bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth Chamber Illumination and Photomorphogenetic Efficacy I. Physiological action of infrared radiation beyond 750 nm
Authors: DEUTCH BENTE , RASMUSSEN OLE 
Published: April 2006

AbstractPlants cultivated in growth chambers under such artificial illumination as fluorescent tubes show certain characteristic differences from plants grown in nature or under incandescent lamps. The plants grown under fluorescent light are shorter and more darkly pigmented; they also show different daylength requirements for certain photoperiodic responses. It was assumed that these effects were caused by the relative deficiency of far red irradiation (λ= 700–750 nm) in the emission from the fluorescent lamps. This assumption was tested on such light sensitive phenomena as stem elongation, flowering, the formation of resting organs, chlorophyll synthesis, and production yield in several plant genera. In all cases the plants were grown under long days (16 h). Six common types of growth chamber illumination were tested for their efficacy for long‐day induction. The spectral energy distribution of the lamps was measured. The emission from the various lamp types showed only small differences within the region of visible light (λ: 400–750 nm), but much larger diversity in the ratio of visible to infrared radiation (λ: 750–1000 nm). A strong correlation exists between the relative emission of infrared radiation and the photomorphogenetic efficacy of the lamps. Under fluorescent light the long‐day effect was weak or missing, but increased with increasing infrared emission. High infrared emission was also favourable for high production yield.
Effect of Ethylene on the Qualitative and Quantitative Composition of the Phenol Content of Carrot Roots
Authors: SARKAR SUBODH K. , PHAN C. TON 
Published: April 2006

AbstractCarrot (Daucus carota L.) roots stored at 3 ± 1°C in an atmosphere containing 100 μ1/I of ethylene had their total phenol content increased markedly as compared to control samples kept in air. The increase was two‐fold: i. higher level of pre‐existing phenols, particularly isochlorogenic acid, ii. de novo synthesis of (at least) four compounds, two of which were identified as 3‐methyl‐6‐methoxy‐8‐hydroxy‐3,4‐dihydroisocoumarin, and 5‐hydroxy‐7‐methoxy‐2‐methylchromone, which are not normally present in carrot tissues.
Esterification and Spectral Shifts of Chlorophyll(ide) in Wildtype and Mutant Seedlings Developed in Darkness
Authors: HENNINGSEN K. W. , THORNE S. W. 
Published: April 2006

AbstractSpectral changes and esterification (presumably with phytol) of newly formed chlorophyllide a in dark‐grown leaves of wildtype bean (Phaseolus vulgaris) and barley (Hordeum vulgare) and a number of chloroplast mutants in barley, were studied by spectrofluorimetry on leaves and on solvent extracts.The shift of the fluorescence emission maximum from 692–694 to 678 nm (excitation shift: 682–684 to 672 nm) and esterification of chlorophyllide a have a similar time course, and both processes are temperature dependent in a similar manner. After completion of the spectral shift and esterification, the fluorescence efficiency of chlorophyll a increases with a subsequent reaccumulation of protochlorophyllide. In leaves of mutants where the shift of fluorescence from 692 to 678 nm is lacking, esterification and the subsequent processes are also blocked. In leaves of mutants with a rapid shift of the fluorescence from 692 to 678 nm, or with direct photoconversion to chlorophyllide a with the fluorescence at 678 nm, esterification is also rapid.The results are interpreted as a sequence of molecular events involving a conformational relaxation of the chlorophyllide holochrome and a translocation of chlorophyll a to reaction centers of the photosystems.
The Effect of Auxin and Low pH on Young's Modulus in Pisum Stems and on Water Permeability in Potato Parenchyma
Authors: UHRSTRÖM INGER 
Published: April 2006

AbstractThe effect of auxin and acid solution on Young's modulus (E) and longitudinal growth has been studied on growing segments of Pisum sativum. The modulus has been determined by means of the resonance frequency method. 2.8·10−5M IAA produces a decrease in E within 4 minutes and an increase in length in about 7 minutes. A 10−4M HCl‐solution produces an almost immediate decrease in E and increase in length. The response to the acid solution only persists for about 10 minutes whereas the auxin response continues for hours. Therefore, it is improbable that the hydrogen ions activate a normal enzymatic process leading to increased elasticity and growth. Further the water permeability in potato parenchyma has been investigated by means of the resonance frequency method. Auxin as well as hydrogen ions increase the water permeability, auxin within 2 minutes and hydrogen ions immediately. The lag of the increase in permeability in the auxin solution and the immediate response in the acid solution indicate that auxin and hydrogen ions do not act in the same way, even if an increased membrane permeability is the most probable explanation in both cases. It is suggested that the hydrogen ions act directly on the membrane by changing the membrane potential and thus the permeability, whereas auxin may increase the proton concentration in the membrane enzymatically and thus change the permeability.
pH Changes Associated with Iron‐Stress Response
Authors: BROWN J. C. , JONES W. E. 
Published: April 2006

