bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature Effects on Shoot and Root Development From Begonia × cheimantha Petiole Segments Grown in vitro
Authors: FONNESBECH MOGENS 
Published: April 2006

AbstractThe effect of different temperatures on the shoot and root formation in isolated petiole segments of Begonia × cheimantha was determined after 10 weeks on a modified White medium containing 0.1 mg/1 NAA and 0.5 mg/1 BA.Temperature proved to be important for the induction of shoot and root formation. At a constant temperature the best plants were obtained at 18 to21°C. If the temperature was higher, fewer cultures survived and the number of roots and shoots were lower. Lower temperatures inhibited the development of plants. A pretreatment at 15 or 18°C for two to four weeks improved the number and size of the shoots developed during a following 24°C treatment. High temperatures throughout the growing period reduced the number of shoots severely. A pretreatment of three days at 24°C or one day at 28°C reduced the shoot number by 50 %. After seven days at 28°C there was not a single shoot in any of the cultures. However, after two weeks at 15 or 18°C it was no longer possible to inhibit the shoot formation by a 24°C treatment.It is concluded that the formation of shoots in petiole segments takes place during the first two weeks after excision, and that high temperature is detrimental to the shoot initiation process.
Growth Promoting Effect of a Transpiration Suppressant on Cotton
Authors: MUKHERJEE ILABANTA 
Published: April 2006

AbstractThe transpiration suppressant Tag 16 (polyethylene emulsion), which is known to form thin films on leaves, was sprayed on cotton plants grown under varying weather and soil moisture conditions. In hot, dry weather and under restricted water supply 10 and 15% solution of the original Tag 16 promoted extension growth and increased fresh and dry weight of plants. In hot, humid weather three sprays at weekly intervals did not have any effect on plant height, fresh and dry weight, leaf number and flowering.
Protein and Ribonucleic Acid Synthesis by Plant Mitochondrial Systems
Authors: GOSWAMI BISWENDU B. , CHAKRABARTI SYAMALIMA , DUBE D. K. , ROY S. C. 
Published: April 2006

AbstractThe incorporation of 14C‐labelled phenylalanine into proteins of the mitochondrial systems obtained from 48‐h germinating seeds of Vigna sinensis (L.) Savi can be stimulated by polyuridylic acid [poly (U)] and depressed by rifampicin, which is, however, ineffective if poly (U) is allowed to interact with the incorporating system before the antibiotic has access to it.A system consisting of a mitochondrial S‐100 fraction and ribosomes from the same source with other cofactors can bring about polymerization of phenylalanine.The incorporation of 14C‐labelled uracil into RNA by the plant mitochondria is greatly dependent on the exogenous addition of adenine, guanine, cytosine and also on 5‐phosphoribosyl‐l‐pyrophosphate (5‐PRPP). It is greatly suppressed by rifampicin and ethidium bromide.
Ethylene and the Regulation of Apple Stem Growth under Stress
Authors: ROBITAILLE H. A. , LEOPOLD A. C. 
Published: April 2006

AbstractBending stree resulted in an increase in the ethylene concentration in the internal atmosphere of apple stem (Malus domestica Borkh. cv. Winesap). reaching a maximum at about 2 days after bending. The rise in ethylene content was followed by a depression of growth at about 14–21 days. Ethylene content returned to control levels after about 3 weeks. Application of a past naphthaleneacetic acit caused a similar increase in ethylene levels, and the application of ethephon pastes brought about an inhibition of elongation growth. Whereas stress treatment resulted in an inhibition of growth in stem diameter as well as elongation of growth in stem diameter as well as elongation, the ethephon applications resulted in a stimulation of growth in diameter. It is suggested that ethylene may be involved in the growth responses to mechanical stress.
Callus and Root Formation in Explants of Beta vulgaris
Authors: WELANDER TORKEL 
Published: April 2006

AbstractCallus from hypocotyl and petiole explants and anthers of Beta vulgaris L. was initiated on a defined agar medium containing IAA and kinetin. The cultures were kept in light (18 hours a day) at 27C for 5 weeks. Differences in dry matter production and root initiation were found between hypocotyl and petiole explants. No shoots were formed. Callus formation in anthers was very rare.
Changes of Onion Epidermal Cell Permeability Due to the Treatment with Alanap
Authors: FENG K. A. 
Published: April 2006

