bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Chromatographic–Mass Spectrometric Identification of 4‐Chloroindolyl‐3‐acetic Acid Methyl Ester in Immature Green Peas
Authors: ENGVILD KJELD C. , EGSGAARD HELGE , LARSEN ELFINN 
Published: April 2006

AbstractImmature green peas were harvested from plants grown in water culture on Johnson's nutrient solution with radioactive chloride. Twenty five g of lyophilized peas were extracted with butanol, the extract chromatographed, first on Sephadex LH 20 and then on silica gel. The radioactive hormone was followed by scintillation counting without the use of any scintillant. The radioactive fractions were taken up in a few μl of chloroform and injected into a gas chromatograph interfaced with a mass spectrometer. Derivatization was not necessary. The electron impact mass spectrum showed the typical peaks of a chloroindolyl‐3‐acetic acid methyl ester: the molecular ion cluster at m/e 223, 225 and the characteristic indole fragment ions at m/e 164, 166 (M‐COOCH3)+. The chlorine atom was assigned to the 4 position of the indole ring after thin layer chromatography of radioactive extract and standards of four different chlorinated indolyl‐3‐acetic acid methyl esters.
Influence of Different Cytokinins on the Transpiration and Senescence of Excised Oat Leaves
Authors: BIDDINGTON N. L. , THOMAS T. H. 
Published: April 2006

AbstractIn order to investigate the possibility that cytokinins control transpiration indirectly through affecting leaf senescence, a direct comparison was made of the effect of different cytokinins on transpiration and senescence of oat leaves (Avena sativa L. cv. Forward). Senescence was assessed by measuring chlorophyll loss. The synthetic cytokinins N6 benzyladenine (BA) and kinetin delayed senescence and increased transpiration of oat leaves to a greater extent than did the naturally occurring compounds zeatin, Nb‐Δ2 isopentenyladenine (i6 Ade) and 6‐ø‐hydroxybenzyladenosine (hyd‐BA riboside).During the early stages of the transpiration experiment zeatin showed similar or greater activity than BA. This period was longest when freshly excised leaves were used, was reduced when leaves were used after incubation in distilled water in the dark for 20 h and was eliminated by incubation in cytokinin solution in the dark. After this period the activity of zeatin declined relative to BA. The effect of cytokinins in increasing transpiration occurred only in the light; no effect was observed in the dark.BA showed higher activity than zeatin in senescence tests but both cytokinins were less effective as the tests progressed, this decrease in activity being more rapid when older leaves were used.The results are discussed in relation to the mechanisms by which endogenous cytokinins might control sensecence and transpiration in oat leaves and to the value of the oat leaf senscence and transpiration bioassays as tests for cytokinin activity of plant extracts.
Translocation and Metabolism of Injected Maleic Hydrazide in Silver Maple and American Sycamore Seedlings
Authors: DOMIR SUBHASH C. 
Published: April 2006

AbstractStudies were conducted to determine the fate of 14C‐maleic hydrazide injected into the stem xylem of 1‐year‐old silver maple (Acer saccharinum L.) and American sycamore (Platanus occidentalis L.) seedlings. Maleic hydrazide was found to translocate to all parts of the plant within 1 day after treatment. The autoradiographs indicated that the radioactivity was accumulated in meristematic regions of the leaves. A significant amount (over 15% of the applied 14C) was exuded out of the roots into the nutrient solution after 30 days. The 14C in the nutrient solution was in the form of unchanged maleic hydrazide, whereas in plant tissue a metabolite possibly a conjugate with sugar was formed. With the passage of time, the amount of metabolite seemed to increase in proportion to that of maleic hydrazide. Approximately 30% of the applied 14C was unextractable with methanol after 30 days.
Investigation of Effects of Plant Growth Regulators on Liposome Fluidity and Permeability
Authors: PARUPS E. V. , MILLER R. W. 
Published: April 2006

