bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Various Mono–and Disaccharides on the Growth of Sphagnum nemoreum Thalli in Sterile Cultures
Authors: Simola Liisa Kaarina 
Published: April 2006

Abstract Sphagnum nemoreum Scop. thalli were grown under sterile conditions in order to study their ability to use certain carbohydrates for their growth, with special reference to the sugars occurring free in Sphagnum peat. It was found that Sphagnum nemoreum thallus could not grow at ail in vitro unless some organic carbon source war present. Growth was dependent on both the quality and the quantity of the sugar. Sucrose (1 per cent) proved to be the best carbon source and light intensity did not have any marked influence on growth under these conditions. Glucose and fructose were also growth promoting. Glucose is the main free sugar in the peat. Mannose (0.25 per cent) was almost as good a carbon source as sucrose in the same concentration. It is known that mannose accumulates in the Sphagnum peat during humification. and so does rhanmose, which was utilized to some extent. These two sugars are inhibitory to many mono–and dicotyledons. Ribose, galactose. arabinose and xylose were found to be toxic to Sphagnum.
Effect of Transverse Gravity Stimulation, Gibberellin and Indoleacetie Acid upon Polar Transport of IAAC14 in the Stem of Helianthus annuus
Authors: Palmer J. H. , Halsall D. M. 
Published: April 2006

AbstractUsing IAAC14, polar transport has been studied in Helianthus annuus shoots in which stem elongation was inhibited by a transverse gravity stimulus induced by horizontal orientation of the plant with daily rotation. Marked inhibition of polar transport of IAA C14 occurred in the treated plants. A similar degree of inhibition occurred in the upper and lower halves of non‐rotated horizontally trained shoots. Horizontal orientation of stem segments during the transport test had no consistent effect upon IAA transport.Pretreatment of erect plants with gibberellin greatly enhanced IAAC14 transport and also reduced the inhibitory effect of horizontal orientation. Pretreatment of erect plants with non‐radioactive IAA or ethylene inhibited transport of IAA C14 and induced the same symptoms in the shoot as the transverse gravity stimulus.The similarities between the response of the auxin transport system to gravity stimulation, IAA and ethylene are discussed.
Photosynthesis, Respiration and Post‐illumination Fixation of CO2 by Corn Leaves as Influenced by Light and Oxygen Concentration
Authors: Poskuta J. 
Published: April 2006

AbstractThe effect of oxygen concentration on the rate of CO2‐uptake in continuous and intermittent light was studied as well as the CO2‐fixation during a short dark period after light was turned off. In addition the dark respiration and the CO2‐compensation point of attached and detached corn leaves were determined. Leaves of 4 to 22‐day old plants were used as experimental material. A closed circuit system of an infrared carbon dioxide analyzer was employed to measure the rate of CO2‐exchange. It was found that in an atmosphere consisting of 100 % oxygen, there was about 50 per cent inhibition of the rate of CO2‐uptake in continuous and intermittent light compared to that in an atmosphere consisting of 21% oxygen. The same was true of the rate of CO2‐fixation in darkness during a short period after the light was turned off. Since the response to oxygen concentration of the CO2‐uptake in light and of the CO2‐fixation in darkness after the light was turned off were similar, it is concluded that the fixation of CO2 in the short dark period represents an over‐ shoot of photosynthesis. The rate of dark respiration was little affected by the oxygen concentration in the ranges used in the experiments. The carbon dioxide compensation point which has been observed in leaves of 4 to 14‐day old plants was not influenced by either oxygen concentration or light intensity. Since the changes in the rate of CO2‐uptake due to changes in the concentration of oxygen and light intensity had no effect on the CO2‐compensation point, it is concluded that a reabsorption of respiratory CO2 by photosynthesis could not account for the low value of this point. These results are interpreted as a further corroboration of the statement that the leaves of corn lack the process of photorespiration and that dark respiration is inhibited in light.It was observed that the rate of the CO2‐uptake gradually increased in plants which were from 4 to 22‐days old. The inhibitory effect of high concentration of oxygen on the rate of CO2‐uptake was relatively higher in old plants than in young ones.
Respirationsintensität in Stäinmen, Zweigen und Blältern von Laubbäumen im tropischen Regenwald und in temperierten Wäldern
Authors: Löhr Erika 
Published: April 2006

