bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes of Some Mitochondrial Enzyme Activities of Cucumber Leaves during Ammonium Toxicity
Authors: MATSUMOTO H. , WAKIUCHI N. , TAKAHASHI E. 
Published: April 2006

AbstractThe following enzyme activities were determined in the mitochondria of cucumber leaves (Cucumis sativus L. cv. Suisei No. 2) during ammonium toxicity: malate dehydrogenase, succinate dehydrogenase, glutamate dehydrogenase, cytochrome c oxidase, NADH diaphorase, NADH oxidase, succinate: cytochrome c oxidoreductase, NADH: cytochrome c oxidoreductase and adenosine triphosphatase. The activities of all enzymes except ATPase increased more or less during ammonium toxicity. Generally speaking the marked increase was found at 7 days treatment with 200 mg/1 NH3‐N. The adenosine triphosphatase activity of injured plants was lower than that of normal plants through treatment. The addition of various organic acids (15 mM) to the culture solution contaning 200 mg/1 NH3‐N (14.3 mM NH4Cl) suppressed the ammonium toxicity.The accumulation of free ammonia in the leaves was also repressed by the addition of organic acids. The results of present and previous reports suggest that the increase of respiratory metabolism due to ammonium toxicity is required for the supply of organic acids, specially δ‐ketoglutaric acid, to counteract ammonia. Uncoupling in mitochondria resulting in the increase of respiration does not seem to occur during ammonium toxicity.
The Influence of Temperature on Nitrate Reductase Activity of Agrostis palustris and Cynodon dactylon
Authors: KAUFMANN JOHN E. , BEARD JAMES B. , PENNER DONALD 
Published: April 2006

AbstractThe influence of temperature was studied in relation to nitrate reductase activity of creeping bentgrass (Agrostis palustris Huds. cv. ‘Toronto’) a cool season grass and bermudagrass (Cynodon dactylon L. cv. ‘Tifgreen’) a warm season grass. Maximum nitrate reductase activity of both species occurred at 20°C. The nitrate reductase level in bentgrass leaves was reduced when grown at 35°C while bermudagrass leaves were relatively unaffected. The activity per se of the bentgrass enzyme preparation was inhibited rather than synthesis of the enzyme.
Effect of Mineral Deficiencies and Other Co‐factors on the Aldolase Enzyme Activity of Citrus Leaves
Authors: BAR‐AKIVA A. , SAGIV J. , HASDAI D. 
Published: April 2006

AbstractCa and S deficiencies cause a strong, N, P and Mg deficiencies a slight, and K deficiency an intermediate decrease in the aldolase activity of Eureka lemon leaves. Fe and Zn deficiencies result in a moderate decrease in the activity.Cysteine increases the enzyme activity (approximately 30 %). Opposed to with yeast aldolase, EDTA inhibits the enzyme activity only moderately in control (full nutrient) lemon leaves nor does Zn EDTA restore it. Gel electrophoresis of yeast and lemon leaves' aldolase isoenzymes also exhibited different patterns.Dialysis studies and other reactivation experiments with different ions failed to establish specific metal requirements of the aldolase in the lemon leaves. However, infiltration of Zn into Zn‐deficient detached and intact citrus leaves brought about a partial restoration of the enzyme activity.In view of these results, the relationship between the citrus leaf enzyme and the varying types of aldolase enzymes is discussed.
Phloem Translocation of Storage Nitrogen in Apple
Authors: TROMP J. , OVAA J. C. 
Published: April 2006

AbstractMobilization of nitrogenous compounds during the spring was studied in ringed isolated shoot sections (bearing one intact bud each) from Golden Delicious apple trees and in intact stem‐ringed apple rootstocks M VII. The changes in total, protein and soluble nitrogen and soluble amino acids and amides were followed in the bark of the shoot sections for 3 weeks during leafing‐out and in the shoot and stem bark of the rootstocks for 6 weeks starting at bud‐break.Ringing prevented nitrogen movement from below the ring both in the shoot sections and in the rootstocks almost completely, thus demonstrating the importance of the phloem as translocation pathway for stored nitrogenous compounds, even over longer distances.Asparagine and arginine were the major soluble amino compounds throughout. The values of the asparagine/arginine quotient in the various tissues suggest that when the distance between points of nitrogen supply and demand is short asparagine is translocated preferentially, but that at increasing distance this preference shifts to arginine.
Physiological Variation in Strains of Aphanomyces astaci
Authors: UNESTAM T. , SVENSSON E. 
Published: April 2006

