bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the Physiology of Host‐parasite Relationship in Orobanche. I. Respiratory Metabolism of Host and Parasite
Authors: SINGH JAI NARAIN , SINGH JAGDISH NARAIN 
Published: April 2006

AbstractThe respiratory rate of the roots of mustard (Brassica cam‐pestris L.) and tomato (Lycopersicum esculentum Mill.) serving as hosts for the total root parasites Orobanche aegyptiaca Pers. and O.cernua Loefll. was measured using Warburg manometric technique. At the same time determinations were made of the respiration of the apical, basal and root regions of the parasites. The effects of sodium fluoride, malonic acid, sodium azide and DNP (2,4‐dinitrophenol) on the rate of respiration of the host roots as well as of the parasites were studied. The Orobanche infection results in a marked increase in the respiratory rate near the host‐parasite contact region. The damaging effect of infection seems to be due mainly to a continuous flow of water, minerals and metabolites from host to parasite. The haustorial invasion creates an obstruction in the translocation of metabolites. The respiration rate is lower in Orobanche than in the host, which might be related to its slower growth rate, inefficient oxidative processes and an escaping of certain energy‐requiring interconversion processes. Roots of O. aegyptiaca are more well‐developed and have higher rate of respiration. They can absorb more water and minerals from the soil. This fact might be connected with the specificity of the two species. NaF and malonic acid inhibit the respiration to a similar extent in healthy and infected roots. This indicates that the pathway of respiration does not change materially after infection. The EMP and Krebs cycle seem to operate at a lower intensity in Orobanche, which is proved by the lower inhibition of the respiration as compared to in the host. Azide causes a stronger reduction of the respiration in infected than in healthy roots. It would imply that the infection stimulates the activity of metal containing oxidases. The weaker inhibition of the respiration in Orobanche tissues indicates a mediation of other enzymes in the oxidation processes than in the host. The respiration is less stimulated by DNP in infected than in healthy roots. Contrary to the general effect of DNP, this substance decreases the O2 uptake in the parasite tissues. This fact may be explained by the occurrence of exceptionally high amounts of endogenous phenolic compounds and an insufficient production of ATP in the parasite.
Effect of Glucose and Auxins in Rooting Etiolated Stem Segments of Populus nigra
Authors: NANDA K. K. , JAIN M. K. , MALHOTRA SHIVA 
Published: April 2006

Abstract2.5 cm long stem segments of Populus nigra L. did not root when cultured in water or in auxins alone but rooted in glucose. The number of rooted segments and roots produced on them increased with rising glucose concentrations up to 0.5%, but decreased with higher concentrations. An addition of 1.0 mg/1 IAA inhibited rooting at 0.01 % glucose, was ineffective at 0.1 % and stimulative at higher concentrations of glucose which were inhibitory when used alone. The results show that the auxin effects on rooting are influenced by the nutritional status of the stem cutting of a species, and that a proper balance of the two is necessary for root development.
Cytokinin Activity During Development of Cotton Fruit
Authors: SANDSTEDT ROBERT 
Published: April 2006

AbstractCytokinins in cotton fruits were detected by the soybean callus bioassay on the 1st day after anthesis. Peak cytokinin activity occurred from the 4th to the 9th day and then declined to little or none by the 18th day after anthesis. The principal cytokinin remained below Rf 0.2, when chromatographed on paper with water‐saturated sec‐butanol, and predominated throughout the period of cytokinin activity. Another cytokinin, migrating to Rf 0.8, remained less active.
Plant Growth Inhibition and Membrane Penetration by a Homologous Series of Dichlorobenzoate Esters
Authors: BUTA J. G. , STEFFENS G. L. 
Published: April 2006

AbstractThe homologous series of n‐alkyl esters (C1–C10) of 3,4‐dichlorobenzoic acid was synthesized and their effects in inhibiting the growth of Nicotiana meristems were studied. The inhibition of growth was considered in terms of penetration of chemicals into the plant tissue and subsequent cell membrane disruption. Penetration was investigated by applying the emulsified ester to the meristem and then measuring the compound recovered with the isolated surface lipids. Decreasing amounts of 3,4‐dichlorobenzoate esters penetrated into the plant as the alkyl chain length of the ester moeity was increased. Essentially no penetration occurred with the n‐C7 through C10 esters tested. The effect of the ester homologues on cell membranes was studied by measuring the efflux of betacyanin from beet root cells. Decreasing amounts of pigments were released as the alkyl chain length of the ester was increased. Minimal cell membrane disruption was found for the C7–C10 esters. Inhibition of the plant meristem may result from the more rapid penetration of the short chain ester homologues into the plant.
The Physiology of Groundnut
Authors: KHAN AZIZ A. , AKOSU FIDELIS I. 
Published: April 2006