Abstract Respiratory Activity in Stem, Branches and Leaves of Evergreen Trees in Tropical Rain Forest and of Deciduous Trees in Temperate Climate.— Reduced to the same temperature, the respiratory activity of different parts of tropical rain forest trees and of corresponding parts of temperate deciduous trees is approximately the same. In particular, the leaf‐blades of Danish deciduous trees and of tropical rain forest trees from the lowland of Côte d'Ivoire (57° north. lat.) have nearly the same respiratory activity at 20°C: the blades of the extreme shade leaves about 0.1 mg CO2, those of the extreme sun leaves about 0.8 mg CO2 per 50 cm2 (one side only) per hour at 20°C. This is in accordance with the fact that the blades of shade leaves, respectively Sim leaves, of the tropical rain forest trees are built in the same way as the blades of deciduous trees in our temperate climate. The respiratory activity shows that they have the same “concentration” of living cells, the same “concentration” of active plasma.The respiratory activity of trunk and branches depends mainly on three factors: diameter of the stem‐section or branch‐section, nutritional condition, and temperature. The respiratory activity of trunk and branches of hardwoods in temperate climate is also dependent on the season. The estimations on stems and branches from the temperature trees were made In July–August. There was in most cases a remarkable agreement in respiratory activity between temperate and tropical hardwoods: Branches with a diameter of about 0.5–2 cm have a respiration of about 70–100 mg CO2 per kg fresh weight per hour at 20°C. Trunk sections with a diameter over 20 cm have a respiratory activity of about 3–5 mg CO2, per kg fresh weight per hour at 20°C. In the older parts of a stem most of the cells are dead. The agreement in respiratory activity probably means that the “concentration” of living cells in the older parts of the stem of tropical and temperate hardwoods is the same.
Cytokinin‐Inhibitor Antagonism in the Hormonal Control of α‐Amylase Synthesis and Growth in Barley Seed
Authors: Khan A. A. 
Published: April 2006

AbstractThe effect of cytokinins and gibberellic acid on the inhibition of growth and α‐amylase synthesis by germination inhibitors was investigated in intact and embryoless seed halves. The cytokinins, kinetin and benzyladenine, effectively reversed the inhibition of coleoptile growth and α‐amylase synthesis by abscisic acid and courmarin in barley seed. An antagonism between cytokinins, kinetin and benzyladenine, effectively reversed the inhibition of coleoptile growth and α‐amylase synthesis by abscisic acid and coumarins in barley seed. An antagonism between cytokinins and germination inhibitors was also shown in root growth. Abscisic acid inhibited coleoptile growth to a greater extent than the root growth while the opposite held true in the case of coumarin.The apparent increase in coleoptile growth and α‐amylase synthesis by gibberellic acid plus abscisic acid (or coumarins) over abscisic acid (or coumarin) appears to be a result of the overall stimulation of growth and metabolism by exogenous gibberellic acid and probably does not involve an interaction of gibberellic acid with the inhibitors. Gibberellic acid reversed root inhibition to some extent.Abscisic acid inhibition of gibberellic acid induced α‐amylase synthesis in the embryoless endosperm was not reversed by excess gibberellic acid or kinetin Cytokinin reversal of inhibition of growth and enzyme synthesis probably depends on some factor(s) in the embryo. Cytokinin reversal of inhibitor action leading to enzymen synthesis and growth may be at the level of genome or at the site protein assembly.
Growth of Suspension Cultures of Sugarcane Cells in Chemically Defined Media
Authors: Nickell L. G. , Maretzki A. 
Published: April 2006

AbstractA chemically defined medium is desirable for nutritional studies and is frequently necessary for biochemical investigations. Several defined media are available for use with tissue and cell cultures from dicotyledonous plants. A fully defined medium has now been developed for cell suspension cultures from sugarcane. Prior to this, the only medium successfully used for cell cultures of monocotyledonous plants was a modification of Straus' synthetic medium (used to grow cell suspensions of corn).Cell suspension cultures from sugarcane stalk parenchyma, originally established in complex media containing coconut milk or yeast extract, can be grown in this synthetic medium, which consists of inorganic salts, vitamins, sucrose, 2.4‐dicliloropheuoxyacetic acid, and a mixture of 13 amino acids. The most important of the amino acids are arginine aspartic acid, and glutamic acid. This simplified medium wilt aid in the investigation of the unusual and important role of arginine in sugar‐cane growth and metabolism.
Transformation of Protochlorophyllide, Formed from Exogenous δ‐Aminolevulinic Acid, in Continuous Light and in Flashlight
Authors: Sundqvist Christer 
Published: April 2006

