bluuebunny/crossref_metadata_2025 huggingface dataset:
Extracellular Lytic Enzymes of Myxococcus virescens II. Purification of Three Bacteriolytic Enzymes and Determination of their Molecular Weights and Isoelectric Points
Authors: HASKA GUNO
Published: April 2006

The bacteriolytic enzymes produced by Myxococcus virescens and previously concentrated and separated from most of the non‐bacteriolytic proteins have been further separated and purified.

The bacteriolytic enzyme solution was concentrated by lyo‐philization. When applied to a Sephadex G‐100 column, three peaks of bacteriolytic activity were eluted. Polyacrylamide gel electrophoresis showed that all the three enzyme fractions were contaminated with at least four non‐bacteriolytic proteins. In the first enzyme fraction the bacteriolytic enzymes could be freed from the contaminating proteolytic activity by adsorption on a hydroxylapatite column. The bacteriolytic enzymes could then be adsorbed on a CM‐cellulose column. The remaining contaminating proteins passed the column un‐adsorbed while the bacteriolytic enzymes could be eluted with a gradient of 0.02–0.10 M ammonium hydrogen carbonate solution. The second enzyme fraction was adsorbed on a CM‐cellulose column and then eluted with 0.03–0.15 M NH4 HCO3. After rechromatography on a new column under the same conditions, all of the contaminating proteins had disappeared. For purification of the third enzyme fraction chro‐matography on one single CM‐cellulose column was sufficient. The elution of the adsorbed enzymes was performed with a gradient of 0.15–0.30 M NH4HCO3. The recovery of activity for each of the ion‐exchange chromatography separations was at least 90%. The purity of the enzymes was tested by polyacrylamid gel electrophoresis. Each of the purified enzymes gave only one coloured band which coincided with the enzyme activity assayed in sliced gels. The molecular weights of the enzymes were determined by electrophoresis on acryl‐amide gels containing sodiumdodecylsulphate. The molecular weights determined in this way (about 40,000, 30,000 and 20,000, respectively) were about 10,000 daltons higher than those obtained by gel chromatography on Sephadex G‐100. This discrepancy seems to depend on interactions between the enzymes and the dextran molecules probably caused by the strongly basic nature of the enzymes or by formation of enzyme‐substrate complexes.
Changes in Endogenous Growth Regulators in the Gladiolus Corm during Dormancy
Authors: TSUKAMOTO YOTARO , KONOSHIMA HARUO
Published: April 2006

Changes in endogenous growth regulators in gladiolus corms during dormancy were studied using paper and column chromatography followed by a bioassay with the test for straight growth of Avena coleoptile. Corms were grown in the field or in a glass room of a phytotron at 20°C in the light. Another lot was grown in a dark room at 20°C in the dark. Half of the daughter corms in each lot were cold‐treated for about one month and the other half were stored at room temperature after harvest. The earliest sprouting was seen in dark grown corms with cold treatment, and the latest sprouting in light grown corms without cold. This pattern was similar in each cultivar over a period of three years. Corms from both lots contained considerable amounts of inhibiting substance just after harvest. However, dark grown corms treated with cold showed a rapid decrease in inhibitor activity and an increase in promoter activity. On the other hand, in light grown corms without cold treatment there was inhibitor activity found consistently even after two months. —There appear to be two inhibiting zones in the chromato‐grams. One of these contains two inhibitory substances, one of which was assumed to be abscisic acid.
3‐Methyleneoxindole and Plant Growth Regulation
Authors: ANDERSEN A. SKYTT , MØLLER IB , HANSEN JÜRGEN
Published: April 2006

The campound 3‐methyleneoxindole was synthesized and tested in three “biological systems for auxin activity: Root initarion in pea stem currings, extension growth of etiolated pea stem segments and Avena first internodes. In none of the systems was found any effect — positive or negative of methyleneoxindole. It thus seems improbable that the compound participates in the growth regulation of these plants.
Gibberellin‐like Activity in the Developing Avocado Fruit
Authors: BLUMENFELD A. , GAZIT S.
Published: April 2006

Gibberellin‐like activity in avocado (Persea americana) fruit extracts was measured by the barley endosperm bioassay. Fruit tissues were anlyzed separately during fruit growth. The level of the activity found was very high in the endosperm and in the seed coats, but decreased in the latter during fruit growth. No measurable gibberellin‐like activity was detected in the mesocarp or in the embryo. It is assumed that the seed coats are a site of production of gibberellin‐like substances in the avocado fruit.
Physiological Responses of Apple Trees to Supraoptimal Root Temperature
Authors: GUR A. , BRAVDO B. , MIZRAHI Y.
Published: April 2006

Ungrafted apple rootstocks were grown in sand cultures at constant root temperatures between 20°C to 40°C. Temperatures of 30°C and above reduced root and shoot growth. Serious damage to the leaves occurred at 35°C and above.

The O2 consumption, CO2 evolution and respiratory quotient (RQ) of the roots showed maximum values at 35°C.

Different rootstock cultivars varied greatly in their susceptibility to damage by supraoptimal root temperatures apparently due to anaerobic respiration. The more susceptible ones differed from resistant types in the larger amount of ethanol they accumulated in their roots at supraoptimal root temperature, and the more severe reduction in the malic acid content of the roots at such temperature. Acetaldehyde was also found in roots and leaves at supraoptimal root temperatures, whereas the organic acid content of the leaves tended to decrease.

Supraoptimal root temperature also caused a reduction of cytokinins in both roots and leaves accompanied by a reduction in the leaf chlorophyll content. This could be prevented by the application of kinetin or benzyladenine to the leaves.

