bluuebunny/crossref_metadata_2025 huggingface dataset:
Labile‐Bound Sulfate in Wheat‐Roots: Localization, Nature and Possible Connection to the Active Absorption Mechanism
Authors: Persson Lennart
Published: April 2006

The aim of the investigation was to identify a readily exchangeable fraction of sulfate in wheat roots and to study the nature of the fraction and its possible connection to the active mechanism for sulfate uptake. The amount of sulfate absorbed during the initial phase of uptake was higher in plants with a low sulfate status (low sulfate plants) than in plants with a high sulfate status (high sulfate plants). By adding selenate to the test solution, the same amount of sulfate belonging to this phase was obtained both in high sulfate plants and in low sulfate plants. The variations between plants of different sulfate status were believed to be due lo different capacities for labile binding of sulfate to positive sites in the roots. Selenate replaced sulfate at these sites. By leaching experiments, the positive sites were shown to be located on or outside of a very delicate barrier in the cells. The maintenance of the positive sites was demonstrated to be dependent on concurrent metabolism by adding 2.4‐dinitrophenol to the test solution and by varying the root temperature. The amount of sulfate bound to positive sites in labile binding was shown to be dependent on the pH of the test solution. At low sulfate concentrations in the test solutions, there was a quantitative connection between the magnitude of the labile‐bound fraction and the rate of active uptake into the symplasm. At higher sulfate concentrations than 0.1 mM, sulfate positive sites of lower affinity to sulfate were believed lo disturb the quantitative connection mentioned above.
Pigments et salinité chez Porphyridium
Authors: Lelclerc J. C.
Published: April 2006

Pigments and salinity in Porphyridium.—An opal glass light transmission method is used for estimating the proportions of pigments in Porphyridium sp. Lewin, grown in artificial media. The cells show an Increase in chlorophyll/B–phycoerythrin ratio in media twice or thrice as saline as sea water, Chlrophyll/carotenoïds ratio is low in media the salinity of which is either low or high. In the case of phycoerythrins, light–absorption ratio at 500 nm and 545 nm vary also with the salinity.

Une méthode de mesure par transmission de lumière á travers des lames opalines est utilisée pour évaluer les proportions de pigments chez Porphyridium sp. Lewin cultivé milieux artificiels. Les cellules montrent une augmentation du rapport chlorophylle/B.‐phycoérythrine dans les milieux deux outrois fois plus salés que l'eau de mer. Le rapport chlorophylle/carotenoïdesest faible dans les milieux dont la salinityé est soit faible soit élevée. Dans le cas des phycoérythrines, le rapport des absorptions de lumière à 500 nm et 545 nm varie aussi avec la salinityé.
Effects of Leaf Shape and Boundary Layer Thickness on Photosynthesis in Cotton (Gossypium hirsutum)
Authors: Baker D. N. , Myhre D. L.
Published: April 2006

In upland cotton (Gossypium hirsutum L.) certain varieties are available with the mutant character “okra” leaves. These deeply lobed leaves were found to have thinner boundary layers than their normal analogues. Apparent photosynthesis and transpiration measurements were made in field‐grown stands under a variety of light intensities and carbon dioxide levels to assess the effect of leaf boundary layer diffusion resistance on photosynthetic efficiency. The thinner boundary layers associated with deeply lobed “okra” cotton failed to euhance carbon fixation rates per unit land area. It was concluded that the leaf boundary layer resistance under field conditions is small compared with the total CO2 diffusion resistance.
Production of Lytic Exoenzymes in Casamino Acids Media by Myxococcus virescens
Authors: Haskå Guno
Published: April 2006

The production of proteolytic enzymes and enzymes active on autoclaved aerobacter cells by Myxococcus virescens, strain B2, was studied In Casamino acids media. By modification of the N III–B media of Norén to a higher concentration of casamino acids and to a lower content of sodium chloride, the maximal production of lytic exoenzymes could be increased at least four times.