AbstractPhysiological variation was found both between and within strains of the crayfish plague fungus, Aphanomyces astaci, in culture.The loss of capacity to produce spores was irreversible while losses of motility and virulence to the crayfish were reversible changes. From the tests with motility it was concluded that mutations of hidden or de novo type readily appear in the phenotype of this fungus which belongs to a taxonomic group that is considered genetically very conservative.The authors gratefully acknowledge the assistance of Mrs. Anita Grandin. This research was supported by grants from the Swedish Natural Science Research Council and the Fishery Board of Sweden.
Quantitative Relationship between Various Growth Substances and Bud Production in Funaria hygrometrica. A bioassay for abscisic acid
Authors: VALADON L. R. G. , MUMMERY ROSEMARY S. 
Published: April 2006

AbstractEleven growth substances were tested for their bud producing capacity in Funaria hygrometrica. IAA and gibberellic acid showed no response, neither did inositol, abscisic acid and adenine. The cytokinins: benzylaminopurine, kinetin and mercaptopurine showed a quantitative relationship while methylaminopurine did not. When different amounts of abscisic acid were added together with 10 μg kinetin (which gave maximal production of buds), there existed a linear relationship between reduction in buds and abscisic acid added. Results are obtained in two weeks and it is therefore a fairly quick method for assaying certain cytokinin and also abscisic acid.
Induced Production of a Sexual Hormone in Yeast
Authors: YANAGISHIMA N. 
Published: April 2006

AbstractWe have already described that α hormone excreted by α type cells expands cells of α type specifically and α hormone excreted by α type cells expands α type cells in Saccharomyces terevisiae. Both substances are steroidal compounds. In the present experiment the third hormonal substance has been found. a Hormone induced excretion of a methylene chloride‐insoluble substance which expands a type cells specifically, when added to a type cells. Testosterone showed the same type of action as that of a hormone. On the other hand, a hormone did not show an action to induce excretion of methylene chloride‐insoluble hormonal substance, when added to a type cells. Relation among three hormonal substances described above seems to be important to make clear the mating process of the yeast.
Retarded Stomatal Closure by Phenylmercuric Acetate
Authors: DAVENPORT D. C. , FISHER M. A. , HAGAN R. M. 
Published: April 2006

AbstractExcised leaves of Nerium oleander, which were treated with phenylmercuric acetate (PMA) 11/2 h before excising, transpired faster than untreated excised leaves. Similarly, PMA‐treated oleander plants transpired more than untreated plants in the dark. These effects were due to retarded stomatal closure caused by PMA. Measurements of stomatal apertures on disks of Vicia faba leaves kept in the dark, and of diffusive resistance to water vapor from Phaseolus vulgaris leaves, confirmed that PMA retards stomatal closing as well as stomatal opening. However, day‐time reductions in transpiration by PMA greatly exceed night‐time increases in water loss. The mechanisms of stomatal movement, as affected by PMA, are discussed. PMA may conceivably decrease the permeability of guard cell membranes to solutes, thereby retarding all stomatal movements that are osmotically induced.
Investigations on Cytokinins. III. Cytokinin Activity in Lemna minor tRNA Hydrolysates
Authors: BEZEMER‐SYBRANDY SYTSKE M. , VELDSTRA H. 
Published: April 2006

AbstracttRNA was extracted from Lemna minor, grown on a cytokinin free medium. Alkaline hydrolysates of the tRNA were active in three cytokinin bioassays: mobilization test, tissue culture and growth of Lemna cultures. Some observations on the growth of Lemna as a bioassay for cytokinins, are given.
The Effect of Coumarin on Root Growth and Root Histology
Authors: SVENSSON SVEN‐BÖRJE 
Published: April 2006

