bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution and Isoenzymes of Aspartate Aminotrans‐f erase in Cotyledons of Germinating Pumpkins
Authors: Splittstoesser Walter E. , Stewart Sheryl A.
Published: April 2006

During germination a steady decline in the reserve protein occurred in dark grown pumpkin cotyledons. By 9 days, 80% of this nitrogen reserve was hydrolyzed but only 50 % was removed from the cotyledons. The remaining nitrogen (30 %) was incorporated into water soluble protein which reached a maximum 9 days after germination. The increase in water soluble protein in pumpkin cotyledons parallel the increase in soluble and particulate aspartate aminotransferase (E.C.2.6.1.1.), suggesting that this enzyme is involved in nitrogen metabolism during germination. Little enzyme activity was found in pumpkin tissues other than the cotyledons.

Four anodally moving isoenzymes were found in the soluble aspartate aminotrans‐ferase fraction and 3 anodally moving isoenzymes were found in the particulate fraction. The slowest moving isoenzymes disappeared first during germination.
Influence of 2‐Chloroethylphosphonic Acid on Anthocyanin Formation, Size, and Yield in Vaccinium macrocarpon cv. Early Black
Authors: Devlin Robert M. , Demoranville I. E.
Published: April 2006

The influence of 2‐chloroethylphosphonic acid (CEPA) on yield, size and pigmentation of cranberries (Vaccinium macrocarpon cv. Early Black) was investigated. Applications of CEPA at 100, 500, and 1000 mg/1 to cranberry vines before bloom and during peak bloom have an adverse effect on yield and size. CEPA applied at these times has litlle influence on color. Applications of CEPA two weeks before harvest significantly accelerates pigment development, peak effect being observed when the vines are treated with 500 mg/1. Size and yield are not noticeably influenced at this time. The possible use of CEPA in the commercial production of cranberries to stimulate color development is considered.
Effect of α‐Naphthalene‐ and α‐Naphthoxyacetic Acid on the Activity of Certain Enzymes of Atropa belladonna cv. lutea Cells in Suspension Culture
Authors: SIMOLA LIISA KAARINA , SOPANEN TUOMAS
Published: April 2006

The growth of Atropa belladonna cv. lutea Döll cells and the activities of several enzymes were studied as a function of time in suspension cultures without added auxin, with α‐naphthaleneacedc acid (NAA) and with α‐naphthoxyacetic acid (NOA). The growth curves were rather similar and therefore easy to compare. The enzyme activities (per mg dry weight of culture) were distinctly higher in cultures grown with NAA than in the other two treatments, in which root formation was common. In some cases the enzyme activities were lower in cultures with NOA than in the control series but usually the curves were quite parallel. Promotion of enzyme activities by NAA (aldolase, aminopeptidase, gluta‐mate: oxaloacetate transaminase) was clearest in the beginning of the phase of rapid cell division (6‐day‐old culture). These three enzymes reach their maxima at this stage of growth in the other series as well. Ribonuclease activity increased in the stationary phase cells (13 and 19 days) with NAA but with the other treatments the level of this activity was relatively stable. Peroxidase and phosphatase did not show any characteristic maxima, glutamate: pyruvate transaminase activity was low and no amylase activity could be demonstrated. The results indicate that synthetic plant growth substances can regulate the physiological state of a tissue by causing alterations in enzyme activities, but their action is clearly specific.
Seasonal Variations in the Occurrence of Indole‐3‐Acetic‐Acid in Buds of Pinus silvestris
Authors: ALDEN TORSTEN
Published: April 2006

Studies with a fluorescence spectrophotometer and gas chromatography confirm earlier results that IAA occurs in buds and sprouting shoots of Scots pine. IAA could be found during the whole vegetation period but not during winter dormancy. The largest amount was obtained during shoot growth in spring and early summer. During the most intensive elongation phase, a gradient could be found in the concentration of auxin with the highest amount in the basal part and a decreasing concentration upwards in the shoot.
Extracellular Lytic Enzymes of Myxococcus virescens
Authors: HASKA GUNO
Published: April 2006

The aim of the investigation was to obtain large amounts of the bacteriolytic enzymes of Myxococcus virescens and to separate these enzymes from the non‐bactcriolytic protemases produced by this organism.