AbstractThe effect of Alanap, N‐1‐naphthylphthalamic acid (NPA), on the permeability of onion (Allium cepa) epidermal cells was studied by means of a plasmometric method. Urea, 1,3‐dimethylurea, and water were used for the test of permeability.It was found that the treatment of onion epidermis with NPA at various concentration (5 × 10–3 to 5 × 10–6M) altered the deplasmolysis rates and the absolute permeability constants. However, NPA did not alter the osmotic value of the treated cells. It was suggested that NPA treatment altered the permeability of onion epidermal cells due to the effect of this herbicide on the plasma membrane.
Distribution of Gibberellins and Abscisic Acid in Geotropically Stimulated Vicia faba Roots
Authors: EL‐ANTABLY HAMED M. M. , LARSEN POUL 
Published: April 2006

AbstractThe occurrence of gibberellins and abscisic acid (ABA) in extracts of roots of Vicia faba was demonstrated by gas‐liquid chromatography (GLC) of the methylated eluates from the relevant zones of thin‐layer chromatograms (TLC) of purified extracts. Quantitative determination of the hormone contents in extracts from upper and lower halves of roots which had been kept in the horizontal position for 30 min indicated a redistribution of the hormones during the geotropic stimulation. Gibberellins whose methyl esters appeared at the retention time of methylated gibberellic acid (GA3), used as a standard, occurred in higher concentration in the upper than in the lower halves (ratio 2.08:1), whereas the concentration of ABA was highest in the lower halves (ratio 3.08:1). The ratio of the hormones in right and left halves of vertical roots was close to 1:1. Indoleacetic acid (IAA) and ABA were found to retard the elongation of roots of Vicia faba and Lepidium during the first 24 h. Additional experiments with Lepidium showed that this retardation occurs within the first hour after application. Low concentrations of GA3, when applied to germinating seeds just after the radicles had broken the seed coat, stimulated root elongation in Vicia faba within 24 h and in Lepidium within 36 h. When applied to Lepidium seedlings with 20 mm long roots, GA3 showed a stimulatory trend within the first 2 h, and distinct stimulation in the subsequent hours, particularly at the lowest concentrations, 0.01 and 0.001 mg/1. These results suggest the possibility of a participation of ABA and gibberellins (in addition to IAA) in the development of the positive geotropic curvature.
The Action of Kinetin in Improving the Water Balance and Delaying Senescence Processes of Cut Rose Flowers
Authors: MAYAK S. , HALEVY A. H. 
Published: April 2006

AbstractKinetin delays the fading of cut rose (Rosa hyb. cv. Golden Wave) flower shoots exposed to water stress conditions. Using leafless flower shoots (i.e., a plant system devoid of stomates), we demonstrated that the main initial effect of kinetin was on increasing water uptake and petal growth. Later, kinetin slowed down processes associated with both senescence and stress (RNase activity and dry weight reduction), and maintained petal turgidity for an extended period.
Nitrate Reductase and Glucose‐6‐phosphate Dehydrogenase Activities as Influenced by Leaf Age and Addition of Protein to Extraction Media
Authors: SCHRADER L. E. , CATALOG D. A. , PETERSON D. M. , VOGELZANG R. D. 
Published: April 2006

AbstractLea fage influences the level of activity and the decay rate of the enzymes nitrate reductase (NR: E.C. 1.6.6.1) and glucose‐6‐phosphate dehydrogenase (G6PD; E.C. 1.1.1.49) extracted with and without protein in the extraction media. Such influence was determined in three plant species: corn (Zea mays L.), oats (Arena sativa L.), and tobacco (Nicotiana tabacum L.). Leaves of different ages were obtained from plants of various ages, or by removal of leaf blades from different positions on a single shoot. NR activity (per g fresh weight) declined as leaves of these plant species became older, especially when extraction was effected with conventional media (i.e. without added protein). The instability of NR in these extracts increased as leaves became older. Decay of NR in vitro was exponential with time. Addition of protein [3 %(w/v) casein or bovine serum albumin] to extraction media markedly increased the level of NR activity and its stability, especially in older leaves of all three plant species. Addition of protein did not affect the level of G6PD extracted from corn leaf blades, but slightly enhanced its activity in extracts from the oldest leaf blade of oats. G6PD activity also declined as leaf blades of corn and oats became older.
Identification of Cell Division Inducing Compounds from Coconut Milk
Authors: VAN STADEN J. , DREWES S. E. 
Published: April 2006