AbstractThe distribution of labelled assimilates following the assimilation of 14CO2 in groundnut (Arachis hypogaea L.) by single leaves at different nodes was investigated using autoradiographic technique. In the vegetative stage growing leaves assimilated most of the 14carbon, while the fully expanded leaves exported most of its radiocarbon to the apices, young expanding leaves and to the roots. Soon after the formation of the pegs and the growth and development of the pods, the developing pods become the major sinks. At this stage translocation from the foliage of each branch was restricted mostly to the pods produced by this branch.
The Effect of Epidermal Cell Water Potential on Stomatal Response to Illumination of Leaf Discs of Vicia faba
Authors: GLINKA Z. 
Published: April 2006

AbstractIlluminated leaf discs of Vicia faba were brought into equilibrium with a series of mannitol solutions. The width of stomatal aperture and the osmotic potential of guard cells and epidermal cells were determined. It was found that the maximal aperture was obtained when epidermal cells were at about incipient plasmolysis and that any increase in their turgor pressure brought about a decrease in stomatal aperture. These findings emphasize the importance of epidermal cells in determining the width of the stomatal pore.
The Influence of Cu on Photosynthesis and Growth in Diatoms
Authors: NIELSEN E. STEEMANN , WIUM‐ANDERSEN S. 
Published: April 2006

AbstractCu in ionic form in a balanced medium affects the rate of photosynthesis and growth in the diatom Nitzschia palea in about the same way as in the green alga Chlorella pyrenoidosa. Remarkable differences are found, however. Small concentrations of Cu influence the rate of photosynthesis considerably more in the diatom than in the green alga whereas the opposite is the case concerning growth. The latter is most likely a consequence of excretion of organic matter by the diatom in presence of Cu whereas this does not take place in Chlorella. Some of the excreted organic matter may bind Cu and thus make the medium suitable for growth. Although pre‐treatment with Cu in the dark has no influence on the subsequent rate of photosynthesis in the light, organic matter is excreted in the dark immediately after the addition of Cu. The influence of Cu on the rate of photosynthesis varies by a factor of about 30 according to the stage of growth in a synchronized culture.
A Labile‐Bound Component of Phosphate in the Free Space of Sunflower Plant Roots
Authors: PETTERSSON SUNE 
Published: April 2006

AbstractAn experimental method is described by which it is possible to follow continuously the uptake and release of certain radioactive isotopes and the uptake of water by the roots of young plants.The method has been used in a study of the ion fractions related to the initial uptake of phosphate in the roots of sunflower plants. Two non‐bound fractions were identified: one which was leachable in distilled water and another which was released from the roots only by a bathing medium containing inactive phosphate. Experiments using conventional analysis technique corroborated the results obtained by the recording technique.
Regulation of Growth in Avena Stem Segments by Gibberellic Acid and Kinetin
Authors: JONES R. A. , KAUFMAN P. B. 
Published: April 2006

AbstractKinetin at physiological concentrations causes significant reduction of GA3‐promoted growth in excised Avena stem segments. Kinetin is therefore considered to be a gibberellin‐antagonist in this system. A Lineweaver‐Burke plot reveals that kinetin acts non‐competitively with GA3. The kinetin inhibition of GA3‐promoted growth can be seen within 6 hours. It was found that soluble protein is markedly increased by kinetin in the tissue during the first 3 hours, thus preceding the inhibition of GA3‐promoted growth by several hours. At the cellular level, kinetin negated the blocking effect of GA3 on cell division in the intercalary meristem portions of these segments. In fact, kinetin promotes both lateral and longitudinal cell divisions in intercalary meristem cells.
Effect of Inorganic Phosphate on the Extracellular Acid Phosphatase Activity of Tobacco Cells Cultured in vitro
Authors: UEKI KATSUJI , SATO SITIRO 
Published: April 2006

