bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nutritional and Hormonal Requirements for the Growth of Vigna sinensis Callus in vitro
Authors: MATSUBARA SATOSHI 
Published: April 2006

AbstractNutritional and hormonal requirements for in vitro growth of callus tissue of Vigna sinensis Endl. were studied. Callus was formed on hypocotyl and root sections, when they were cultured on Linsmaier and Skoog's basal medium solidified with 10 g/1 agar and supplemented with only 0.5 mg/12,4‐D or 2 mg/1 IAA. Further addition of 0.2 mg/1 kinetin and 1 g/l yeast extract resulted in more active callus formation. For unlimited vigorous growth of subcultured callus which was originally isolated from root sections, yeast extract was indispensable besides 2,4‐D and kinetin. Such growth‐promoting activity was observed also in malt extract and Ebios (dried cell powder of brewery yeast). Of known compounds tested, nicotinic acid, nicotinamide., methyl nicotinate and NAD were promotive to the growth of the callus, although much less effective than yeast extract. Other pyridine derivatives, vitamins and amino acids tested were ineffective or slightly effective. Sucrose was the most suitable carbon source. Fructose, glucose and maltose also supported the growth. Kinetin stimulated cell proliferation of the callus and cell differentiation to tracheary element.
Photosynthesis in Wood
Authors: WIEBE HERMAN H. 
Published: April 2006

AbstractThe capacity for photosynthesis, measured as light enhanced 14CO2 uptake, was demonstrated in the wood of first and fourth year twigs of Betula pendula Roth, Populus tremuloides Michx., Syringa vulgaris L., and Tilia Americana L, but not in Gleditschia triacanthos L. In Betula and Syringa, but not in the others, photosynthesis occurred in the secondary xylem as well as in the primary xylem.
Effects of the Commercial Polychlorinated Biphenyl Mixture Aroclor 1242 on Growth, Viability, Phosphate Uptake, Respiration and Oxygen Evolution in Scenedesmus
Authors: LARSSON CARL‐MAGNUS , TILLBERG JAN‐ERIC 
Published: April 2006

AbstractThe commercial polychlorinated biphenyl (PCB) mixture Aroclor 1242 was tested regarding its effects on the uni‐cellular green alga Scenedesmus obtusiasculus Chod. The algae were grown in liquid medium at PCB concentrations between 10 and 1000 ppb. Growth was inhibited at 300 ppb and above, viability was only affected at the highest concentration, 1000 ppb. Reduction of phosphate uptake was seen at 300 ppb and above. The inhibition of phosphate uptake had almost exactly the same appearance in light as in darkness. It is suggested that this inhibition is mainly caused by PCB action on the plasmalemma. At 800 ppb some experiments indicated an uncoupling of the oxidative phosphorylation. 1000 ppb inhibited both respiration and O2 evolution.
Hormonal Regulation of Pedicel Abscission in Begonia Flower Buds
Authors: CATE CH. H. HÄNISCH TEN , BERGHOEF J. , VAN DER HOORN A. M. H. , BRUINSMA J. 
Published: April 2006

AbstractIn order to analyse the hormonal regulation of flower bud shedding in Begonia, levels of indoleacetic acid (IAA), abscisic acid (ABA) and ethylene were determined in buds and pedicels. The translocation and metabolism of 14C‐labeled IAA in pedicel segments were also studied.In a monoecious Begonia fuchsioides hybrid, abscising male flower buds contain about 1% of the IAA present in non‐abscising female flowers. In a male Begonia davisii hybrid, the seasonal variation in bud drop coincides with changes in the IAA content of the buds, while also the release of IAA from the bud to the pedicel is hampered.Abscission zones of these pedicels always contain abscission promoting ethylene concentrations. The tissue is prevented from responding with abscission by IAA from the flower buds. The buds also contain ABA but without influencing abscission considerably.Pretreatment with ethylene or ABA does not affect IAA transport in pedicel segments. The rate of this transport is 4–6 mm × h–1:; the capacity increases with the transverse area. In young segments, IAA is decarboxylated and also otherwise metabolized.
Evidence for Three Different Systems of Movement of Indoleacetic Acid in Intact Roots of Phaseolus coccineus
Authors: MITCHELL E. K. , DAVIES P. J. 
Published: April 2006

