bluuebunny/crossref_metadata_2025 huggingface dataset:
Modification of Tobacco Leaf Glycolate Oxidase Activity by Chlorogenic Acid and Other Polyphenols
Authors: DE JONG DONALD W.
Published: April 2006

Glycolate oxidase extracted from tobacco leaves (Nicotiana tabacum L. cv. NC‐95) and assayed by the 2,6‐dichlorophe‐nolindophenol reduction method was stimulated by chlorogenic acid and other o‐diphenols but not by p‐diphenols such as hydroquinone. Chlorogenic acid also protected the enzyme against certain enzyme antagonists. A novel assay utilizing horseradish peroxidase with the chromogen o‐dianisidine was developed for detecting glycolate oxidase in conjunction with disc electrophoresis. Dissociation of glycolate oxidase into an active monomer during ammonium sulfate fractiona‐tion was confirmed electrophoretically. After electrophoresis, flavin mononucleotide was required for monomer activity whereas chlorogenic acid was inhibitory to enzyme band development.
Simulation of Rhythmic Tree Growth under Constant Conditions
Authors: BORCHERT R.
Published: April 2006

The observed rhythmic growth of trees under relatively uniform environmental conditions has been ascribed by some authors to endogenous factors, by others to slight fluctuations of environmental factors. A model for the simulation of rhythmic growth was developed based on the assumption that endogenous rhythms can result from feedback interaction between two potentially continuous processes, like shoot and root growth, if the slower process is rate limiting for the faster one. Rhythmic growth in trees would be the consequence of feedback mechanisms needed for maintaining a constant shoot: root ratio. Period length of the rhythms depends upon the rates of the growth processes involved. Environmental factors modify period length through affecting growth rates. Growth patterns predicted by the model compare well with growth measurements of tropical trees. The transition from intermittent to continuous growth, as observed under certain conditions, can be simulated by varying a single parameter in the model.
Subcellular Distribution of Basal and Cation‐sensitive ATPases in Roots of Phaseolus vulgaris
Authors: WILKINS J. A. , THOMPSON J. E.
Published: April 2006

A smooth microsomal fraction isolated from homogenates of Pbaseolus vulgaris root tissue has been found to possesss a highly active basal ATPase (measured in the absence of added cations). The microsomal membranes also feature a cation‐sensitive ATPase which responds to Mg2+, Na+ and K+, but in a manner that is highly variable with pH. In contrast, membrane fragments prepared by a technique designed to yield purified plasma membrane were capable of little or no hydrolysis of ATP either in the presence or absence of added cations. This suggests that the microsomal activity is a reflection of membrane‐bound ATPase which has been derived from cytoplasmic membranes, possibly the tonoplast, rather than plasma membrane.
Abscisic Acid Inhibition of Gibberellic Acid and Cyclic 3′,5′‐Adenosine Monophosphate Induced α‐Amylase Synthesis
Authors: BARTON K. A. , VERBEEK R. , ELLIS R. , KHAN A. A.
Published: April 2006

The induction of α‐amylase synthesis in barley aleurone by cyclic 3′,5′‐adenosine monophosphate or GA3 was inhibited by abscisic acid. The concentration of ABA required to inhibit α‐amylase induction by the cyclic nucleotide in the extract was one‐fiftieth to one hundredth of that required for GA3‐induced α‐amylase. It is concluded that the effects of ABA on GA3 and cyclic nucleotide induced α‐amylase synthesis in the aleurone are independent and indirect.
Effect of Light, Temperature and Substrate during Spore Formation on the Germinability of Conidia of Colletotrichum falcatum
Authors: SINGH PRITAM
Published: April 2006

This paper presents results on the effect of light, temperature and substrate during spore formation on the germinability of conidia in Colletotrichum falcatum. Light seems to have no effect on the germination of conidia unless the cultures were exposed to a high intensity of light during sporulation, in which case the spores showed a reduced germination and an increased appressoria formation. Conidia produced at temperatures higher than the optimum showed better germination and less appressoria formation than the spores produced at the temperature optimum for the growth and sporulation of the fungus. A similar increase in germination was also observed in conidia obtained from inoculated sugarcane leaves as compared to those produced on culture media.

The light type virulent isolates of C. falcatum showed greater sensitivity to all these treatments than the dark type weakly pathogenic isolates.
La dormance embryonnaire chez Taxus baccata: Influence de la composition du milieu liquide sur I'induction de la germination Par
Authors: LE PAGE‐DEGIVRY M. TH. , GARELLO G.
Published: April 2006

Embryo dormancy of Taxus baccata var. fastigiata is eliminated when cultured continuously in nutritive liquid medium. An equivalent percentage of germination is obtained when the embryos are transferred to agar medium after 8 days of liquid culture. There is no morphological development of the embryo during the period in the liquid medium. But we have ascertained that water‐soluble germination inhibitors present in the embryo are leached out into the medium, permitting germination.

Germination is totally absent when the embryos are cultured continuously in distilled water, alone or with minerals; incidental in sucrose solution; and maximal when the medium contains sucrose and Ca2+ or K+ ions.

The extent of germination on agar medium depends upon the composition of the liquid medium in which the embryos are cultured for the initial 8 days. But this preliminary culture in the liquid medium does not always remove the endogenous inhibitors, irrespective of its composition. This can be achieved only in the presence of sucrose; and this process can be made more effective by the addition of Ca2+ ions.
Utilization of Carbohydrates by Rhynchosporium secalis II. Absorption and Metabolism of Glucose, Galactose and Galacturonic acid
Authors: AYRES P. G. , OLUTIOLA P. O.
Published: April 2006

Glucose, galactose and galacturonic acid were taken up at different rates by the fungus Rhynchosporium secalis and were intracellularly converted to other forms of carbohydrate at different rates. These differences explain why, when there is only a single source of nutrient carbon in the growth medium, development of the fungus is greatest when glucose is present and least when galactose is present.

