bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photosynthetic Activity during the Life Cycle of Synchronous Skeletonema Cells
Authors: Jørgensen Erik G. 
Published: April 2006

AbstractA culture of Skeletonema costatum grown at a light intensity of 3 klux and at 20°C was synchronized in diurnally intermittent illumination of 12 hour light and 12 hour dark. The culture was hardly fully synchronous as the cell division period lasted about 9 hours. The cell division started in the middle of the light period. The concentration of the pigments: chlorophyll a, chlorophyll 6 and fucoxanthin and the rate of light‐saturated photosynthesis were followed every hour during the 24 hour period. Both the concentration of pigments and the photosynthetic activity showed a rhythmical variation. The concentration per cell of all three pigments examined increased during the development of the cells and decreased automatically during the period of cell division. An increase in the pigment concentration was found only in the light period. The rate of light‐saturated photosynthesis calculated per unit of cell number increased during the cell development and decreased during the division period. The increase in the photosynthetic activity at light‐saturation started about 4 hours after the end of cell division, which was 4 hours before the light was turned on while the increase in the concentration of chlorophyll a first started 1–2 hours after this moment.The variation in photosynthetic activity was compared with that found by other workers. The results found with Chlorella ellipsoidea by Japanese scientists (Nihci et al.) was explained as an inhibition phenomenon because the cells were not adapted to the experimental conditions.
Influence of Iodine and Bromine on Growth of Some Red Algae in Axenic Culture
Authors: Fries Lisbeth 
Published: April 2006

AbstractSome red algae in axenic culture have been cultivated with different additions of iodine and bromine. Polysiphonia urceolata appeared to have an absolute demand for iodine. Additions could be made either as organically bound iodine or as inorganic iodine. A linear correlation between amount of added iodide and growth was found for iodide concentrations from 1 μmol up to at least 8 μmμmumol per 1. Nemalion proved to be indifferent to iodide additions, while Goniotrichum elegans was inhibited by concentrations higher than 0.4 μumol per 1, which corresponds to that of natural seawater.High additions of iodine generally inhibited growth of nonaxenic algae. Acrochaetium made an exception, being stimulated by 4 μumol per I.Bromine in the same concentration as that of seawater, viz. 814.3 μmol pa 1 inhibited growth of most species, but amounts smaller than 50 μumol had in some experiments a slightly increasing effect. Bromine seems, however, not to play an essential part in the metabolism of Polysiphonia urceolata.
Nitrogen Fixation by the Blue‐green Alga Anabaena flos‐aquae A‐37
Authors: Davis Edith B. , Tischer R. G. , Brown Lewis R. 
Published: April 2006

AbstractNitrogen fixation has been demonstrated in a bacteria‐free culture of a semithermophilic blue‐green alga, Anabaena flos aquae A‐37, employing the criterion of an increase in cellular nitrogen as a basis for determining nitrogen fixation. This is apparently the first time that nitrogen fixation has been demonstrated in a pure culture of a blue‐green alga which grows at 40 C and which produces abundant quantities of an extracellular heteropolysaccharide.
Internal Control of Rate of Leaf Production in Sngar Beet
Authors: Humphries E. C. 
Published: April 2006

AbstractThe theory that the rate at which leaves appear is little affected by the current environment has been tested with sugar‐beet plants. Seedlings were raised vinder 4 different conditions, viz., 8 hour photoperiod 20°C, 16 hour photoperiod 20°, continuous light or in the glasshouse. After 2 weeks all were put in the glasshouse under the same growing conditions. The treatments wbich the seedlings received continued to affect the rate at which leaves were produced during the next 20 weeks.
Photosynthetic Adaptation to Light Intensity in Plants Native to Shaded and Exposed Habitats
Authors: Björkman Olle , Holmgren Paul 
Published: April 2006