The bacteria were grown in Casitone broth. When the bacteriolytic activity had reached its maximal value, the cells were removed from the culture medium by centrifugation. Polyethylene glycol 4000 (20 g/1) and potassium phosphate (about 210 g/1) were added to the cell‐free solution. The additions resulted in the formation of two liquid phases. The bottom layer was removed, and polyethylene glycol was added to it at a final concentration of 10 g/1. Again two liquid phases formed. The two top phases thus obtained were pooled and 1.6 volumes of cold acetone were added to the mixture. The precipitate formed was dissolved in water and desalted on a Sephadex G‐25 column. The desalted protein solution was applied to a carboxymethyl‐cellulose column equilibrated with 0.025 M sodium phosphate buffer of pH 6.0. Most of the proteins and the proteinases but none of the bacteriolytic enzymes passed the column unadsorbed. The column was washed with 0.05 M glycine‐NaOH buffer of pH 8.8, whereupon the adsorbed bacteriolytic enzymes together with small amounts of proteinases and other proteins were eluted with 0.2 M ammonium carbonate.

The material not adsorbed on the CM‐cellulose column contained 22 % of the proteolytic activity of the initial cell‐free solution and had a 26‐fold higher specific activity. The enzyme solution eluted with carbonate contained 24 and 0.3 %, respectively, of the initial bacteriolytic and proteolytic activities. The specific activity of the bacteriolytic enzyme system was about 5000‐fold higher than that of the original solution.
Subcellular Organization of Developing Embryos of Bidens cernua
Authors: SIMOLA LIISA KAARINA
Published: April 2006

Anatomical and submicroscopical changes in the cotyledons and radicles of Bidens cernua L. have been studied at five developmental stages. In the subcellular structure, these two plant organs are relatively similar but each developmental stage is characterized by a distinct fine structure. Protein bodies, which occupy the bulk of the cell in dormant embryos, develop as filling products of vacuoles. Ribosomes are seen abundantly at this stage, both in the nucleus and the plasma strands. Small vesicles which are the initials of globoids can be detected in the vacuoles even of rather young cells. They later associate at the periphery of protein masses secreted in the vacuoles. Many light globoids are seen in the protein bodies of mature cells. Some amyloplasts are present in the early developmental stages but not in the dormant cells. The endoplasmic reticulum becomes filled with osmiophilic storage fat, and later many spherosomes are seen between the protein bodies. Some osmiophilic material is also found in the intercellular spaces.
Growth Regulators in Populus tremula
Authors: ELIASSON LENNART
Published: April 2006

The seasonal variation in capacity to form suckers and in auxin level in bark and wood was determined in root segments of aspen (Populus tremula L.). Auxin occurred in the roots from May to October but not in November. The highest auxin level was found during the period of shoot growth. During this period the capacity of root segments to form suckers was low. Auxin level decreased in isolated root segments during the first 24 hours after excision and was low during the period of sucker induction. The relation of endogenous auxin level to control of sucker formation is discussed. The experiments do not exclude the possibility that the auxin effect is mediated through inhibitors.
Regulation of Growth and Invertase Activity by Kinetin and Gibberellic Acid in Developing Avena Internodes
Authors: JONES R. A. , KAUFMAN P. B.
Published: April 2006

Evidence presented here indicates that there is a complex interaction between kinetin, gibberellin, and sucrose in the regulation of turnover of invertase in vivo. The synthesis of invertase is maintained in the presence of GA3 and sucrose over relatively long periods of time. Kinetin, on the other hand, inhibits the full development of invertase activity seen in the sucrose and gibberellin control treatments. Moreover, the peak in invertase activity occurs earlier with kinetin treatment. During invertase turnover, once the peak is reached, kinetin enhances the rate of decay of enzyme activity relative to synthesis. The regulatory significance of invertase in intercalary growth and possible modes of kinetin action in this process are discussed.
Boundary Layer Effects in Ion Absorption by Roots and Storage Organs of Plants
Authors: POLLE E. O. , JENNY HANS
Published: April 2006

In plant nutrition studies with culture solutions it is tacitly assumed that replenishment of ions at the root surface is guaranteed by the turbulence of the stirred solution. That this belief may be erroneous is demonstrated in this study with barley roots and discs of beet roots and potato tubers. At very low concentrations of RbCl (in presence of CaCl2) the uptake of Rb by roots is strongly controlled by the rate of stirring. The results are interpreted in the light of the Nernst hydrodynamic boundary film which surrounds solids and through which ions must diffuse to reach the root surface. “Film‐controlled” and “root‐controlled” ion uptake is visualized.
The Change in Arginine Levels and the Metabolism of Urea and Ornithine in Cucurbita moschata Seedlings
Authors: LIGNOWSKI EDWARD M. , SPLITTSTOESSER WALTER E.
Published: April 2006