AbstractThe use of chromatographic techniques coupled with mass spectrometry, infra‐red analysis and nuclear magnetic resonance revealed that the amino acid phenylalanine might be responsible for a large proportion of the cell division activity of coconut milk as determined by the soybean bioassay. The observation that zeatin can be removed very readily by partitioning against ethyl acetate at alkaline pH values, cautions against inclusion of this method as a purification step for extracting cytokinins from plant extracts. Mass spectrometry revealed the presence of an unidentified cell division substance with a molecular ion of 279 and which co‐chromatographed with zeatinriboside on Sephadex LH‐20.
The Uptake of 63Ni by the Diatom Phaeodactylum tricornutum
Authors: SKAAR HARALD , RYSTAD BRITT , JENSEN ARNE 
Published: April 2006

AbstractKinetic studies of the uptake of 63Ni by cultures of the diatom Phaeodactylum tricornutum Bohlin revealed that the uptake capacity of the cells depended strongly on their metabolic state. Phosphate‐starved cells gave saturation‐type uptake curves and had low nickel‐binding capacity. This was increased markedly by the addition of phosphate to the cultures. When nickel ions were added before or together with the phosphate, the increase in nickel‐binding capacity of phosphate‐starved cells failed to appear more or less completely. Uptake of phosphate and formation of polyphosphate by the cells were not affected by the addition of nickel to the growth medium. The phosphate dependent synthesis of the principle involved in nickel binding was induced 15–20 h after the addition of phosphate to starved cells. Whether phosphate was directly or indirectly involved in this process could not be established.
Effect of Aflatoxins on the Changes in Fats and Carbohydrates during Germination and on the Symbiotic Fixation of Nitrogen in Peanuts [Arachis hypogaea]
Authors: SINGH RANGIL , SINGH AJIT , VADHERA SHYAMA , BHATIA I. S. 
Published: April 2006

AbstractThe rate of hydrolysis of fats during germination of peanuts decreased with the increase in the concentration of aflatoxins. Free‐reducing sugars increased up to 96 h of germination, and thereafter their concentrations remained more or less constant. However, the rate of formation of free‐reducing sugars decreased with increase in the concentration of aflatoxins. At all the stages of germination the rate of formation of sucrose decreased with increase in the concentration of aflatoxins. The aflatoxins stimulated the fixation of nitrogen during the preflowering stage, leading to an increase in the concentrations of soluble nitrogen in roots and protein in shoots: the maximum amount of total nitrogen fixed and that excreted into the soil was at a concentration of 2.5 μg/ml aflatoxins.
Effect of Abscisic Acid and Other Plant Hormones on Growth of Apical and Lateral Buds of Seedlings
Authors: BELLANDI DEISE MAURI , DÖRFFLING KARL 
Published: April 2006

AbstractThe effect of abscisic acid (AbA) on the growth of lateral and apical buds was studied in seedlings of Pisum sativum and some other species. The hormone was applied in three different ways: 1) directly to the lateral bud on the second node of decapitated pea seedlings as 5 μI droplets in an ethanolic solution; 2) to the cut surface of decapitated seedlings: 3) to the apical bud of intact plants.AbA directly applied in amounts of 5 to 0.1 μg to the lateral bud of the second node of decapitated seedlings had a strong inhibitory effect on the bud. Application to the cut surface of seedlings decapitated about 5 mm above the second node resulted in slight inhibition of the lateral bud on the second node and in growth promotion of the bud on the first node. When AbA at 10 to 0.1 μg was applied to the apical bud of intact seedlings, the growth of this bud was inhibited but the lateral buds grew out.It is concluded that the release of the lateral buds from apícal dominance is the result of the inhibitory effect of AbA on growth of the apical bud and of low transport of AbA. This conclusion is supported by application of GA3 and IAA, individually and each combined with AbA.
Aspartate Kinase from Some Higher Plants and Algae
Authors: AARNES HALVOR 
Published: April 2006

AbstractRegulation of aspartate kinase activity was examined in some higher plant seedlings (Helianthus annuus, Raphanus sativus, Cucutnis sativus, Sinapis alba), a green (Chlorellapyrenoidosa), and a blue‐green alga (Anacystis nidulans). In Cucumis sativus a concerted feedback regulation by L‐lysine and L‐threonine was indicated. In all the other species examined, aspartate kinase was inhibited by both L‐lysine and L‐threonine and it depended upon the species which of them was the strongest inhibitor. Only slight effects of L‐leucine, L‐isoIeucine and L‐valine were observed, except in the Sinapis alba enzyme.
Enzyme Activities in Urtica dioica: Effects of Daylength and Leaf Age on Glutamate Dehydrogenase, Aspartate Aminotransferase and Alanine Aminotransferase
Authors: WELANDER MARGARETA 
Published: April 2006

