND A. E. 
Published: April 2006

AbstractThe effect of abscisic acid on plant growth and survival during water deprivation was studied in barley and wheat seedlings. Under conditions of both limited and ample water supply, treatment with abscisic acid greatly reduced transpiration and, in addition, suppressed root growth. In water‐deprived seedlings, abscisic acid increased the total dry matter, reflecting improved efficiency in water‐use. In addition, the growth period and survival of water‐deprived seedlings were markedly prolonged. In field trials, however, abscisic acid had no significant effect on waterdeprived seedlings. Possible reasons for this lack of response are discussed.
Qualitative Characterization of Some Peptides Inducing Morphogenesis in the Nematode‐ Trapping Fungus Arthrobotrys oligospora
Authors: NORDBRING‐HERTZ BIRGIT , BRINCK CARITA 
Published: April 2006

AbstractSome peptides inducing capture organ formation in Arthrobotrys oligospora were characterized with regard to their amino acid contents. The N‐terminal, C‐terminal and total amino acids were determined as their dinitrophenyl‐derivatives by thin layer chromatography on silica gel in two different solvents. The amino acid composition was further confirmed by gas‐liquid chromatography.The peptides investigated had a high proportion of non‐polar and aromatic residues. Thus, leucine, isoleucine, valine, proline, and tyrosine were present in all the peptides. In addition, phenyl‐alanine, glycine, and alanine occurred in some preparations. Tyrosine, valine, and phenylalanine were found in N‐terminal position, and leucine or isoleucine were C‐terminals.
Redistribution of Potassium, Calcium, Magnesium, and Manganese in the Plant
Authors: VAN GOOR B. J. , WIERSMA D. 
Published: April 2006

AbstractThe extent of redistribution in apple was described by calculating the fruit/leaf ratio of the cation content. It was found that the redistribution diminishes in the sequence K > Mg > Ca ∼ Mn. These results are more or less in agreement with those found elsewhere.Investigations were made to see whether it was possible to account for the differences in redistribution by the phloem by means of the solubility of these cations in the sieve tube sap. As model plants Yucca flaccida and Ricinus communis were used, plants from which it was possible to obtain phloem sap in a rather pure state. It was found that the addition of potassium and magnesium as a chloride in the usual investigated range of concentrations did not give precipitation. With calcium and manganese, however, a precipitate soon occurred. Manganese was demonstrated to be less soluble than calcium. For Ricinus the maximum amount of calcium and manganese the sieve tube sap could contain before precipitation set in was higher than for Yucca sap.The results confirm the possibility that the redistribution of the different cations in the plant can be related inter alia to their solubility in the sieve tube sap.It was also found that the calcium in the phloem sap is present in ionic condition. Thus the normal laws of solubility should be applicable.
Resistance and Sensitivity of Chloroplast Ribosomes to Streptomycin in Mutants of Chlamydomonas reinhardi
Authors: BOSCHETTI ARMINIO , NIGGLI VERENA , OTZ URSULA , WIEDMER THERESE 
Published: April 2006

Abstract

In a mendelian (sr3) and an uniparental (sr35) streptomycin resistant mutant of Chlamydomonas reinhardi the influence of streptomycin on protein synthesis on the chloroplast and cytoplasmic ribosomes was investigated in vitro. Hetero‐, mixo‐ and phototrophic agar cultures and heterotrophic liquid cultures were used.
Protein synthesis on the cytoplasmic ribosomes, measured by the activity of glyceraldehyde‐3‐phosphate: NADP dehydrogenase (EC 1.2.1.9), was not inhibited, but rather stimulated by streptomycin.
Protein synthesis on the chloroplast ribosomes of sr3, measured by the activity of ribulose‐1,5‐diphosphate carboxylase (EC 4.1.1.39), was greatly inhibited by streptomycin, especially in hetero‐ and mixotrophic cultures. In sr35 the chloroplast ribosomes were resistant to streptomycin.
Heterotrophically grown cultures of sr3 and of a streptomycin‐sensitive strain are yellow in the presence of streptomycin and form no or only reduced thylakoids on solid media. But 70‐S organelle‐ribosomes are present in a normal amount.
The relationship between chloroplast protein synthesis and thylakoid formation is discussed.
L'Indole et le Tryptophane “régulateurs” de croissance, en culture “in‐vitro”, pour les tissus de parenchyme médullaire de Tabac, normaux et tumoraux
Authors: BEAUCHESNE GILDAS 
Published: April 2006