Too high a concentration of casamino acids (more than 17 g/1) and sodium chloride (30 mM), as well as too low a concentration of sodium chloride, inhibited the enzyme production.
The Effect of Various Mono–and Disaccharides on the Growth of Sphagnum nemoreum Thalli in Sterile Cultures
Authors: Simola Liisa Kaarina
Published: April 2006

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

Using 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

The 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

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

The 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

A 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

δ‐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

Activities 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

Measurements 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

The 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

The 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

If 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

In 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

A 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

Respiration 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

Roots 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

The 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

The 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

The 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.
“Adaptation” and Chromosome Variability in Excised Roots of Cereals
Authors: Beuzenberg E. J. , Ferguson J. D. , Pearson B. E.
Published: April 2006

Heteroploidy, often coinciding with phenotypic or metabolic changes, was found in cereal root cultures. In some cases the changes were apparent after only 4 passages and affected the roots of bread wheat as well as those containing all or some of the wheat and rye genomes. It is unsafe to assume that cultured organised tissues are cytologically stable. The cause of the abnormality is not known but possible mechanisms are discussed.
The Adaptation of Plankton Algae IV. Light Adaptation in Different Algal Species
Authors: Jøsrgensen Erik G.
Published: April 2006

Two types with regard to adaptation to different light intensities are described: tbe Chlorella type and the Cyclotella type. The Chlorella type is mostly found among the green algae, the Cyclotella type among the diatoms. The Chlorella type adapts to a new light intensity mainly by changing the pigment content. Therefore the cells adapted to a high light intensity have a lower chlorophyll a content per cell than cells adapted to a low light intensity. Light saturation is mostly rather low for cells adapted to low light intensities. The light‐saturated rate of photosynthesisist mostly lower for cells adapted to a high light intensity than for cells adapted to a low light intensity. The actual photosynthesis is not much higher at a high light intensity than at a low one. The actual photosynthesis is the photosynthesis at the light intensity where the cells are grown. – The Cyclotella type adapts only by changing the light‐saturated rate. The chlorophyll content is the same in cells grown at low and high light intensities. Light saturation for cells grown at a low light intensity is rather high. The light‐saturated rate is much higher in the case examined at the high light intensity than at the low one. The actual photosynthesis is considerably higher for cells grown at the high light intensities than for cells grown at low light intensities.‐ The two adaptation types are not sharply separated since transition types occur.
α‐Aminoadipic Acid and α,ɛ‐Diaminopimelic Acid in Inoculated Pea Plants (Pisum sativum) and Root Nodule Bacteria (Rhizobium leguminosarum)
Authors: Roponen Ilma E.
Published: April 2006

Observations were made on the content of α‐aminoadipic acid and α‐aminophimelic acid (DAP) in pea plants, nodules and Rhizobium leguminosarum, strain HT3. The preparations were purified by ion exchange chromatography, Qualitative analyses were made by paper chromatography, and quantitative analyses by means of an automatic amino acid analysator.

In the whole plant and seeds the content of α‐aminoadipic acid soluble in 70% ethanol varied between 10 and 80 μg/g dry weight. The shoot and red nitrogen fixing nodules contained more of this acid than roots and green inactive nodules. In the insoluble fraction of the shoot its concentration was 0.4–0.6 mg/g dry weight. α‐Aminoadipic acid was not found in free living rhizobia, which again contained a considerable amount of α‐aiaminopimelic acid, about 0.5 mg/g dry weight. The synthesis of DAP was intensive also in root nodules. In red nodules, which fixed molecular nitrogen, the content of DAP was 2.1 mg/g dry weight and in green inactive nodules 1.3 mg/g dry weight. It was shown that in the nodules DAP is closely connected with cell wall peptides of bacteroids. DAP could not be found in pea plants outside the nodules.
The Effect of Various Aliphatic Aldehydes and Related Compounds on the Growth of Dipodascus aggregatus
Authors: Nyman Brita
Published: April 2006