Abstractδ‐Aminolevulinic acid supplied to dark grown isolated leaves or wheat causes an accumulation of protochlorophyllide which is only partly transformed to chlorophyllide α in continuous light At the same time a considerable photodestruction of both pigments takes place. By a suitable combinations of short lights flashes and dark periods it is possible, however, to obtain at least double the amount of the protochlorophyllide transformed without photodestruction. The transformation isshown to be dependent on the dark interval between the light flashes. Possible connections with the formation of the protein part of the protochlorophyllide holochrome are discussed.
Distribution of Acidic‐ and Neutral Peptidases in Germinating Barley
Authors: Prentice Neville , Burger W. C. , Wiederholt Elizabeth 
Published: April 2006

AbstractActivities of barley peptide hydrolases A (acidic peptidase) and H (neutral peptidase) were examined in the growing embryo and in the embryoless tissues of Himalaya barley incubated for 70 hours. Tissues examined were roots, shoots, embryo residue (scutellum + seutellar node + coleorhiza) and the embryoless portion of the kernel. Activity of the hydrolase A increased mainly in the embryo residue during 0 to 30 hours but little thereafter. Activity of hydrolase B increased mainly in the embryo residue but did so linearly over the 70 hour period. A small linear increase occurrence in the embryoless portion during this lime.
Effects of Water Deficit on Phosphorus Nutrition of Tomato Plants
Authors: Greenway H. , Hughes P. G. , Klepper Betty 
Published: April 2006

AbstractMeasurements were made of phosphorus uptake by intact tomato plants from solutions labelled with 32P. The plants were exposed to low water potentials by the addition of mannitol to culture solutions. The amounts of labelled phosphorus in the roots and in the shoots wore determined after a one‐ or two‐hour period. Down to ‐5.4 atmospheres, the amount of labelled phosphorus in the roots remained constant, hut the amount transported to the shoots was reduced. However, potentials of ‐10.4 atm reduced the amount of labelled phosphorus in both the root and the shoot. Similar results were obtained when plants were tested immediately after water stress was imposed and when tested after water potentials had been lowered gradually.Plants were treated for one hour at low water potentials and then returned to control solutions (−0.4 atm). For a considerable time, these plants had a much lower phosphorus uptake than plants which had remained continuously at −0.4 atm. These data support the idea that a disturbance in mineral nutrition is partly responsible for reduced growth in plants which experience a moderate water deficit.
Succinyl CoA Synthetase of Tobacco
Authors: Bush Lowell P. 
Published: April 2006

AbstractThe isouition and partial purification of succinyl CoA synthetase from Nicotiana tabacum is described. Enzynio activity had a pH optimum of pH 7.0 and apparent Km values for succinic acid. ATF and MgCl2. are 3.5 × 10−2 5.7 × 10−3 and 4.0 × 10−3 M, respectively. The euzyme is specific in requirement for ATP. Enzyme activity was low in seed, decreased during germination and seedling development, then increased to maximum in physiologically mature leaf tissue. Plauts with the apical apical meristem removed had less euzyme activity in leaves but more enzyme activity in the roots than plants with apical meristem intact. Most enzyme activity observed was associated with the soluble fractions of the cell.
Effects of Flooding the Root System of Sunflower Plants on the Cytokin in Content in the Xylem Sap
Authors: Burrows W. J. , Carr D. J. 
Published: April 2006