AbstractAcid phosphatase activity in culture medium of tobacco cells growing in suspension increased with the age of the culture from which the medium was obtained. The increase in the activity was accelerated by omitting inorganic phosphate from nutrient medium, and it was depressed by addition of inorganic phosphate or cycloheximide. Amylase and β‐galactosidase activities were not induced by the omission of inorganic phosphate. It was concluded that derepression of acid phosphatase synthesis was involved in the increase in the extracellular acid phosphatase activity upon inorganic phosphate depletion.
Physiological Studies with Heavy Water. II. Germination and Growth Inhibition of Barley by D2O
Authors: BHANDARKAR M. K. , BHATTACHARYA S. , GAUR B. K. 
Published: April 2006

AbstractSeed germination and barley seedling growth in various D2O concentrations have been studied. It was observed that the emergence of root and shoot was delayed, there being greater delay in shoot than in root emergence. A complete block was observed in germination in pure D2O and the germination rate was slowed down significantly in lower concentrations.An initial germination delay by different D2O concentrations seemed to cause a subsequent retardation in the growth measured as shoot and root length. A comparison of root and shoot length with their respective dry weights suggested that the growth by cell division/elongation might have been affected more than the transport of food materials from the endosperm to the embryo.Analysis of the total sugars of the endosperm and the embryo at 8 hour intervals showed that while the hydrolysis of starch to sugars was progressively decreased by increasing D2O concentrations, the transport rate from endosperm to embryo showed a sharp inhibition in 50% D2O and above. This indicated that the inhibition in the transport of materials, besides less hydrolysis of reserve food materials, may also be a causal factor of germination and growth inhibition in D2O.
Effect of Gibberellic Acid, 2,3,5‐Triiodobenzoic Acid and Indole Acetic Acid on Growth and Development of Impatiens balsamina during Different Photoperiods
Authors: SAWHNEY S. , TOKY K. L. , NANDA K. K. 
Published: April 2006

AbstractThis paper deals with the effect of 100 mg/1 each of GA3 TIBA and IAA singly and in combination with each other on stem elongation, development of lateral branches and floral bud initiation in Impatiens balsamina plants exposed to 8‐, 16‐ and 24‐h photoperiods. GA3 enhances stem elongation, the enhancing effect decreasing with IAA as well as with TIBA during 8‐h but increasing during 16‐ and 24‐h photoperiods. It decreases the number of lateral branches, the decrease being greatest during 16‐, less during 8‐ and the least during 24‐h photoperiods. The time taken for floral buds to initiate with and length of branches during 16‐h photoperiods.During 8‐h photoperiods, IAA delays the initiation of floral buds, while GA3 hastens it when used together with TIBA or IAA or both. GA3 increases the number of floral buds on the main axis but decreases it on lateral branches, while TIBA decreases the number on the main axis but increases it on lateral branches. IAA reduces the number of floral buds on the main axis only when used alone, but on both the main axis as well as on lateral branches when used together with GA3 and TIBA. Floral buds were not produced on lateral branches when plants were treated with GA3, TIBA and IAA all together.GA3 and TIBA induced floral buds even under non‐inductive photoperiods, the number of buds and reproductive nodes being less in TIBA‐ than in GA3‐treated plants during 24‐h photoperiods. The time taken for floral buds to initiate with GA3 and TIBA during noninductive photoperiods is much longer than that during 8‐h inductive photoperiods with or without GA3 or TIBA application. IAA completely inhibits the GA3‐ and TIBA‐caused induction during 24‐h, but only delays it and reduces the number of reproductive nodes and floral buds during 16‐h photoperiods.
Triterpeneglycosides as Inhibitors of Fungal Growth and Metabolism
Authors: OLSEN ROLF A. 
Published: April 2006

AbstractAvenacin, the resistance factor ioat roots against Ophiobolus graminisi ν graminis, and a related triterpeneglycoside, aescin, inhibited growth of various fungi, while the growth of a few fungi was unaffected.The triterpenoidal saponins tested seemed to be fungicidal, as the mycelia did not grow after exposure to the inhibitors. The fungicidal effect, however, depended on the medium used. The inhibitors did not seem to act primarily on the endogenous respiration, since the oxygen uptake, although much reduced, continued after the time required to destroy the growth capacity. The leakage of UV‐absorbing substances from fungi, sensitive to the inhibitors, and the decrease of UV‐absorbing substances in the transient pool of the cells indicate a change in the cell membrane.
Characterisation of the High Temperature Inhibition of Germination of Lettuce (Lactuca sativa)
Authors: REYNOLDS T. , THOMPSON P. A. 
Published: April 2006