Glucose and galactose were taken up by the same mechanism for their uptake showed a reciprocal competitive inhibition. Uptake mechanisms had a high affinity for glucose (apparent Km 2.76 mM) and galacturonic acid (apparent Km 3.10 mM) and a low affinity for galactose (apparent Km 29.67 mM). After uptake, galactose accumulated in the mycelium, whereas glucose and galacturonic acid were rapidly converted to other soluble carbohydrates, principally trehalose and mannitol. The insoluble carbohydrates within the mycelium were little affected by the type of carbohydrate that was supplied to the fungus.
Peptide‐Induced Morphogenesis in the Nematode‐Trapping Fungus Arthrobotrys oligospora
Authors: NORDBRING‐HERTZ BIRGIT
Published: April 2006

The present investigation shows the ability of peptides to induce capture organ formation in Arthrobotrys oligospora when applied in a synthetic low nutrient medium.

Under certain conditions casitone was shown to induce capture organ formation. The active principle in casitone was concentrated and purified by alternating procedures of ion exchange chromatography and gel chromatography in pyridine‐acetic acid buffers. Crude casitone solutions were applied to columns of Dowex 50 W‐X2 and eluted stepwise with 0.1–1.0 M pyridine‐acetic acid pH 3.2–5.1. Active portions, free from most acid and neutral amino acids, were further purified on columns of Sephadex G‐10 in 0.1 M pyridine‐acetic acid pH 4.6. Aromatic amino acids and large molecules in the void volume could be separated from an active peptide mixture which was subjected to renewed ion exchange chromatography on Bio‐Rad AG 50 W‐X2. By stepwise and/or gradient elution in 0.1–0.5 M pyridine‐acetic acid pH 3.2 fairly purified peptides were obtained.

The composition of the test medium is an important factor in spontaneous capture organ formation. The peptides isolated from casitone induced capture organ formation, when given to the fungus in a synthetic mineral salt medium supplied with thiamin and biotin. Similar effects were obtained with small synthetic peptides in the same concentration (0.1 mg/ml). A large variety of peptides seem to be active when applied in a suitable medium. This was especially true for peptides with Rf > Rfleu on thin layers of cellulose developed with butanol‐acetic acid‐water (4: 1: 1). Of the peptides investigated valyl‐peptides exerted the most drastic effect.
Antibiotic Activity of the Chrysophyte Ochromonas malhamensis
Authors: HANSEN JENS AAGE
Published: April 2006

The effects were studied of extracts from the chrysophyte Ochromonas malhamensis on Staphylococcus aureus, Bacillus megaterium, Bacillus subtilis and Escherichia coli. The extracts contained three different antibiotically active substances, one of which was produced during the extraction. The other two had no effect on E. coli, but inhibited the growth of the three other bacteria.

The present experiments show that one of the products increases its antibiotic activity when exposed to visible light, and that its activity is enhanced by boiling the extracts for 5 minutes. The other active substance is not affected by light, but shows increased activity after being boilt for 5 minutes.
Mineral Nutrient Requirements ofVaccinium vitis idaeaandV. myrtillus
Authors: INGESTAD TORSTEN
Published: April 2006

The mineral nutrient requirements ofVaccinium vitis idaeaL. andV. myrtillusL. have been studied. It is found that the optimum nutrient proportions are similar to those of birch seedlings except for a relatively low potassium requirement. The nitrogen sources ammonium and nitrate are both usable at low concentrations. A system with both sources present seems preferable. The ammonium uptake is then much more rapid than the nitrate uptake. The optimum total concentration falls within the low salt range and is about the same as found for birch seedlings, but the sensitivity to high salt concentrations is more pronounced in the Vaccinium species. A very marked characteristic of the nutrient absorption is the rapid calcium uptake. The results are discussed in relation to similar experiments with birch and cucumber seedlings, representing species with a wide or calcareous ecological adaptation.
Properties of the Ribosome‐Bound Peroxidase/IAA‐oxidase of Cabbage Roots
Authors: RAA JAN
Published: April 2006

The ribosomal fraction of cabbage roots contains IAA‐oxidase and peroxidase activity. EDTA dissociates these enzymes from the ribosomal RNA. The IAA‐oxidase of intact ribosomes shows allosteric, whereas that of EDTA disintegrated shows conventional kinetics. Gel electrophoresis separated three peroxidases from the ribosomal RNA.
The Mechanism of Low Temperature Dormancy in Mature Seeds of Syringa Species
Authors: JUNTTILA OLAVI
Published: April 2006

