bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inducible Formation of Glutamate Dehydrogenase in Rice Plant Roots by the Addition of Ammonia to the Media
Authors: KANAMORI TETSUO , KONISHI SHIGEKI , TAKAHASHI EIICHI 
Published: April 2006

AbstractThe activity of glutamate dehydrogenase (l‐glutamate: NAD oxidoreductase, EC 1.4.1.2.; GDH) of rice plants changes in response to the nitrogen source supplied to the culture solution. The activity of NADH‐GDH(aminating) in roots is rapidly increased by the addition of ammonia, whereas the activity in shoots is much less affected by nitrogen supply. The activity increased with increasing concentration of ammonia at least up to 14.3 mM. In roots GDH activity was found in both the mitochondrial and soluble fractions. The increase of NADH‐GDH activity caused by the ammonia treatment occurs mainly in the latter fraction. The new band with GDH activity was detected on the zymogram of polyacrylamide gel electrophoresis and this inducible enzyme is active with both NAD and NADP. On the other hand, the constitutive enzyme activity active with NAD is also increased by the ammonia treatment. The increase of enzyme activity is prevented by the addition of cycloheximide or chloramphenicol to culture medium. The incorporation of 14C‐leucine(U) into GDH proteins was also studied using polyacrylamide gel electrophoresis. Higher radioactivity was found in induced samples than in non‐induced ones. These results show that the increase of GDH activity in roots by ammonia treatment seems to depend on de novo protein synthesis.
Translocation and Persistence of 1,2‐14C‐(2‐Chloroethyl)‐phosphonic Acid (Ethephon) in Thompson Seedless Grapes
Authors: WEAVER ROBERT J. , ABDEL‐GAWAD HESHAM A. , MARTIN GEORGE C. 
Published: April 2006

AbstractApplications of 1,2−14C‐(2‐chloroethyl)phosphonic acid (ethephon) were made to the surface of mature Vitis vinifera cv. Thompson Seedless berries. After 7 days, 62 % of the recovered radioactivity was still on the outside surface and was easily washed off. Within the berry, radioactivity was present only in the carbon‐labeled ethephon fraction, as revealed by chromatographic analysis. Similar results were obtained when the compound was injected directly into the berries. Application of ethephon to the first leaf above the cluster, or to a berry pedicel or a peduncle, failed to result in measurable movement of the compound into the berries. Autoradiographic studies with young shoots indicated that ethephon translocated in the phloem in a source to sink relationship.
Control of the Biosynthesis of Phenylalanine and Tyrosine in Plant Tissue Cultures: Lack of Repression of Chorismate Mutase
Authors: CHU MARGARET , WIDHOLM J. M. 
Published: April 2006

AbstractTobacco, rice, carrot and tomato tissue cultures were grown in liquid media containing l‐phenylalanine or l‐tyrosine, or both together. The addition of these amino acids increased their respective cellular levels (4–20 fold), but did not lower the level of chorismate mutase, an enzyme in the biosynthetic pathway of phenylalanine and tyrosine. These results indicate that the biosynthesis of phenylalanine and tyrosine in cultured plant cells is not regulated by repression of the synthesis of chorismate mutase by phenylalanine or tyrosine.
Deoxyribonucleotide Pools in Plant Tissue Cultures
Authors: NYGAARD PER 
Published: April 2006

AbstractTwo dimensional thin‐layer chromatography on anion‐exchange cellulose enables the separation of the normally occurring ribo‐ and deoxyribonucleoside triphosphates. This technique was applied to perchloric acid extracts of callus tissue of sycamore and tobacco and of pine pollen grown in 32P‐orthophosphate labelled media to quantitate the nucleoside triphosphate pools under different growth conditions.The results showed that the ratio of the deoxyribonucleo‐side triphosphates to their corresponding ribonucleoside triphosphates is low in plant cells, similar to the ratio previously found for animal cells.During the period of most rapid DNA synthesis in the callus tissue, the deoxyribonucleoside triphosphate pools reach their highest values. This effect is also demonstrated with cells of Escbericbia coli.
Malate Dehydrogenase Isoenzymes in Cotton Leaves of Different Ages
Authors: O'SULLIVAN STEPHEN A. , WEDDING RANDOLPH T. 
Published: April 2006