In a short experiment a rise in root temperature up to 40°C caused an increase in transpiration and a decrease in the resistance of the leaves to the passage of water vapor, whereas in prolonged experiments transpiration reached a maximum and leaf resistance a minimum at 30°C. The leaf water potential increased also with increasing root temperature. Leaf temperature increased with increasing root temperature, irrespective of increasing or decreasing transpiration rates.
Influence de la carence hydrique sur la repartition cellulaire de l'acide ribonucleique foliaire chez le cotonnier
Authors: MARIN BERNARD , DA SILVA JORGE VIEIRA
Published: April 2006

Water stress, induced by addition of polyethyleneglycol 600 to the nutrient solution, reduces the ribonucleic acid content of cotton leaves. The chloroplastic compartment, especially its ribosomal fraction, was most affected, even losing ribonucleic acid to the cytoplasmic compartment. Decrease of ribonucleic acid content on dehydration of leaf tissue is linked with an increase of ribonuclease.
Photosynthesis, Transpiration, Leaf Stomatal and Mesophyll Resistance Measurements by the Use of a Ventilated Diffusion Porometer
Authors: BRAVDO BEN‐AMI
Published: April 2006

A ventilated diffusion porometer was modified and adapted for simultaneous measurements of leaf resistance and photosynthesis (using 14C). The system enables measurements to be made under field and laboratory conditions with different concentrations of CO2 and vapor pressure gradients between the evaporating surfaces inside the leaf and the external atmosphere. The leaf is subjected to the porometer's atmosphere only for short periods (up to 30 seconds) and it is assumed that stomata are not affected. Establishing the linear regression of the effect of CO2 concentration on net photosynthesis makes it possible to extrapolate for CO2 compensation point, to calculate the overall resistance to CO2 and the mesophyll resistance to CO2.
Changes of the Protein Synthesis System during the Maturation of Potato Tubers
Authors: COCUCCI S. M. , GARLASCHI F. M. , BIANCHI E. , MARRÈ E.
Published: April 2006

Respiratory activity, RNA contents and protein synthesis capacity of isolated ribosomes of tubers of Solanum tuberosum, cv. Tonda di Berlino, at progressive stages of development have been determined. In the immature, still growing tubers, respiration steadily decreases with the increase of fresh weight. The entering into dormancy of the tubers collected when immature corresponds to a rapid drop of respiration to the values characteristic of mature tubers. The RNA contents per tuber increase progressively during maturation. A decrease of the RNA contents per tuber (ca. 50 %) is observed in the period between the moment of harvesting and the end of dormancy. The endogenous capacity of isolated ribosomes to carry on amino acid polymerization strongly decreases during tuber development, while the activity supported by polyuridilic acid remains almost unchanged when measured at optimum Mg2+ concentrations, and becomes larger for the more mature tubers at superoptimum Mg2+ concentrations. These changes of the protein synthesis system during tuber development are compared with those occurring during seed maturation.
Conversion of Indole‐3‐acetaldehyde Oxime to 3‐Indolylmethylglucosinolate in Sinapis alba
Authors: JOSEFSSON EGON
Published: April 2006

dl‐Tryptophan(methylene)‐14C and indole‐3‐acetaldehyde oxime(methylene)‐14C were supplied to cut shoots of 7‐day‐old plants of Sinapis alba L. Although both compounds were effective as precursors of 3‐indolylmethylglucosinolate, the incorporation of the aldoxime radioactivity was more effective than the incorporation of the amino acid radioactivity. This, together with other information, suggests that indole‐3‐acetaldehyde oxime is an intermediate in the biosynthesis of 3‐indolylmethylglucosinolate from tryptophan.
On the Nature of the Proteinases Secreted by the Aleurone Layer of Barley Grain
Authors: SUNDBLOM NILS‐OLOF , MIKOLA JUHANI
Published: April 2006

The nature of the proteinases which are secreted by barley aleurone layers in response to gibberellic acid was studied by constructing pH vs. activity curves for the hydrolysis of gelatin by incubation media and aleurone layer extracts. The results indicate that the aleurone layers release several different proteinases. The main component is a labile sulphydryl enzyme with an optimum pH of 3.9. The other enzymes include two sulphydryl proteinases with pH optima between pH 5 and 6.5 and a metal‐activated enzyme active at pH 7.0. No differences could be demonstrated between the proteinases released by and retained in the aleurone layers.
Effect of Wind on Plant Respiration
Authors: TODD GLENN W. , CHADWICK DON L. , TSAI SING‐DAO
Published: April 2006

Various plant species were placed in a 13.5 liter belljar equipped with a motor‐driven fan directly above the plants. Air was continually circulated from the belljar through an infrared CO2 analyzer at the rate of 1.5 1/min. Species tested included Triticum aestivum, Hordeum vulgare, Avena sativa, Zea mays, Sorghum vulgare, Phaseolus vulgaris, Glycine max, Pisum sativum, and Magnolia grandiflora. Increases in respiration of shoots or intact plants were detected at windspeeds of 3.6 m/s and above. All species responded in a similar fashion with increases in respiration of 20 to 40% being typical at a windspeed of 7.2 m/s which is similar to windspeeds under many natural conditions. The respiration rate returned to the initial rate within a short time after the wind had stopped. In Magnolia a sustained elevated respiration rate was measured over an exposure period of 3 hours to a wind velocity of 7.1 m/s. In some experiments flutter of the leaves was prevented but the respiration rate of bean and Magnolia was still elevated in the wind. This would suggest that the response is subcellular and not due to gross movement of the leaf itself. It is suggested that such an elevated respiration rate (maximum increase measured was 56%) might be expected to interfere with net assimilation and may be responsible for lower yields obtained in windy regions.
Oxindole‐3‐acetic Acid: Physical Properties and Lack of Influence on Growth
Authors: HENDERSON J. H. M. , PATEL C. S.
Published: April 2006

The auxin activity of OAA was studied.