The mechanism of seed dormancy at low temperatures (15‐9°C) was investigated in the seeds of Syringa josikaea, S. reflexa and S. vulgaris. Low temperature dormancy in Syringa species was mainly imposed by endosperm embedding the radicle. Different degrees of embryo dormancy may occur in S. reflexa seeds. In most cases the low temperature dormancy was broken completely by removing the endosperm around the radicle. The endosperm did not seem to contain significant quantities of germination inhibitors, and the results indicate that it prevents germination mainly due to its mechanical resistance. The mechanical resistance of endosperm did not change during chilling or during induction of dormancy by high temperature incubation. The strength of the endosperm decreased rapidly in non‐dormant seeds before visible germination. Similar changes were not observed in dormant seeds. Generally, the strength of the endosperm was lower in the non‐ (or less) dormant species S. josikaea and S. vulgaris than in the more dormant S. reflexa seeds. The growth potential of the embryos, measured as their ability to germinate in osmotic solutions (mannitol or polyethylen glycol 4000), was increased by chilling and by GA3‐treatment. The growth potential of untreated S. josikaea and S. vulgaris embryos was generally higher than that of S. reflexa embryos. Acid ethyl acetate fractions of methanol extracts from embryos of all three species contained substances with GA3‐like activity in the lettuce hypocotyl test. The activity was found at Rf 0.9–1.0 on paper chromatograms run in distilled water. No significant changes in the activity were detected during chilling or prior to visible germination.
Gibberellin‐like Substances in Developing Barley Grain and Their Relation to Dry Weight Increase
Authors: MOUNLA M. A. Kh. , MICHAEL G.
Published: April 2006

Gibberellin‐like activity of two varieties of barley (Hordeum vulgare L.) at different stages of grain development was determined by barley endosperm bioassay (acid phosphatase bioassay).

Activity of the acidic ethyl‐acetate fraction (“free” GAs) in both varieties displayed two maxima, a first maximum at the 9th day and a second one 20 to 21 days after pollination.

Activity of the n‐butanol fraction (“bound” GAs) first dropped to a minimum level at the 9th day, then increased to reach a maximum 32 days after pollination, and finally decreased again towards maturity. From the 9th day after pollination, a conversion of “free” GAs to “bound” GAs has probably occurred.

From the 12th day after pollination, the curves of rate of dry weight increase and of “free” GAs run nearly parallel, but the latter reached its maximum about 2–4 days earlier than the former.

The results indicate that gibberellins may participate in the regulation of the accumulation processes into the barley grain.
Spring Mobilization of Protein Nitrogen in Apple Bark
Authors: TROMP J. , OVAA J. C.
Published: April 2006

Mobilization of protein nitrogen in the spring was studied in bark of stems of unringed and double stem‐ringed apple rootstocks M.7 given different nitrogen treatments.

A ready protein hydrolysis occurred; the proteins contributed the greater part of the storage nitrogen exported to the growing parts. Protein hydrolysis was little affected by the supply of newly absorbed nitrogen. Movement of nitrogen out of the bark between the rings could not be demonstrated. Protein breakdown in the isolated bark sections was slightly reduced.

Arginine was the predominant amino acid in the proteins of the trees with a high level of storage nitrogen but was not conspicuous in the low‐nitrogen trees. The protein composition changed little during hydrolysis. Only the share of arginine in the high‐nitrogen trees dropped appreciably. It is suggested that the high‐nitrogen trees possess a special storage protein characterized by a high arginine content.

Analysis of the nitrogen fraction of isolated bark sections showed that the composition of the soluble nitrogen was characterized by a high level of asparagine and especially of arginine, and was quite different from the composition of the proteins. The data suggest that the asparagine in particular originated largely from transformation of the various amino acids set free during protein hydrolysis.
Evaluation of UV‐Induced Mutants of Chlorella vulgaris for Single Cell Protein I. The Screening Effect of Cycloheximide and 6‐Methylpurine
Authors: PASSERA CALVINO , FERRARI GIOVANNI
Published: April 2006

Chlorella vulgaris was irradiated with UV doses allowing a 0.1 per cent survival. Dark recovery and photoreactivation were carried out either in the presence or in the absence of an inhibitor of protein synthesis. Faster growing and faster greening colonies were selected, and the amino acid composition of the mutant strains were evaluated. Higher growth and photosynthetic rates, higher chlorophyll content and lower respiration rate were shown by all mutants irrespective of the selection procedure. Selection against cycloheximide led to higher protein and RNA, but lower carotenoid content, whereas mutants selected against 6‐methylpurine showed, in addition to a protein and carotenoid increase, a more favourable protein: RNA ratio.
Chlorophyll Formation in the Dark I. Chlorophyll in Pine Seedlings
Authors: BOGDANOVIĆ M.
Published: April 2006

In black pine (Pinus nigra) chlorophyll was first detected two days after planting of the soaked seeds. There was a slight change in the chlorophyll content between two and five days, then a faster chlorophyll synthesis started. The maximum chlorophyll content was found after 15 days of germination. Thereafter the content showed a gradual decrease. The chlorophyll a/b ratio decreased from 10 at two days to 3 after five days. Protochlorophyllide did not accumulate after 6 days of germination.
Chlorophyll Formation in the Dark II. Chlorophyll in Wheat Leaves Transplanted to Pine Megagametophytes
Authors: BOGDANOVIĆ M.
Published: April 2006

Chlorophyll production in wheat (Triticum vulgare) leaves takes place in the dark when wheat embryos are transplanted to the megagametophytes of black pine (Pinus nigra).

The chlorophyll content in the wheat leaves is about half that in black pine cotyledons of the same age.
Effect of Water Stress, Temperature, and Light on Photosynthesis in Alder Seedlings
Authors: HARI PERTTI , LUUKKANEN OLAVI
Published: April 2006

Seedlings of Alnus incana (L.) Moench were studied in controlled environmental conditions. Net photosynthetic capacity of four plants simultaneously as well as light, temperature, and atmospheric water pressure deficit were continuously recorded during approximately two months. The potted plants were continuously given known quantities of water.