AbstractMalate dehydrogenase isoenzymes from the blades of different aged leaves of the cotton plant have been investigated. The total extractable malate dehydrogenase activity varied widely between leaves of different ages and different locations on the plant. Malate dehydrogenase zymograms developed from the extracts which contained significantly different levels of enzyme activity appear to indicate the presence of different groups of malate dehydrogenase isoenzymes in leaves of different ages. However, under appropriate conditions of polyacrylamide gel electrophoresis, the same number of malate dehydrogenase isoenzymes with the same relative mobilities were detected in all the leaves studied.These findings are discussed in relation to reports that malate dehydrogenase isoenzymes change with plant development or that they have different roles in the plant.
Callus and Cell Suspension Cultures of Carnation
Authors: ENGVILD K. C. 
Published: April 2006

AbstractCallus cultures of carnation, Dianthus caryophyllus L. ev. G. J. Sim, were grown on a synthetic medium of half strength Murashige and Skoog salts, 3 % sucrose, 100 mg/l of myo‐inositol, 0.5 mg/l each of thiamin, HCl, pyridoxin, HCl and nicotinic acid and 10 g/l agar. Optimal concentrations of growth regulators were observed to be 3 × 10−6M indoleacetic acid (JAA) combined with 3 × 10−6M benzylaminopurin (BAP) or 10−6M 2,4‐dichlorophenoxy acetic acid (2,4‐D) alone. IAA + BAP caused a 100 fold increase in fresh weight over 4 weeks at 25°C. Addition of casein hydrolysate increased growth further.Cell suspension cultures worked best in media containing 2,4‐D in which they had a doubling time of about 2 days. Filtered suspensions were successfully plated on agar in petri dishes, but division was never observed in single cells. The cultures initiated roots at higher concentrations of IAA or NAA, but all attempts to induce formation of shoots or em‐bryoids gave negative results.
Evidence for the Activation of NADH‐cytochrome c Reductase during Germination of Lettuce
Authors: ELDAN M. , MAYER A. M. 
Published: April 2006

AbstractA very rapid increase in particulate cytochrome c reductase activity during the very early stages of germination of lettuce is demonstrated. The increase in activity does not parallel water uptake or the increase in cytochrome oxidase activity. The increase is reversible on drying of imbibed seeds and is not inhibited by cyanide. It is concluded that the increase in activity is due to some kind of activation process and not to de novo synthesis of protein. Possible mechanisms of activation were investigated. It was not possible to simulate the activation process in vitro, in the isolated particulate fraction.
Physiological Studies on Pea Tendrils VIII. The Relationship of Circumnutation to Contact Coiling. — With a Description of a Laboratory Intervalometer Using Integrated Digital Circuits
Authors: JAFFE M. J. 
Published: April 2006

AbstractThe average rate of rotation of circumnutating tendrils of Pisum sativum L. ev. Alaska, was 1.57 ± 0.29 mm/min. 53% of the tendrils rotated clockwise and 47% counterclockwise. Circumnutation is apparently dependent on the maintenance of sufficient turgor as it stopped when either the roots or all the shoot appendages except the terminal tendril were excised, but resumed when the aerial wounds were covered with petroleum jelly.Both circumnutation and contact coiling were similarly retarded when the plant was cut in the middle of the top inter‐node, or by the use of either juvenile or senescent organs.As the tendril circumnutated rapidly during the sweeping portion of its circuit, it was capable of coiling at only about 57% of the rate of which it could coil if stimulated during the relatively slow moving turn, Conversely, when the tendril was mechanically stimulated to coil, its rate of circumnutation decreased markedly and remained retarded as long as the tendril continued to coil.On the basis of these observations, it is concluded that contact coiling does not seem to be simply a modified form of circumnutation, but the two modes of movement might be related through a negative feedback system.
Interaction of Kinetin and Abscisic Acid in the Avena Straight‐Growth Test
Authors: HEMBERG TORSTEN 
Published: April 2006

AbstractDifferent amounts of abscisic acid, 2.7 × 10−9− 5 × 10−8 moles, were chromatographed in isopropanol: ammonia: water (100:14:6), firstly alone and secondly together with 5 × 10−8 moles kinetin. The same amount of kinetin was also chromatographed alone. The chromatograms were tested biologically with the Avena straight‐growth test. Whereas a large part of the chromatograms of kinetin gives growth stimulation, the Rf region 0.4–0.6 of abscisic acid chromatograms is strongly growth‐inhibiting. The inhibition within this Rf region does not become less if abscisic acid and kinetin are chromatographed together.
A Comparative Study of the Changes in Root Growth, Induced by Coumarin, Auxin, Ethylene, Kinetin and Gibberellic Acid
Authors: SVENSSON SVEN‐BÖRJE 
Published: April 2006