AbstractThe effect of coumarin on the root growth was studied on roots from intact plants, isolated roots and isolated elongating zones. All material was cultivated aseptically. A new method was developed for sterile culture of intact plants in flowing nutrient medium.The effects on cell division and cell elongation were studied separately. An effect on both these processes can be established at all concentrations that affect the root growth. The concentration‐growth curve has an “all‐or‐none” appearance.Coumarin inhibits the transverse divisions in all cell layers; the perivascular layers seem to be more sensitive. Also the mitotic activity that is involved in the initiation of laterals is inhibited. The longitudinal divisions within the stele are enhanced.Coumarin decreases the cell length in all cell layers, most likely with greater relative sensitivity in the perivascular layers. Studies on the time course of cell elongation in both attached corn roots and isolated elongating zones reveal that the decrease in cell length is caused exclusively by a decrease in the maximal rate of elongation, whereas the duration of the elongation is unchanged.With each decrease of the cell length, the cell diameter is increased. The two changes are intimately connected within the greater part of the active region of concentration. Studies on the time course of the radial expansion in isolated elongating zones show a strict connection in time between cell elongation and radial expansion.The radial expansion leads to unchanged or increased cell volume at most concentrations and for most cell types.Coumarin causes an inhibition of the longitudinally directed processes and a stimulation of the radially directed ones. This is interpreted as indicating that the formative system is disengaged or reorientated, i.e., the polarity of the cells is changed.Through experiments partly with isolated elongating zones and partly by disruption of the linear phase by means of mannitol, the inhibitory effect of coumarin could be localized to the first non‐linear phase of the elongation.The results were compared with earlier findings in the literature. The microtubuli are proposed as a conceivable main Component in the formative system common to both cell division and cell elongation. These are assumed to be affected by changes in the SH/SS balance produced by coumarin.
Endogenous Gibberellins in Floating Plants and Turions of Wolffiella floridana
Authors: PIETERSE ARNOLD H. , BHALLA PRITHVI R. , SABHARWAL PRITAM S. 
Published: April 2006

AbstractEndogenous gibberellins from floating plants and in vitro induced turions of Wolffiella floridana (Lemnaceae) were extracted and partially purified. Gibberellin‐like activity was detected in two zones of the chromatogram corresponding to Rf 0‐0.1 and Rf 0.4‐0.5 by dwarf pea bioassay. The active compounds in the two zones have been referred to in this paper as factor I and factor II respectively. There were quantitative differences in the gibberellin‐like substances of floating plants and turions. The floating plants contained more of factor I but less of factor II as compared to the turions. The chromatographic behavior of factor I was similar to either gibberellin A1 and A3 while the identity of factor II was uncertain.
Evergreen Foliage Contributions to the Spring Growth of Taxus
Authors: SPLITTSTOESSER WALTER E. , MEYER MARTIN M. 
Published: April 2006

Abstract Taxus media cv. Hicksii plants were grown one season under a low and high level of nitrogen fertilization. Before growth in the spring the plants were divided into two groups, one of which was defoliated and the other left intact. The growth and spring utilization of the nitrogen and carbohydrate reserves of defoliated plants were compared to the intact plants 0, 2, 4 and 6 weeks after growth started in the spring. The plants were separated into buds (all new growth), roots and stems and analyzed for changes in total nitrogen, basic and non‐basic amino acids, hemicelluloses, soluble sugars, organic acids and chlorophyll.The older evergreen needles from plants grown under low nitrogen levels contain 20 % of the carbohydrate and 24% of the nitrogen used in spring growth. The needles from plants grown under high nitrogen levels contained 56% of the carbohydrate and 49% of the nitrogen used in spring growth. Removal of the old needles before spring growth removed this nitrogen and carbohydrate reserve and reduced the total plant chlorophyll content after 6 weeks of growth to 50% of that found in intact plants, with the result that defoliated plants did not show a growth response to nitrogen. Amino acids accumulated in the stems and buds of defoliated plants as carbohydrates became limiting. The defoliated plants removed 25% more available carbohydrates from the roots and stems than intact plants and their buds contained 50% less available carbohydrates.Plants without old needles showed similar growth rates under low and high nitrogen regimes and produced 33% of the dry weight of intact plants grown under high nitrogen levels and 66% of the dry weight of intact plants grown under low nitrogen levels.The old needles of taxus plants contain substantial amounts of reserve nitrogen and carbohydrate and these needles greatly influence the extent and rapidness of growth in the spring. When the needles are removed, the other tissues can supply an adequate amount of nitrogen but the carbohydrate supply becomes limiting for spring growth.
The Effect of 6‐Benzylaminopurine on the Starch Metabolism of Stellaria media
Authors: HÄGGMAN JUHANI , HAAPALA HEIKKI 
Published: April 2006