AbstractIndoleacetic acid, tryptophan and indole promote growth of pith tissues of tumorous Nicotiana glauca×N. langsdorffii amphidiploïd hybrid, but only indoleacetic acid gives the potentiality of continuous development to the tumorous tissues after some days of contact on a medium without growth substances. In combination with 6‐benzylaminopurine, tryptophan and especially indole are promoting substances like auxin for the non‐tumorous pith tissues of tobacco, and allow a considerable organogenesis.
The Regulatory Role of the Embryo on the Development of Isocitrate Lyase Activity during Germination of Ponderosa Pine Seeds
Authors: BILDERBACK D. E. 
Published: April 2006

AbstractThe specific activity of isocitrate lyase rapidly increased in the megagametophytic tissue of cold‐stratified seeds of ponderosa pine (Pinus ponderosa Laws) prior to and after germination. When the embryo was removed at germination, isocitrate lyase activity continued to develop. However, in the total absence of the embryo, only a small increase in the specific activity of the enzyme was observed. The development of the enzyme was inhibited by cycloheximide, actinomycin D and abscisic acid.The embryo produced an unidentified factor which enhanced the development of isocitrate lyase activity in the megagametophytic tissue. This embryo factor could not be replaced by the hormones indoleacetic acid (IAA), gibberellic acid (GA3) or benzylaminopurine (BA). Indoleacetic acid had little effect upon enzyme development. Gibberellic acid and benzylaminopurine inhibited isocitrate lyase development in the megagametophytic tissue of the seed.
Stimulation by Ethylene of Axis and Hypocotyl Growth in Bean and Cocklebur Seedlings
Authors: GOTÔ N. , ESASHI Y. 
Published: April 2006

AbstractEffects of ethylene on the elongation of bean (Phaseolus vulgaris) embryonic axes and hypocotyls, and of cocklebur (Xanthium pennsylvanicum) hypocotyls were studied. In the bean axes, exogenous ethylene was promotive in stimulating longitudinal growth during the early germination period, but thereafter it turned inhibitive. This transition of the ethylene action is likely involved in the appearance of newly differentiated tissues in the hypocotyl, which are negatively sensitive to the gas. The ethylene stimulated elongation of the axes was hardly affected by light or by the presence of the cotyledons. In the bean hypocotyl segment unit, elongation was stimulated by ethylene in its limited zone, when the concentration of ethylene and the exposure times to ethylene were adequate (0.3 to 30 μl/l, 6 to 8 h): Elongation in the much younger region near to the elbow was inhibited by ethylene treatment, whereas the treatment of the upper region of the shank with ethylene finally resulted in significantly increased growth as compared to the untreated controls. In the continuing presence of ethylene over 3 days, the elongation of every region was retarded markedly and radial growth was induced in most regions of the shank from just below the elbow. These ethylene responses occurred independently of red light irradiation, but the ethylene promotion of elongation was lost by shortening the segment height, by removing the hook portion from the segment unit, or with its natural disappearance as a result of ageing. Fundamentally, similar effects of ethylene was observed in cocklebur hypocotyls.
Agglutinating Effects of Concanavalin A on Isolated Protoplasts of Daucus carota
Authors: GLIMELIUS KRISTINA , WALLIN ANITA , ERIKSSON TAGE 
Published: April 2006

AbstractThe agglutinating effects of Concanavalin A (Con A) on protoplasts isolated from cell suspensions of Daucus carota were studied. Con A was shown to agglutinate the plant protoplasts in a manner similar to the way some animal cells are agglutinated. The agglutination process is dependent on the Concanavalin A concentration, protoplast density, treatment time, the temperature, and the membrane condition, α‐D‐Methylgluco‐pyranosid completely inhibited Con A induced agglutination. The results are discussed in relation to membrane structure and morphology.
Endogenous Sugar Levels and Their Effects on Root Formation and Petiole Yellowing of Detached Mustard Cotyledons
Authors: LOVELL P. H. , ILLSLEY ANN , MOORE K. G. 
Published: April 2006

AbstractDetached cotyledons of Sinapis alba rooted readily in water in petri dishes in the light. The addition of (6 × 10−2M) galactose, mannose or 2‐deoxy‐D‐glucose to the culture medium proved toxic to cotyledon growth. Of the other sugars tested that were not toxic, sucrose was the most inhibitory to root formation and increased petiolar yellowing to the greatest extent. Glucose was more inhibitory than fructose which in turn increased petiolar yellowing more than methyl‐D‐glucose.Sucrose, glucose, or fructose at 6 × 10−2M in the culture medium gave rise to very substantial increases in the cotyledon petiole of reducing sugar and starch with smaller increases in sucrose. Methyl‐D‐glucose had much less effect on internal sugar levels. It was found that the higher the internal level of glucose the more rapid the rate and final extent of petiolar yellowing. In general, the degree of petiolar yellowing was inversely related to the ability of the cotyledon to root. Methyl‐D‐glucose differed from the other sugars in that it delayed and reduced root formation but had very little effect on petiolar yellowing.
Induction of Isocitrate Lyase in Synchronous Cultures of Chlorella fusca
Authors: AASBERG KARL ERIK , LIEN TORLEIV , KNUTSEN GJERT 
Published: April 2006