AbstractEnzymes, important to protein synthesis, were investigated in young and old leaves of Urtica dioica. The plants, divided into two groups, were exposed to either 18‐hour or 12‐hour photo‐periods. One group of plants from each photoperiodic regime was subjected to an irradiance of 28 W × m‐2, and the other group of plants to 42 W × m‐2. The enzymes investigated were glutamate dehydrogenase (GDH), aspartate aminotransferase (glutamate‐oxaloacetate transaminase, GOT), and alanine aminotransferase (glutamate‐pyruvate transaminase, GPT), GDH and GOT were determined by means of electrophoretic separation on polyacrylamide and spectrophotometric measurements. GPT was determined only by the latter method.Plants exposed to 18‐hour photoperiods showed much higher GDH activity than did those exposed to 12‐hour photoperiods. The activity of GDH also increased with leaf age. Besides one uniform NAD+‐dependent GDH, two other NAD+‐independent enzymes, showing GDH activity, were identified on polyacryl‐amide gel electrophoresis. The distribution of NADH and NAD+‐dependent GDH activity between young and old leaves was similar under different growth conditions.The activity of GOT was insensitive to environmental changes. The results regarding GPT indicate that this enzyme responded to different photoperiods in the same way as GDH. A correlation coefficient of 0.928 was obtained for the relationship between GDH and GPT activity.
Nitrate Reductase Activity of Wheat Seedlings during Exposure to and Recovery from Water Stress and Salinity
Authors: PLAUT ZVI 
Published: April 2006

AbstractNitrate reductase activity was inhibited as a result of reduced soil moisture potentials or application of NaCI to nutrient solutions. The decrease in enzyme activity of wheat seedlings exposed to salinity, was found 24 hours after exposure to stress. The effect of stress on nitrate reductase was found in cell‐free extracts as well as in riro in assays of intact leaf sections.A recovery in enzyme activity was found after irrigation or after removal of seedlings from salinity. While relative water content of the leaves was restored within 3 hours after removal of stress, full recovery of enzyme activity occurred only after 24 hours.Cycloheximide and chloramphenicol suppressed the activity of nitrate reductase in non‐stressed seedlings, but had no effect on the activity of plants exposed to salinity. However, during removal of stress, cycloheximide prevented completely the recovery of nitrate reductase, while chloramphenicol did not interfere with the recovery of the inhibited enzyme activity. It is concluded that a fraction of nitrate reductase may be located in the cytoplasm and lost activity during stress, probably due to inhibited protein synthesis. Another fraction which may be associated with chloroplasts, was inhibited by stress due to conformational changes or partial denaturation.
Changes in Sapwood of Roots of Norway Spruce, Attacked by Fomes annosus. Part I
Authors: JOHANSSON MARTIN , THEANDER OLOF 
Published: April 2006

AbstractChemical and physiological changes occurring in root sapwood of Norway spruce (Picea abies [L.] Karst.), when attacked by Fomes annosus (Fr.) Cke, were studied. The transformation of sapwood to reaction zone, induced by the fungal attack, implies a very sharp increase of carbonate content, correlated with higher amounts of potassium, calcium and magnesium. The buffer capacity of the reaction zone is strong, especially in the pH range 6–9. The high peroxidase activity in the rays of the sapwood is almost totally absent in the reaction zone, probably due to inactivating phenolic compounds. o‐Diphenol oxidase was detectable only in the presence of microorganisms. p‐Diphenol oxidase was active in connection with decaying wood but not in the reaction zone.
Sorption of Heavy Metal Cations by Corn Mitochondria and the Effects on Electron and Energy Transfer Reactions
Authors: BITTELL J. E. , KOEPPE D. E. , MILLER RAYMOND J. 
Published: April 2006