AbstractLactuca sativa L., lettuce (Arctic King) fruit germination is inhibited in the light at temperatures above 27°C(±1.5°). This value, which is precise and repeatable is referred to as the upper temperature cut‐off point, and is characteristic for a particular species. It was found, that this cut‐off point is shifted upwards by applying kinetin solutions (0.1–1 mg/1) or downwards by applying (±)‐abscisic acid solutions (over 1 mg/1), the amount of shift being proportional to the level of active compound. In the presence of both compounds a balance was achieved. Effects of stimulators and inhibitors can most explicitly be described by reference to the direction and magnitude of the shift in the upper temperature cut‐off point, which results from their application.
Some Effects of Amo‐1618 on Growth, Peroxidase and α‐Amylase Which Cannot Be Easily Explained by Inhibition of Gibberellin Biosynthesis
Authors: CASPAR THOMAS , VERBEEK RITA , KHAN ANWAR A. 
Published: April 2006

AbstractGrowth and peroxidase activity of roots and stems of lentil seedlings were compared after treatment with Amo‐1618, alone or in combination with gibberellic acid (GA) at varying concentrations. The peroxidase enhancement in Amo‐1618 treated stems could not be attributed to a decrease in the gibberellin content since GA alone had no effect on this enzyme.In other experiments, AMO, at low concentrations, was able to induce α‐amylase production in barley aleurone layers; the lag period needed for this induction, was longer than for GA.These facts seem to indicate that some growth retardants might act at least in some cases by mechanisms other than inhibition of gibberellin biosynthesis and reversal of GA action.
The Effect of Deleterious Concentrations of Mercury on the Photosynthesis and Growth of Chlorella pyrenoidosa
Authors: KAMP‐NIELSEN LARS 
Published: April 2006

AbstractThe effect of mercury ions on the photosynthesis and growth of Chlorella pyrenoidosa in a balanced medium has been studied and compared with the effect of copper. In many ways Hg treated algae behave like algae treated with Cu in concentrations of the same molarity, but important deviations occur. Hg acts at a lower and in a more narrow range of concentrations than does Cu due to a more specific binding. The depressing effect of Hg is not counteracted by other cations such as potassium and sodium, and iron has only a slight effect. Cell division is stopped after Hg addition and there is no accumulation of assimilation products. On the contrary the cells become pale yellow. Preliminary studies indicate a light‐independent leakage in the cytoplasmatic membrane leading to an outflow of potassium ions. This is the primary action of both Hg and Cu poisoning, but the leakage does not seem to be correlated with the decrease of photosynthesis. After a lapse of time — dependent on the mercury/cell concentration ratio — a detoxication takes place probably due to the binding of Hg to “insensitive sites” in the cells. Probable mechanisms for the action of Hg on photosynthesis and growth are discussed.
Changes in Nucleic Acids Associated with Maturation and Senescence in Hedera helix
Authors: MILLIKAN D. F. , GHOSH B. N. 
Published: April 2006

AbstractSignificant changes in nucleic acids are associated with both maturation and senescence of Hedera helix leaf tissues. DNA content was unaffected by senescence, and there were no quantitative differences between juvenile and transitional forms. The adult tissue, however, contained less DNA than the other forms. The total RNA content was reduced by senescence in juvenile and transitional tissue but not in adult. Maturation, on the other hand, progressively decreased the total RNA content. Similar changes in sRNA and rRNA indicate that maturation involves quantitative changes in these fractions. Quantitative differences in the nucleotide analyses suggest that different sRNA and rRNA species are responsible for the biological processes associated with maturation.
Étude de la discrimination strontium‐calcium chez le Haricot en fonction du rapport et des teneurs respectives en Sr et Ca de la solution nutritive
Authors: MYTTENAERE C. , MASSET M. 
Published: April 2006