AbstractNaturally occurring plant growth regulators gibberellic acid (GA), indole‐3‐acetic acid (IAA), abscisic acid (ABA), ethylene and other growth regulating compounds such as 5‐methyl‐7‐chloro‐4‐ethoxycarbonylmethoxy‐2,1,3‐benzothiadiazole (TH) and 2,4 dichlorophenoxyacetic acid (2,4‐D), had no effect on the partition behavior of a piperidine based spin label in liposomes composed of pure or mixed phospholipids or a phospholipid‐sterol mixture. Although no effect on fluidity was observed, TH significantly increased the initial rate of swelling of soybean lecithin‐sitosterol liposomes in isotonic glycerol. IAA and ethylene did not influence this rate but ABA, GA and 2,4‐D inhibited the initial rate of swelling. Lipid composition of liposomes determined the extent and direction of the effects on swelling rates. The observed swelling behavior was, therefore, not related to fluidity of the bulk membrane lipids but was due, instead, to modification of the access of glycerol to the phospholipid bilayer surface or, alternatively, to the creation of polar channels into the liposomes.
The Effects of Age, Darkness and Nitrate on Poly‐β‐hydroxybutyrate Levels and Nitrogen‐Fixing Ability of Rhizobium in Lupinus angustifolius
Authors: GERSON T. , PATEL J. J. , WONG M. N. 
Published: April 2006

AbstractThe effects of age, darkness and nitrate on nitrogenase activity, poly‐β‐hydroxybutyrate (PHB) and β‐hydroxybutyrate dehydrogenase (BOHB DH) activity in Rhizobium lupini while in symbiosis with Lupinus angustifolius were assessed. It was concluded that PHB functions as a reserve material in root nodules and is involved in the maintenance of nitrogen fixation when the availability of photosynthates is restricted. PHB accumulation and the development of BOHB‐DH activity did not take place until the peak of nitrogenase activity had passed. All three parameters reached a steady level when the host plant was approximately 24 days old. Deprivation of photosynthates due to continuous darkness resulted in major losses of PHB and BOHB‐DH activity until N2‐fixation ceased. Nitrate addition without restriction of photosynthates resulted in diminished nitrogenase activity. Apart from a slight delay in accumulation. PHB levels were not affected. It was found important to standardize sampling since N2‐fixation was affected by plant culture and diurnal cycles.
Excitation of System I and System II in Photosynthesis as a Possible Control Mechanism of Glycolate Metabolism in the Blue‐Green Alga Anacystis nidulans
Authors: SØRENSEN L. , HOLMEN AA. T. , HALLDAL P. 
Published: April 2006

AbstractPhotosynthetic enhancement studies performed at 619 nm (excitation of Systems I and II) and at 446 nm (mainly excitation of System I) revealed an 18% photosynthetic enhancement simultaneously with a 31% reduction in glycolate excretion. This observation supports the hypothesis that some glycolate may be consumed in an oxidation process associated with System I when System II is poorly excited and the supply of electrons from the water splitting process of photosynthesis is low.
Growth and Composition of Rye Seedlings Cultured in Sea Water
Authors: SIEGEL S. M. , SIEGEL B. Z. 
Published: April 2006

AbstractTwo‐week‐old Balbo rye seedlings cultured in aerated sea water are similar in fresh weight and linear dimensions to plants grown in aerated fresh and brackish waters. No significant differences were found in dry matter, nitrogen, sulfur or phosphorus content but tissue chloride increased markedly. Most of the Cl uptake was retained as chloride, but a small quantity was water insoluble and possibly in organic combination.We suggest that rye is a good prospect for development of lines suitable for sea water agriculture.
The Physiology of Rooting Populus Cuttings
Authors: OKORO O. O. , GRACE J. 
Published: April 2006

AbstractActivity of endogenous cytokinin of cuttings was investigated in relation to the process of rotting. The levels of cytokinin in hardwood cuttings of easy‐to‐root Populus × euramericana (Dode) Guinier and difficult‐to‐root Populus tremula L. were monitored at various stages of root formation. In cuttings of P. tremula was found a higher cytokinin activity than in P. × euramericana and this condition persisted throughout the rooting period. There was a general initial decrease of cytokinin activity in both upper and lower halves of cuttings of both species. The declining level was reversed in the easy‐to‐root species when roots had formed and to a lesser extent in the difficult‐to‐root species when leaves expanded. In both cases this increase was relatively higher in the lower halves than in the upper halves.
Translocation and Metabolism of Leaf Applied Hexachlorophene in Peanuts
Authors: AUKEN OSCAR W. VAN , HULSE MICHAEL 
Published: April 2006