The growth of Dipodascus aggregatus in cultures inoculated with cells from the acceleration phase of growth was stimulated by the saturated and unbranched aliphatic C3 C4, and C6 to C11 aldehydes (80 μM]. Nonanal was most active in stimulating growth. The C12 aldehyde inhibited growth. The C5, aldehyde generally inhibited growth. – Nonan did not affect growth. 2‐Nonanone and 5‐nonanone promoted growth insignificantly. – In cultures inoculated with cells from the exponential phase growth was unaffected or even inhibited by all the aldehydes tested. The C4, C5, C10, and C11 aldehydes inhibited growth to a larger extent than nonanal.
The Effect of Age on the Phytochrome‐Mediated Chlorophyll Formation in Dark‐grown Bean Leaves
Authors: Akoyunoglou George
Published: April 2006

The effect of red and far‐red treatment on chlorophyll synthesis in dark‐grown bean leaves was studied at various ages. Although the effect was pronounced in the old leaves, no effect was observed in the young ones (4 days old). In the 5‐day old leaves a measurable effect of red light pretreatment can be observed, whereas the far‐red reversal effect was not observed. — The length of the dark period between the red pretreatment and the continuous illumination is also age dependent. Leaves older than 6 days show a maximum at about six hours, while in the young leaves the red light effect increases with the time of dark incubation up to the 24 hours tested. — The reversal effect of far‐red light on protochlorophyllide regeneration was also examined. The far‐red light has no reversal effect on leaves younger than 6 days old, while on the old leaves it has such an effect.
Auxin Effects on the Aggregation and Heat Coagulability of Cytoplasmic Proteins and Lipoproteins
Authors: Morré D. James
Published: April 2006

The kinetics of induction of heat stability of cytoplasmic proteins and lipoproteins by auxin (2,4,‐D) were determined for basal sections of soybean hypocotyl. Maximum heat stabilization occurred after 4 h of tissue incubation with 10‐5M 2,4‐D. The effect was less pronounced or absent with longer incubations. Membrane fractions sedimenting between 10,000 and 100,000 g and proteins of the 100,000 g supernatant were most affected. The auxin‐induced protein aggregation response varied among experiments. With many tissue lots, the response was small or absent even though the tissue responded to the auxin uniformly by increased growth. The magnitude of response was proportional to the logarithm of auxin concentration but with low 2,4‐D the portion of the homogenate protein coagulated by heat was increased and with supraoptimal concentrations it was decreased relative to the control. The smallest auxin‐induced change in heat coagulability was observed at the auxin concentration nearest the optimum for growth. No direct correlation was found between the auxin‐induced protein and lipo‐protein aggregation phenomenon and total protein, chloroform‐extractable lipid, residual lipid, growth or tissue deformability. Total sulfhydryl equivalent of the homogenates, however, did correlate with auxin effects on aggregation. This result, plus experiments where homogenates were exposed to oxidizing or reducing conditions, suggests that heat stabilization and associated protein aggregation phenomena are related to conversion of protein sulfhydryl to intramolecular disulfide bonds. No significance is attached to heat stabilization of cytoplasmic proteins as a requisite of auxin‐induced growth.
Mineral Uptake in Fusarium oxysporum f. sp. vasinfectum
Authors: Shere S. M. , Jacobson L.
Published: April 2006