AbstractWhen Fe‐inefficient T3238fer and Fe‐efficient T3238FER tomatoes were supplied iron, and nitrogen as nitrate, they increased the pH of the nutrient culture. When they were supplied nitrogen as ammonium, they decreased the pH. When Fe supply was limited, Fe‐stress response developed in T3238FER that opposed the usual nitrate response and decreased, rather than increased, the pH. A “reductant” which reduced Fe3+ to Fe2+ was released from the roots of these plants and lowered the pH; and there was a tremendous increase in the uptake of Fe. T3238fer did not produce “reductant” in response to Fe‐stress; the pH increased, and the plants developed Fe‐deficiency when nitrogen was supplied as nitrate. Nitrogen nutrition and iron‐stress response are important factors associated with iron chlorosis in plants. Release of hydrogen ions from roots of Fe‐stressed plants is caused by more than response to imbalanced uptake of cations and anions.
Root Formation in Pea Cuttings
Authors: ERIKSEN E. NYMANN , MOHAMMED SHAFAAT 
Published: April 2006

AbstractCuttings were either decapitated or both decapitated and disbudded at different time intervals. Auxin, at different concentrations, was applied to the cuttings in lanoline.Auxin applied to decapitated and disbudded cuttings promoted root formation in the early stage of the initiation phase.Auxin treated cuttings, which were only decapitated, did not show an increase in number of roots per cutting. However, an increase in the root mass was found in the early stage of the initiation phase.The results seem to indicate that auxin is active only in the first part of the initiation phase. It is acting alone, not together with other substances synthesized in the shoot meristem.
Effect of Auxins, Cytokinins, Gibberellins, Abscisic Acid and Ethephon on Regeneration and Growth of Bulblets on Excised Bulb Scale Segments of Hyacinth
Authors: PIERIK R. L. M. , STEEGMANS H. H. M. 
Published: April 2006

AbstractThe effect of various growth substances on regeneration and growth of bulblets on excised bulb scale segments of Hyacinthus orientalis L. cv. Pink Pearl was studied. Bulblet formation was promoted by the auxins IAA and IBA but was inhibited by NAA at high concentrations. IAA hardly affected bulblet weight, whereas IBA and NAA at high concentrations decreased it. Cytokinins had hardly any effect on bulblet regeneration and bulblet weight, Gibberellins inhibited both bulblet regeneration and bulblet weight; GA4+7 acted much stronger than GA3. ABA and ethephon decreased bulblet regeneration and bulblet growth.
Changes Induced in Peroxidase Activity under Simulated Hypo‐gravity
Authors: WABER J. , WILLIAMS B. J. , DUBIN J. , SIEGEL S. M. 
Published: April 2006

AbstractA new method of inducing and maintaining a hypo‐gravity environment is described. Using this new technique (buoyancy compensation), the effect of reduced gravitational stress on dwarf marigolds (Tagetes patula) was studied. It was found that the specific activity of peroxidase was elevated significantly in gravity compensated seedlings. This effect, discovered with the buoyancy compensators, was confirmed with plants grown on traditional clinostats.
Ethylene Evolution Stimulated by Succimc Acid‐2,2‐Dimethylhydrazide in Apple Shoots
Authors: JINDAL K. K. , ANDERSEN A. SKYTT , DALBRO S. 
Published: April 2006