Two different effects of water stress were found in the experimental plants. When sufficient amounts of water had been available to them, photosynthetic CO2 fixation rates largely followed the variation in temperature and light. On the other hand, after prolonged water stress, higher temperatures caused a large decrease in net CO2 uptake even if the plant apparently had sufficient water during the actual measurements. Possible mechanisms for this effect are discussed.

Effects of water stress on photosynthesis were studied at a constant temperature as well as in conditions where temperature, light, soil water content, and atmospheric water vapor pressure were allowed to vary in a complex pattern. Mathematical models for expressing net CO2 uptake as a function of environmental variables were constructed for both of these experimental situations. However, only the latter approach clearly demonstrated the fundamental role of temperature in controlling the photosynthesis of plants under water stress.
Mating Reaction in Saccharomyces cerevisiae. IV. Retardation of Deoxyribonucleic Acid Synthesis
Authors: SHIMODA CHIKASHI , YANAGISHIMA NAOHIKO
Published: April 2006

When a and a type haploid cells of Saccharomyces cere‐visiae were mixed and cultured, deoxyribonucleic acid synthesis was retarded but ribonucleic acid and protein syntheses were not. It was found that culture filtrate of a type cells inhibited deoxyribonucleic acid synthesis of a type cells and that of a type cells inhibited that of a type cells. Thus, sex‐specific diffusible substances secreted by opposite mating type cells are thought, at least partly, to be responsible for the retardation of deoxyribonucleic acid synthesis.
Glycolate Metabolism in Eurasian Watermilfoil (Myriophyllum spicatum)
Authors: STANLEY RONALD A. , NAYLOR A. W.
Published: April 2006

The metabolism of glycolate by Eurasian watermilfoil (Myriophyllum spicatum L.), a submersed angiosperm, was studied by feeding radioactive glycolate and glyoxylate and by analysis of glycolate and glycolic acid oxidase. Evidence for operation of the glycolate pathway is given. Glycolic acid oxidase occurs at levels comparable to amounts in species showing photorespiration. This species has a high affinity for CO2 and a possible mechanism for it is described.
Golgi Apparatus Mediated Polysaccharide Secretion by Outer Root Cap Cells of Zea mays. III. Control by Exogenous Sugars
Authors: JONES DANIEL D. , MORRE D. JAMES
Published: April 2006

Sugars supplied to germinating seedlings of maize (Zea mays L.) regulate the secretion of polysaccharides by the outer cells of the root cap. The polysaccharide secreted by these cells adheres to the root tip as a droplet and the size of the droplet was used to quantitate polysaccharide secretion. The polysaccharide contains glucose, galacrose, and galacturonic acid residues with smaller quantities of mannose, arabinose, xylose, fucose and rhamnose. These sugars supplied to maize seedlings had marked effects on the rate of polysaccharide secretion by root tips. The effects on secretion were independent of the growth rates of the roots. Glucose, fucose and xylose increased droplet size 1.5–2 fold (as did sucrose, maltose, lacrose, fructose and ribose) whereas galactose, arabinose and galacturonic acid were inhibitory. Mannose increased dropler size 5–7 fold.

The marked effect of mannose on polysaccharide secretion was due to an increased rate of secretion combined with a longer phase of extrusion of polysaccharide into the forming droplet. The effect of mannose was partially reversed by inorganic phosphate and other sugars (except for fucose which had no effect or promoted secretion in the presence of mannose). In contrast to sucrose, mannose stimulated secretion in a maize variety having a high sugar endosperm (high endogenous sugar). The results suggest that regulation of secretion by mannose is due to an alteration of normal sugar metabolism; whereas stimulation of secretion by sucrose and other sugars may be due to an increased availability of sugars for metabolism.
The Influence of Heat Processing and Mechanical Disintegration on Yeast for Single‐Cell Protein
Authors: MOGREN HAKAN , HEDENSKOG GUDMUND , v. HOFSTEN ANGELICA
Published: April 2006

Yeast was processed by means of different technical drying procedures, heating in water suspension, and mechanical disintegration. The influence on the ultrastructure, the nutritive value and on the availability of the cell nitrogen‐containing compounds to chemical extractants was studied.

On micrographs no cell wall disrupture could be observed after any of the heat treatments. The internal cell structure was affected at the higher temperatures. After drum drying this structure was destroyed to a large extent. The heat treatments increased the nutritive value compared to unheated yeast cells but did not increase the availability of the cell content to chemical extractants. Mechanical disintegration increased both the nutritive value and the availability to chemical extractants.

Heat processes and mechanical disintegration give high nutritive value to the yeast. Mechanical disintegration is advantageous when processing steps such as extraction with chemicals are necessary for obtaining specific protein products.
The Role of Hormones in Controlling the Mechanically Induced Dormancy of Suaeda spp.
Authors: BOUCAUD JEAN , UNGAR IRWIN A.
Published: April 2006

Seeds of several taxa in the genus Suaeda with a mechanically resistant testa were stimulated to germinate with applications: of 1 × 10−4M gibberellic acid (GAg). The barley endosperm bioassay indicated that the non‐dormant taxa, S. macrocarpa, had high initial gibberellin‐like activity while the dormant varieties, S. flexilis and S. vulgaris, had not. Soaking for 2 days increased the gibberellin‐like activity of the dormant taxa. At 20 days hormonal activity was repressed, and few seeds germinated. The barley endosperm bioassay also revealed an inhibitor activity in the dormant varieties. The wheat coleoptile bioassay and UV irradiation of thin layer chromatograms indicated that an inhibitor occurred at the Rf of cochromatographed ABA and that it had similar inhibitory characteristics.
A Comparison of Mitochondria Isolated from Male‐Sterile and Nonserile Cytoplasm Etiolated Corn Seedlings
Authors: GENGENBACH B. , KOEPPE D. E. , MILLER RAYMOND J.
Published: April 2006

Toxins from Helminthosporium maydis race T and Phyllosticta maydis have been found to affect the functional processes of corn mitochondria isolated from Texas male‐sterile (T) cytoplasm, but not of mitochondria isolated from nonsterile (N) cytoplasm.

