bluuebunny/crossref_metadata_2025_split huggingface dataset:
Time course of uptake of 14C‐abscisic acid by Lemna gibba in relation to growth
Authors: TILLBERG ELISABETH , ELIASSON LENNART , ERICSSON TOM 
Published: April 2006

AbstractThe time course of growth of Lemna gibba L. in low concentrations of abscisic acid (ABA) and of uptake of 14C‐labelled ABA into the plants was followed for up to 15 days. Fresh weight increase was arrested when the plants were transferred to ABA solutions. This inhibition was greatest during the first days after which a marked recovery took place. Dry matter production was only slightly affected by ABA.On a culture basis, the uptake of ABA was almost linear with time during the experimental period. The rate of uptake on a fresh weight basis was highest during the first two days but decreased rapidly from the third day. Most of the applied 14C remained in the culture solution throughout the experiments. Plants transferred to a solution without ABA retained most of their accumulated 14C. Possible explanations for the decrease in rate of ABA uptake and restoration of growth are discussed.
Relations polyphenols‐croissance: Lignification et limitation de croissance chez Lycopersicum esculentum
Authors: Et GÉRARD MARIGO , BOUDET ALAIN M. 
Published: April 2006

Abstract Polyphenols and growth – Lignification and limitation of growth in Lycopersicum esculentum.When fed with quinic acid, young tomato seedlings (Lycopersicum esculentum Mill. cv. St. Pierre) exhibited reduced growth and marked changes in cell wall composition: cellulose concentrations decreased whereas those of lignin increased. Exogenously supplied growth substances (IAA, GA3) affected both the size of the plants and the lignification process: IAA treatments resembled quinic acid induced modifications with regard to both size and lignification: GA3 applied to quinate treated plants counteracted the effects of this compound by reducing the lignin content and improving the growth. The possible effect of abnormal lignification as a limiting factor in cell growth is supported by the characterization of lignins in tissues different from xylem.
Functional organization and plasticity of the photosynthetic unit of the cyanobacterium Anacystis nidulans
Authors: VIERLING ELIZABETH , ALBERTE RANDALL S. 
Published: April 2006

Abstract Anacystis nidulans grown under high and low light, 100 and 10 μE m−2 s−1, respectively, was analyzed with respect to chlorophyll/P700, phycobiliproteins/P700, chlorophyll/cell, and oxygen evolution parameters. The photosynthetic unit sizes of this cyanobacterium, measured as the ratio of total chromophores (chlorophyll and bilin) to P700, were shown to be similar to those of higher plants and green algae. High light grown cells possessed a photosynthetic unit consisting of a core of 157 ± 6 chlorophyll a molecules per P700 associated with a light harvesting system of 95 ± 3.5 biliprotein chromophores. Low light grown cells had substantially more biliprotein chromophores per P700 (125 ± 3.1) than high light cells, but showed no significant difference in the numbers of chlorophyll a molecules per P700 (149 ± 4). Analyses of aqueous biliprotein extracts indicate that low light grown cells produce proportionately more phycocyanin relative to allophycocyanin than high light cells. Calculations of the molecular weight of biliproteins per P700 suggest that there is less than one phycobilisome per reaction center I under both growth conditions.Differences in chlorophyll/cell ratios and oxygen evolution characteristics were also observed. High light cells contain 6.3 × 10−12 mg chlorophyll cell−1, while low light grown cells contain 12.8 × 10−12 mg chlorophyll cell−1. Photosynthetic oxygen evolution rate vs. light intensity curves indicate that high light grown cells reach maximal levels of oxygen evolution at higher light intensity than low light grown cells. Maximal rates of oxygen evolution were 16.6 μmol oxygen min−1 (mg chlorophyll)−1 for high and 8.4 μmol oxygen min−1 (mg chlorophyll)−1 for low light cells. Maximal oxygen evolution rates per cell were equivalent for both cell types, although the amount of P700 per cell was lower in high light cells. High light grown cells are therefore capable of producing more oxygen per reaction center I than low light grown cells.
The influence of kinetin on the endogenous content of indoleacetic acid in swelling seeds of Phaseolus, Zea and Pinus and young plants of Phaseolus
Authors: SALEH ADIRUKMI NOOR , HEMBERG TORSTEN 
Published: April 2006