AbstractThe effect of coumarin, IAA, ethylene, kinetin and gibberellic acid on roots of maize and wheat was investigated. Sterile attached and detached roots and isolated elongation zones were used. In some experiments a semi‐sterile procedure was followed. The effects of the different regulators separately or in various combinations together with coumarin were studied on the root growth with regard to division, elongation and swelling of the cells. The ethylene production in isolated elongation zones was measured after treatment with coumarin, IAA, PCIB, kinetin, colchicine and dinitrophenol.The results show the following: 1) Each substance produces a specific morphologic pattern. 2) Changes in polarity were demonstrated for auxin‐induced swelling in cell divisions and cell expansion and for coumarin‐induced swelling in cell divisions. Other cell expansion in swollen parts was due to cylindric cells increasing in width while retaining their cylindric form. 3) Coumarin‐induced inhibition could not be counteracted by IAA, PCIB, carbon dioxide, kinetin, gibberellic acid or Cycocel. 4) The ethylene production in isolated elongation zones increases noticeably after kinetin treatment, less strongly after auxin treatment and least after coumarin treatment. The production of ethylene does not seem to be correlated with the morphogenetic effect of the different substances. 5) The isolated elongation zones reacted to a) IAA and kinetin with an increase in length in some cases and b) gibberellic acid with a reduction of their width. 6) The inhibitory effect of coumarin on the growth in length of the elongation zones was diminished by kinetin. The swelling produced by coumarin in these zones was reduced by gibberellic acid. The effects just mentioned of kinetin and gibberellic acid were considered as indirect ones. ‐ From the present findings it was concluded that concomitant effects of auxin, ethylene, cytokinins and gibberellins are not obligatory for coumarin to exert its morphogenetic effects on root growth. In discussing the results some pitfalls in studies of growth reactions after application of hormones to roots containing meristem were emphasized.
The Influence of Atrazine, Benzyladenine, and the Embryonic Axis on Chlorophyll Synthesis in Cucumber and Squash Cotyledons
Authors: PENNER DONALD , WILEY LORRAINE 
Published: April 2006

AbstractExcision of the embryonic axis prior to 3 1/2 days of germination in the dark followed by 8‐h of light decreased the total chlorophyll content of cucumber cotyledons but not squash cotyledons. Benzyladenine stimulated the accumulation of chlorophyll in the cotyledons of intact embryos and excised cotyledons in both cucumber and squash. Gibberellic acid had no effect. Atrazine inhibited chlorophyll formation in excised squash cotyledons. Benzyladenine also increased the carotenoid and xanthophyll content in the cotyledons from intact squash seedlings.The results suggest that pigment synthesis in cotyledons may be controlled by a number of substances produced in the embryonic axis and that cytokinin‐like benzyladenine can simulate the action of one of them.
Effect of Several Transpiration Suppressants on Carbon Dioxide and Water Vapor Exchange of Citrus and Grapevine Leaves
Authors: BRAVDO BEN‐AMI 
Published: April 2006

AbstractSeveral transpiration suppressants, (phenyl mercuric acetate, Tag 16 (polyethylen emulsion) R14‐poly (ethylene adipate) 4–4 Diphenylmethan diisocyanate), which are known to either close stomata or form thin films on leaves, were sprayed on citrus and grapevine seedlings. Water vapor and carbon dioxide exchange of single leaves were measured by means of infra red gas analyzer and L1C1 hygrosensors. The effects of the chemicals were evaluated by analyzing net photosynthesis, transpiration, mesophyll resistance to CO2 compensation concentration and respiration. All the chemicals tested increased either mesophyll resistance or CO2 compensation point to various degrees. It is concluded that none of the chemicals tested acted solely on epidermal resistance. All chemicals reduced photosynthesis, but the ratio of photosynthesis to transpiration increased in most cases in grapevine but not in citrus. Different chemicals acted differently on citrus and grapevine. The method of analysis used enabled us to evaluate separately the relative effect of a chemical on mesophyll resistance and respiration.
Influence of Nitrogen Supply on Uptake and Translocation of Strontium and Calcium in Wheat Seedlings
Authors: ANDERSEN A. J. , JACKSON W. A. 
Published: April 2006