AbstractThe effect of 6‐benzylaminopurine (BAP) was studied by measuring the amylase activity of leaf extracts and the starch content of chloroplasts in Stellaria media‐plants cultivated for five days in solutions containing different quantities of BAP.Small amounts of BAP decreased amylase activity in weak‐growing plants. In strong‐growing ones the effect was variable. However, in all experiments very high amount of this growth regulator caused a great increase in amylase activity which was accompanied by a relatively high concentration of starch in the chloroplasts. The induction of amylase activity was thus not high enough to diminish the starch content. This is supposed to be due to the lack of a sink organ since the growth of roots and shoots was greatly inhibited in concentrated BAP‐solutions (10‐5M or more). In these cases the plants usually died during the first week.In some cases small amounts of BAP increased the growth of S. media, and high concentrations inhibited it causing characteristic morphological changes, such as creeping growth pattern, small, thick leaves and the turning up of the leaf margins.Benzylaminopurine also caused increased resistance to aging, especially in low concentrations (10–7–10–6M).
Der Glucosestoffwechsel dereprimierten pflanzlichen Speicherparenchyms nach Hemmung der Mitoseaktivitat durch Tris‐ (hydroxymethyl‐) aminomethane
Authors: LANGE HORST , KAHL GÜNTER , ROSENSTOCK GÜNTER 
Published: April 2006

AbstractThe transition from resting to mitotically active potato tissue (excised disks) is accompanied by and virtually dependent on transcription, translation and increased metabolic activity. Thus enhanced RNA‐ and protein‐syntheses are well known features of potato tuber slices, allowing the cells to raise the level of several metabolic pathways (i.e., starch breakdown, pentose phosphate shunt, glycolysis, respiration and others) and ultimately leading to mitotic activity. Mitosis can be totally, yet reversibly suppressed by incubation of the tissue fragments in Tris (hydroxymethyl)‐aminomethane buffer. Neither total respiration nor its sensitivity to several inhibitors is affected during blockage of mitosis. Fluctuations in the levels of glucose‐6‐phosphate, fructose‐6‐phosphatc, phospho‐enolpyruvate and pyruvate are exactly the same in Tris‐inhibited as in non‐inhibited cells. Thus the Tris ion is not modifying glucose catabolism. The same is true for the time‐course of activity of hexokinase, glucose‐6‐phosphate‐ and 6‐phosphogluconate dehydrogenase, glucosephosphate isomerase, triosephosphate isomerase, enolase, phosphoglyceromutase and “malic enzyme”. Although the rapid decrease in activity of phosphoglucomutase, aldolase, pyruvate kinase and glutamic‐pyruvic transaminase after slicing (characteristic for non‐inhibited cells) does not occur in Tris‐treated tissue, these small differences are not thought to be causative in inhibition of mitosis.The results indicate, that nucleic acid metabolism is more likely the target of the Tris‐ion.
Effects of Freeze‐Drying on Permeability and Respiration of Germinating Lily Pollen
Authors: DAVIES MICHAEL D. , DICKINSON DAVID B. 
Published: April 2006

AbstractThe germination of lily pollen (Lilium longiflorum cv. Ace) was impaired by freeze‐drying. This loss of viability was associated with a modified pattern of respiration and an increased leakage of soluble carbohydrates, phosphate, and ninhydrin‐positive material into the culture medium. 2,4‐Dinitro‐phenol, (DNP), an uncoupler of oxidative phosphorylation showed a decreased ability to stimulate O2 uptake in freeze‐dried pollen. The altered viability, respiration, and permeability resulted from drying under vacuum and not the initial freezing of the pollen. Mature lily pollen contained approximately 0.3 “Ai phosphate, of which 15 % was inorganic phosphate and about 50 %> was acid soluble organic phosphate of unknown identity.
Relationships of Histones to RNA Synthesis in Plant Tissues
Authors: SRIVASTAVA B. I. SAHAI 
Published: April 2006