During germination a decrease in both soluble and protein argmine occurs in pumpkin cotyledons (Cucurbita moschata Poir.) and this decrease parallels the decrease in total nitrogen. Arginine is readily metabolized to urea and ornithine and the metabolism of the latter compounds were studied by allowing cotyledons of intact plants to absorb urea−14C and by incubating cotyledon discs with ornithine‐2−14C. Of the urea absorbed, 90 % of the label was metabolized to 14CO2 with little free urea remaining in the plant. Urease activity in the cotyledons reached a maximum at 4 to 6 days of germination. Ornithine was extensively metabolized with 37 % of the label being incorporated into protein by 3 h. Soluble and protein arginine accounted for 23 % of the label suggesting that Krebs‐Henseliet cycle enzymes were present.
Inhibition de ľAccumulation des Chlorophylles dans les Feuilles Primordiales de Phaseolus vulgaris après Irradiation Neutronique
Authors: KIRCHMANN R.
Published: April 2006

Etiolated bean leaves have been irradiated in an experimental cavity of a nuclear reactor. The greening is allowed either under continuous light or under intermittent light. A relationship between the decrease of the chlorophyll accumulation and the exposure dose is observed; moreover, the accumulation of chlorophyll b is more strongly decreased than the accumulation of chlorophyll a, by irradiation. A recovery phenomenon of the chlorophyll accumulation has been observed.

Ľauteur remercie le Personnel du Service Exploitation du BR1 et du Département de la Physique des Réacteurs pour le concours précieux apporté, ainsi que Messieurs E. Fagniart, Y. Hauglustaine et Madame El. Bonnijns‐Van Gelder pour leur collaboration technique.
Orientation and Geotropic Reaction of Seminal Roots of Wheat
Authors: BURSTRÖM H. G.
Published: April 2006

The geotropic orientation of seminal roots of wheat has been studied on seedlings grown in five different positions, stationary and on clinostats. The roots perceive a geoinduc‐tion before they have emerged from the grain and perform curvatures inside the grain. These are very sharp and transient, the following root growth is straight in any direction unless the positions are shifted. The roots are insensitive to a static gravi‐induction but react to a change in gravitation with a geotropic curvature in positive direction. The roots may not reach or reach, or even pass the plumb‐line. The orientation of a root depends upon the direction of its initiation and the geotropic curvature attained before the reaction has ceased. There is no nastic component in the reactions. The ‘plagiotropic’ orientation is explained by the limited positive reaction followed by an ageotropic state. Main root and adventitious roots react in the same way. Reactions to later stimuli give likewise limited curvatures which are weaker but of longer duration. — The effect of temperatures from 10°C to 25°C has been studied and compared to the temperature effect on cell elongation. It is concluded that the whole reaction may be explained by the regular auxin effects on cell elongation. No other hormone should be required and no plagiotropic mechanism is necessary.
Effect of Ammonia and Nitrate on Growth, Photosynthesis, and Ribulosediphosphate Carboxylase Content of Dunaliella tertiolecta
Authors: PAASCHE E.
Published: April 2006

When the marine Chlorophycean flagellate Dunaliella tertiolecta Butcher was grown with short photoperiods of bright light, the use of ammonia rather than nitrate as a nitrogen source led to a 30 % reduction of the doubling time of cell matter. The cell cycle (onset of light to completion of cell division) was shortened by about 10% only. Ammonia‐grown cells possessed a greater capacity for photosynthetic oxygen evolution at light saturation than did nitrate‐grown cells; their content of ribulosediphosphate carboxylase was likewise greater. The faster growth of Dunaliella tertiolecta with ammonia may be partly a consequence of a general increase in net protein synthesis resulting in a greater content of photosynthetic enzymes.
Simple Methods for the Calibration of Light Measuring Equipment
Authors: BJöRN L. O.
Published: April 2006

Simple methods are described for

absolute calibration of thermal radiation detectors (thermopiles, bolometers);

absolute calibration at various wavelengths of photoelectric devices;

obtaining the relative spectral sensitivity of the detector systems of spectrofluorimeters.