The effects of chemicals known to induce responses similar to those of the toxin were compared on mitochondria isolated from T and N cytoplasm inbreds (W64A, Zea mays L.). Valinomycin, gramicidin, and decenylsuccinic acid (DSA) each caused more swelling (measured by transmission changes in %) of N mitochondria than of T mitochondira. The stimulation of exogenous NADH oxidation was the same for N and T mitochondria in the valinomycin, DSA, and Ca2+ plus phosphate treatments, was greater for T mitochondria than for N mitochondria in the gramicidin and DNP treatments, and was greater for N mitochondrai than for T mitochondira in the Ca+2 minus phosphate treatment. Sodium azide inhibited NADH oxidation equally for N and T mitochondria. In addition, N and T mitochondria had similar respiration rates for various substrates and equal efficiencies of oxidative phosphorylation. In contrast to the specificity of toxins for T mitochondria, none of the treatment effects were specific for N or T mitochondria. The results indicate that mitochondria isolated from N and T cytoplasm generally respond similarly to various conditions, but that there can be quantitative differences in the response. The extent to which these differences represent cytoplasmically controlled modification of mitochondrial physiology or structure is not known.
Selective Formation of Photosystem 1 under Illumination at Low Intensity
Authors: OGAWA TERUO , SHIBATA KAZUO
Published: April 2006

Analyses of chlorophylls a and b and P700 in the wheat leaves grown for 8 days under illumination with white light at different intensities suggested selective formation of photosystem 1 of the photosynthesis at low light intensities. This was confirmed for the two types of chloroplasts isolated from leaves grown at light intensities of 1.1 and 240 μ W/cm2, respectively, by measuring their pigment compositions, activities of photosystems 1 and 2, and absorption and fluorescence spectra. The chloroplasts developed at the low intensity showed properties only of photosystem 1 while those developed at the high intensity showed properties of both photosystems 1 and 2. Only photosystem 1 particles were obtained by fractionation of low intensity chloroplasts by treatment with digitonin followed by centrifugation, while high intensity chloroplasts could be fractionated into photosystem‐1 and photosystem‐2 particles. When the leaves grown at low light intensity were illuminated with strong light, photosystem 2 was developed. The fluorescence emission spectrum of low intensity chloroplasts at 77°K showed two peaks at 685 and 734 nm, and the spectrum of high intensity chloroplasts showed three peaks at 685, 697 and 740 nm.
A Specific Response to Toxic Cadmium Levels in Red Kidney Bean Embryos
Authors: IMAI IRMA , SIEGEL S. M.
Published: April 2006

Cadmium salts are highly toxic to excised embryos ofPhaseolus vulgariscv. Red Kidney, inhibiting growth at concentrations in excess of 3 mg/L Inhibition is accompanied by specific toxic responses, namely inhibition of greening and induction of acute curvature in the embryonic axis. Comparisons among some 24 elements at 10 mg/l for cadmium‐like effects showed silver to affect curvature, but not greening, while cobalt and nickel were the converse.
Effects of Gibberellic Acid and Abscisic Acid on Shoot Formation in Tobacco Callus Cultures
Authors: THORPE TREVOR A. , MEIER DONALD D.
Published: April 2006

Tobacco (Nicotiana tabacum L. cv. W. 38) callus grown on a shoot‐forming medium was exposed to gibberellic acid (GA3) and abscisic acid (ABA) for varying lengths of time and at different periods during culture. The results suggest that if the tissue accumulated sufficient GA3 prior to the initiation of meristemoids and shoot primordia, repression of shoot formation occurred. This repression was not reversed by increasing the levels of auxin or cytokinin in the medium, but ABA could partially overcome the GA3 repression of shoot formation.
Rhizomorph Formation in Fungi III. The Effect of Ethanol on the Synthesis of DNA and RNA and Uptake of Asparagine and Phosphate in Armillaria mellea
Authors: SORTKJÆR O. , ALLERMANN K.
Published: April 2006

Growth and rhizomorph formation in Armillaria mellea (Vahl ex Fr.) Quél. can be stimulated by ethanol when grown on a synthetic glucose medium. The content of DNA (deoxy‐ribonucleic acid) and RNA (ribonucleic acid) in cultures of A. mellea have been followed during a growth period in relation to growth (dry weight) and ethanol uptake with 3 different initial ethanol concentrations. The continuous increase in dry weight as well as DNA and RNA contents during growth showed similar exponential rates as long as ethanol was present in the medium. The final amounts were proportional to the initial ethanol concentration.