AbstractPhotosynthetic adaptation to light intensity has been studied in clones of populations from shaded and exposed habitats of Rumex acetosa and Geum rivale. Clones of the shade species Lamium galeobdolon and the sun species Plantago lanceolata were also included for comparison. The plants were grown under controlled conditions at a high and a low light intensity. The capacity of photosynthetic carbon dioxide uptake at low as well as at saturating light intensities was determined on single attached leaves.As was previously demonstrated in Solidago virgaurea, clones of populations native to shaded and to exposed environments show differences in the photosynthetic response to light intensity during growth. The data provide evidence that populations of the same species native to habitats with contrasting light intensities differ in their photosynthetic properties in an adaptive manner Ln a similar mode as sun and shade species.
Alteration in the Geotropic Response of Allium Seedlings by Growth Regulators
Authors: Guha Sipra , Maheshwari S. C. , Jouri B. M. 
Published: April 2006

AbstractIndoleacetic acid (1AA) brings about a striking alteration in the normal geotropic response in the seedlings of onion and several other species of Allium. The seedlings which are normally positively geotropic, become ageotropic. Besides IAA several other auxins like IBA, NAA and 2,4‐D also showed a similar response. An anti‐auxin like triiodobenzoic acid (TIBA) enhanced the auxin‐effect instead of reversing it. A marked enhancement of the auxin‐effect was also brought about when sucrose (in the culture medium) was replaced by L‐arabinose which appeared to act synergistically with the auxin.
Effect of Chrysanthemum Plant Extract on Flower Initiation in Short‐Day Plants
Authors: Biswas P. K. , Paul K. B. , Henderson J. H. M. 
Published: April 2006

AbstractAn extract was prepared from Chrysanthemum plants in flower. It was separated into eight different fractions putting emphasis on the sterol components of the extracts. Fractions 5 and 6 were found to contain active substance (s), which to some extent, brought about floral bud initiation in both Chrysanthemum and Xanthium.The active substance (s) present in the above two fractions might be a sterol (s), similar to those of sitosterol and stigmasterol or other related compounds.Gibberellic acid brought about stem elongation as usual, but was found ineffective in causing any tissue differentiation in both Chrysanthemum and Xanthium.Investigations are underway to separate and identify the different compounds present in fractions 5 and 6. The effects of these compounds on test plants, both individually and in combinations, might provide some valuable information as to the nature of the flowering hormone.
The Effect of Light, Carhon Dioxide, and Nitrogen Nutrition on the Incorporation of S from External Sulphate into Different S‐Containing Fractions in Scenedesmus, with Special Reference to Lipid S
Authors: Kylin Anders 
Published: April 2006

AbstractThe experiments showed that incorporation of S from the sulphate in the medium into normal cells of Scenedesmus was enhanced by light, relatively most in the case of lipid S and least in the inorganic sulphate fraction. The effects of light were, generally, increased by the presence of CO2 and nitrogen salts. CO2 did not significantly alter the proportions between the fractions, but the presence of nitrogen increased the formation of protein S more than the synthesis of S‐containing lipids.—It is suggested that lipid S is formed as a “sink”, when a step between sulpbite and ‐SH becomes increasingly rate‐limiting in the overall reduction of sulphate. Furthermore, incorporation as SO42− and as lipid S may be regulated by more or less independent processes.
Effect of Tobacco Mosaic Virus Infection on Amino Acid Incorporation into Isolated Mitochondria from Tobacco Leaves
Authors: Takahashi Tsuyoshi , Hirai Tokuzo 
Published: April 2006

AbstractMitochondria isolated from tobacco leaves incorporated 14C‐leucine into the protein and the rate was enhanced by tobacco mosaic virus (TMV) infection as compared with noninfected level. In vitro amino acid incorporation by mitochondria required adenosine triphosphate (ATP), Mg2+, and KC1 and the energy sources from oxidative phosphorylation as well as from ATP‐generating system. This incorporation was inhibited by ribonuclease (RNase), deoxyribonuclease (DNase), actinomycin D, mitomycin C, puromycin, and chloramphenicol added in the reaction medium. The pretreatment of the mitochondria with DNase and actinomycin D reduced the rate of incorporation. The mitochondria incorporated 3H‐guanosine triphosphate (GTP) and this activity was blocked by actinomycin D. The presence in this system of 15,000 g supernatant cell sap fraction or bacterial contamination was carefully checked obtaining a negative result. The reaction product into which l4C‐amino acids incorporated was solubilized by trypsin. The nature of the amino acid incorporating activity of isolated mitochondria obtained from TMV‐infected tobacco leaves is discussed.
Effect of Fluoride on Nucleic Acids and Growth in Germinating Corn Seedling Roots
Authors: Chang Ghong W. , Thompson C. Ray 
Published: April 2006