AbstractTranslocation, distribution, metabolism and photolysis of hexachlorophene (HCP) were investigated in peanut plants (Arachis hypogea L., Spanish type) grown under standardized conditions and treated with l4C‐ring‐labeled HCP. Treatment time ranged from 0–114 days. Autoradiographic analyses were performed on all plants. Selected plant tissues were extracted and chromatographed, using both thin layer and gas liquid chromatography.No translocation of HCP was detected in the plant tissue. No HCP metabolites were found. Some HCP was lost from the leaves and inert controls at a specific rate per unit time. The rates were slightly different, being slower on the leaves than on the controls.At the end of the 114‐day treatment and based on regression analysis of thin layer chromatographic plates, an average of 68% of the applied HCP remained unaltered on the treated plants and an average of 77% remained on the controls. This indicated that, respectively, 32 and 23% of the original HCP had been altered. This 9% difference was statistically significant. Upon further analyses of the above data, using gas chromatographic methods, as many as 14 peaks were found in the treated samples and the controls, including some parent material.Ultraviolet photolysis seems to be the mechanism responsible for alteration of the HCP on the treated plants and controls. Two photolysis products have been identified by gas liquid chromatography‐mass spectral analysis. Twelve other electrophylic compounds have been found in various treated plant or control extracts.Further analyses will be necessary to verify the identification and quantification of the other degradation products.
Chemical Control of Ripening in Banana
Authors: DESAI B. B. , DESHPANDE P. B. 
Published: April 2006

AbstractA post‐harvest dip of banana (Musa paradisiaca L.) fruits into the aqueous solutions of abscisic acid and indoleacetic acid significantly hastened the banana ripening, judging from increases in total sugars, acidity, ascorbic acid and units of von Losecke's colour chart during storage at 20°C. The treatment of bananas with gibberellic acid and kinetin, on the contrary, retarded banana ripening as indicated by higher values for firmness, starch, cellulose and hemicellulose. The results obtained suggest that ripening of banana can be controlled chemically.
Photosystem II and Hypoxic Quiescence in Alligatorweed
Authors: QUIMBY P. C. , POTTER J. R. , DUKE S. O. 
Published: April 2006

AbstractStem cuttings of alligatorweed [Alternanthera philoxeroides (Mart.) Griseb.] were subjected to various light and chemical inhibitor treatments to obtain information about the physiological nature of the hypoxic quiescence induced by dark submergence. White or red light at 40 μE m−2 s−1 stimulated growth from submerged stem cuttings but far‐red at 5 μE M−2 s−1 did not. Photo‐system II inhibitors, such as 3‐(3,4‐dichlorophenyl) 1,1‐dimethylurea (DCMU) at 1.4 × 10−5M or 2‐chloro‐4,6‐bis(ethylamino)‐s‐triazine (simazine) at 10−5M, completely inhibited the growth that normally occurs in a submerged state under continuous white light at 40 μE m−2 s−1. These concentrations of DCMU or simazine did not reduce nonphotosynthetic growth from underwater nodes of emersed stem cuttings partially exposed to air in the light for 1 week. Hydrogen peroxide at 50 mg/1 added every other day partially relieved the simazine‐induced inhibition of growth from submerged, illuminated cuttings. These data indicated that sprouting and early growth of submerged, illuminated alligatorweed depended on the oxygen produced by photosystem II to support respiration and to overcome hypoxic quiescence.
Separation of Two Forms of Anthranilate Synthetase from 5‐Methyltryptophar Susceptible and ‐Resistant Cultured Solarium tuberosumCells
Authors: CARLSON JOHN E. , WIDHOLM J. M. 
Published: April 2006

AbstractPotato cell suspension cultures (Solanum tuberosumL. cv. Merrimack) have been selected which are resistant to growth inhibition by D,L‐5‐methyltryptophan. Anthranilate synthetase activity in crude extracts from resistant cells was less sensitive to feedback inhibition by L‐tryptophan and D,L‐5‐methyltryptophan than the activity from the sensitive line. This altered feedback control apparently accounts for the cell's resistance to growth inhibition since there is a 48‐fold increase in free tryptophan in one of the resistant cell lines. Preparative polyacrylamide gel electro‐phoresis separated feedback‐sensitive and ‐resistant forms of anthranilate synthetase in extracts from both 5‐methyltryptophan‐susceptible and ‐resistant cells, with a predominance of the corresponding form in the respective cell type. The anthranilate synthetase activity from the 5‐methyltryptophan‐resistant line was inactivated more slowly by incubation of crude extracts at 50°C than the activity from the sensitive line. These results suggest the presence of two isoenzymes of anthranilate synthetase in cultured potato cells.
Factors Affecting Ethanol Induced Luminescence in Dark‐Treated Chloroplasts
Authors: SIGFRIDSSON BJÖRN 
Published: April 2006