The assays used were the Avena coleoptile curvature and section tests, and the first internode test.

OAA was completely inactive to these assays.

Physical tests indicated no color reaction with modified Salkowski reagent (Gordon‐Weber) and no activity of any of the biochromatograms run with OAA.

These data indicate that OAA is inactive as an auxin due to its characteristics of structural difference from IAA and further lends some speculation as to the site of activity of IAA as an auxin.
Studies on the Nitrogen Metabolism in Ectomycorrhizae
Authors: KRUPA SAGAR , FONTANA ANNA , PALENZONA MARIO
Published: April 2006

Free and bound amino acids in the mycorrhizal and nonmycorrhizal root systems of Pinus nigra Arnold and Corylus avellna L. grown under semi‐natural conditions were analyzed through automatic amino acid analyzers. Tuber brumale Vitt. and T. melanosporum Vitt. were the respective fungal symbionts. Arginine and citrulline were found to accumulate in large quantities in the free pool of the uninoculated P. nigra and C. avellana root systems respectively. In the mycorrhizal root systems these substances decreased in their levels with a parallel increase in the concentrations of glutamine and asparagine. Implications of these changes are discussed with reference to ectomycorrhizae. In general the majority of the identified free amino acids were found in larger concentrations in both the types of mycorrhizal root systems. Results obtained suggested that this may not be due to proteolysis but due to increased biosynthesis. Possible interrelationships in ectomycorrhizal root systems with reference to nitrogen metabolism are presented in the form of a scheme.
Allosteric Properties of Chorismate Mutase from Quercus pedunculata
Authors: GADAL PIERRE , BOUYSSOU HUGUETTE
Published: April 2006

Chorismate mutase from Quercus pedunculata Ehrh. leaves has been purified by ammonium sulfate precipitation, molecular sieving and hydroxyapatite chromatography. Some results obtained during the purification suggest the presence, in oak, of two isofunctional forms of the enzyme, the one sensitive, the other insensitive to the action of aromatic amino acids. The regulable form exhibits a molecular weight of about 45,000. It is inhibited by tyrosine and by phenylalanine and is activated by tryptophan. In addition to its activating properties, this latter compound, endowed with a great affinity for the enzyme, reverses the inhibition due to the two other amino acids.

The H+ concentration of the medium plays an important role in the sensitivity of the enzyme with regard to its effectors. Inhibition by tyrosine and by phenylalanine is maximal at pH 6.5, at which value the two ligands present an identical effect. At alkaline pH values, the rate of inhibition decreases regularly, tyrosine becoming the most effective inhibitor. Activation by tryptophan is particularly acute in a mildly acid medium; at pH 6.5, this effector increases the enzymatic activity threefold. Its action is weak (20% activation) in the optimum pH zone (pH 7.8) and increases towards the more basic pH values. As a result, tryptophan maintains a constant level of enzymatic activity throughout a large pH zone (between 6.5 and pH 9.0). The physiological significance of these results is discussed.
The Growth of the Primary Roots and Root Hairs of Sinapis alba and Lepidium sativus in Triton X‐100
Authors: HAAPALA EVA
Published: April 2006

Seeds of Lepidium and Sinapis were germinated and grown for 3 days in different concentrations of Triton X‐100 (0.001–0.1 % v/v). The elongation of the primary root was slightly stimulated by low concentrations. In concentrations above 0.01 %, Triton inhibited root growth and forked root hairs developed. The hairs elongated both at the apex and at the base, exhibited protoplasmic streaming and activity of particulate non‐specific esterase. In contrast the growth of the hypocotyl of both Lepidium and Sinapis diminished steadily in increasing concentrations of Triton. Triton also affected the percentage germination of Lepidium, which increased or decreased according to the concentration used. The changes in root growth and germination and the appearance of branched root hairs in abundance coincide with a change in the detergent solution from monomer to aggregated molecules.
The Uptake and Fractional Distribution of Differentially Labeled Indoleacetic Acid in Light Grown Stems
Authors: DAVIES P. J.
Published: April 2006

The uptake of exogenously applied indoleacetic acid (IAA) by light grown stems of bean (Phaseolus vulgaris L. cv. Red kidney) and pea (Pisum sativum L. cv. Alaska) was examined. The IAA was labeled in the 1 and 2 side chain positions with 14C and the 5 ring position with 3H. The distribution of label in the sections was analyzed by recording the elution into water, ethanol and 1.0 N NaOH, and the amount in the insoluble residue also recorded. Total uptake consisted of a rapid uptake for about 1 h followed by continued uptake at a slower rate for 24 h to give a radioactive concentration in the tissues four to five times, that of the external solution. Most of the radioactivity was initially extractable by water, later by ethanol. With IAA‐2‐14C there was a slow increase in radioactivity in NaOH and residue fractions but with IAA‐1‐14C most of the radioactivity was present in insoluble residue at times longer than 3 h. From the different residue patterns estimates of the extent of decarboxylation of the IAA were made. The radioactivity in the tissues was largely IAA after 1 h and the content increased until 6 h but there after there was little further increase. The water fraction initially contained the most IAA but by 24 h most IAA was found in the NaOH fraction in bean and the ethanol fraction in pea. The NaOH fraction was the only fraction in which the IAA content continually increased.
Wind Flow Characteristics on a Soybean Leaf Compared with a Leaf Model
Authors: PERRIER EUGENE R. , ASTON ALAN , ARKIN GERALD F.
Published: April 2006