AbstractIndoleacetic acid (IAA)‐5‐3H (2 × 10−9M) was applied to intact roots of Phaseolus coccineus seedlings, at the apex or 2 cm above the apex, at various pHs and in the presence of Cu2+ and NaCl. The transport of label in the roots was then examined after 6 h by cutting the roots into 1 mm sections above and below the zone of treatment. Basipetal movement from 2 cm above the apex was unafected by pH, Cu2+ or NaCl. Acropetal movement from the same area decreased with increasing pH from 5.4 to 8.0, probably due to an effect of pH on the entry of IAA into the cells. pH had no effect on sucrose transport. Cu2+ also inhibited acropetal movement but NaCl had no effect. Basipetal movement of label from the apex was reduced by Cu2+ and increasing pH, but not as much as with acropetal movement, and increased by the presence of NaCl. These facts are interpreted as showing 3 different systems of IAA movement in intact roots: basipetal from 2 cm up the root in some extracellular physical system; acropetal from 2 cm up the root, and basipetal from the apex, in a metabolically dependent intracellular system, but in different tissues of the root. It is proposed that endogenous IAA not only moves into the root from the stem but is also synthesized in the root apex, and moves basipetally for a short distance to the root growing zone in a separate system from the IAA descending from the stem.
Some Effects of Triazines on Growth, Photosynthesis and Translocation of Photosjuthate in Pinus Species
Authors: SHAUKAT S. SHAHID , MOORE K. G. , LOVELL P. H. 
Published: April 2006

AbstractThe effects of triazines on growth, 14CO2‐fixation and translocation of 14C‐assimilates by young Pinus seedlings were investigated. Post‐emergenceroot application of moderate and high concentrations of simazine and atrazine resulted in severe toxicity to the seedlings of Pinus nigra and P. coniorta as depicted by reduction in dry weight, chlorosis, wilting and mortality. Atrazine was more toxic than simazine and P. nigra was more susceptible than P. contorta to both the triazines. Simazine treatment to the roots of P. nigra seedlings, not only caused inhibition of 14CO2‐fixation but also reduced the short‐term downward transloca‐tion of l4 C‐assimilates. Various possible mechanisms whereby simazine reduced the downward movement of I4C‐assimilates in Pinus seedlings are discussed.
Comparisons between Photosynthesis and Transpiration in Birch
Authors: HARI PERTTI , LUUKKANEN OLAVI , PELKONEN PAAVO , SMOLANDER HEIKKI 
Published: April 2006

AbstractChanges in photosynthesis and transpiration of a potted birch seedling were simultaneously followed in the field using two infrared gas analyzers. Wet and dry temperature measurements alone explained 81% of the variation in the transpiration rate when the plant was not suffering from water deficit. During drought and the period after the water balance had been restored, net photosynthesis decreased more distinctly than transpiration. This result was in accordance with our previous results on the after‐effects of water deficit on photosynthesis, and it was also interpreted as evidence for at least partly separate control mechanisms for photosynthesis and transpiration.
Effect of Debudding on Photosynthesis in Leaves of Cotton
Authors: NAGARAJAH S. 
Published: April 2006

AbstractAn experiment was carried out to study the effect of reduced growth on the photosynthetic rate of leaves in cotton (Gossypium hirsutum). It was planned to reduce growth by the continuous removal of axillary buds.The results show that debudding did not reduce the growth of plants but only altered the distribution pattern of assimilates. The shoot weight of the control and debudded plants was not significantly different. However, debudding prevented reproductive development in the debudded plants. Comparison of the photosynthetic rates of the control and debudded plants indicate that reproductive development did not affect the photosynthesis of young fully expanded leaves but slightly increased the rate of decline in photosynthesis during their ageing.
The Effect of IAA on Sugar Accumulation and Basipetal Transport of 14C‐labelled Assimilates in Relation to Root Formation in Phaseolus vulgaris Cuttings
Authors: ALTMAN A. , WAREING P. F. 
Published: April 2006