The procedures require no special standard lamp or other exotic equipment. The methods depend on the computation of the radiation characteristics of an ordinary tungsten lamp at various measured voltages and currents.
Changes of Some Mitochondrial Enzyme Activities of Cucumber Leaves during Ammonium Toxicity
Authors: MATSUMOTO H. , WAKIUCHI N. , TAKAHASHI E.
Published: April 2006

The 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

The 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

Ca 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

Mobilization 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

Physiological 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

Eleven 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

We 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

Excised 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

tRNA 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

The 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

Endogenous 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

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

The 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

The 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

The 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

The 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

Using 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

Pea 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

At 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

The 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.
Germination Promotion of Loblolly Pine and Baldcypress Seeds by Stratification and Chemical Treatments
Authors: BISWAS P. K. , BONAMY P. A. , PAUL K. B.
Published: April 2006

The effects of 4 chemicals on the germination promotion of stratified and unstratified seeds of loblolly pine (Pinus taeda) and baldcypress (Taxodium distichum) were studied. The chemicals used were gibberellic acid, kinetin, potassium nitrate and thiourea, each at 3 different concentrations.

Stratification promoted the germination of both seed species. Certain concentrations of gibberellic acid, potassium nitrate and thiourea improved the germination of unstratified loblolly pine and baldcypress seeds while kinetin had no stimulatory effect.

All 4 chemicals at specific concentrations promoted the germination of loblolly pine seeds stratified for a short period of time. Considering both speed and completeness of germination, best results were obtained when 21‐day stratified seeds were treated with either gibberellic acid (100 mg/1) or kinetin (10 mg/1). In baldcypress, on the other hand, none of these chemicals had any stimulatory effect on the germination of stratified seeds. Germination of both species of seeds was either partially or completely inhibited by the highest concentration of thiourea (30,000 mg/1) used.
Ion Relations, Chlorophyll Synthesis and the Question of ‘Bulk’ Phytochrome in Pisum sativum
Authors: KENDRICK RICHARD E. , HILLMAN WILLIAM S.
Published: April 2006

Lack of correlation between spectrophotometric phytochrome assays and physiological experiments has led to the concept of a ‘bulk’ phytochrome that is measurable but inactive, in contrast to an active form that is not measured in the standard assay. Because of suggestions that phytochrome action involves changes in membrane permeability, particularly to potassium ions, we investigated potassium and sodium uptake and efflux in Pisum sativum epicotyl sections which were equally de‐etiolated yet differed three‐fold in their phytochrome contents. Although dependent on the metabolic integrity of cell membranes (as shown by respiratory inhibitors) the selective uptake of potassium in this tissue is not under phytochrome control. Experiments were also conducted to see whether a three‐fold difference in phytochrome content affects chlorophyll synthesis in Pisum. Differences in chlorophyll synthesis observed can be related to the effectiveness of the pretreatments in eliminating the lag phase, not to their differences in phytochrome; Pfr decay rate has no effect on chlorophyll synthesis. The failure to find any correlation with the amount or state of ‘bulk’ phytochrome in these and previous experiments indicates that no function of this material is yet known.
Effect of 2,4‐Dichlorophenoxyacetic Acid on Growth and on β‐Glucan Synthetases of Peroxyacetyl Nitrate Pretreated Avena Coleoptile Sections
Authors: ORDIN LAWRENCE , GARBER MORRIS J. , KINDINGER JUANITA I.
Published: April 2006

Coleoptile sections from Avena sativa L. were exposed to non‐lethal concentrations of peroxyacetyl nitrate (PAN). The sections were then incubated in solutions of 50 mM glucose plus 2.5 mM potassium phosphate with various concentrations of 2,4‐dichlorophenoxyacetic acid (2,4‐D). Growth after 4 hours was measured. A corresponding series of experiments was carried out and the effect of the 2,4‐D treatments on enzymes utilizing uridine diphosphate glucose (14C‐glucose) to form glucolipid and β‐glucans including cellulose was determined. Growth in the PAN‐treated sections was inhibited less at optimal and superoptimal auxin levels than at low auxin levels. Glucolipid synthetase activity was only slightly inhibited by PAN pretreatment and was reduced by increasing levels of auxin. Responses of alkali‐soluble glucan and cellulose synthetases were similar to growth in both control and PAN treated tissues. It was concluded that the earlier reported response of cell wall metabolism in vivo probably is due to effects on these enzyme levels.
Entrainment of Geotropic Oscillations in Hypocotyls of Helianthus annuus– An Experimental and Theoretical Investigation
Authors: ANDERSEN H. , JOHNSSON A.
Published: April 2006

The effects of periodically repeated geotropic stimulations (geotropic pulses) on sunflower hypocotyls are studied. The experimental results agree with predictions from a theory for geotropic movements of the hypocotyl.