The purpose of this paper is to describe momentum boundary layer flow parameters on a soybean leaf [Glycine max (L.) Merrill] at various velocities of the bulk air stream and these data are compared with similar measurements on an artificial leaf. The wind structure is measured at three different bulk air velocitìes (u∞= 39, 148 and 271 centimeters per second) on an individual soybean leaf and is compared to structural effects on an artificial leaf (flat metal plate) in a small closed‐circuit wind tunnel. The boundary layers were homogeneous for the metal plate, but only at the lower velocity for the soybean leaf. The boundary layer thicknesses decrease with increasing bulk air velocity for laminar flow regimes, whereas in the turbulent flow regime the boundary layer thickness greatly increases. The effect of turbulence on the soybean leaf boundary layer made the eddy diffusivities at least three times greater than in the laminar flow regime at the calculated roughness height above the leaf surface. The structure of the leaf boundary layer flow is comparable to that of the metal plate only at the lower bulk air velocity.
Effect of Abscisic Acid on Sucker Development and Callus Formation on Excised Roots of Populus tremulaides
Authors: SCHIER GEORGE A.
Published: April 2006

Abscisic acid (ABA) inhibited sucker development and promoted callus formation from cambium exposed at cut ends of excised roots from two clones of trembling aspen, Populus tremuloides Michx. Clonal differences in response to ABA inhibition of sucker outgrowth appeared to be related to the developmental stage of the preexisting shoot primordia. When ABA treatment was followed about a month later by gibberellic acid, ABA inhibition was partially reversed. This is one of few investigations in which both promotive and inhibitory effects of ABA have been demonstrated simultaneously on the same plant part.
On Auxin‐Induced pH Drop and on the Improbability of its Involvement in the Primary Mechanism of Auxin‐Induced Growth Promotion
Authors: ILAN I.
Published: April 2006

When sunflower hypocotyl segments were floated on a solution containing potassium, auxin brought about a pH drop in the medium. The effect was detectable about 2–3 hours after the application of the auxin, and persisted during the 26 hours of the experiment. When ammonium was applied instead of potassium, an auxin‐induced pH drop was also noted in the first hours of the incubation. Afterwards, the pH of the auxin‐treated medium became higher than that of the control solution. It is suggested that the difference in the action of the auxin in the presence of the two cations is related to the contrast between its effects on their absorption.

The data are discussed in relation to the recently proposed hypothesis that auxin‐induced growth promotion is a result of an auxin‐induced pH drop in a cell wall compartment. It is concluded that the results do not support the hypothesis.
The Effect of Cadmium on Electron and Energy Transfer Reactions in Corn Mitochondria
Authors: MILLER R. J. , BITTELL J. E. , KOEPPE D. E.
Published: April 2006

The effects of cadmium on isolated corn shoot mitochondria were determined. In the absence of phosphate cadmium stimulated the oxidation of exogenous NADH optimally at 0.025 mM, but was inhibitory at 0.1 mM and above. The presence of phosphate negated the cadmium stimulation of exogenous NADH oxidation and permitted inhibitions only at higher cadmium concentrations. Succinate or malate + pyruvate oxidation in the absence of phosphate was inhibited to a greater extent by cadmium than when phosphate was present. ADP/O and respiratory control ratios were reduced by cadmium but generally were less sensitive to cadmium than state 4 or minus phosphate respiration. The data suggest that the site of cadmium effect is likely to be early in electron transport. Cadmium had a pronounced effect on mitochondrial swelling under either passive or active conditions. When succinate or exogenous NADH were being oxidized swelling occurred at 0.05 mM cadmium, but with malate + pyruvate the cadmium concentration had to exceed 1.0 mM. Phosphate (2 mM) prevented the swelling. Dithiothreitol, a SH group protector, prevented any effect of cadmium on swelling or respiration which suggests that sulfhydryl groups are likely involved in the cadmium‐membrane interaction.
In vivo Characterization of Nitrate Reductase Activity in Cotton
Authors: BILAL I. M. , RAINS D. W.
Published: April 2006

The in vivo nitrate reductase activity in leaf tissue of cotton (Gossypium hirsutum L.) was characterized. Enzymatic activity was linear with time up to 60 min. The assay for nitrate reductase activity was optimized in leaf slices 400 μm wide incubated in an anaerobic system at 30°C, in a 0.02 M KNO3 medium at pH 7.0 with 1 % propanol.

In vivo activity was highest in recently matured leaves at the top of the plant.

Both light and nitrate enhanced in vivo enzymatic activity. The activity was highest after 9 hours in the light and then decreased steadily for several more hours even in the presence of light.