AbstractThe effect of indol‐3yl‐acetic acid on root formation, accumulation of 80% ethanol‐soluble sugars and basipetal transport of 14C‐labelled assimilates has been investigated in Phaseolus vulgaris (cv. Canadian Wonder) hypocotyl cuttings. The removal of leaves reduced root formation in the hypocotyl, while excision of the apical bud was less detrimental. The expression of the IAA effect in inducing more roots was dependent on the area of leaves, and was found to be better when all leaves were present. Sugars accumulated slowly at the base of cuttings during a four‐day period after excision, and IAA greatly enhanced this accumulation. By comparing sugar content at the base of green and starved cuttings it was established that IAA greatly increased it concurrently with root formation.IAA applied in solution to the hypocotyl greatly enhanced the basipetal transport of 14C‐labelled assimilates and their accumulation at the hypocotyl during a 24‐h period. The IAA‐induced accumulation was found to be connected with a greater mobilization of labelled assimilates from upper parts of the cutting. Experiments involving pretreatment with IAA and transport in cuttings already possessing root primordia, suggest a dual effect of IAA: (I) a direct effect on transport, and (2) an increase in the root‐“sink”. It is concluded that both may be operating in inducing basipetal accumulation of labelled assimilates. It is suggested that one of the roles of IAA in promoting rooting of cuttings is to increase sugar availability at the site of root formation.
Cytological Studies on Tissue Culture of Pinus cembra
Authors: SALMIA M. AULIKKI 
Published: April 2006

AbstractCallus tissue of Swiss stone pine, Pinus cembra L. var. sibirica Loud., has been grown successfully for 9 months through 7 transfers. Excellent initial growth was obtained from hypocotyl segments of 7‐day‐old seedlings. A complex agar medium was used supplemented with 2 mg/l 2,4‐D, 0.05 mg/l kinetin, 1 g/l Edamin and 10% v/v coconut milk. No deterioration of growth was observed on this medium after numerous transfers. The callus tissue did not produce shoots or roots, but showed an ability for cytodifferentiation. Tracheids or tracheid‐like structures were formed in every passage, but the tracheids of the primary callus culture differed markedly from those of the subcultures. The tracheids of the primary culture probably already existed in the hypocotyl, whereas those of the subcultures were formed in vitro. The callus tissue was mainly diploid during the period studied, and more than 86% of the mitoses were diploid. A few mitoses with tetraploidy or a higher ploidy also occurred, but the tissue did not show any tendency to polyploidization.
Regulation of Water Loss by Citrus Leaves
Authors: HALL ANTHONY E. , CAMACHO‐B SAUL E. , KAUFMANN MERRILL R. 
Published: April 2006

AbstractThe factors responsible for the low transpiration rates of citrus were investigated. Leaf resistance to water vapor exchange by orange seedlings (Citrus sinensis L. cv. Koethen) including a substantial boundary layer resistance, was as low as 1 s cm−1 in humid air. Leaf resistance of well watered plants increased to values as large as 5 s cm−1 when the difference in absolute humidity between leaf and air was increased. Leaf resistance was only slightly influenced by temperature between 20 and 30°C providing the humidity difference between leaf and air was kept constant. Leaf resistance increased when leaf temperature was increased between 20 and 30°C when the absolute humidity external to the leaf was kept constant. Increased humidity differences resulted in greater increases in leaf resistance during initial experiments than when the experiments were repeated with the same leaves indicating acclimation by the plant. It was concluded that the effects of humidity differences on leaf resistance are partially responsible for the low transpiration rates of citrus.
Inhibition and Requirement of Natural Stimulator for Cambial Xylem Production in Isolated Stem Segments of Pinus silvestris
Authors: ZAJACZKOWSKI STEFAN , WODZICKI TOMASZ J. 
Published: April 2006

AbstractFormation of xylem in sterile culture of isolated pine stem segments supplied with synthetic media continues only for 4–6 weeks. The stem segments originally do not contain an eluable inhibitor affecting elongation in the test of pine hypocotyl sections. After 4 weeks inhibition is detected. Supplying the medium with a methanolic extract from the cambial region of pine stem prolongs xylem production up to 15 weeks. IAA interacts synergistically with a natural stimulator of cambial activity.
Triterpeneglycosides as Inhibitors of Fungal Growth and Metabolism 8. Induced Leakage of Nucleotide Materials
Authors: OLSEN ROLF A. 
Published: April 2006