AbstractIsocitrate lyase (ICL) of Chlorella was induced with acetate, and induction kinetics followed in autospores and 6 h old cells of a synchronous culture.The enzyme could not be induced in illuminated cells. With both cell types 1.2 mM acetate was the optimal inducer concentration. Freeze‐thawed cells and acetone powders were used for measurement of activity. With the former the time course of increase in activity was different at the two cell ages. With 6 h old cells the activity fluctuated: There was first a period of increase, then one with decrease and again one of increase. No such variation was found with freee‐thawed autospores or with acetone powders of both cell stages. Darkening 6 h old cells for different periods of time before induction reduced the peak of activity, leaving the rate of the third phase unchanged. Illumination of darkened cells before induction increased the peak. Increasing the duration of both treatments increased their respective effects.Acetone extracts taken at different times after start of induction inhibited the ICL activity of a test preparation. The inhibition decreased concurrently with the variation in the ICL activity‐found‐when freee‐thawed cells were used in the enzyme assay.The inducibility, taken as the rate of the third phase, was measured at different times during the 24 h synchronous cycle. Using three different acetate concentrations and both methods of cell preparation, we found that the inducibility was constant for 17 h whereafter it increased rapidly to a final level.
Embryogenesis and Organogenesis in Pumpkin Explants
Authors: JELASKA SIBILA 
Published: April 2006

AbstractEmbryogenic callus was induced by culturing explants of pumpkin hypocotyls on Murashige‐Skoog‐medium with the addition of 3% glucose and one of the following growth substances (or combinations of them): β‐indolylbutyric acid, 2,4‐dichlorophenoxyacetic acid, β‐indolylacetic acid, α‐naphthyl‐acetic acid, adenine (natural), kinetin, autoclaved water‐melon sap and yeast extract (Difco). A large number of embryoids and adventive buds were produced. These were able to develop to normal plants.The 17 strains of embryogenic tissue obtained have maintained their embryogenic characteristics for more than 3 years. The induction of embryogenic callus in pumpkin seems to be strongly dependent on the genetic constitution of each individual plant.
Relationship of Auxin Transport to Branch Dimorphism in Cordyline, a Woody Monocotyledon
Authors: FISHER J. B. , BURG S. P. , KANG B. G. 
Published: April 2006

AbstractLanolin containing 3H‐IAA was applied to apical cut ends of stem segments and decapitated plants of Cordyline terminalis, a monocotyledon possessing true secondary growth. Distribution of extracted label showed that: 1) in horizontal stems up to 7 times as much label accumulates in the lower surface compared to the upper surface, and this ratio increases with distance from the cut apical surface; 2) in upright stems most label (62%) occurs in the cambial and cortical regions, external to the primary and secondary vascular tissues; and 3) in upright stems having the cambium and cortical regions removed by a girdle, label accumulates above the girdle (c. 10 times greater than the control). These data are in accord with a theory of branch dimorphism derived from morphological studies, which suggested that high auxin levels initiate and maintain rhizomes and low levels initiate leafy shoots.
Multiphasic Uptake of Sulfate by Barley Roots
Authors: HOLMERN KARI , VANGE MARTA S. , NISSEN PER 
Published: April 2006

AbstractUptake of sulfate by excised barley roots increases upon their washing in aerated water or dilute CaCl2 solutions. Washing increases the values for Vmax and the sulfate concentrations required for transition between the lower phases, but the KM‐values remain essentially constant. At low sulfate concentrations, phase transitions do not occur in the absence of calcium or other divalent cations. These ions are about equally effective in enhancing short‐term sulfate uptake. Phase transitions were not principally altered by sulfhydryl or protein reagents. These concentration‐dependent transitions appear unrelated to temperature‐dependent phase transitions as evidenced by similar multiphasic patterns at low and high temperature.
The Excretion of the β‐Carboline Alkaloid Harman in Passionfruit
Authors: COPELAND L. , SLAYTOR M. 
Published: April 2006

AbstractBy feeding (methylene‐14C)‐L‐tryptophan, a biosynthetic precursor of the alkaloid harman, to Passiflora edulis it can be shown that the concentration of (3‐14C)‐harman initially increases and then decreases. By feeding (3‐14C)‐harman, the decrease has been further investigated and found to be due to excretion and not catabolic reactions.