AbstractCorn seeds were treated with 0.01 M sodium fluoride for various time periods. The treated seeds were germinated and grown until the seedling roots reached a standard size of 12±3 mm.Analyses were made for RNA and DNA contents of 3‐mm seedling root tips. Determinations also were made for growth rate, rate of cell elongation, cell multiplication, and tissue maturity of 12‐mm roots.RNA contents of 3‐mm root tips were found to be directly proportional to the growth rates of the entire seedling root of corn seeds treated with sodium fluoride for various periods of time. The RNA content was reduced on a cell basis and was independent of the root tip cell number. The amount of DNA was not related to the growth rate of the intact seedling roots. Since fluoride reduced the number of mitotic figures, it was likely that fluoride inhibited DNA synthesis during the interphase of the mitotic cycle.Growth by cell multiplication was inhibited more than that by cell elongation in the sample treated with fluoride for a shorter period. The two types of growth, however, showed a similar level of growth reduction in the sample treated with fluoride for a longer period. Fluoride seemed to reduce the rates of cellular elongation and multiplication not more than about 40 per cent of the control value in these tissues under present experimental conditions. Fluoride also induced maturity in the seedling roots in proportion to the periods of fluoride treatment.
Boron Deficiency and Translocation Profiles in Sunflower
Authors: Lee Kung‐Woo , Whittle Catherine M. , Dyer Hurert J. 
Published: April 2006

AbstractThe distribution of carbon‐14 down the stems of comparable boron‐deficient and boron‐sufficient sunflower plants after photosynthesis of 14CO2 by a single exposed leaf was investigated. In boron‐deficient plants the advancing front of radioactivity was always found less far down the stem than in boron‐sufficient plants. The general shape of the profile is the same in the two sets of plants. We conclude that the velocity of translocation is reduced in the boron‐deficient plants.
Chlorine Nutrition of Tomato: Observations on Inadvertent Accretion and Loss and Their Implications
Authors: Bkoyer T. C. 
Published: April 2006

AbstractDevelopment of research on chlorine nutrition of plants is reviewed. Imbalances of supply and recovery of chlorine are discussed. Results elucidate losses to be related to moisture percentages of tissues in preparation for analysis and to ashing techniques. Accretions are related to various advertent contaminations and inadvertent accessions through aerosols in the atmosphere during growth.
The Role of Auxins in Root‐Knot Nematode‐Induced Growth on Excised Tobacco Stem Segments
Authors: Sandstedt Robert , Schuster Max L. 
Published: April 2006

AbstractRoot‐knot nematodes, Meloidogyne incognita, induced lumps of callus tissue on the cambial surfaces of peeled tobacco stem segments cultured in vitro. Except for a layer 1 to 3 cells thick, callus was limited to the basal ends of control segments. Indole‐3‐acetic acid (IAA) applied in agar blocks to the centers of stem segments, when it had any effect on the cambial surface, induced streaks of callus extending from the blocks toward the basal ends of the segments. IAA in agar blocks also increased callus growth at the basal ends of the segments, increased the growth of pith on the undersides of the segments, promoted root initiation, but inhibited bud initiation. Nematodes produced none of these effects, nor did they change the type of organs induced by various concentrations of IAA in the medium. Callus tissue did grow on the cambial surface of stem segments surrounding agar blocks containing 2,3,5‐triiodobenzoic acid, an inhibitor of polar auxin transport.Paraffin sections showed that the nematodes were confined to the callus tissue on the cambial surfaces of the segments. Except for occasional syncytia and areas of cell division, nematode‐induced callus was composed of thin‐walled, irregularly shaped cells arising from the cambium.Differences between the responses of tobacco stem segments to root‐knot nematodes and IAA‐agar blocks indicate that auxins were not freed from the plant tissue nor secreted by the nematodes. Instead, it is suggested that nematodes enabled the tissue to retain and use endogenous auxins that otherwise would have been transported to the basal ends of the segments.
Elongation of Stem Internodes in the Japanese Morning Glory (Pharbitis nil) in Relation to Auxin Destruction
Authors: Yoneda Y. , Stonier T. 
Published: April 2006