AbstractThe passive sorption of Pb+2, Cd+2, Zn+2, Co+2, Ni+2, and Mn+2 by isolated corn mitochondria was determined, and, except for Pb+2, the maximum sorption for each cation was about 58 nmol per milligram of protein. Sorption of Pb+2 was apparently ten times greater, but precipitation may have been the cause of this larger value. The effects of Pb+2, Cd+2, Zn+2, Co+2, and Ni+2 on acceptorless rates of electron transport for three substrates were determined. Greater than 50% inhibitions of oxidation were observed for succinate after additions of >0.1 mM Cd+2, Zn+2, or Pb+2: for NADH after additions of >0.5 mM Cd+2 or Zn+2; and for malate + pyruvate after additions of >0.1 mM Cd+2. Some inhibition of the rate of substrate oxidation was observed for most cations at higher concentrations. Coupling, as measured by ADP/O ratios, was inhibited at lowest concentrations by Cd+2 or Zn+2 and at higher concentrations by Co+2 or Ni+2. Substantial swelling of mitochondria oxidizing succinate was observed following additions of O.1 mM Cd+2 or Pb+2, Correlations are drawn between the effects of Pb+2, Cd+2, Zn+2, Co+2, and Ni+2 and their sorption to mitochondrial membranes.
Nonuniform Transport of Phosphorus from Single Roots to the Leaves of Zea mays
Authors: STRYKER R. B. , GILLIAM J. W. , JACKSON W. A. 
Published: April 2006

AbstractThe postulate that single roots of Zea mays transport their absorbed phosphorus nonuniformly to the leaves was tested. Plants were grown under growth chamber conditions for three to four weeks in nutrient solution. At this stage of growth a series of plants was placed into a system in which two roots on each plant were allowed to absorb either 33P or 32P from uptake solutions for time intervals of up to 24 hours. Plants subsequently were harvested such that each leaf was partitioned into samples containing tissue from one side or the other of the midrib. All samples were assayed for 33P and 32P and the results were expressed as the amount of total P transported into different plant parts from a single root.Nonuniform P accumulation in the leaves occurred and different patterns of accumulation, dependent on the type of root chosen for uptake were observed. Nearly uniform P accumulation occurred between one side and the other of a given leaf when transport was from radicle roots. In marked contrast, transport from adventitious roots resulted in an alternating pattern of accumulation between one side and the other of each successive leaf up the stem. The seminal root system supplied more P to the older leaves than did the adventitious root system. The nature of these nonuniform P transport patterns is attributed to the vascular organization between roots and leaves.
Action of Abscisic Acid on Auxin Transport and its Relation to Phototropism
Authors: NAQVI SHAMSHAD M. , ENGVILD K. C. 
Published: April 2006

AbstractThe action of abscisic acid on the kinetics of auxin transport through Zea mays L. (cv. Goudster) coleoptiles has been investigated. Abscisic acid applied simultaneously with indoleacetic acid‐2‐14C in the donor block reduced the transport intensity without materially affecting the basipetal velocity or the uptake. No effect on acropetal transport was observed. The data have been used to discuss the similarities in effects of abscisic acid and visible radiation and a hypothesis is proposed to explain the phenomena of phototropism.
Effect of Potassium Supply on the Transport of Photosynthates to the Fruits of Tomatoes (Lycopersicon esculentum)
Authors: MENGEL KONRAD , VIRO MAIJA 
Published: April 2006

AbstractIn experiments with intact tomato plants the effect of potassium on the translocation of photosynthates was studied. Four series of plants were grown in nutrient solutions with two different potassium levels (K1 and K2 treatments). When the fruits of the first truss had developed the plants were treated with labelled CO2 for 2 h in a glove box. The plants were then divided in roots, stems, fruits and leaves, which were prepared for chemical analysis.In all experimental series the plants with the higher K supply grew better and therefore assimilated higher amounts of labelled CO2 (cpm/plant). The assimilation rates per g fresh material, however, were not increased in each experimental set by the K2 treatment. The absolute quantities of labelled photosynthates transported from leaves and stems to the fruits were also greater in the plant with the higher potassium supply. In all experimental series the proportion of labelled material found in the fruits was higher in the plants of the K2 treatment (total label of the plant=100%) than in the plants of the K1 treatment. This beneficial effect of potassium was also observed in cases, where potassium had not affected the CO2 assimilation rate. Expressing the distribution of labelled material in relative terms (percentage proportions) means that the effect of CO2 assimilation on the transport of photosynthates was excluded to a high extent. The higher percentage proportions of labelled material found in fruits and roots of the K2 as compared to the K1 treatment is, therefore, predominantly dependent on a specific effect of potassium on the translocation of assimilates.The labelled material found in the soluble fraction of the stems consisted of about 90% sugars, nearly half of which was sucrose, the rest being mainly glucose and fructose. This finding suggests that sucrose is the most important transport form of carbohydrates in tomatoes.