The nitrate reductase activity was more strongly correlated to the levels of NO3‐N in the culture solution than to the NO3‐N level in the tissue. The utility of this technique in nitrate reductase assay in a tissue containing large amounts of phenolic compounds is discussed.
Studies on the Genetic Control of a Nitrogenase Component in Leguminous Root Nodules
Authors: PHILLIPS DONALD A. , HOWARD ROBERT L. , EVANS HAROLD J.
Published: April 2006

An attempt was made to determine whether Rhizobium or the host legume carries genetic information required for synthesis of the enzyme complex nitrogenase. No rhizobial mutants were found which could reduce N2. Anaerobically‐grown rhizobial cells contained neither component of nitrogenase. Rhizobium strain 32H1 was used to produce root nodules on Vigna sinensis and Phaseolus aureus. Other V. sinensis plants were inoculated with Rhizobium strain 29C2. The iron‐molybdenum component of nitrogenase (fraction I) from these three combinations was purified by DEAE‐cellulose chromatography and preparative electrophoresis. The final sample formed a single band after analytical electrophoresis on polyacrylamide gel. No differences in mobility were observed between the three nitrogenase samples during short periods of analytical electrophoresis. Longer periods of electrophoresis produced degradative products with similar electrophoretic mobilities from each nitrogenase sample. Amino acid analysis of fraction I samples from the three host‐symbiont combinations suggested that the protein from the V. sinensis‐Rhizobium 29C2 combinations was different from the other two samples. These results are interpreted as preliminary evidence that Rhizobium carries the genetic information for fraction I of nitrogenase.
Studies on the Flowering Mechanism in Lemna
Authors: MAENG JUESON , KHUDAIRI A. KARIM
Published: April 2006

A nitrogen source was needed for the flowering of Lemna gibba L., a long‐day plant, and L. perpusilla Torr., a shortday plant. The level of endogenous amino acids analyzed by an Amino Acid Analyzer, rose during the first few inductive cycles, but was reduced during later stages of the flowering process. Serine and threonine levels increased during the light period and decreased during the dark period in L. perpusilla. Exogenous serine and threonine added to the culture medium at 10−6M increased the rate of flowering by more than 35% over the controls. Cysteine inhibited flowering, while other amino acids had little or no promotive effect on flowering. Serine and threonine increased flowering rate in L. perpusilla only when added during a dark period of the inductive cycle. The addition of amino acids during a light period not followed by a dark period had no effect on flowering.
Geotropic Curvatures in Roots of Cress (Lepidium sativum)
Authors: IVERSEN TOR‐HENNING
Published: April 2006

Roots of cress growing between two agar slices develop an asymmetry in the extreme root tip region after 10 to 20 min of horizontal stimulation. After prolonged stimulation (exceeding 50 min) the asymmetry disappears and after 3 h the curvature is distributed over the entire growing region. The course of the initial stages in the geotropic curvature has been followed by light microscopy and scanning electron microscopy. — When stimulated at an angle of 135° with the gravitational force, the asymmetry in the root tip is clearly visible after 10 min of stimulation.

The asymmetry in the root cap can be explained by a difference in the elongation rate of the epidermal cells on the upper and lower sides of the stimulated root. The disappearance of the asymmetry is followed by a second phase in which there is a differential growth of the cortical cells on the two sides of the elongation zone. The average growth rate of cells in the upper half of the apical region during the first 50 min of continuous stimulation is 1.5 μm per min, while the elongation rate of the entire root is 16.2 μm per min. Only small modifications in the elongation rates were observed when stimulated and unstimulated roots were rotated parallel to the horizontal axis of a klinostat at 2 rpm.

The ultimate curvature developed after 50 min is unaffected by stimulation times exceeding the reaction time which for cress roots has been found to be about 5 min.

The two phases in the development of geotropic curvature are discussed in view of the statolith theory.
Gibberellin‐like Substances from Norway Spruce (Picea abies)
Authors: DUNBERG ARNE
Published: April 2006

By use of methanol extraction, two different consecutive partition procedures, repeated polyvinylpyrrolidone column chromatography, silicic acid partition column chromatography and the dwarf rice, lettuce, and barley half‐seed bioassays, several gibberellin‐like substances were detected in elongating shoots of Picea abies (L.) Karst. No significant differences in the content of gibberellin‐like substances could be detected between juvenile and mature trees. The shoot axes were found to contain fewer gibberellin‐like substances than the needles.
Formation of Proteinase Inhibitors in Developing Barley Grain
Authors: KIRSI MARKKU
Published: April 2006

Assays have been made of the activities of trypsin inhibitors and Aspergillus‐proteinase inhibitors in developing grains of barley (Hordeum vulgare L.) grown under controlled conditions. Trypsin inhibitor activity appeared early in the development, reaching a near‐maximal value 24 days after anthesis, but Aspergillus‐proteinase inhibitors were synthesized quite late in the development. A half‐maximal value was attained about 25 days subsequent to anthesis. The corresponding half‐maximal value for all the proteins synthesized was about 16 days.

The trypsin inhibitor present in developing grains appeared to be immunologically identical with the endospermal inhibitor in mature grains.

The concentrations of Aspergillus‐proteinase inhibitors varied between different cultivars of barley. Moreover, each cultivar displayed an almost linear relationship between inhibitor activity and the increasing content of total protein. Great differences between different cultivars were also observable with regard to trypsin inhibitor activities. However, the activities in each cultivar were constant, regardless of the total protein content.