AbstractThe rate of ethylene production in the shoot tips of the apple cultivar ‘Ingrid Marie’ (Red motant) after succinic acid‐2,2‐dimethylhydrazide (SADH) treatment was investigated. The shoots were treated with SADH at 12.5, 25 or 50 mM in the months of June, July and August. The samples were analysed 7,15, 30 and 60 days after SADH spray.Ethylene production was considerably higher in the SADH‐treated shoots than in the untreated ones. Application of 12.5 or 25mMSADH late in June stimulated ethylene production 3‐fold, while 50 mM produced a 5‐fold increase in ethylene production 7 days after spraying. There was a continuous decrease in ethylene production at the subsequent samplings. In untreated control shoots there was a slight increase. However, even 60 days after spraying the shoots treated with 50 mM had higher ethylene production than the control shoots. The same relationship was found in the shoots treated in the months of July and August. A parallelism has been established between the rate of ethylene production and growth retardation, A residual effect of SADH treatment in earlier years was demonstrated and is discussed.
Changes in Endogenous Plant Hormones in Cherry Tomato Fruits during Development and Maturation
Authors: ABDEL‐RAHMAN M. , THOMAS T. H. , DOSS G. J. , HOWELL L. 
Published: April 2006

AbstractHormonal extracts of cherry tomato fruits (Lycopersicon esculentum Mill.) cv. Small Fry at different stages of fruit development and maturation were bioassayed for their auxin, gibberellin, cytokinin and growth inhibitor activities. In general, the levels of endogenous growth promoters were much higher in the young developing fruits than in the more mature fruits. Free cytokinin levels were highest in the first two weeks of development then declined rapidly. However, cytokinin activity in the ribotide fraction, after treatment with alkaline phosphatase, decreased during thefirst three weeks of development then increased rapidly over the following four weeks. Auxin levels increased during early development to reach a maximum in three‐week‐old fruits after anthesis. Gibberellin levels during the first two weeks of development were much lower than those of auxins and cytokinins, but then increased to reach a peak in the fourth week after anthesis.A growth inhibiting substance with Rf similar to that of abscisic acid was found in the acidic fraction of the fruit extracts. This inhibitor increased gradually during fruit growth and development and reached a peak at the age of five weeks which coincides with the green mature stage.
Rôle des polyphénols dans la croissance. Définition ?un modèle expérimental chez Lycopersicum esculentum
Authors: MARIGO GÉRARD , BOUDET ALAIN M. 
Published: April 2006

AbstractUsing young plants of Lycopersicum esculentum Mill., we attempt to define a system for a new evaluation of the physiological role of polyphenols, particularly of their regulating properties on growth and development, Exogenously supplied qoinic acid causes an important increase of the phenolic content and a reduced growth of the plants.The decrease in size is proportional to the stimulation of the phenolic pool and is equally obtained using other precursors of aromatic compounds like phenylalanine and cinnamic acid. Non‐precursors of polyphenols structurally related to quinic acid are ineffective. It appears from these data that polyphenol levels and growth could be related in tomato plant and that this material would be convenient for studies on interactions between growth and polyphenols.
Protein Synthesis in Plant Microsomal System
Authors: DUBE SYAMALIMA , DUBE D. K. , GOSWAMI BISWENDU B. , ROY S. C. 
Published: April 2006

AbstractAn active microsomal system from 48‐h germinating seeds of Vigna sinensis (L.) Savi has now been developed. It can incorporate amino acids into protein under both in vitro and in vivo conditions, provided dithiothreitol (a protective reagent for SH groups) and phenylthiourea (an inhibitor of phenol oxidase) are present in the buffer system for extraction; and provided the assay mixture contains added dithiothreitol.The system consists of microsomes or ribosomes, tRNA or pH 5 fraction and 20 natural amino acids, ATP and an ATP‐generating system and GTP with requirement for Mg ions. The cell fractions possess aminoacyl‐RNA synthetase activity as indicated by the aminoacylhydroxamate formation. Microsomal synthesis is stimulated by exogenous tRNA from Escheriehia coli or rat liver and sensitive to various inhibitors such as cyclo‐heximide, chloramphenicol, fusidic acid. The ribosomal transfer reaction has absolute dependence on the microsomal wash, on the crude enzyme from the same participate source, and on a synthetic messenger. It is greatly suppressed by fusidic acid and by cycloheximide.
Regulation of Prenyl Chain Synthesis in Etiolated Hordeum Seedlings by Far‐Red and White Light
Authors: LICHTENTHALER HARTMUT K. 
Published: April 2006

AbstractThe kinetics of prenyl chain formation (C20 phytyl in chlorophylls, vitamin KI and α‐tocopherol; C40 carotenoids and C45 in plastoquinone‐9) in plastids of etiolated Hordeum seedlings was compared in continuous darkness and after far‐red and white light treatments:

Continuous far‐red (via phytochrome Pfr) enhances the synthesis rate of all prenyl chains, but does practically not change the dark pattern of prenyl chain accumulation. Free C20 phytyl chains could not be detected by means of thin layer chromatography.
White light induces a much stronger enhancement of prenyl chain formation than does far‐red. It also changes the pattern of prenyl chain synthesis by a particularly strong promotion of the synthesis of phytyl chains, which get bound to chlorophyll a. The rate of chlorophyllide formation seems to determine the rate of enhanced phytyl formation.
It is assumed that the enzyme, which esterifies chlorophyllide a with the phytyl chain, is formed or activated by far‐red treatment, but only starts working in white light, when the protochlorophyllide holochrome is re‐arranged to the chlorophyllide holochrome.
Preferential Assimilation of Ammonium Ions from Ammonium Nitrate Solutions by Apple Seedlings
Authors: FRITH G. J. T. , NICHOLS D. G. 
Published: April 2006

AbstractApple seedlings, Pyrus malus L., were grown in complete nutrient solutions containing nitrate, ammonium, or ammonium plus nitrate as the nitrogen source. Uptake of nitrogen was calculated from depletion measurements of the nutrient solutions and by using 15N labelled nitrate and ammonium salts.If the plants received nitrogen as ammonium only or as nitrate only, the amounts of nitrogen taken up were similar. However, if the seedlings were supplied with ammonium nitrate, the amount of nitrate‐nitrogen assimilated was only half that of ammonium. Nevertheless, if ammonium and nitrate were supplied to a plant with a split‐root system, with each root half receiving a different ion, the uptakes were similar.The possibility of independent inhibition by ammonium of both nitrate uptake and reduction in the roots is discussed.
Physiological Changes of Carrot Cells in Suspension Culture during Growth and Senescence
Authors: OKAMURA S. , SUEKI K. , NISHI A. 
Published: April 2006

AbstractChanges in the synthetic activities of nucleic acids and protein and in the amount of adenine nucleotides in Daucus carota cells have been examined during a period of rapid cell division and during the stationary phase. Cell growth and the syntheses of those macromolecules in the logarithmic phase were significantly enhanced by increasing the concentration of phosphate in the medium. In a phosphate‐rich medium, RNA and protein rapidly degraded and the number of cells with denatured cytoplasm increased when the culture entered into a stationary phase because of exhaustion of glucose. On the other hand, when the growth ceased by exhaustions of phosphate and nitrogen, the cells slowly underwent physiological changes leading to cellular senescence. The value of adenylate energy charge during the growth period was about 0.8–0.9 irrespective of the growth rate. After cessation of growth the value declined to about 0.5.
Activities of Two Peptidases in Resting and Germinating Seeds of Scots Pine, Pinus sylvestris
Authors: SALMIA M. AULIKKI , MIKOLA JUHANI J. 
Published: April 2006

AbstractExtracts prepared from resting seeds of Scots pine, Pinus sylvestris L., rapidly hydrolysed two peptides, Leu–Tyr and Ala–Gly, at pH 8.6 and 7.8, respectively. In gel chromatography on Sephadex G‐100 the two activities were eluted as separate peaks, which indicates that they are due to two different peptidases.The seeds were allowed to germinate at 20°C, the activities of the two enzymes were assayed separately on extracts from the endosperm and seedling tissues at different stages of germination, and compared with corresponding changes in dry weight and total nitrogen. Both enzyme activities were relatively high in the endosperm of resting seeds, and they increased about 2‐ and 3‐fold during germination (expressed as enzyme units per seed), the increases coinciding with the time of rapid reserve protein mobilization. Both enzymes were also abundant in the embryos of resting seeds, and during germination their activities increased even more rapidly than those in the endosperm.The possible role of these two “alkaline peptidases” in reserve protein hydrolysis is discussed.
Influence of Light on the Bioelectric Potential of the Bean (Phaseolus vulgaris) Hypocotyl Hook
Authors: HARTMANN ELMAR 
Published: April 2006