AbstractAddition of aescin to mycelia of Ophiobolus graminis and Neurospora crassa induced leakage of ribonucleotide material together with pentose phosphate or pentose.In O. graminis a rapid release of mono‐ and dinucleotides together with nucleosides and pentose occurred. In addition some oligonucleotides were released during the first 30 min of the treatment. A slow leakage of polynucleotides was also observed.In N. crassa aescin induced only slight leakage during the first hour, and the mono‐ and dinucleotide leakage was actually decreasing. From that time on, however, a rapid release of mono‐ and dinucleotides together with nucleosides and pentose phosphate or pentose was observed. Only small amounts of poly‐ and oligonucleotides leaked and the cell content of oligonucleotides seemed to be released only during the last hour of the treatment period.In Aspergillus niger, which was insensitive to the inhibitor, aescin only induced leakage of pentose or pentose phosphate and small amounts of mono‐ and dinucleotides.Loss of viability in mycelia of O. graminis and N. crassa seemed to be correlated with the loss of oligonucleotides from the cells.
Studies on Moss Spores. IV. Mass Spectrometric Identification of Saturated and Monoenoic Long Chain Fatty Acids in the Triglyceride Fraction of Polytrichum commune Spores
Authors: KARUNEN PIRJO 
Published: April 2006

AbstractThe saturated long chain fatty acid methyl esters of the triglyceride fraction of Polytrichum commune spores were separated by silver nitrate TLC and identified by a combination of gas chromatographic‐mass spectrometric technique. The saturated fatty acid methyl esters were straight‐chained, and even‐numbered with carbon numbers ranging from 12 to 26 or odd‐numbered with carbon numbers ranging from 13 to 25. The major components of the fraction containing saturated fatty acid methyl esters were methyl palmitate and methyl stearate.The fatty acid methyl esters of the monoenoic fraction isolated by silver nitrate TLC were converted to TMSO derivates which were analysed by gas chromatography‐mass spectrometry. The analysis gave evidence of positional isomers. The fraction contained the following straight chain monoenoic fatty acid methyl ester isomers: methyl 7‐cis‐hexadecenoate, methyl 9‐cis‐hexadecenoate, methyl 9‐cis‐heptadecenoate, methyl 9‐cis‐octadecenoate, methyl 11‐cis‐octadecenoate, and methyl 11‐cis‐eicosenoate. The major components were methyl 9‐cis‐octadecenoate and methyl 7‐cis‐hexadecenoate.
The Role of Abscisic Acid in Senescence of Detached Tobacco Leaves
Authors: EVEN‐CHEN ZEEV , ITAI CHANAN 
Published: April 2006

AbstractThe role of abscisic acid in the regulation of senescence was investigated in detached tobacco leaves (Nicotiana rustica L.). Leaves senesced in darkness showed a sharp rise in abscisic acid level in the early stage of aging, followed by a rapid decline later. The same trend was found when leaves were aged in light, but the rise in abscisic acid occurred four days later than in darkness. Senescence was slower in light than in darkness, while salt stress accelerated the processes. Leaves treated with kinetin which senesced in light and darkness, did not show an increase in abscisic acid. Application of kinetin led to a transformation from free to bound ABA. These results may indicate that ABA and cytokinin are involved in a trigger mechanism which regulates senescence; the stage at which this trigger is activated determines the rate of senescence.
Divalent Cations and K/Na Selectivity in Excised Barley Roots
Authors: BANGE G. G. J. 
Published: April 2006

AbstractThe effect of Ca2+ and Mg2+ on the rate of K+ (Na+) uptake from different external concentrations ranging from 0 to 1 mM and in the absence and presence of a fixed concentration of Na+ (K+) in the same range, was determined. The object was to examine to what degree the qualitatively well‐established action of the polyvalent cations on these processes could be understood quantitatively from a twofold starting‐point: in the first place the theory of carrier competition (Bange 1962, Acta Bot. Neerl. 11: 139–146) and secondly the hypothesis that polyvalent cations influence carrier site accessibility at the cell surface.It appears that along these lines a semi‐quantitative description of the phenomena observed is feasible. Possible causes of deviations are discussed.
Nitrogen Uptake by Apple Seedlings as Affected by Light, and Nutrient Stress in Part of the Root System
Authors: FRITH G. J. T. , NICHOLS D. G. 
Published: April 2006