AbstractTreatment of different plant materials, seeds of Phaseolus vulgaris, Zea mays and Pinus silvestris and young plants of Phaseolus, with kinetin increased the level of extractable IAA. For seeds this increase was most pronounced in bean seeds, which contained the lowest amount of endogenous IAA and cytokinins, and lower in maize seeds with high endogenous content of IAA and cytokinins. – For young bean plants the kinetin treatment significantly increased the extractable amounts of IAA from all parts of the plant, hypocotyls, cotyledons, epicotyls and primary leaves, when the cut plants were placed for 24 h in kinetin solution. For plants sprayed with kinetin solution only the primary leaves showed a significantly higher level of extractable IAA, which could be explained by the fact that the plants were growing very close together, so that the primary leaves received most of the kinetin during spraying.
Promotion of flowering in the Pinaceae by gibberellins
Authors: PHARIS RICHARD P. , ROSS STEPHEN D. , McMULLAN ELEANOR 
Published: April 2006

AbstractSignificant male and female flowering (cone bud production) by girdled branches of 6‐year‐old Douglas fir (Pseudotsuga menziesii (Mirb. Franco) seedlings was promoted by applications (mid‐April to June) of 1.6 or 3.2 mg per branch (in total) of certain non‐polar gibberellins (GA's). Girdling alone was ineffective. When tested alone, a mixture of GA4/7 was most effective. GA9 less so, while GA5 and the more polar GA3 were essentially ineffective. For female cone buds GA4/7+ GA9 were synergistically effective, but for male cone buds GA4/7 alone was best. The auxin naphthaleneacetic acid (NAA) was not tested alone, but at low dosage (0.175 mg/branch in total) NAA enhanced the flowering efficacy of GA's for both sexes; at a high dosage (0.875 mg/branch in total) male cone bud production was further enhanced, but only at the expense of females. For female flowering the best treatment (90% frequency of flowering 6.8 cone buds/branch), was GA4/7+ GA9+ low NAA; for male flowering, it was GA4/7+ high NAA (30% frequency and 4.2 cone buds/branch. Frequency of flowering for controls was 18% and 0%, average number of cone buds/branch was 0.9 and 0, for females and males, respectively. The successful treatments did not affect promordia initiation, rather they caused the differentiation of previously initiated, but undetermined, lateral primordia into cone and latent buds at the expense of vegetative bud differentiation.The lack of success reported by earlier workers in promoting flowering in Pinaceae species by GA's appears to be the unfortunate result of selecting GA3 for initial testing. The practical implications of this early and enhanced flowering by non‐polar GA's seedlings of a commercially important conifer are discussed in relation to accelerating the processes of tree improvement.
Morphactin transport and metabolism in tree bark tissues: comparative studies in vitro
Authors: BACKHAUS RALPH A. , SACHS ROY M. , PAUL JACK 
Published: April 2006

AbstractBark banding of morphaction is an effective means of controling stem elongation in Pinus radiata D. Don (Monterey pine) but not Juglans regia L. (English walnut). Diffusion coefficients of 14C‐labeled morphactin across excised disks of tree bark, measured in specially designed diffusion chambers, were 11 to 85 fold greater in pine than walnut. In seedlings of comparable age, the suberin layer of walnut bark is much thicker than that of pine; if the layer is removed, diffusion of 14C‐morphactin is enhanced 39‐fold in pine and 285‐fold in walnut.Morphactin applied to the bark as an ester is rapidly hydrolyzed to its carboxylic acid derivative in both pine and walnut. This conversion occurs rapidly in the bark of both species and does not appear to limit the rate of morphactin movement across the bark.These results suggest that diffusion across the suberin layer and not metabolism limits morphactin transport across the bark.
Distribution of labelled auxin and derivatives in stem tissues of intact and decapitated broad‐bean plants in relation to apical dominance
Authors: EVERAT‐BOURBOULOUX ANDREE , BONNEMAIN JEAN‐LOUIS 
Published: April 2006

Abstract[3H]‐auxin (0.13 to 0.18 nmol) was applied to the apical bud of broadbean plants (Vicia faba L. cv. Aguadulce). After 24 h, the exportation from the donor organ was ended. After 48 h, i.e. 10–15 h after the passage of the [3H]‐auxin pulse into the root system, the distribution and the nature of labelled molecules located in the basal part of the stem and in the axillary buds were investigated. Chromatographic analyses concerned both intact plants and plants decapitated 12 h, 24 h or 42 h after the [3H]‐auxin application. In intact plants, there was no significant amount of [3H]‐auxin in the axillary buds, whose radioactivity was very low compared to the stem tissues. The labelled molecules with the Rf of auxin represented 50% or more of the whole radioactivity of the stem tissues. The distribution of [3H]‐auxin was not uniform along the stem. In particular, the cotyledonary node zone, bearing the most inhibited buds, which is known to be an important centre of label retention, contained the highest amounts of labelled auxin both in intact and decapitated plants. The decapitation was quickly followed by a decrease of the [3H]‐auxin amount in the stem base more than 15 cm away from the wound, particularly in the scale leaf nodes, whose axillary buds were mainly the ones to grow after relief from apical dominance. The induction of this early decrease was clearly distinct in plants decapitated when auxin exportation from the donor organ was ended.
Obtention d'épinastie des cotylédons de Sinapis alba en éclairement rouge Iointain continu.
Authors: BAUMGARTNER NICOLE , FONDEVILLE JEAN‐CLAUDE 
Published: April 2006