AbstractsDark‐treated chloroplasts emit light when treated with a high ethanol concentration. The ethanol treatment causes chlorophyll solvation. The light is red and emanates from a singlet excited molecule, probably a chlorophyll peroxide. It is quenched by acetone, sodium dodecyl sulfate treatment of the chloroplasts before the addition of ethanol, boiling, reducing substances and low pH. It is enhanced by ferricyanide and high pH. This is interpreted as a requirement for an organized structure and for an energy transfer system for light emission to occur.
Seasonal Changes in Water Potential and Turgor Maintenance in Sorghum and Maize under Water Stress
Authors: FERERES E. , ACEVEDO E. , HENDERSON D. W. , HSIAO T. C. 
Published: April 2006

AbstractLeaf water (Ψ) and solute (ψ) potential were measured in field sorghum and maize under well irrigated (I) and dryland (NI) conditions throughout a season. Despite decreases in ψ due to slow soil water depletion and to apparent increases in liquid phase plant resistance, midday leaf turgor (ψp) in the NI sorghum was maintained at similar levels as in the I treatment throughout the season due to concomitant decreases in ψs. Osmotic adjustment was also observed in maize, although ψp was significantly lower in the NI treatment as compared to I during the final stages of grain filling. A seasonal shift in the ψ vs. relative water content relation of NI sorghum leaves was observed, more water being retained by the older leaf at any particular ψ. The major factor for turgor maintenance was a net increase in solutes per unit of tissue. The role played by increases in the proportion of tissue volume occupied by cell wall was also evaluated. No stomatal closure due to water stress was found in NI sorghum even though leaf ψ reached —20 bars late in the season. Under similar conditions, stomata closed at —14 to —16 bars in younger plants where water stress was made to develop much faster.
Somatic Hybridization of Nitrate Reductase Deficient Mutants of Nicotiana tabacum by Protoplast Fusion
Authors: GLIMELIUS KRISTINA , ERIKSSON TAGE , GRAFE REINHARD , MÜLLER ANDREAS J. 
Published: April 2006

AbstractProtoplasts were isolated from two mutant cell lines of Nicotiana tabacum L. cv. Gatersleben and fused with the aid of polyethylene glycol. Both mutants lacked nitrate reductase and were thus auxotrophic for reduced nitrogen. The fusion resulted in a high frequency of hybrid cells which were detected by their regained ability to grow in media containing nitrate as sole nitrogen source. Thus, the two mutants were found to complement each other in the hybrids. In control experiments, back mutation and cross‐feeding were excluded as possible explanations for the occurrence of cell lines utilizing nitrate. A total of 1061 hybrid lines capable of sustained proliferation were isolated. Some of them were further characterized with respect to nitrate reductase activity, chlorate sensitivity, chromosome number, and shoot formation.The results demonstrate that protoplast fusion can be used for the genetic analysis of cell variants of higher plants and that nitrate reductase‐deficient mutants provide efficient selective systems for hybrid cells.
Induction of Adventitious Buds on Embryos of Norway Spruce Grown in vitro
Authors: ARNOLD SARA VON , ERIKSSON TAGE 
Published: April 2006

AbstractAdventitious buds were induced when isolated embryos of Norway spruce (Picea abies L.) were cultured on a defined medium containing 2iP. Anatomically different bud primordia were formed at high and low cytoldnin concentrations. The highest percentage of embryos forming bud primordia was obtained after 4–5 weeks on 2iP medium. Buds developed after transfer of the induced embryos to medium without growth regulators. Many of the buds developed into elongated shoots. No root primordia were observed in any of the induced embryos.
High Performance Liquid Chromatographic Analysis of Cytokinins in Sorghum bicolor Leaves
Authors: KANNANGARA T. , DURLEY R. C. , SIMPSON G. M. 
Published: April 2006