A further supply of ethanol caused a similar proportional increase in dry weight and also in the DNA and RNA contents, which indicates that the growth stimulated by ethanol is caused by cell divisions rather than an accumulation of lipids or polysaccharides. Uptake of asparagine and phosphate were also stimulated by ethanol.
The Characterization of a Cerebroside Sulfate from the Mycelia of Glomerella cingulata
Authors: ANEKWE GREGORY E. , LEE LINDA L.
Published: April 2006

A sulfur‐containing lipid with chromatographic properties in several systems equal to the commercial sulfolipid (extracted from bovine spinal cord, Applied Science) has been isolated in 0.6 % yield (dry weight basis) from the mycelia of Glomerella cingulata. About 35 % of exogenous Na35SO4 incubated with the mycelial medium for 72 hours was recovered in the cerebroside sulfate fraction, with only traces of 35S activities in other lipid fractions.
A Comparison of the Effect of 6‐Benzylaminopurine Derivatives on some Aspects of Plant Growth
Authors: VAN STADEN J.
Published: April 2006

Soybean callus treated with 6‐benzylaminopurine and its riboside elicit better growth than 6‐benzyladenosine 5′‐monophosphate. This can probably be attributed to differences in the rate at which the different compounds are taken up and/or metabolized. In the case of lettuce seed germination the ribotide is unable to substitute for red light in the dark; this supports previous suggestions that in certain situations it is physiologically less active than the free base or riboside.
The Glycoprotein Nature of Indoleacetic Acid Oxidase/Peroxidase Fractions and their Development in Pea Roots
Authors: DARBYSHIRE BEN
Published: April 2006

IAA oxidase/peroxidase active fractions were separated using concanavalin A‐sepharose into glycoprotein and non‐glycoprotein fractions. No IAA oxidase peak was separable from peroxidase activity. The development of these fractions were followed in pea roots over a four day period. Initially the nonglycosylated IAA oxidase/peroxidase was the dominant fraction with the IAA oxidase/peroxidase ratio remaining close to unity. The glycosylated fraction developed later with IAA oxidase the dominant activity. Differential carbohydration of IAA oxidase/peroxidase fractions may determine the intracellular sites of activity of this molecular species.
Multiphasic Uptake in Plants II. Mineral Cations, Chloride, and Boric Acid
Authors: NISSEN PER
Published: April 2006

Uptake of alkali cations, metal ions, chloride, and boric acid is shown by reanalysis of available data to be mediated by single, multiphasic mechanisms which may be fundamentally similar in a variety of plants and tissues.
Control of Ethylene‐Induced Responses in Plants by a Substituted Benzothiadiazole
Authors: PARUPS E. V.
Published: April 2006

The compound 5‐methyl‐7‐chloro‐4‐ethoxycarbonylmethoxy‐1,2,3‐benzothiadiazole inhibited the uptake and translocation of auxin, promoted bean hook opening and inhibited abscission of florets and epinastic responses in plants. The inhibition of epinasty was not eliminated by rectifying the ethylenepromoted unequal distribution of auxin normally thought to be responsible for epinastic curvature.
The Water Relations of Pinus sylvestris II. Comparative Field Studies of Water Potential and Relative Water Content
Authors: HELLKVIST JERK
Published: April 2006

Comparative field studies of water potential and relative water content in needles of Scots pine, Pinus sylvestris L., were carried out in September‐October 1965, in June 1966 and in July‐August 1968. The sample trees were grafts, planted in 1946 and belonging to two clones, growing in close proximity and under the same environmental conditions. The main subject of the investigation was to determine whether differences in water potential and/or relative water content existed between these two clones, and if these differences could be correlated to the growth differences and thus aid in the development of selection criteria. The results obtained demonstrate such differences in water potential but not in relative water content. The differences were not consistent through the experimental periods. The clone which had the highest water potentials in June 1966, had the lowest in September‐October 1965 and in July‐August 1968. The results revealed that the clone which showed the fastest total growth, normally had the lowest water potentials when irradiated. In 1968 the current and the previous season's needles were separately investigated. The water potential and relative water content were always higher in the current season's needles. Highly significant negative correlations between water potential or relative water content and irradiance, temperature, and vapour pressure deficit were found.
Analysis of Rice Mutants by Low Temperature‐Derivative Spectrophotometry in Relation to Pigment Compositions and Photochemical Activities
Authors: INOUE YORINAO , OGAWA TERUO , KAWAI TAKESHI , SHIBATA KAZUO
Published: April 2006

The chloroplasts of five rice (Oryza sativa) mutants examined in the present study possessed the following pigment and activity characteristics as compared with those of normal strain (Nohrin No. 8); a) less chlorophylls (especially, chlorophyll b, the molar ratio of a to b= 6 ∼ 41) and less carotenoids but higher ratios of β‐carotene to chlorophylls; b) only photosystem 1 particles were obtained by density gradient centrifugation of digitonin‐treated mutant chloroplasts while both photosystem 1 and 2 particles were obtained from normal strain chloroplasts; c) the photosystem 2 activities of mutant chloroplasts were lower (48 ∼ 81 %) than that of normal chloroplasts while their photosystem 1 activities were 1.9 ∼ 2.4 times higher. The derivative absorption spectrum of the normal chloroplasts (a/b= 4) measured at liquid nitrogen temperature showed many small but distinct maxima and minima in the red region in addition to those observable for chlorophylls in solution. These band structures including the French inflection were lost partially in the derivative spectra of three mutants with a/b= 6, 8 and 11 and almost completely in those of the remaining two mutants with a/b= 18 and 41. The lack of such band structures reflecting specific states of chlorophylls in vivo was attributed to the absence of some conformational structures such as those expected in photosystem‐2 particles, which are formed by the presence of chlorophyll b and are resistant to the digitonin treatment. Chlorophylls in specific states in such structures were thought to exhibit a higher photosystem 2 activity.
Rhythmicity of Flowering in Pharbitis nil
Authors: SPECTOR CALVIN , PARASKA JOHN R.
Published: April 2006