Abstract Obtention of epinasty in the cotyledons of Sinapis alba under continuous far‐red illumination. Relation to the development of hypocotyl and cotyledons. Treatment by far red light induces epinasty of the cotyledonary leaf. The effects of light treatments of different intensities were recorded for hypocotyl length, percentage of epinasty and the cotyledon leaf area. The percentage of epinasty increases as a function of treatment duration and light intensity. As from the second day of treatment a correlation is obtained between the percentage of epinasty and hypocotyl length when the seedlings are given far‐red light treatment of different durations.
Glycolate and glyoxylate stimulation of growth in Lemna gibba
Authors: TILLBERG ELISABETH 
Published: April 2006

AbstractA 10 to 20% stimulation of growth in Lemna gibba L. G3 occurred following the addition of 0.5 to 3 mM glycolate or glyoxylate, although concentrations of 5 mM or higher were inhibitory. Glyoxylate gave a higher stimulation than glycolate. The stimulating effect on growth was obtained in media with or without 2% added sucrose. A higher stimulation was obtained when the plants were cultivated in open flasks in comparison to cultivation in flasks plugged with cellulose stoppers, which presumably retarded gas exchange.
Regulation of adenosine 5′‐phosphosulfate sulfotransferase by sulfur dioxide in primary leaves of beans (Phaseolus vulgaris)
Authors: WYSS HANS‐RUDOLF , BRUNOLD CHRISTIAN 
Published: April 2006

AbstractSO2 inhibited the light‐induced increase of extractable adenosine 5′‐phosphosulfate sulfotransferase in greening primary leaves of bean seedlings (Phaseolus vulgaris L. cv. Saxa (Radio) Stamm Vatter). In green primary leaves containing appreciable extractable adenosine 5′‐phosphosulfate sulfotransferase activity, SO2 treatment for 20 h decreased the activity of the enzyme to between 10 and 20% of the initial level. After removal of SO2 from the air, the extractable adenosine 5′‐phosphosulfate sulfotransferase activity increased after a lag, both in green and greening primary leaves, and was back to the control level after about 48 h. The sulfate concentration was increased about fourfold during SO2 treatment. An increase in sulfate sulfur accompanied by a decrease in adenosine 5′‐phosphosulfate sulfotransferase was also observed when bean seedlings, after excision of the roots, were transferred to nutrient solutions containing high sulfate concentrations, suggesting that sulfate is involved in the regulation of the enzyme.
Alterations in membrane transport properties by freezing injury in herbaceous plants:
Authors: PALTA JIWAN P. , LI PAUL H. 
Published: April 2006

AbstractLeakage of ions from a thawed tissue is a common phenomenon of freezing injury. This leakage is usually assumed to be due to loss of membrane semipermeability or membrane rupture by freezing injury. Freeze injured, yet living, onion (Allium cepa L.) epidermal cells were used to study alterations in cell membranes that result in leakage of ions. In spite of a large efflux of ions, freeze injured cells could be plasmolysed and they remained plasmolysed for several days just like the unfrozen control cells. Injured cells also exhibited protoplasmic streaming.Passive transport of KCl, urea and methyl urea across the cell membranes of injured and control cells was also studied. No difference could be detected for the transport rates of urea and methyl urea between control and injured cells. However, a dramatic increase in the transport rate of KCl was found for the injured cells.Depending upon the extent of initial freezing injury, an increase or a decrease in injury symptoms was found in the post‐thaw period. During the progress of freezing injury, 10 days after thawing, a swelling of the protoplasm was seen in the irreversibly injured cells. In spite of this swelling, these cells could be plasmolysed. It appears that the high amount of K+ that leaks out into the extracellular water, due to freezing injury, causes protoplasmic swelling by replacing Ca2+ in the plasma membrane. We conclude that protoplasmic swelling is a sign of secondary injury.The results presented in this study show that membrane semipermeability is not completely lost and membrane rupture does not occur during the initial stage of freezing injury. In fact, the cells have the ability to repair damage depending upon the degree of injury. Our results show there are specific alterations in membrane semipermeability (e.g., transport of K+) which could be repaired completely depending on the degree of injury. These findings suggest that ion leakage due to freezing injury is due to alteration in the membrane proteins and not in the membrane lipids.
Kinetic characterization of barley root plasma membrane‐bound Ca2+‐ and Mg2+‐dependent adenosine triphosphatase activities
Authors: CALDWELL CHARLES R. , HAUG ALFRED 
Published: April 2006