A method for growing Fusarium oxysporum, a mycelial fungus, and a technique for its use in mineral uptake studies have been described. Some general characteristics of the uptake process were determined. The fungus, grown for 54 hours, was found to take up as much K as 15 to 20 meq/100 g dry weight in 2 to 4 hours from a solution of 5 meq/l KCl. Approximately 3 to 5 meq of this uptake was readily removed by a CaCl2 rinse. The uptake was only slightly sensitive to pH over the range of 4 to 9. Below pH 4 uptake dropped rapidly. The age of the culture appeared to be the dominant factor in determining the rate of uptake. In contrast to other fungi, the presence of glucose during uptake was detrimental to K uptake. Conditions unfavorable for metabolic activity as low temperature, anaerobiosis, or the presence of DNP markedly reduced the uptake rate. Although the fungus took up Na from single salt solutions nearly as well as K, the latter ion was much preferred in mixtures of the two ions. The organism showed no significant metabolic uptake of Ca or Cl. During uptake from KCl solutions, the organic acid content increased. The increase, chiefly in succinic acid and to a lesser extent in acetic and citric acids, amounted to about half the K uptake. The remainder of the K taken up was correlated with a roughly equivalent efflux of cellular Mg.
Properties of Wheat Mitochondria. Study of Substrates, Cofactors and Inhibitors
Authors: Srivastava Hari K. , Sarkissian Igor V.
Published: April 2006

Isolated mitochondria of wheat shoots oxidize α‐ ketoglutarate, DL‐malate succinate and NADH with good relative respiration control and ADP: O ratio. They have high affinity for α‐ketoglutarate and NADH as substrates and utilize malate and succinate with a respiration ratio of about one‐half of α‐ketoglutarate. The average ADP : O ratios approach the expected theoretical values, i.e., 3.6 ± 0.2 for α‐ketoglutarate, 1.8 ± 0.2 for succinate, and 2.8 ± 0.2 for malate. The ADP: O ratio with NADH is 1.8 ± 0.2. The maximum coupling of oxidation and phosphorylation is obtained at concentrations of 10 mM, 2 mM, 10 mM and 8 mM for α‐ketoglutarate, NADH, malate and succinate, respectively. — Wheat mitochondria have little or no dependence on added cofactors. Mitochondria prepared by our procedure apparently retain sufficient amounts of endogenous cofactors required for NAD‐linked systems. FAD+ is found to improve succinate oxidation. Cytochrome c does not have any significant effect on respiratory parameters of wheat mitochondria. — Wheat mitochondria are some ‐what resistant to DNP at 1.7 × 10‐5M. Malonate seems to improve coupling of α‐ketoglutarate oxidation. Other Krebs cycle intermediates have been tested on three major substrates of TCA cycle, i.e., α‐ketoglutarate, malate and succinate.
The Localization of Aluminium in the Cortex Cells of Bean and Barley Roots by X‐Ray Microanalysis
Authors: Waisel Y. , Hoffen Avia , Eshel A.
Published: April 2006

The distribution of aluminium, nitrogen, calcium and phosphorus in the cortex cells of bean and barley roots was investigated by means of X‐ray microanalysis. Aluminium was apparently localized inside the cell‐lumens and its distribution over ‐lapped that of nitrogen. More calcium was observed in the cell walls. No correlation between the distribution of aluminium and phosphorus was found.
Root Permeability as Affected by Picloram and Other Chemicals
Authors: Reid C. P. P. , Hurtt W.
Published: April 2006

The effects of picloram (4‐amino 3,5,6‐trichloropicolinic acid) and several other chemicals on root permeability were studied. Initially, effects on cell permeability were investigated by measuring the betacyanin efflux from red beet (Beta vulgaris L.) root sections. Picloram solutions ranging from 10‐3M to 10‐6M had no significant effect on betacyanin efflux when compared to controls. Similar results were found for 10‐4M and 10‐5M 2‐methoxy‐3,6‐dichlorobenzoic acid (dicamba), 10‐4M 2,4‐dichlorophenoxyacetic acid (2,4‐D) and 10 μl/l of ethylene. Compounds that caused significant pigment leakage were 10‐4M and 10‐5M phenylmercuric acetate (PMA), 10‐3M and 10‐4M 2,4‐dinitrophenol (DNP), 10‐3M and 10‐4M 2,4,5–trichlorophenoxyacetic acid (2,4,5‐T) and 10‐3M 2,4‐D.