When young seedlings of Pharbitis nil are grown under continuous light, except for a single inductive dark period, they flower to a varying degree, depending on when this dark period is given. Plants become sensitive to this induction approximately three days after the seedlings emerge from the soil. The expression of flowering varies in a rhythmic fashion for three or more cycles, when an inductive dark period is given at progressively later times. The time between maximum expression of flowering is 24 hours or somewhat longer. It appears necessary that the inductive dark period be of sufficient duration, to only partially induce the plants to flower for this rhythm to be expressed. Under the conditions employed in this study, this duration is 12 hours. If this rhythm is endogenous, it exists at least from when the plants emerged from the soil since no environmental cues are given after that time, and it raises questions of the interpretations of data from previous studies with this organism.
Activity of Various Growth Substances in the Avena First Internode Test
Authors: JUNTTILA OLAVI , HEIDE OLA M.
Published: April 2006

The elongation growth of the Avena first internode segments was studied in the presence of one or several of the following growth substances: indoleacetic acid (IAA), 6‐fur‐furylamino purine (FAP, kinetin), 6‐benzylamino purine (BAP), gibberellin A3 (GA3) and A4+7 (GA4+7), and abscisic acid (ABA).

The cytokinins at concentrations of 10−7 to 10−6M stimulated growth with 4 to 6 per cent but this effect was not statistically significant. Concentrations higher than 5 × 10−6M inhibited growth. FAP and BAP (from 10−8M to 10−6M) had no significant interaction with any other growth substance used.

The two‐factor interactions of IAA × ABA, IAA × GA3, and GA3× ABA, as well as the three‐factor interaction IAA × ABA × GA3 were significant. However, the IAA × ABA interaction was significant only when high concentration (10−6M) of ABA was used. The growth inhibition produced by 10−7 and 10−6M ABA was overcome by about equimolar concentrations of IAA.

The stimulation of growth by GA3 and GA4+7 (10−9 to 10−7M) was prevented by simultaneous application of ABA, and it was reduced significantly by application of IAA (10−7 to 10−8M). GA3 at 10−8M combined with different concentrations of IAA gave slightly higher elongation than IAA alone but the observed values were significantly lower than expected assuming independent additive action.
The Effects of Canavanine on Protein and Nucleic Acid Synthesis in Canavanine Resistant and Sensitive Species of Higher Plants
Authors: WEAKS T. E. , HUNT G. E.
Published: April 2006

The effectiveness of the inhibitor, canavanine, was evaluated by examining its action in Canavalia ensiformis and Glycine max. Isolated roots were grown in culture tubes containing White's medium plus canavanine or arginine. A differential effect of canavanine on the incorporation of precursors of DNA, RNA, and protein was found, which is assumed to be related to the ability of the plant to utilize canavanine in reactions typically involving arginine. Canavanine was not found to affect DNA, RNA, or protein synthesis in Canavalia ensiformis, a plant in which this amino acid is synthesized naturally. In the canavanine sensitive species, Glycine max, of the same subfamily Papilionoideae, canavanine was observed to inhibit strongly DNA, RNA, and protein synthesis. A primary inhibition of the RNA synthesizing system is suggested. The data indicate the canavanine inhibitions are more complex than a simple competition with arginine in protein synthesis.
Comparative Studies on Physiological and Morphological Features of Bearing and Non‐Bearing Spurs of the Apple Tree II. The Effect of Fruiting and Growth Regulator Sprays on Respiration Mate of Leaves
Authors: GROCHOWSKA MARIA J. , LUBIŃSKA ANNA
Published: April 2006

The respiration rate was investigated in leaves of bearing and non‐bearing spurs of biennially fruiting apple trees, Landsberger Reinette cultivar, with a Warburg apparatus. Trees in “off year” were sprayed with gibberellic acid (GA) and those in “on year” with succinic acid‐2,2‐dimethylhydra‐zide (SADH) and naphthaleneacetic acid (NAA). Two‐year results showed that the respiration rate of leaves of bearing spurs was 10 to 25 per cent higher than that of the non‐bearing spur leaves. GA increased the respiration of leaves of non‐bearing spurs about 25 per cent, on an average. SADH and NAA greatly decreased the respiration of bearing spur leaves; the latter about 30 per cent of that of the controls. At the same time SADH and NAA caused a marked reduction of growth in terminal shoots of trees in “on year” while GA increased the growth in “off year” trees about 50 per cent. The surface of the spur leaves was inversely correlated with the respiration rates. It is suggested that the low respiration rate of spur leaves may be a condition for flower bud formation.
Disc Electrophoretic Studies of IAA Oxidases and their Relationship with Rooting of Etiolated Stem. Segments of Populus nigra
Authors: NANDA K. K. , BHATTACHARYA N. C. , KAUR N. P.
Published: April 2006

Stem segments of Populus nigra did not root in water but rooted in glucose + IAA. Rooting was completely inhibited by cyclobeximide or actinomycin‐D, added to the medium. The synthesis of two existing and one new isoenzyme was repressed at 24 h in segments cultured in glucose + IAA, but that of two new ones was induced in water. Cycloheximide and actinomycin‐D induced the synthesis of some new isoenzymes although they inhibited the fresh turn‐over of some others.
The Effect of Oxalate and Ethylenediaminetetraacetic acid on the Absorption of Calcium into Lemna
Authors: DeKOCK P. C. , OHTA Y. , INKSON R. H. E. , KNIGHT A. H.
Published: April 2006