AbstractThe relationship between auxin destruction and stem internode elongation was investigated in the vines of the Japanese morning glory (Pharbitis nil Choisy). In young plants an age‐dependent gradient was demonstrated in which the decreasing rate of elongation of older internodes correlated with an increasing ability of such tissue to destroy indoleacetic acid. Fragments of tissue from old internodes when incubated with indoleacetic acid (IAA), destroyed the hormone immediately and rapidly; in contrast, young, rapidly elongating internode tissue destroyed IAA only after a lag of several hours. In older plants the gradient was more erratic towards the middle of the plant but old and young tissue behaved as in young plants, i.e., old internodes destroyed IAA rapidly whereas young internodes did not. It appears reasonable to conclude that cessation of elongation in maturing internodes is brought about by developing an internal environment in which auxin is rapidly destroyed.
Relationship of Apical Dominance to the Nutrient Accumulation Pattern in Pisum sativum var. Alaska
Authors: Husain Syed Mushtaq , Linck Albert J. 
Published: April 2006

AbstractDecapitation of the pea plant resulted in the growth of all the lateral shoots. The initial growth of all lateral buds was somewhat similar. The differential growth rates developed later on. The pattern of growth of lateral shoots varied with the age of the plant when decapitation was performed. The basal shoots dominated when the plants were decapitated at the 2‐leaf stage. At 3‐leaf stage decapitation resulted in the dominance of shoot 5. Decapitation at 4‐or‐more‐leaf stage resulted in the eventual dominance of the suhterminal lateral shoot.As a rule P‐32 moved to the most actively growing part of the plant, i.e. apex in intact vegetative plant, the growing lateral shoots in a decapitated plant, the elongating subapical parts of the stem and the roots. The various metabolic sinks seemed to compete actively for this nutrient, therefore P‐32 accumulation in any particular growing region of the plant was taken as an indicator of nutrient utilization potential of that part.The stem apex of an intact plant seemed to loose its dominance with the increasing age of the plant. The loss of apical dominance was almost complete during the reproductive phase of the plant, during which the upper lateral shoots initiated growth. Their growth, however, was inhibited soon because of competition with the other developing sinks, viz., the flower and the fruit.The amount of soluble carbohydrates in various parts of the pea plant followed essentially the same pattern as did P‐32 accumulation. These distribution patterns were apparently correlated with the growth of the plant.
Germination and Flowering in Arabidopsis thaliana in Sterile Culture
Authors: Anand Renu , Maheshwari S. C. 
Published: April 2006

AbstractThe optimal conditions for the germination, growth, and flowering of an Indian strain of Arabidopsis thaliana were investigated in sterile culture. Seeds require a cold treatment to germinate, and the most effective temperature is 8†C for 48 hours. Germination after vernalization is promoted by red light and inhibited by far‐red. Unvernalized seeds germinated after 31 days and flower buds appeared in 61 days. On verbalization and subsequent transfer to a temperature of 25†C and a light intensity of 4300 lux of fluorescent light, plants flowered in 25 days. Under 7000 lux of light rich in both blue and red region of the spectum, plants flowered in only 12 days. A minimum of five long‐day photocyeles appeared to be necessary for flowering. Kinetin (10−7M) and gibberellic acid (10−7M, 10−6M) accelerated flower formation. Kinetin and 2,4‐D also catised specific types of callussing from different regions of the plant.
Auxin Activity of Glucobrassicin
Authors: Andersen A. Skytt , Muir Robert M. 
Published: April 2006

AbstractThe indole‐glucosinolate, glucobrassicin, which is found in large amounts in members of the genus Brassica, was subjected to tests in the standard Avena curvature bioassay. Both the tetramethylammonium salt of glucobrassicin and the non‐crystallizted material induced curvature at a concentration of 5 × l0−4M. The curvature from the salt was, however, only half of that induced by the acid form.Bioassays of chromatograms of fresh methanolic extracts of savoy cabbage indicated the presence of indole‐3‐acetic acid as well as indole‐3‐acetonitrile in small amounts along with large amounts of glucobrassicin.Segments of green hypocotyl tissue of savoy cabbage respond with limited growth to high concentrations of glucobrassicin. Segments of etiolated hypocotyls or green epicotyls give no growth response to glucobrassicin.Pea stem segments which do not respond to indoleacetonitrile responded with similar growth to glucobrassicin and indoleacetic acid.Nitrilase activity was found in savoy hypocotyl and epicotyl tissue by chromatography of incubation media.The growth regulation in savoy cabbage in conjunction with data on the distribution of glucobrassicin in the plant, leads to the conclusion that glucobrassicin is a special, inactive storage and transport form of the active auxin in cabbage.
Metabolic Flux in Yeast Cells with Oscillatory Controlled Glycolysis
Authors: Betz Augustin 
Published: April 2006