The author is greatly indebted to Dr. Juhani Mikola for many helpful discussions during the course of the work, and for several valuable suggestions in regard to the manuscript. I also wish to thank Mrs. Marja‐Leena Niku‐Paavola, Lic. Phil., for valuable help in the immunodiffusion experiments, and Miss Outi Karkkainen for skilful technical assistance. This work was supported by grants from the Emil Aaltonen Foundation and from the E. J. Sariola Foundation.
Development of Ascorbate Oxidase Activity and Its Iso‐enzyme Pattern in the Roots of Pea Seedlings
Authors: SUZUKI YONEZO , OGISO KAZUKO
Published: April 2006

Early in the germination of peas, ascorbate Oxidase activity increased markedly in the root and epicotyl, but not in the cotyledons. The activity in the root was suppressed by the administration of 6‐methylpurine, thiouracil, cyclohexi‐mide, thioproline, and phenylthiourea. Although enzyme development was inhibited by phenylthiourea and thioproline, root elongation was not affected by these reagents. As germination progressed, the ascorbate oxidase activity in the extract of the seedling's root could be separated into at least 3 to 7 isoenzymes.
The Effect of Sodium Chloride on the Balance between the C3‐ and C4‐Carbon Fixation Pathways
Authors: SHOMER‐ILAN ADIVA , WAISEL Y.
Published: April 2006

Young leaves of salt‐depleted Aeluropus litoralis Parl. plants show CO2 fixation by the C3‐carbon fixation pathway. No detectable activity of phosphoenol pyruvate (PEP) carboxylase was found. When A. litoralis plants were exposed to a NaCl solution, the leaves showed a high activity of PEP carboxylase as well as a significant CO2 fixation by the C4‐pathway. — Also in Zea mays L. and Chloris gayana Kunth., the presence of NaCl in the medium influences the balance between phosphoenol pyruvate carboxylase and ribulose‐1,5‐diphosphate carboxylase.
α‐Amylase in the Barley Grain Influenced by the Auxin‐Cytokinin Interaction in the Coleoptile
Authors: VERBEEK RITA , VAN ONCKELEN H. A. , GASPAR TH.
Published: April 2006

Two phases are distinguished in the α‐amylase production in barley (Hordeum vulgare) grains. There is an increase in activity extended to the third or fourth day of germination, then a slight decrease follows. This decrease is accelerated by kinetin while it is prevented by IAA applied at the top of the embryo coleoptile. IAA reverses partially the kinetin action. IAA applied in the germination medium has practically no effect. Removal of the coleoptile stops further increase in α‐amylase activity and induces complete insensitivity to hormone treatment.

The results indicate that auxin metabolism in the coleoptile participates in the control of α‐amylase evolution in the barley grain and that kinetin could act through auxin metabolism in this coleoptile.
Levels of Indol‐3yl‐acetic acid (IAA), IAA‐oxidase and Peroxidase in Developing Cucumber Seedlings
Authors: ELKINAWY MAHASEN , RAA JAN
Published: April 2006

The level of indol‐3yl‐acetic acid (IAA) in the cotyledons of cucumber seedlings increases in the period 4 to 11 days after germination. In hypocotyls and roots the IAA level decreases. IAA‐oxidase activity of homogenates of cotyledons, hypocotyls and roots decreases with age. The soluble fraction of all three organs contains an IAA‐oxidase, which may be allosteric. It is suggested that this IAA oxidase limits the upper level of IAA in the cell. The cell wall fraction of the three organs contains IAA‐oxidases with conventional kinetics. The function of this IAA oxidase is probably to degrade exogenous IAA.
Oxygen Release from Rice Seedlings
Authors: JOSHI M. M. , IBRAHIM I. K. A. , HOLLIS J. P.
Published: April 2006

Oxygen release from root systems of individual rice seedlings was measured polarographically employing an oxygen monitor with a Clark electrode. The oxidizing capacity of four rice varieties was correlated with their relative yielding abilities and with their reactions to Straighthead (SH) and Mild Sulfide Disease (MSD). These data support previous findings which link SH and MSD with rice‐toxic levels of soluble sulfides in Gulf Coast (U.S.A.) rice soils containing excess iron.
Effect of Different Osmotic Potentials of Media on Germination of Three Safflower Varieties
Authors: SIONIT N. , KHERADNAM M. , GHORASHY S. R.
Published: April 2006

The effect of osmotic potentials, 0 to −13.5 atm (−1.37 M Pa), on the germination of three safflower varieties (Carthamus tinctorius L.) was studied at a controlled temperature (30±2°C) using a non‐electrolyte substance, polyethelene glycol 6000. The varieties were cv. Ute, cv. Iranian local 3151, and cv. Iranian local 2811. The percent germination of the three varieties averaged over all osmotic potentials were: 86, 77 and 61 for local 3151, local 2811 and “Ute”, respectively. The Ute variety had the highest, and the local 3151 variety had the lowest rate of germination reduction. The variations among the varieties in the percent and rate of germination were due to osmotic effects of the media.
Seasonal Variations in Absorption and Metabolism of Carbon‐14 Labelled Arginine in Intact Apple Stem Tissue
Authors: HILL‐COTTINGHAM D. G. , LLOYD‐JONES C. P.
Published: April 2006

At intervals through the year a study was made of the absorption and metabolism of arginine‐C 14(U) which had been perfused into the wood of apple stem internodes. Absorption was greater during the period May to September than at any other time of the year. The metabolic breakdown of arginine took place only after absorption but the products found varied widely with season. From the analyses it is concluded that arginine is metabolized by the Krebs‐Henseleit cycle at all times of the year, in addition to which during the period from May to August there are other pathways in operation that result in a more extensive breakdown so that all the N in arginine becomes available for new growth.
Utilization of Carbohydrates by Rhynchosporium secalis. I. Growth and Sporulation on Glucose, Galactose, and Galacturonic acid
Authors: OLUTIOLA P. O. , AYRES P. G.
Published: April 2006

The fungus Rhynchosporium secalis (Oud.) Davis grew and speculated in liquid nutrient media that contained glucose, galactose or galacturonic acid, or a pair of those substances, as the sole carbon source. Sporulation was inhibited by high concentrations of glucose and galacturonic acid. Growth and sporulation were greatest on glucose, and least on galactose. Growth was increased when glucose and galacturonic acid were mixed. Nitrogen concentration affected sporulation but not growth.
Auxin Stimulation of Cambial Activity in Pinus silvestris II. Dependence upon Basipetal Transport
Authors: WODZICKI T. J. , WODZICKI ALINA B.
Published: April 2006