A sunflower hypocotyl performs circumnutations around or across the plumb line with a period of about 2.5 hours. These oscillations can be entrained to periodically repeated geotropic pulses with a period in a region around 2.5 hours. The limits of this “region of entrainment’ for geotropic pulses are studied. In the region of entrainment resonance curves, i.e., the amplitude of the oscillations plotted as a function of the period of the geotropic pulses, are obtained. The phase differences (measured as time differences) between the geotropic pulse rhythms and the resulting oscillations are also studied. Beat phenomena are predicted and recorded outside the region in which the plants can be entrained.

The results are discussed in relation to oscillating phenomena of circadian type (i.e., with a period close to 24 hours), and many similarities are pointed out.
Oxygen Evolution and Oxygen Uptake by Isolated Chloroplasts of Wheat Irradiated with Monochromatic Light, without the Addition of an Oxidant
Authors: EGNÉUS HANS
Published: April 2006

The oxygen exchange obtained when isolated chloroplasts of wheat are irradiated, without the addition of a Hill oxidant, has been investigated. Depending on the wavelength, two types of oxygen exchange are obtained. In light absorbed by both photosystems an oxygen gush appears directly upon irradiation. This oxygen evolving reaction is soon replaced by an oxygen uptake which is present until the end of the irradiation period. In light absorbed mainly in photosystem I, no oxygen gush can be observed, instead an oxygen uptake appears directly upon irradiation. An oxygen evolving process can also be observed in irradiations performed with photo‐system I light, but this process appears after 10–15 seconds of irradiation. The influence of various external factors on the oxygen gush and the oxygen uptake, e.g. different wavelengths, light intensity, length of the dark periods between irradiations, was studied.

The results show that the oxygen evolving reaction appearing upon irradiation with light absorbed by photosystem II and I, reflect the reduction of an oxidant, probably plasto‐quinone, in the electron transport chain between the two photosystems. The reoxidation of this oxidant can be brought about after irradiating with light absorbed in photosystem I, or by prolonging the dark period between irradiations, or through some unknown process connected to photosystem II.

The oxygen uptake which consists of two components, one appearing directly upon irradiation and the other one appearing after about 10 seconds of irradiation, confirms earlier observations that oxygen can be reduced in photosystem I. The electrons for the oxygen uptake appearing directly upon irradiation, are obtained from the reduced intermediates in the electron transport chain between the two photosystems. The electrons for the other oxygen uptake process are obtained from a reductant in the chloroplasts with access to the carrier chain between the photosystems. Whether the two oxygen uptake reactions reflect two sites of interaction of oxygen with the electron transport chain or only one site is discussed.
Growth Regulators in Picea abies
Authors: STEEN INGA
Published: April 2006

The occurrence of growth regulators active in the Avena coleoptile straight‐growth test in sprouting buds and seedlings of Norway spruce (Picea abies Karst.) was investigated.

The acid ether fraction contained a growth stimulator, the Rf of which in isopropanol: ammonia: water was 0.2–0.4. This substance behaved as indole‐3‐acetic acid (IAA) in elec‐trophoresis, in chromatography in various solvent systems on paper and on a Sephadex column. It gave the colour typical of IAA when sprayed with Ehrlich reagent and its fluorescence characteristics corresponded to IAA. Acid ether‐soluble inhibitors showed most activity at Rf 0.4–0.7, but due to tailing they interfered with the determination of the stimulator at the Rf of IAA in the bioassay. They also masked the activity of other stimulators. Colour reactions were obtained with Ehrlich reagent in the inhibiting chromatogram zone. When eluates from this zone were tested in high dilutions or after gel filtration growth stimulation was obtained. The acid fraction of seedling shoots also contained a stimulator with Rf 0.7–0.8. In the neutral‐basic ether‐soluble fraction growth stimulation was obtained at Rf 0.5–0.7. The extracts also contained stimulatory substances insoluble in ether but soluble in n‐butanol and partly in ethyl acetate. When the butanol fraction was hydrolyzed in 1 M NaOH a substance behaving as IAA when chromatographed was released.
Transpiration and Water Uptake in the Fruit Bodies of Some Hymenomycetes
Authors: ZOBERI M. H.
Published: April 2006

The relationship between relative humidity and transpiration was studied in the basidiocarps of Coprinus, Amanita, Agaricus, Tricholoma, Collybia and Polyporus. Transpiration decreases with an increase in the humidity and there is virtually no transpiration in nearly saturated air.

To determine the relationship between uptake and transpiration, stipes were immersed in solutions of various osmotic ally active substances and inhibitors. Results showed that uptake has no influence on the transpiration.

Additional data suggested that uptake in a detached basi‐diocarp proceeds as long as the fruit body is young and healthy. Studies with fluorescein dye and mannitol showed that most transpiration occurs at the surface and edges of the hymenium.