The effects of picloram on root permeability were also studied with bean plants (Phaseolus vulgaris L. cv. Black Valentine) grown in nutrient solution under controlled environmental conditions. Roots treated for 3 hours with 10‐5M picloram showed no significant electrolyte leakage as determined by conductivity measurements of the root‐bathing solution over a period of 52 hours. When bean plants were root‐trated for 3 hours with 10‐5M, and 10‐7M picloram and then decapitated, increased stem exudation by the treated plants as compared to controls was observed. Xylem exudate of the teated plants also showed increased electrolytic conductivity. The increased exudation rate accompanied by increased conductivity indicates that picloram has little effect on root cell membrane integrity, appears not to act as a metabolic inhibitor in the root system, and in some way stimulates salt secretion into the xylem.
Reversal of Ethionine‐Induced Inhibition of Elongation of Avena Coleoptiles by Purines, Adenosine, and Glutamic Acid
Authors: Norris W. E. , Mangum H. E.
Published: April 2006

Ethionine‐induced inhibition of elongation of Avena coleoptile segments has been measured in water and in indol‐3yl‐acetic acid. In the presence of 10 mM L‐ethionine the inhibition amounts to about 70 %. It has been shown previously that the addition of adenosine triphosphate effectively counteracts this inhibition; optimal ATP concentrations are between 0.25 and 0.5 mM. Adenine, adenine sulfate, adenosine, guanine, S‐adenosylmethionine, and glutamic acid have now been shown to act similarly to ATP in reversing the ethionine‐induced inhibition of elongation.
Occurrence of Indole‐3‐Acetic Acid in Buds of Pinus silvestris
Authors: Aldén Torsten , Eliasson Lennart
Published: April 2006

The major ether‐soluble, growth‐stimulating substance detected by the Avena coleoptile straight‐growth test in extract from sprouting buds of Scots pine (Pinus silvestris L.) was identified as indole‐3‐acetic acid by Rf values in 5 solvent systems and by its elution volume in ethanol on a Sephadex LH‐20 column. When the substance was applied to the growth solution of wheat roots in a special test the growth in length of the roots was at first inhibited, but growth was recovered after about 6 hours in the same manner as when small quantities of IAA were applied. The extracts also contained large amounts of growth inhibitors which interfered with the auxin response if they were not removed.
Growth in Axenic Culture of Isolated Shoot Apices of Eichhornia crassipes
Authors: Raman K. , Narayanaswamy S.
Published: April 2006

Apical meristem culture of Eichhornia crassipes has shown that for successful regeneration, the excised meristem dome must be associated with at least the youngest leaf primordium as part of the explant and a culture medium containing coconut milk (10 %, v/v), IAA (0.1 mg/l) and kinetin (1 mg/l) as growth supplements with 2 % sucrose as carbon source.
The Effects of Benzylaminopurine on Growth and 14Carbon Translocation in Excised Mustard Cotyledons
Authors: Lovell Peter , Moore Keith
Published: April 2006

When localized areas of blades of recently excised mustard cotyledons were fed with 14CO2 it was found that the fixation products passed rapidly into the veins and then were translocated to the petiole. Since other cotyledons similarly treated subsequently rooted at the petiole base, this suggested that it acted as a sink for assimilates. Treatment of excised cotyledons with benzylaminopurine (BAP) resulted in the enhancement of blade growth and the suppression of root initiation and development. Quantitative determinations of labelled assimilate in both the cotyledon blade and the terminal 2 mm portion of the petiole were made. It was found that cotyledons treated with BAP at a concentration high enough to suppress completely root initiation had a higher level of radioactivity in the petiole base than the terminal segments in untreated petioles, whether expressed as specific activity or as a percentage of the total radiocarbon fixed. BAP‐treated cotyledons also fixed consistently higher levels of 14CO2, probably due to an increase in photosynthetic area. The results suggest that BAP alters the pattern of differentiation at the base of the petiole rather than the polarity of movement of assimilates to the petiole base.
The Ultrastructure of Spirulina platensis— A New Source of Microbial Protein
Authors: Hedenskog Gudmund , Hofsten Angelica v.
Published: April 2006