Natural auxin content has been determined in the cambial region of large Pinus silvestris L. trees at various dates during the year. The tissue was collected from the stem of intact or ring‐barked trees and from stumps remaining after the trees were cut down at breast height in early summer or late autumn. No seasonal decrease of concentration of the extractable auxin in the cambial region could be detected. Decapitation or ring‐barking produced severe reduction in auxin content and arrested cambial division. In the next season the auxin level and the cambial activity remained completely depressed. It is concluded that without tissue continuity in the region external to xylem and without basipetal supply of substances, no mechanism operated by roots or remaining stem tissue near the tree base can ensure a high level of auxin in the cambial region or activate and maintain the cambial division. The activity of extracted pine auxin was found not to be identical with the stimulatory potential of authentic IAA determined by standard bioassays. The possibility of interaction with other extracted substances is discussed.
Effects of Daylength on Endogenous Gibberellins in Solanum andigena III. Gibberellin Production by the Leaves
Authors: RAILTON I. D. , WAREING P. F.
Published: April 2006

Using an agar diffusion technique, it was found that leaves from potato plants growing under long days produced more gibberellin‐like substances than did leaves from plants growing under short days. Short day plants irradiated with red light during the long dark period and harvested during the ensuing light period, contained levels of gibberellin‐like substances approximating those found in long day grown plants.

Red irradiation during the long dark period also resulted in an increase in gibberellin production in short day plants. Four zones of gibberellin‐like activity (A, B, C, D) were separated by thin layer chromatography in extracts from potato leaves. Red light treatment reduced the levels of peak D and brought about a concomitant increase in the levels of peak A.
Further Investigations on the Nature of the Heat Resistance of Thermophilic Bacteria
Authors: LJUNGER CLAES
Published: April 2006

When cells of Bacillus stearothermophilus, strain NCA 1503, were grown in tryptone starch broth and subsequently transferred to tris buffer, a fraction of the cells: rapidly died in ttie buffer. This fraction increased with increasing content of calcium chloride in the growth medium. The' addition of sodium, potassium or magnesium chloride to the growth medium had no such effect. The rapid dying of the cells in tris buffer was associated with a leakage of organic material and calcium ions from the cells. The results obtained are probably caused by a damage to the osmotic barrier of the cells during their contact with the buffer. Observations: made during the present investigation and a previous one (Ljunger 1970) indicate that the heat resistance of thermophilic bacteria depends on the maintenance of a high intracellular concentration of free calcium ions.
A Technique for Studying the Adsorption, Absorption and Metabolism of Amino Acids in Intact Apple Stem Tissue
Authors: HILL‐COTTINGHAM D. G. , LLOYD‐JONES C. P.
Published: April 2006

Solutions of amino acids are introduced rapidly into the xylem of short lengths of stem. At sampling the intact stem is first perfused with a salt solution to remove the amino acids still reversibly adsorbed by cation exchange. This fraction of the applied amino acids is thus distinguished from that absorbed into the tissues which is subsequently extracted from the disintegrated stem by aqueous ethanol.

The potential value of this technique is discussed and illustrated with some results using carbon‐14 labelled amino acids in apple stems.
Short‐ and Long‐term Effects of High Temperatures (47–49°C) on Tobacco Leaves. II. O2 Uptake and Amylolytic Activity
Authors: ITAI C. , BENZIONI ALIZA
Published: April 2006

Detached tobacco (Nicotiana rustiest L.) leaves were exposed for 2 min to a temperature range of 24° to 47.5°C. The heat treatment enbanced O2 uptake by 30 Vs. Likewise, amylolytic activity in chloroplast extracts was intensified; this activity being observed also in situ. The enhancements can be reversed either by short‐term cold treatment (7°C for 10 min), or by application of kinetin.
Action Spectrum of Photosynthesis for Skeletonema costatum Obtained with Carbon‐14
Authors: IVERSON RICHARD L. , CURL HERBERT
Published: April 2006

The quantized action spectrum of photosynthesis for Skeletonema costatum was obtained from values of photosynthetic 14CO2 uptake at various wavelengths of light isolated “with a diffraction grating monochromator. The quantized action spectrum of photosynthesis exhibited maxima at wavelengths similar to maxima in the absorption spectrum, in vivo, of a suspension of S. costatum cells. While the 14CO2 technique will provide an accurate action spectrum of photosynthesis for diatoms, a large number of samples is required in order to minimize sampling error.
Variations in Uptake of Sodium and Rubidium Along Barley Roots
Authors: ESHEL A. , WAISEL Y.
Published: April 2006

Variations in uptake of sodium and rubidium were ob) served along the apical 8 cm segments of barley roots. Dif) ferent patterns of uptake were obtained for low‐ and for high‐salt roots. The validity of using batches of entire barley roots for kinetic analysis of ion uptake is questioned.
Leaf Water Potential Response to Transpiration by Citrus
Authors: CAMACHO‐B SAUL E. , KAUFMANN MERRILL R. , HALL ANTHONY E.
Published: April 2006