AbstractThe discrimination between strontium and calcium is not only conditioned by the Sr/Ca ratio of the nutrient solution but also by the total dose (Ca + Sr) of the medium. The variation of the observed ratio in relation to the total dose is closely related with the Sr/Ca ratio of the solution. Sr is preferentially fixed by the roots when the Sr/Ca ratio of the solution is low; such a result is observed in the shoots for higher ratios. For all the treatments, the OR of the leaves is lower than unity (discrimination against strontium). When the stable strontium concentration of the solution is not detectable, an increase in the calcium concentration reduces the radiostrontium retention by the roots.
Methoxyhydroquinone, a Growth Inhibitor of Ophiobolus graminis, in Leaves of Oat Seedlings
Authors: OLSEN ROLF A. 
Published: April 2006

AbstractA methanol extract of leaves of oat seedlings grown in sand cultures in the dark contained a compound which inhibited the growth of Ophiobolus graminis. The inhibitory factor was isolated and proved to be present in the plant as methoxyhydroquinone glucoside. The glucoside was readily hydrolysed to the corresponding aglucone. The methoxyhydroquinone, or possibly its oxydation product, methoxy‐P‐benzoquinone, was inhibitory to both Ophiobolus graminis var. graminis and Ophiobolus graminis var. avenae, whereas Fusarmm oxysporum var. lycopcrsici was not affected. Synthetic methoxyhydroquinone at 80 mg/l gave a 100% inhibition of Ophiobolus graminis var. graminis. After being exposed to 80 mg/l of the inhibitor for 24 h the mycelium was unable to initiate growth when transferred to a fresh nutrient solution. Only extracts from young leaves showed inhibitory activity, extracts from mature leaves giving no inhibition. The hydroquinone, or its glucoside, was not detected in roots of young seedlings, where avenacin was the only antifungal compound present.
The Mechanism of Apical Dominance in Coleus
Authors: THIMANN K. V. , SACHS TSVI , MATHUR K. N. 
Published: April 2006

AbstractThe development of lateral buds in isolated stems of Coleus blumei is inhibited by low concentrations of indoleacetic acid or other auxins, just as in other plants. The inhibition can be fully reversed by kinetin, about 3 times as much kinetin as IAA being needed. However, the outgrowth of the same lateral buds on intact Coleus plants is sensitive to environmental conditions, well‐nourished plants in full daylight often showing little inhibition by applied auxin. It is shown that (a) the solvent used for IAA, (b) the light intensity and (c) the nitrogen and phosphorus nutrition, all control the sensitivity of the buds to auxin inhibition. Using water instead of lanolin, lowering the light intensity or decreasing the supply of either nitrogen or phosphorus all increase the degree of apical dominance.
The Influence of Salinity and Temperature on Seed Germination in Salicornia bigelovii
Authors: RIVERS W. G. , WEBER D. J. 
Published: April 2006

AbstractSeeds of Salicornia bigelovii were germinated at 4.4°C, 15.5°C, and 26.6°C in saline solution containing from 0% to 8.08% sea salt. At 4.4°C, germination was delayed until the 26th day, but the final germination per cent was high in all salinities. At 15.5°C, germination was delayed until the 19th day, and the germination per cent was higher in the higher salinities. At 26.6°C, the germination began within one day and the germination per cent was higher at the lower salinities. With the exception of 26.6°C data, the maximum germination occurred at a sea salt concentration at 4.04 % which is very close to the salinity of the sea.
Gibberellin‐like Substances in Developing Watermelon Seeds
Authors: BHALLA PRITHVI R. 
Published: April 2006

AbstractWatermelon seeds were analyzed 4, 7, 9, 11, 19, 25 and 35 days after pollination. The gibberellin‐like substances were low up to 7 days after pollination, but increased rapidly in the next two days attaining a peak on the 9th day after pollination. The amount then declined and remained low till the seeds matured. Since the peak of gibberellin‐like activity coincided with (but did not precede) the time when the seeds attained their maximum size, it was concluded that it could not account for their growth. Instead, evidence was obtained to show that the peak may be correlated with the growth of the embryo and endosperm. Thin‐layer chromatography revealed the presence of three active gibberellin‐like factors at the 9th day after pollination. The chromatographic behavior of two of these active factors are similar to gibberellins A1 and A3. The data currently available are insufficient regarding the identification of a third gibberellin from watermelon seeds.