Oxalate supplied to Lemna gibba L. in sterile culture was readily absorbed, stimulating growth and increasing the uptake of calcium when this element was present in the nutrient medium; in the absence of calcium, deficiency symptoms rapidly appeared. EDTA at low concentrations stimulated growth, but concentrations equivalent to those of calcium reduced the uptake of both calcium and oxalate; developing daughter fronds were chlorotic and cells from these tissues appeared to be calcium deficient.
The Effect of Stratification on the Endogenous Cytokinin Levels of Seed of Protect compacta and Leucadendron daphnoides
Authors: BROWN N. A. C. , VAN STADEN J.
Published: April 2006

The soybean callus assay was used to study the effect of stratification on the cytokinin levels of the embryo dormant seed of Protea compacta R.Br. and the seed of Leucadendron dapbnoides Meisn., where dormancy is coat imposed. Chilling the seed for 30 days increased germination significantly, and resulted in a simultaneous increase in the butanol soluble cytokinins of both species. It would appear as if these compounds are either synthesized or released from a bound form in embryo dormant seed. In contrast, an interconversion from water soluble to butanol soluble cytokïnins appears to account for the increase where dormancy is coat imposed. The results also indicate that for germination to take place a threshold concentration of cytokinin may be required.

It is suggested that the increase in butanol soluble cytokinins may lead to the breaking of dormancy, probably by increasing radicle elongation and/or cotyledon expansion.
Effect of DCMU, Simazine and Atrazine on Nitrate Reductase Activity in Hordeum vulgare in vitro
Authors: ASLAM M. , HUFFAKER R. C.
Published: April 2006

The effect of three herbicides—DCMU (1,1‐dimethyl‐3‐ (3,4‐dichlorophenyl) ‐urea), Simazine (2,4‐bis(ethylamino)‐ 6‐chloro‐s‐triazine), and Atrazine (2‐chloro‐4‐ethylamino‐6‐iso‐propylamino‐5‐triazine)—on the induction of nitrate reduc–tase and its in vivo activity was studied in detached leaves of Hordeum vulgare L. All increased both extractable nitrate reductase activity and nitrate content. The increases occurred at optimum temperatures for growth and at several concentrations of nitrate. It was also determined that the herbicides did not protect the enzyme against inactivation in vivo. Although the extractable nitrate reductase was greater, the in vivo activity of nitrate reductase was decreased in the presence of the herbicides resulting in a higher internal concentration of nitrate. Since in viva nitrate reduction is dependent upon photosynthesis it is reasonable that reduction is decreased by these known inhibitors of photosynthesis. Hence, the effect of the inhibitors on induction of nitrate reductase activity may be secondary. The higher concentration of nitrate resulting from a decreased rate of in vivo reduction in the presence of the inhibitors could conceivably be responsible for the greater corutent of nitrate reductase.
Etude des proteines an cours de la germination des graiues: Isolement et analyse des histories de radis Par
Authors: GRELLET F. , GUITTON Y.
Published: April 2006

Histories of radish seedlings liave been characterised by comparison with pea histones extracted and purified under the same conditions.

Submitted to acrylamide gel analysis the radish histones are resolved into main protein bands comparable to those of pea or calf thymus histones. However, protein bands of lesser importance which are not to be found in electrophoretic profils of pea or calf thymus histones, appear together with the main bands of radish histones. Study of these supplementary proteins through isoelectric focusing makes it possible to distinguish two groups: contaminating acid proteins and weakly basic proteins characterised by their high amide content.
Effects of Abscisic Acid on Senescence, Permeability and Ribosomal Patterns in Mimosa Hypocotyl Callus Tissue
Authors: BROWN GREGORY N. , SUN CATHERINE Y.
Published: April 2006

Abscisie acid effects on 32P uptake, polysomal patterns and senescence in mimosa (Albizzia julibrissin Durazzini) hypocotyl callus tissues were compared. Incubation of hypocotyl callus tissue with, abscisic acid for 4.5 h significantly decreased tissue uptake of 32P, and quantitatively, but not significantly, decreased incorporation of 32P into ribosomal fractions after adjusting for uptake. Abscisic acid accelerated senescence in the callus tissues. Abscisic acid inhibition of 32P uptake is presented as a possible source of misinterpretation of ribosomal 32P incorporation data.
Ascorbic Acid and Heterocyst Development in the Blue–Green Alga Amabaema ambigua
Authors: WAHAL C. K. , BHATTACHARYA N. C. , TALPASAYI E. R. S.
Published: April 2006

The nitrogen–fixing blue–green alga Anabaena ambigua was grown in a medium which contained either ammonium chloride as nitrogen source or molecular nitrogen. In the latter case the alga produced heterocysts. The material was analysed for ascorbic acid, dehydro‐ascorbic acid and diketogulonic acid. The amount of a,scorbic acid was found always to he higher in the alga grown with molecular nitrogen. When the alga grown with combined nitrogen was transferred to the medium lacking it, there was an increase in the ascorbic acid content. Conversely, when material cultured on the nitrogen–free medium was suspended in the medium containing ammonium chloride, there was a decrease in the cellular ascorbic acid. Esogenously added ascorbic acid, up to 0.5 mg per ml, increased the heterocyst frequency to nearly three times that of the control. D–isoascorbic acid, an analogue of ascorbic acid, also showed an enhancement of heterocyst production.

Algal extracts were fractionated by poiyacrylamide electro–phoresis, and the presence of ascorbic acid oxidase was detected on the gels. Two bands, with Rf values 0.34 and 1.0, were found to give positive test: for the enzyme. The total enzyme activity was 16.7 % higher in cells grown with molecular nitrogen than in those grown with combined nitrogen. The exact location of the enzyme in the alga ist not known although the heterocysts were earlier shown to contain ascorbic acid. Cytochemical tests, however, indicated strong per–oxidase activity in the heterocysts.