AbstractIn yeast cells with oscillating glycolysis the fluctuations in metabolite concentrations are rather small compared with the total glycolytic flux. Glucose is consumed in a pulsatory manner, indicating highly efficient control at one of the first enzymatic steps. Cycling fluctuations in the apparent equilibriums constant of aldolase demonstrate this step being a retarding one and are indicative of different flow rales in the lower and in the upper part of the glycolytic sequence. Alternating phases of inhibition and activation at phosphofructokinase and glyceraldehydphosphatdehydrogenase, two steps interconnected by the retarding aldolase step and further connected by feedback in the ATP/ADP system, are considered as being the source of the observed oscillations.
On Dark‐Germination and Antheridium Formation in Anemia phyllitidis
Authors: Näf Ulrich 
Published: April 2006

AbstractSchraudolf's finding is confirmed that gibberellic acid induces antheridia in Anemia phyllitidis and Lygodium japonicum. The activity spectra of gibberellic acid and the native antheridiogen of Anemia phyllitidis are similar: Both induce antheridia in the tested species of the family Schizaeaceae but are inactive towards the tested representatives of other fern families. However, the native antheridiogens of two schizaeaceous species are more species‐specific in their action than is gibberellic acid.Anemia medium cancels the light requirement for spore germination as is the case with gibberellic acid. Chromatographic studies indicate that the dark‐germination‐inducing factor is identical with, or very similar to, the earlier demonstrated antheridiogen. The specificities of the active factors towards dark‐germination in A. phyllitidis and L. japonicum are similar to those encountered with antheridium formation.Anemia medium induces dark‐germination and induces antheridia on the dark‐grown protonemata to a concentration ca. 30 times lower than it induces antheridia on light‐grown prothalli. The studies indicate that this differential activity results from a differential competence of the prothalli to react to the active substance in light and darkness.
Location of a Protease and its Inhibitor in the Barley Kernel
Authors: Burger W. C. , Siegelman H. W. 
Published: April 2006

AbstractTissues of barley caryopsis and seedling were examined for the protease, BAPAase, and an inhibitor. The enzyme was present in extracts of alevn‐one but was absent from aleurone incubation media and extracts of: embryo with scutellum; seedling with scutellum and rootlets, and endosperm that was free of aleurone tissue. The enzyme was present in non‐incubated aleurone and did not increase significantly during incubation under conditions where alpha‐amylase increased in the medium and tissue. Addition of gibberellie acid produced no detectable increase in BAPAase.Extracts of endosperm had weak BAPAase‐inhibitory activity; embryo or seedling extracts produced strong inhibition. The inhibitor present in these extracts was dialyzable.
Inhibition of Plant Root Growth by Enzymes and Histones
Authors: McLaren A. D. , Bradfute O. E. 
Published: April 2006

AbstractIt has been shown previously that root growth can be inhibited by basic, animal proteins. In an effort to see if a plant histone was more efficacious than the animal protein, roots were grown in the presence of wheat histone. Otber basic polymers were also tested.Polycations, including salmine, lysozyme, ribonuclease, wheat germ histone, thymus histone and polylysine inhibit root elongation of barley and wheat. Polyglutamate and lysylglycine at comparable weight concentrations are not inhibitory. No difference in the efficacy of tbe plant and the animal histones could be found with either plant, which suggests that the action is non‐specific.Growth of roots inhibited by histone, trypsin, or lysozyme can resume after removal of the polycation.The mechanism whereby polycations influence root growth is not known, but it is clear that the polymeric state of ionic functional groups is of paramount importance in the binding of the polycations to cell surfaces.