AbstractHigh performance liquid chromatography with octadecylsilica (Bondapak C18/Poracil B) column packing was used to purify and separate cytokinins in Sorghum leaf extracts. The column size was 56 × 0.21 cm i.d. By gradient elution, using acidified water with increasing amounts of methanol, the major peaks of cytokinin activity, as determined by the callus tissue bioassay. were effectively separated from large amounts of extraneous impurities. These cytokinins were further separated on a microoctadecylsilica column (μBondapak C18, 30 × 0.4 cm i.d.) with a gradient of acidified water‐acetonitrile. Zeatin and zeatin riboside gave distinct ultra violet absorption peaks which could be used for quantitative estimation. Biological activity corresponded to the elution of these peaks. These two cytokinins are the major cytokinins in Sorghum leaves.
Effects of Season and Low Temperature on Polypeptides from Thylakoids Isolated from Chloroplasts of Pinus silvestris
Authors: ÖQUIST GUNNAR , MARTIN BJÖRN , MÅRTENSSON OLLE , CHRISTERSSON LARS , MALMBERG GUNILLA 
Published: April 2006

AbstractThylakoids isolated from pine chloroplasts were solubilized by sodium dodecyl sulphate and the polypeptides were separated by polyacrylamide gel electrophoresis. The chlorophyll‐protein complexes, P700‐CPa1 and LH‐CPa/b, had apparent molecular weights of 92,000 and 25,000, respectively. When the chlorophyll of P700‐CPa1 was extracted or photobleached, the apoprotein of P700‐CPa1 appeared as a pronounced peak in the polypeptide scan profile. The molecular weight of the apoprotein was 70,000. During autumn and winter the complex P700‐CPa1 was destroyed. This was primarily caused by bleaching of chlorophyll, as the 70,000 apoprotein increased in the scan profile when the complex P700‐CPa1 decreased. The winter destruction of P700‐CPa1 was less pronounced in old needles than in young. Freezing of frost‐hardened seedlings did not change the polypeptide scan profile, unless the temperature was lowered below the frost‐killing point followed by thawing and post‐treatment in light or darkness above 0°C. Again the main destruction occurred in the P700‐CPa1 complex, but in this case no significant increase of the apoprotein was observed. These alterations in the polypeptide scan profile of frost‐killed needles were not caused by the low temperature treatment as such, but they occurred after thawing of the needles.
The Effect of Dew on Plant Water Balance in Citrullus vulgaris and Cucumis melo
Authors: WENT FRITS W. , BABU V. RAMESH 
Published: April 2006

AbstractA temperature gradient air‐leaf can be created purely by radiation loss with a sky‐radiator. Loss of radiation from leaf to an artificial sky causes water vapor condensation from a saturated atmosphere as dew on the leaves of plants. The condensed water was found to be taken up by the leaves of melon (Cucumis melo) and water melon (Citrullus vulgaris) bringing about a favorable water balance by reduction in the water saturation deficit and by increase of the water potential. In a number of individual experiments with matched plants a minimum 31% and maximum 117% increase of leaf fresh weight due to uptake of condensed water was noted.
Free and Bound Gibberellin Activities and Ent‐kaurene Synthesis during Induction of Cold Hardiness in Black Locust Seedlings
Authors: NOWAK JOANNA , BROWN GREGORY N. 
Published: April 2006

AbstractThe role of gibberellin in the development of cold hardiness in black locust (Robinia pseudoacacia L.) seedlings was investigated. Free and bound gibberellin activities were followed during induction of cold hardiness using ethyl acetate partitioning and pH variation, with subsequent paper chromatographic fractionation and gibberellin bioassay. While total gibberellin activity decreased during the induction of cold hardiness in black locust seedlings, no convincing evidence was found to support conversion of free gibberellin to a bound form. However, bound gibberellin activity did appear to be more stable than did free gibberellin activity during the final stages of cold hardening at freezing temperatures. Gibberellin synthesis was followed using 14C‐mevalonate conversion to ent‐kaurene in a cell‐free extract of the tissue. Ent‐kaurene synthesis decreased during cold hardening with no detectable synthesis in fully hardened seedlings. However, since growth cessation precedes development of cold hardiness, decreased gibberellin synthesis and corresponding trends in free and bound fractions might have been expected, and a cause and effect relationship is difficult to establish. Even so, a decline in one step in gibberellin synthesis and a greater stability of bound than free gibberelin activity are associated with induction of cold hardiness in black locust seedlings.