AbstractThe RNA‐synthesizing activity of the tissue, template activity of the chromatin, histones and other parameters were analyzed for young leaves, senescent leaves and the pith tissue of tobacco. The amount, of RNA, DNA and the extent of incorporation of 32P into RNA was much lower in old leaves and the pith tissue than in young leaves. Furthermore, the 32P sucrose density gradient patterns of RNA from the three tissues were very different. In old leaves, the label was found mostly in low molecular weight RNA region, presumably as a result of degradation of RNA by soluble and chromatin‐associated ribonucleases which were higher in old leaves. — In addition to significant differences in the composition of chromatin, large differences in the ratios of FI : FII : FIII : : histone fractions from the three tissues were noted and the fully differentiated old leaves and the pith tissue had proportionately more FIIand FIII histones than the less differentiated young leaves. The FIII histone of tobacco differed from that of pea and calf thymus in having lys/arg = 1.2. — Although some correlation between RNA‐synthesizing activity of the tissue, template activity of chromatin and the histone composition was noted for the pith tissue and the young leaves, the situation with old leaves was more complicated, probably due to the occurrence of chromatin‐associated deoxyribonuclease and involvement of other factors which may also effect RNA synthesis.
Role of Cell Wall‐degrading Enzymes in Auxin‐induced Cell Expansion in Yeast
Authors: SHIMODA CHIKASHI , YANAGISHIMA NAOHIKO 
Published: April 2006

AbstractUsing auxin‐responsive diploid strains of Saccharomyces cerevisiae and S. ellipsoideus, we studied the role of cell wall‐degrading enzymes in the auxin‐induced cell expansion. Highly purified fungal β‐l,3‐glucanase added to cell suspension caused cell expansion in these strains. The cell expansion induced by auxin was inhibited by the addition of õ‐glucono‐lactone, which inhibited the activity of a crude β‐l,3‐gluca‐nase preparation from yeast in a competitive manner. Laminarinase activity was significantly higher in the extract from auxin‐treated yeast cells than in the extract of cells not treated with auxin. These results support the idea that auxin induces expansion of yeast cells of certain strains through enhancement of the activity of wall polysaccharide‐degrading enzymes.
Imbibition Influenced by Hydrostatic Pressure
Authors: STREBEYKO PIOTR , RUFELT HENRY 
Published: April 2006

AbstractPea seeds were soaked in distilled water or in saturated D‐mannitol solution either under normal or under high external pressures (10‐30 atms.) for approximately 24 hours. Imbibition in distilled water was independent of the hydrostatic pressure. However, imbibition in D‐mannitol solution was enhanced by the pressure. It was concluded that hydrostatic pressure caused by turgor could enhance imbibition of the protoplast. Under high turgor, the protoplast may swell even at a high osmotic potential. Turgor seems to be of importance for the physiological activity of the plant cell.
Acid Phosphatases in Germinating Lettuce — Evidence for Partial Activation
Authors: MEYER HANNA , MAYER A. M. , HAREL E. 
Published: April 2006

AbstractAt least nine acid phosphatases and a distinct phytase are present in different cell fractions of germinating lettuce. The enzymes could be partially characterised using acrylamide gel electrophoresis. Phosphatase formation is only partially inhibited by cycloheximide. A new soluble ATPase arises between 24 and 48 hours of germination. Its formation is not inhibited by cycloheximide. Phosphatase activity in the particulate fraction of the cell can be liberated and activated by detergent or trypsin treatment. It is suggested that the newly formed soluble ATPase arises by release and activation of a particulate phosphatase.
The Appearance and Development of Photosynthetic Activity in Etiolated Barley Leaves and Isolated Etio‐chloroplasts
Authors: EGNÉUS HANS , REFTEL SVEN , SELLDÉN GUN 
Published: April 2006

AbstractThe appearance and development of the oxygen exchanging capacity of greening barley leaves were measured using a manometric technique and an oxygen race electrode. An oxygen evolution could first be detected after one hour of greening. During the first hour of greening a light‐dependent oxygen uptake was observed. The oxygen evolving capacity, calculated on a chlorophyll weight basis, showed a fast rise in activity during the first hours of greening. A maximal activity was reached after 5 to 10 hours of greening; the oxygen evolution then declined.Using oxygen electrodes different aspects of the electron transport in etio‐chloroplasts prepared from the greening barley leaves were also investigated. The activity in photosystem I and II, as well as the cooperation between the two photosystems, were studied by measuring the oxygen exchange from the etio‐chloroplasts in the absence and presence of added oxidants and reductants. An activity in photosystem I could be detected already after 5 minutes of greening. The activity of photosystem I, when calculated on a chlorophyll basis, had the same appearance as the oxygen evolution from the intact plant material. An activity in photosystem II and a cooperation between the two photosystems were first detected after 3 hours of greening. After about 15 hours of greening a cooperation corresponding to that from chloroplasts prepared from normal green leaves was observed.