bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of Hormones in Controlling the Mechanically Induced Dormancy of Suaeda spp.
Authors: BOUCAUD JEAN , UNGAR IRWIN A. 
Published: April 2006

AbstractSeeds 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

AbstractToxins 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

AbstractAnalyses 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

AbstractCadmium 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

AbstractTobacco (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

AbstractGrowth 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

AbstractA 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

AbstractSoybean 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

AbstractIAA 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.
Control of Ethylene‐Induced Responses in Plants by a Substituted Benzothiadiazole
Authors: PARUPS E. V. 
Published: April 2006

AbstractThe 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

AbstractComparative 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

AbstractThe 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

AbstractWhen 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractStem 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

AbstractOxalate 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

AbstractThe 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

AbstractThe 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

AbstractHistories 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

AbstractAbscisie 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.