This paper reports on further studies of a model for interpreting leaf water potential data for Citrus. Experimental data confirmed the assumption that the ratio of vapor pressure deficit to leaf diffusion resistance adequately estimates transpiration when leaf‐to‐air temperature differences are small. Data collected diurnally indicated that the relationship between leaf water potential and transpiration followed a sequence of steady states without hysteresis. No difference in water transport characteristics was found for Valencia orange on three rootstocks in well‐watered soil, but the two rootstocks Cleopatra mandarin and Rangpur gave slightly greater leaf water stress in Valencia orange leaves than‘Troyer’ citrange rootstock at high transpiration rates under mild soil water deficits. In laboratory studies, previously unstressed seedlings had higher leaf water potentials than field trees at equivalent transpiration rates. After several drying cycles, however, leaf water potentials were similar to those observed in the field.
Distribution of Physiological Activities in the Cotyledons of Germinating Seeds
Authors: MOROHASHI Y. , SHIMOKORIYAMA M.
Published: April 2006

From autoradiographical experiments on water‐imbibing pea (Pisum sativum) or Phaseolus mungo cotyledons supplied with glucose‐14C or iodoacetic acid‐14C, it was shown that the compounds did not penetrate into the innermost part of the cotyledons but remained in the peripheral region during the early germination period. Changes in the rates of incorporation of 14C into alcohol from glucose‐14C were examined during the early period of germination, and it was concluded that glucose supplied exo‐genously was actively metabolized in the peripheral region. Endogenous alcohol formation was supposed to occur mainly in the peripheral region in the early phases of germination. On the basis of these results, the heterogeneity of the distribution of physiological activities in the cotyledon is discussed.
Characterization and Properties of a Protochlorophyllide Ester in Leaves of Dark Grown Barley with Geranylgeraniol as Esterifying Alcohol
Authors: LILJENBERG CONNY
Published: April 2006

The protochlorophyllide ester isolated from dark grown barley leaves was shown to contain geranylgeraniol as esterifying alcohol. No phytylester was found. The qualitative analyses were performed with combined gas chromatography‐mass spec‐trometry. Chromatographic separation and spectrofluorometric determination of the protochlorophyll and chlorophyll pigments before and after irradiation of the dark grown leaves with light flashes at 2°C showed that part of the protochlorophyllide ester was photoconverted to chlorophyll a.
The Effect of Age, Pre‐conditioning, and Water Stress on the Transpiration Rates of Douglas‐Fir (Pseudotsuga menziesii) Seedlings of Several Ecotypes
Authors: UNTERSCHEUTZ P. , RUETZ W. F. , GEPPERT R. R. , FERRELL W. K.
Published: April 2006

Seedlings of Douglas‐fir from seed of a number of mesic and xeric origins were grown in growth chambers and a nursery to various ages up to 16 weeks. Measurements were made to determine the effect of seedling age, growth chamber and nursery pre‐conditioning, and seed source on transpiration rates under closely controlled laboratory conditions. Additional experiments were conducted on seedlings of two contrasting ecotypes to determine the effect of different pre‐conditioning combinations of plant and soil water potential on seedling transpiration rates. Results show that well‐watered seedlings of two mesic ecotypes show no decline in transpiration rates per unit leaf area up to 16 weeks of age while corresponding seedlings of three exeric ecotypes do decline. The growth chamber pre‐conditioning results in lower seedling transpiration rates and more decline in seedling transpiration rates with increasing plant water stress than for nursery pre‐conditioning. In a similar way, the xeric ecotype seedlings have more decline in transpiration rates with increasing plant water stress than do the mesic ecotype seedlings. Soil water potential influences transpiration rates through pre‐conditioning effects. Seedlings which have experienced prior soil moisture stress decrease transpiration more in response to low plant water potentials than do plants which have experienced no soil moisture stress. These behavioral characteristics illustrate adaptive means by which seedlings conserve water through the interaction of genetic and preconditioning mechanisms.
Stacking Capacity and Chlorophyll Forms of Thylakoids in Normal and Mutant Maize Chloroplasts of Different Granum Content
Authors: DEMETER S. , HORVÁTH G. , JOÓ F. , HALÁSZ N. , FALUDI‐DÁNIEL ÁGNES
Published: April 2006

Stacking of chloroplast lamellae, isolated from normal and carotenoid mutant chloroplasts of maize (Zea mays L.), was determined after a high‐salt treatment.

Stacking of isolated lamellae under favourable ionic conditions was almost identical with that occurring in intact chloroplasts; thus, differences in granum content could be attributed to the architectural properties of lamellae.

Gaussian analyses, performed on the red band of room temperature absorption spectra, have shown that chloroplasts with lamellae of high stacking capacity contain relatively more Chl a662 than chloroplasts containing lamellae of low stacking capacity. The presence of Chl a705–708 was characteristic of preparations containing considerable amounts of stroma lamellae.
Action Spectrum for Photoactivation of the Water‐splitting System in Plastids of Intermittently Illuminated Wheat Leaves
Authors: INOUE YORINAO , KOBAYASHI YOSHICHIKA , SAKAMOTO EMIKO , SHIBATA KAZUO
Published: April 2006

The chloroplasts from wheat leaves developed under intermittent illumination (1 ms light + 12 min dark) were able to photoreduce DPIP with DPC as electron donor but unable to photoreduce DPIP with water as electron donor. On exposure of these leaves to continuous light, the Hill activity with water as electron donor was rapidly induced. The photoactivation was sensitive to the treatment with DCMU prior to exposure to continuous light. The action spectrum for the photoactivation showed a sharp band at 680 nm with a distinct shoulder at 650 nm, and was similar to the absorption spectrum of photosytem‐2 particles. These data suggest that the electron transfer driven by photosystem 2 is essential for the activation of the water‐splitting system in the chloroplasts of intermittently illuminated leaves.