AbstractA plasma membrane‐rich microsome fraction isolated from barley (Hordeum vulgare L. cv. Conquest) roots contained considerable divalent cation‐dependent ATPase activity when assayed at 16°C. The maximal divalent cation‐stimulation of the apparent basal ATPase activity varied as Ca2+ > Mg2+ > Mn2+= Zn2+ > Co2+ > Ni2+, with all other divalent cations tested being inhibitory. Double reciprocal plots of the Ca2+‐ and Mg2+‐dependent ATPase velocities as a function of substance concentration were nonlinear, suggesting the presence of multiple catalytic sites. Both MgATP2‐ and CaATP2‐ served as the true substrates and apparently bind to the same catalytic sites. Free ATP and Ca2+ could inhibitit the Ca2+‐ and Mg2+‐dependent ATPase. Increasing free Mg2+ levels enhanced the affinity of the Mg2+‐dependent ATPase for MgATP2‐, while slightly inhibiting the Vmax values. Other divalent cation‐nucleoside triphosphate complexes produced maximal enzyme velocities equal to or greater than those generated by CaATP2‐ and MgATP2‐. However, the ATPase had significantly higher affinities for CaATP2‐ and MgATP2‐, than for the alternative substrates. The high and low affinity components of the Ca2+‐ and Mg2+‐dependent ATPase exhibited optimal Vmax values at pH 5 and 6, respectively. Analysis of the pH‐dependence of the enzyme Km values indicated enzyme‐substrate binding with charge neutralization at neutral and alkaline pH's. Nonlinear double reciprocal plots were obtained at all assay temperatures. However, the complexity of the enzyme kinetics became less apparent at the higher assay temperatures. The kinetics of the barley root divalent cation‐dependent ATPase activities are discussed in terms of the kinetics of ATPases from other plants and the methods used to obtain them, and compared to the kinetics of ion transport ATPases from animal membranes.
Phytochrome mediated induction of nitrate reductase activity in etiolated maize leaves
Authors: RAO L. VIJAYA MOHAN , DATTA NEERAJ , SOPORY SUDHIR K. , GUHA‐MUKHERJEE SIPRA 
Published: April 2006

AbstractThe effects of red and far‐red light on the enhancement of in vitro nitrate reductase activity and on nitrate accumulation in etiolated excised maize leaves were examined. Illumination for 5 min with red light followed by a 4‐h dark period caused a marked increase in nitrate reductase activity, whereas a 5‐min illumination with far‐red light had no effect on the enzyme activity. The effect of red light was completely reversed by a subsequent illumination with the same period of far‐red light. Continuous far‐red light also enhanced nitrate reductase activity. Both photoreversibility by red and far‐red light and the operation of high intensity reaction under continuous far‐red light indicated that the induction of nitrate reductase was mediated by phytochrome. Though nitrate accumulation was slightly enhanced by red and continuous far‐red light treatments by 17% and 26% respectively, this is unlikely to account for the entire increase of nitrate reductase activity. The far‐red light treatments given in water, to leaves preincubated in nitrate, enhanced nitrate reductase activity considerably over the dark control.The presence of a lag phase and inhibition of increase in enzyme activity under continuous far‐red light‐by tungstate and inhibitors of RNA synthesis and protein synthesis‐rules out the possibility of activation of nitrate reductase and suggests de novo synthesis of the enzyme affected by phytochrome.
Effects of caffeine on germination and differentiation in spores of the fern, Onoclea sensibilis
Authors: MILLER JOHN H. , BASSEL ALIX R. 
Published: April 2006