AbstractThe severe chlorosis observed in the lower most of flooded sunflower plants (Helianthus annuus L. cv. Tall Single) may lie initiated by a reduction in the import of cytokinins by the stoot from the flooded root system. Experiment indicates that during 12 hours following the release of flooding, plants previously flooded for 72 hours or less recover their ability to exude sap when the root systems are aerated, and the root systems synthesize and export amino‐acids to the shoot. Plants flooded for longer periods lose these abilities. The metabolic activity of the root apices declines parallel with the decline in eytnkinin concentration in the sap with increase in flooding time up to 72 hours. Flooding for 96 hours drastically reduce all four parameters of root activity. After flooding for this period there was a large increase in the number of blackened and tetrazolium‐negative root apices which were in all probability dead. The correlation between the metabolic activity of the root apices and the total cytokinin content of the sap supports tbe view that root apices may be sites of cytokinin synthesis.
The Effect of Deleterious Concentrations of Copper on the Photosynthesis of Chlorella pyrenoidosa
Authors: Nielsen E. Steemann , Kamp‐Nielsen L. , Wium‐Andersen S. 
Published: April 2006

AbstractIf a single salt solution of CuSO4 is used, Cu penetrates immediately iuto the plasma of Chlorella cells, reducing the rates of photosynthesis at both high and low illumination. If CuSO4 is added to ordinary Österlind culture‐medium (pH 8) it takes some hours before any influence of deleterious concentrations of Cu is observed and initially only at light saturation. The algae must have been illuminated during the whole period. Maximum influence of CuSO4 is found duriug the first 24 hours of treatment. A significant deleterious influence of Cu concentrations as low as about 1 μg/l is found. The influence of Cu increases with decreasing concentrations of the alga. If a culture medium at pH 5 is used instead of the ordinary one at pH 8, copper concentrations ahout 10 times as high must he used be order to obtain the same deleterious effect. An increase of the cotncentration of K reduces the influence of Cu to some extent. These facts show that the effect of deleterious concentrations of Cu in halanced solutions is not due to a marked penelration of this ion into the plasma but to a binding to the cytoplasmic membrane whereby the celts i.a. become more or less unable to divide. The cells become saturated with assimilation products which have a depressant effect on the rate of photosynthesis. Other cations compete with Cu for the “active sites” on the membranes.
Stomata Constellation in the Leaves of Cotton, Maize and Wheat Plants as a Function of Soil Moisture and Environment
Authors: Gindel I. 
Published: April 2006

AbstractIn two locations, one subtropical and the other semidesert, the following three agricultural plant species were studied: cotton, maize and wheat. In each zone species were examined in irrigated and nonirrigated experimental plols for four leaf parameters: density of stomata and epidermis cells and length of stomala and leaf area. The following conclusions follow from the results: 1) The water deficit in the soil accompanied by extreme climatic conditions (August‐September) led to a significant increment in the density of stomata and epidermis cells; in some of the varieties a decrease in length of stomata was observed. The decrease in leaf area in the nonirrigated plant was accompanied by an increase in ash content. Identical xeromorphic changes were stated in selected leaves the area of which was equal to those of the irrigated plants. In spite of the maximal number of stomata per unit area on both sides of Ihe blade a full turgor was maintained in the cells of the nonirrigated plants during the hottest and driest months and they survived until rains started (Novemher), although no significant changes were then noted in soil moisture within the sphere of the root dispersion.
Nutrition of Cosmarium turpinii
Authors: Kokn Robert W. 
Published: April 2006

AbstractA defined medium for Cosmarium turpinii Bréb. was established. The optimal concentrations of major elements (Ca, N, P, S, and Mg) were detemiined, with the calcium level found to be most demanding. Iron, boron, and manganese were found to be essential micronutrient elements. Vitamin B12 is also required, eitber as the planar group of cyanocobalamin alone or with adenine or benziniizole derivatives. Survival of cells during plateau pbase of growth can be extended by tbe addition of eitber 10‐3 M urea, isoleucine, or glycine.
Some Aspects of Respiration and Respiration Inhibitors in Low Temperature Effects of the Cotton Plant
Authors: Amin J. V. 
Published: April 2006