The ultrastructure of the blue‐green alga Spirulina platensis has been investigated. The appearance of photosynthetic thylakoids, polyphosphate and cyanophycin granules and nucleoplasm was studied. Cells of Spirulina have also been disintegrated and extracted with different concentrations of sodium hydroxide and the amount of extractable and isoelectrically precipitable nitrogen has been determined. High yields were obtained with about 60 % of the nitrogen precipitable after extraction of disintegrated cells.
Renouvellement des protéines et effet spécifique de la kinétine sur des cultures de cellules de Tabac
Authors: Jouanneau Jeam‐Pierre
Published: April 2006

Determination and fractionation of proteins of tobacco cell suspensions requireing kinetin for cell division. — Cell suspensions either in stationary phase without kinetin in the medium or dividing in the presence of this factor have been compared. It was found a) that the specific rates of protein synthesis and protein degradation were not changed by the addition of kinetin during the early period of growth. A quantitative change ocurred only after the first generation period, b) Soluble proteins of these cells were mapped by polyacrylamide gel electrophoresis. The observed protein patterns were very similar as well as the patterns or radioactivity incorporated into the same proteins during the incubation period of the cells. However, a small number of specific discrepancies appeared in the pattern of cells growing in the presence of kinetin matched to the patterns of stationary cells. At least one specific difference in these patterns could be observed before the first cell division occurred.
Pathways of IAA Production from Tryptophan by Plants and by Their Epiphytic Bacteria: A Comparison
Authors: Libbert Eike , Fischer Elfriede , Drawert Anneliese , Schröuder Roswitha
Published: April 2006

Metabolites of tryptophan were investigated using 2 systems: a bacterial (Peastem homogenates containing the epiphytic bacteria) and a plant system (pea stem sections under sterile conditions).

The plant system produces: indolepyruvic acid (IPyA), indoleacetaldehyde (IAAld) indoleacetic acid (IAA), indoleethanol (tryptophol, IAAol), indolecarboxylie acid (ICA), indolecarboxaldehyde (ICAld). Bacteria produce additionally: indoleactic acid (ILA), tryptamine (TNH2) and the unknown Xb and Yb, but IAAld was not detected.

A nonacidic inhibitor extract from pea stems decreases the gain of IAA, IPyA, ILA, Yb. It increases the gain of IAAld, IAAol, TNH2, Xb, and (only in the bacterial system) ICA and ICAld. Three sites of inhibitor action are suggested, namely the steps Try → IPyA, TNH2→ IAAld, IAAld → IAA.
The Influence of Phosphate Uptake on Cation Uptake in Fusarium oxysporum f. sp. vasinfectum
Authors: Shere S. M. , Jacobson L.
Published: April 2006

Fusarium oxysporum grown in a low phosphate medium was found to take up several times as much K from KH2PO4 as from KCI solutions. Large amounts of phosphate also were taken up from KH2PO4. Similar large uptakes of Na and phosphate took place from solutions of NaH2PO4. Substantial quanties of phosphate were taken up from solutions of Ca(H2PO4)2 in the absence of any appreciable Ca uptake. When the fungus was grown in a medium containing high phosphate, little or no uptake of phosphate from KH2PO4 solutions occured and the K Uptake was at the same level as from KCI solutions. During large phosphate uptake sizable reductions in the organic acid content of the fungal cells were observed. Much, but not all, of the data could be explained on the basis of maintenance of charge balance within the cells. – The respiratory rate of fungus, grown in a low P medium, was markedly increased in KH2PO4 solution. Fungus, grown in a medium with high phosphate, had a higher respiratory rate which showed only a slight response to KH2PO4 solution. Fungus, grown in a medium with high phosphate, had a higher respiratory rate which showed only a slight response to KH2PO4.