AbstractSupplying nitrate to N‐depleted wheat seedlings (Triticum vulgare cv. Knox) stimulated the uptake and translocation of both 83Sr and 45Ca. Since the increase in 45Ca accumulation was greater, the 85Sr/45Ca ratio in the plant tissue was decreased. Nitrate had relatively little influence on the amount of the divalent cations and 85Sr/45Ca ratio in the exchangeable fraction on the root surfaces, whereas it greatly increased the uptake into root tissue and translocation to shoots. The increase in percent transported to shoots occurred largely in the period of most rapid nitrate uptake.A split root study indicated that nitrate was ineffective when it was supplied to a different portion of the root system than that exposed to 85Sr and 45Ca. Nevertheless, ammonium and urea also increased the translocation of the two cations, indicating that the effects of nitrate could not entirely be ascribed to a direct effect of the nitrate anion.
The Effect of NAA (1‐Naphthaleneacetic Acid) and Morphactin (Methyl 2‐Chloro‐9‐hydroxyfluorene‐9‐carboxylate) on RNA and Protein Synthesis in Senescing Bean Endocarp
Authors: SALMINEN SEPPO O. , GAGIANAS ATHAN A. , BERG ARTHUR R. 
Published: April 2006

AbstractThe effect of NAA (1‐naphthaleneacetic acid) and morphactin (methyl 2‐chloro‐9‐hydroxyfluorene‐9‐carboxylate) on the uptake and incorporation of uridine‐5‐3H and l‐leucineU‐14C was studied in senescing bean endocarp (Phaseolus vulgaris L. cv. Kentucky wonder pole beans) sections. Both growth regulators inhibited uptake of these precursors and appeared to affect different components of the uptake mechanism. A possible synergistic inhibition was seen in case of leucine, but in case of uridine, the effect was less than additive.A strong synergistic increase in the incorporation of l‐leucine into protein was seen. Thus, morphactin interacted with an exogenously applied auxin at the level of the protein synthesizing apparatus.
Temperature Response of Adenosine Triphosphatase of Bean Roots as Related to Growth Temperature and to Lipid Requirement of the Adenosine Triphosphatase
Authors: KUIPER P. J. C. 
Published: April 2006

AbstractThe ATPase activity of the cell wall, mitochondrial and microsomal fractions of bean roots (Phaseolus vulgaris) shows non‐linear curves when plotted logarithmically against temperature, producing high Q10‐values in the low temperature range and low Q10‐values in the high temperature range. The Q10‐valuc of supernatant ATPase is constant and low as well as the Q10‐value of soluble ATPase liberated from membranes. Cell wall ATPase from bean roots adapted to a low temperature has a much smaller temperature response. Such roots contain a larger quantity of membrane‐bound ATPase and a smaller amount of soluble ATPase than roots adapted to a high temperature.Extraction of soluble ATPase with acetone reduces activity to practically zero, but activity could be partially restored by the addition of lipid. The temperature response of reconstituted phosphatidyl choline‐ATPase is inconsiderable. That of reconstituted sulfolipid‐ATPase is much larger.I am indebted to Bep Stuiver for skillful assistance with the experiments, to Ir. F. Kuiper and Mr. C. H. Vermeulen for help with the cultivation of the bean plants and to Prof. Dr. E. C. Wassink for reading the manuscript.Communication 292 of the Laboratory of Plant Physiological Research, Agricultural University, Wageningen, The Netherlands.
Effect of Light on the Response of Pea Seedling Roots to 2,4‐Dichlorophenoxyacetic Acid
Authors: ELIASSON LENNART , PALÉN KJELL 
Published: April 2006

AbstractWhite light increases the inhibition of growth in length of pea seedling roots caused by 2,4‐D. This effect is most pronounced in the case of lateral root growth. The effect is obtained also if the shoots above the cotyledons are removed and is probably due to the direct influence of light on the roots. While light also weakly enhances the inhibition of pea root growth caused by 1‐naphthylacetic acid, light does not increase the sensitivity of wheat roots to 2,4‐D or naphthylacetic acid.
Effect of Gibberellic Acid on Dark and Light Germination at Different Temperatures of Calluna, Ledum andRhododendron Seeds
Authors: JUNTTILA OLAVI 
Published: April 2006