AbstractRespiration of leaf tissue from cotlon plants in the nine leaf stage was found to be severely reduced at temperatures below 15°C. In another study, young cotton plants were exposed to chilling temperature (2.8°C) for 72 hours and the ability of the plant tissues to recover respiration at normal temperatures (15 and 25°C) was examined at periodic intervals. Chilling exposures of 12 hours injured cotton tissues as indicated by increased respiratiou of leaves and roots at 25°C. Further chilling malerially reduced the capacity of the leaves to re‐estahlish normal respiration rales at higher temperatures. Picolinic acid, Dexon and matonate were used to study the influence of respiratory inhibitors on the chill damage of the collon plants. The chemicals were applied six hours before cold exposure aud fhe growth and development of cold injured plants was studied to indicate the effectiveness of the treatments. Tissue weights at the final harvests indicated that picolinic acid and Dexon treated plants recovered better after cold injury than the untreated plauts. The results suggest thai 15°C may be a critical temperaliire for many physiological processes of the cotton plant because the supply of energy needed for plant reactionsis restricted due to inadequate respiration. They also indicate that the disturhances in respiration are among the early effects of chilling colton plants and may be the cause of delayed growth and development of cotton plants subjccled to non‐lethal chilling exposures. It is concluded that chemicals like picolinie acid and Dexon may he effective through protection of specific systems rather than a general reduction of respiration.
Elimination of Geotropic Responsiveness in Roots of Cress (Lepidium sativum) by Removal of Statolith Starch
Authors: Iversen Tor‐Henning 
Published: April 2006

AbstractRoots of garden cress (Lepidium sativum L.) seedlings were made starch‐free by treatment with gibberellic acid and kinetic for 29 hours at 35°C in the dark. After 3 hours of temperature adaptation at 21°C the starch‐depleted roots were unable to respond to gravity, but elongated 0.48 mm por hour. Under the same conditions control roots pretreated in plain water at 21 and at 35°C elongated 0.64 and 0.33 mm per hour, respcetively (at 21°C). When the hormone‐treated seedlings were illuminated, their roots reformed starch after 20 to 24 hours; simultaneously the geotropic responsiveness was restored. The results are interpreted in support of the statolith theory.
Free Amino Acid Pools and Enzymes in Teratonia and Habituated Tobaceo Tissue Cultures
Authors: Foster D. M. , Weber D. J. 
Published: April 2006

AbstractThe free amino acid content of habituated (normal) and teratoma (abnormal) tobacco tissue cultured on white's medium were compared. Significant qualitative differences (twofold or more) were observed for serine, proline, alanine, leucine, phenylalanine, and lysine. There were qualitative differences in several unidentified ninhydrin sensitive compounds. One unknown which co‐chromatographed with homo‐serine was present in high concentrations (9.96 μmol/g dry weight) in habituated but was lacking in teratoma tissue, Isoenzymes of an esterase, acid phosphatase, and oxidase were demonstrated in both tissues. The distinct differences in the isoenzyme pattern of acid phosphatase suggests a differential regulatory capacity of certain phosphomonoester intermediates and P1. The invertase activity was higher in habituated tissue, implying a greater capacity to utilize the sole carbon source, socrose.
Stimulating Effect of Pentoses on the Utilization of Galactose in Ophiostoma multiannulatum
Authors: Lindberg Martin 
Published: April 2006

AbstractThe influence of some pentoses on the ability of the fungus Ophiostoma multiannulatum to grow on d‐galactose was investigated. There is no measurable growth of the wild type Ophiostoma when galactose is the sole carhon source, d‐xylose has a stimulating effect on the utilization of galactose in this fungus. Even when d‐xylose is added in low concentrations as compared to the concentration of galactose in the mixtures the growth‐promoting effect is high. The xylose can be added in amounts which are directly growth‐limiting. The addition of l‐arabinose also results in growth on gatactose if the concentration ratio arabinose: galactose is selected high enough. The results are discussed and compared to previously published data on stimulating effects from other hexoses on the utitization of galactose in this fungus.
Growth Regulators in Populus tremula I. Distribution of Auxin and Growth Inhibitors
Authors: Eliasson Lennart 
Published: April 2006

AbstractThe content of acid ether‐soluble auxins and inhibitors in vegetative tissues of aspen (Populus tremula L.) was determined with the Avena coleoptile straightgrowth assay. A growth promotor, tentativety identified as indol‐3‐yl‐acetic acid, occurred in highest concentration in the growing stem parts. It was also detected in various parts of the roots. Large amounts of inhibitors (inhihitor β) were found in growing stem tissue and in upper mature stem parts. Considerably lower content of inhibitors was found in leaves, in the basal stem part and in the roots. Nonwoody growing roots and the wood of older root segments, especially, contained very smalt quantities of inhibitors. The elution volume of a part of the inhibitory activity on a Sephadex column was similar to that of abscisic acid.