AbstractDuring spore germination in the fern, Onoclea sensibilis L., the nucleus moves from a central position to one end, and an asymmetrical cell division partitions the spore into two cells of greatly unequal size. The smaller cell differentiates directly into a rhizoid, whereas the larger cell and its derivatives give rise to the prothallus. In the presence of 5 mM caffeine, the nuclei of most of the spores undergo mitotic replication, whereas cell wall formation is blocked. Multinucleate single cells are produced, which are capable of growth, but no rhizoid differentiation occurs. In some cases a partial cell wall is produced, but the nucleus moves through the discontinuity back to the center of the spore, and the enucleate, incompletely partitioned small “cell” fails to differentiate into a rhizoid. In less than 1% of the spores a broad protuberance, whose wall is yellow‐brown, is formed in a multinucleate single cell. The color, staining reaction to ruthenium red, and ultrastructural appearance of the protuberance resemble that of the rhizoid wall. It appears that infrequently in the caffeine‐treated spores, a feature which is characteristic of rhizoids is expressed, in the absence of asymmetric cell division, in a cell which otherwise is unable to produce a rhizoid. The results are interpreted to mean that the spore has a highly localized, persistent differentiated region. For rhizoid differentiation to occur, a nucleus must be confined in that region – a confinement which normally is accomplished by the geometrically asymmetric first cell division of germination.
Seasonal changes of the different components of the inhibitor β complex in potato tubers
Authors: FRANKLIN JEEVALATHA , HEMBERG TORSTEN 
Published: April 2006

AbstractSeasonal changes of the inhibiting substances in the inhibitor β complex were studied in diethyl ether and methanol extracts of peelings from potato tubers, cv. Majestic, prepared during dormancy and cessation of dormancy. In both extracts the acidic ether soluble substances were investigated. From the methanol extracts also non‐ether soluble but butanol soluble substances were studied. At each extraction time experiments were performed to determine the stage of rest in the tubers.Four different inhibitory zones were found with the Avena straight growth test of thin layer chromatograms. One of these was probably an artefact formed during chromatography. The level of all these substances decreased when rest ceased. – Thin layer chromatograms of the butanol fraction of methanol extracts, which should have contained the bound forms of the inhibitors, showed the same inhibitory zones as the ether fractions. This probably resulted from hydrolysis of the bound inhibitors when the extracts were chromatographed in an alkaline solvent system during purification.
Isolation of active ribulose 1,5‐bisphosphate carboxylase from glanded cotton (G. hirsutum)
Authors: QUAYLE THOMAS J. , KATTERMAN FRANK R. , JENSEN RICHARD G. 
Published: April 2006

AbstractRibulose, 1,5‐bisphosphate carboxylase has been isolated from leaves of glanded cotton, (Gossypium hirsutum L. cv. TM1), by techniques described. A yield exceeding 4.5 mg enzyme per gram leaf tissue has been obtained by utilizing a sodium homogenizing buffer without the addition of any reducing agent. Sodium dodecylsulfate gel electrophoresis of the enzyme shows the fraction to be relatively free of contaminants. Enzymic assays of the isolate give a specific activity of 1.1 μmol CO2 fixed (min‐mg protein)−1 at 30°C.
Action de la proline exogène sur l'activité de la voie du glycolate chez Nicotiana tabacum cv. Xanthi n.c.
Authors: VALLEE J. C. , VANSUYT G. , PREVOST J. 
Published: April 2006

AbstractThe effect of exogenous proline on the activity of the glycolate pathway in Nicotiana tabacum cv. Xanthi n.c.An exogenous proline supply in the light provokes an increase in free glycine concentration in apical tissues or in leaf disks of vegetative Nicotiana tabacum L. cv. Xanthi n.c. This does not occur in the equivalent tissues of tobacco plants after floral induction, these being naturally rich in proline. In vegetative tobacco, we have tried to determine this specific action of exogenous proline. With 14C glycine, 14CO2 experiments (Pulse‐chase) and glycine decarboxylase activity determinations, we observed that glycine‐serine transformation was inhibited by proline supply. Presently it is important to determine if endogenous proline acts on the same reaction.
Cell wall polysaccharidase activities and growth processes: a possible relationship
Authors: GOLDBERG RENEE 
Published: April 2006

AbstractIn Vigna radiata (L.) Wilczeck hypocotyl, the maximal growth zone is located right under the hook and moves 5 mm lowe exogenous auxin. A good correlation has been obtained between the magnitude of the growth response and the cell wall β 1→3 endoglucanase activities. In cell walls from segments with different growth potentials, the kinetic constants of the β 1→3 endoglucanases are not identical. When the enzymes are rendered soluble, their behaviors become almost similar. These data indicate a relationship between the kinetic behavior of the immobilized enzymes and the structure of their support, i.e. the cell wall organization, which is modified during cell elongation. The possible involvements of these enzymes in some pathways of growth processes are discussed.