AbstractThe aim of the experiments was to study the effects of gibberellic acid (GAs) on the germination of Calluna vulgaris L., Ledum palustre L. and Rhododendron lapponicum (L.) Wahlenb. seeds under different environmental conditions.Under continuous light from white fluorescense tubes (3000 lux), untreated seeds of Calluna were partly dormant at all temperatures studied (9, 15, 21, 27, 27/9, 8/16 hours). Percentage of dormant seeds increased, however, with decreasing temperature, and it varied also from seed lot to seed lot. Untreated seeds of Ledum were dormant in light at 9° and 15°C but not at higher temperatures. Untreated seeds of Rhododendron were completely dormant in light at temperatures from 13° to 24°C. Seeds of all species were completely dormant in darkness both at 15° and 27°C. GA3 stimulated greatly the germination of all species under all studied environmental conditions. The used concentrations (0.2–3.2 mM) gave nearly 100% germination in most cases. At 9°C the dormancy in some seed lots of Calluna and Ledum was only partly broken by the used concentrations of GA3.
Enhancement of Intact Bean Leaf Senescence by NaCl Salinity
Authors: PRISCO JOSE TARQUINIO , O'LEARY JAMES W. 
Published: April 2006

AbstractRed kidney bean (Phaseolus vulgaris L.) plants were grown in nutrient solution and in nutrient solution plus four bars of added NaCl. Chlorophyll and protein decay occurred much more rapidly in intact leaves from plants subjected to four bars of added NaCl in the growth medium than in intact leaves from plants without added NaCl. Ribonucleic acid (RNA) content in intact leaves of salt treated plants was higher than in intact leaves from plants grown in nutrient solution alone. However, the tendency for RNA content variation in leaves during the experimental period was the same for both control and salt treated plants. The results support the idea that salinity enhances senescence and suggests that hormone imbalance plays an important role in this process.
Extracellular Lytic Enzymes of Myxococcus virescens
Authors: HASKÅ GUNO 
Published: April 2006

AbstractTwo bacteriolytic hexosaminidases isolated from Myxococcus virescens were characterized. When acting on purified cell walls of Micrococcus lysodeikticus they liberated reducing groups and N‐acetylhexosamines. By chromatography on Sephadex G‐50 and G‐25 columns disaccharides were isolated from degraded cell walls. After reduction of the disaccharides with sodium borohydride the acid hydrolysis products were identified by thin layer chromatography. Only pale spots of glucosamine appeared after this treatment but the spots of muramic acid remained unchanged. The enzymes were found to be devoid of exo‐β‐N‐acetylglucosaminidase activity. These results are compatible with the action of endo‐β‐N‐acetylglucosaminidases.
Interpreting Leaf Water Potential Measurements with a Model of the Soil‐Plant‐Atmosphere Continuum
Authors: ELFVING DON C. , KAUFMANN MERRILL R. , HALL ANTHONY E. 
Published: April 2006

AbstractA water flux model, which assumes that the dynamic functioning of the soil‐plant‐atmosphere continuum may be described by a series of steady states, was examined as a means for interpreting leaf water potential measurements in ‘Valencia’ orange trees (Citrus sinensis (L.) Osbeck). According to the model, leaf water potential should be related to transpirational flux, which in this experiment was estimated by the ratio of vapor pressure deficit of the atmosphere to leaf diffusion resistance (VPD/rleaf). Leaf water potentials decreased in a specific relationship with increasing values of VPD/rleaf provided that soil water was adequate and soil temperature was not too low, but regardless of season of the year or climatic or edaphic differences among 3 field locations. When soil water tensions exceeded 0.3 bar or when soil temperatures were lower than 15°C, deviations from the model occurred in the form of more negative leaf water potentials than predicted by VPD/rleaf. The model predicts from simple measurements made on intact plants that these differences were due to the modification of flow resistances by cool temperatures and the modification of both resistances and the potential of water at the source in the case of soil water depletion. The model may be a useful tool for interpreting plant water potential data under contrasting environmental conditions.
A Re‐examination of the Functional Significance of Aerenchyma
Authors: ARMSTRONG W. 
Published: April 2006

AbstractModel roots of known length and internal porosity were assayed for ROL (radial oxygen loss) by the cylindrical Pt electrode technique and a series of curves were obtained which express the inter‐relationships between ROL and diffusion path length over a wide range of internal porosity levels.The results indicate that internal porosity can exert considerable control on the amount of oxygen lost from roots, the more so the narrower the root.Because radial oxygen loss is necessary for survival and competitiveness, doubt is therefore cast on the currently held view that aerenchyma formation furnishes the wetland plant with an oxygen diffusion pathway excessive to its requirements.The results also suggest that cellular partitions and diaphragms in wetland species may impede gas transport far less than has hitherto been thought.