AbstractThe adaptation of apple seedlings, Pyrus malus L., to localized nutrient stress was studied by measuring nitrogen uptake. Seedlings with split root systems were grown in nutrient solution. Various proportions of the roots were subjected to nutrient stress by placing some of the roots in water. The nitrogen uptake by stressed plants was measured under constant and varied lighting. Under optimum lighting it was found that if part of the root system was deprived of nitrogen, then the remainder partially compensated for this deficiency by increasing its uptake. This adaptation, however, was substantially reduced under low levels of lighting.
Influence of N‐Deficiency on the Abscisic Acid Content of Sunflower Plants
Authors: GOLDBACH EVA , GOLDBACH H. , WAGNER H. , MICHAEL G. 
Published: April 2006

AbstractSunflower plants (7 weeks old) were transferred from a modified Hoagland solution to a N‐free nutrient medium and kept there for 7 days. Abscisic acid (ABA) was determined in several parts of the plants and in exudates collected from the roots of some of these plants.N‐deficiency considerably increased the ABA content of the leaves, especially the older ones, and also considerably increased the ABA content of the upper parts of the stem when compared to the control plants. In the roots and the exudates of these plants no ABA could be detected.After dissecting the stems the ABA content in the roots of the control plants with normal N supply dropped quickly, probably due to rapid metabolization. Judging by results obtained, it seems unlikely that the roots are responsible for the remarkable increase of the ABA content in the shoots caused by N‐deficiency.
Bicarbonate Utilization in Anabaena
Authors: KEENAN JOHN D. 
Published: April 2006

AbstractBlue‐green algal growth frequently occurs in water with relatively high pH and high levels of organic carbon which are related by the pH‐dependent ionization of inorganic carbon. This relationship, which may regulate natural populations, was examined using a factorial experimental design in which the metabolic response of Anabaena flos‐aquae was measured as a function of pH and total inorganic carbon. The concentration of the products of ionization were calculated. Algal responses were determined manometrically as rates of photosynthesis and respiration. The overriding factor regulating the growth of Anabaena was pH, and no obvious relationship was found to exist between oxygen evolution or uptake and the concentration of any form of inorganic carbon.
Light‐induced Activation of Cytoplasmic Protein Synthesis in Verticillium agaricinum
Authors: VALADON L. R. G. , TRAVIS R. L. , KEY JOE L. 
Published: April 2006

AbstractThe level of protein synthetic activity in dark‐grown cultures of Verticillium agaricinum was significantly enhanced by light. As expected the enhancement of protein synthetic activity was accompanied by a transformation of cytoplasmic monoribosomes to polyribosomes. Amino acid incorporation studies utilizing the synthetic mRNA, poly (U), suggest that the transformation was preceded by an activation of pre‐existing ribosomes. The change in ribosome activity related, at least in part, to an increase in the level of peptidyl‐tRNA associated with the ribosomes. In this regard the response of V. agaricinum ribosomes was similar to ribosome activation in several higher plant systems. The initial response at the level of the ribosome remains to be elucidated.
The Effects of Germination on the Subcellular Distribution of Cholinesterase in Cotyledons of Phaseolus vulgaris
Authors: LEES G. L. , THOMPSON J. E. 
Published: April 2006

AbstractHomogenates of Phaseolus vulgaris cotyledons have been found capable of hydrolyzing acetylthiocholine. The hydrolysis occurs optimally at pH 8.0, and is inhibited by neostigmine but not eserine. Total activity of the enzyme increases about three‐fold between the second and third days of germination, and remains high until day 6 before dropping coincident with the appearance of visible morphological symptoms of senescence in the tissue.Fractionation studies have revealed that the enzyme is enriched in preparations of purified cell wall and plasma membrane and is also present in a soluble fraction. The soluble enzyme accounts for more than 70% of the total cholinesterase activity two days after planting but by the fourth day of germination only about 30% of the total activity in the tissue is soluble. During the same period there is a large increase in the specific activities of both the cell wall and plasma membrane enzymes. By the seventh day of germination the particulate and soluble forms of the enzyme both show much reduced activities, but the specific activities of the cell wall and plasma membrane enzymes subsequently increase again. This is thought to reflect breakdown of protein other than cholinesterase in these structures as they in turn become subject to the increasing pressures of senescence.Cholinesterase in plant tissue presumably serves to regulate the endogenous titre of acetylcholine. The behaviour of this enzyme in bean cotyledons has been interpreted in terms of patterns of physiological and ultrastructural change known to characterize this tissue during germination.