AbstractBy use of surface electrodes electropotenlial measurements were carried out on hypocotyl hooks of Phaseolus vulgaris seedlings. The hooks were illuminated with a small spot of white, blue, red or far red light.The potential changes in bean hypocotyl hooks do not show the red‐far red reversible characteristics of phytochrome‐mediated processes. By experimenting with inhibitors of photosynthesis we could demonstrate that the light‐triggered potential changes in green bean hooks are correlated to photosynthetic electron transport phenomena. The red‐light‐induced transient is a depolarization, whereas blue light induces a hyperpolarization. Etiolated beans exhibit no bioelectric potential changes when subjected to red or far red irradiations. Blue light and white light induce a strong hyperpolarization in etiolated hooks cells. This transient seems to be an action potential induced by light. The action potential is influenced by inhibitors of electron transport and oxidative phosphorylation. By comparing the action spectrum of the action potential induced by light with the absorption spectra of extracted carotenoids and xanthophylls from etiolated bean hypocotyl hooks, we observed similarities.
Cell Wall Solubilization in Pedicel Abscission of Begonia Flower Buds
Authors: GATE CH. H. HÄNISCH TEN , VAN NETTEN J. , DORTLAND J. F. , BRUINSMA J. 
Published: April 2006

AbstractEffects of metabolic inhibitors and growth regulators on the course of abscission and on the activities of cell wall solubilizing enzymes were studied in pedicel explants of Begonia flower buds.Actinomycin D, chloramphenicol and 2,4‐dinitrophenol slightly retarded abscission, whereas cycloheximide exerted a strong inhibition if applied until 10.5 h after explant excision.Indoleacetic acid retarded and ethylene promoted abscission and cell wall solubilization. However, the activities of cell wall solubilizing enzymes did not correspond with the course of abscission. No polygalacturonase and pectic acid and pectin transeliminases could be detected in the abscission zone during abscission, whereas a low pectin methylesterase activity did not change. Endo‐ and exocellulase activities did not increase until about 10 h after the onset of abscission, indicating that they are the result rather than the cause of abscission.
Metabolite Concentrations and Phase Relations in d‐Fructose Induced Glycolytic Oscillations
Authors: BETZ A. , BECKER J.‐U. 
Published: April 2006

AbstractThe frequency of glycolytic oscillations in yeast cells is only slightly modified by the consumption rate of either glucose or fructose, but it is reduced to 1 /2 to 2/3 if the ketohexose is the only substrate.Phase relations between NADH, adenine nucleotides and sugar phosphates (G‐6‐P, F‐6‐P, FDP, DAP) are independent of the hexose fermented.With fructose as a substrate the amplitudes of adenylates and hexose phosphates are distinctly smaller than with glucose. The maximum of G‐6‐P is higher with glucose and the minimum concentration of FDP is higher with fructose.In the transition to anaerobiosis FDP, adenosine 5′‐diphosphate and adenosine 5′‐phosphate are extremely high, whereas G‐6‐P, F‐6‐P and ATP concentrations are lower if fructose is the substrate fermented.The results are indicative for different control characteristics of the phosphofructokinase step, but on their basis it cannot be distinguished between a direct interaction of fructose (or one of its derivatives) on the phosphofructokinase kinetics or the existence of a bypass for fructose which might be able to withdraw a part of the substrate from the control point at the phosphofructokinase.
Photoassimilation of CO2 by Isolated Bundle‐Sheath Strands of Zea mays I. Stimulation of CO2 Assimilation by Adding Various Intermediates of the Photosynthetic Cycle; Evidence for a Deficient Photosystem II Activity
Authors: FARINEAU JACK 
Published: April 2006

AbstractIsolated bundle‐sheath (BS) strands from leaves of mature maize plants show enhanced rates of CO2 fixation in the presence of reduced intermediates of the photosynthetic cycle (R5P, DHAP, FruDP.) 3PGA is the major labelled product of 14CO2 fixation whatever the substrate added. CO2 fixation is much lower with PGA than with reduced intermediates, suggesting a limited capacity of the cells to regenerate RuDP (the CO2‐acceptor) from PGA. These two experimental facts, which are characteristic features of bundle‐sheath photosynthesis for maize (a species with agranal bundle‐sheath chloroplasts) indicate that phaotosystem II activity is a limiting factor for the evolution of the bundle‐sheath photosynthetic process. Nevertheless, a reducing capacity arises as proved by sensitivity of CO2 fixation to DCMU, particularly when PGA is added to the bundle‐sheath.PGA synthesis occurs, in the presence of non‐limiting amounts of CO2, according to the equation: RuDP + CO2→ 2 PGA; the oxygen effect on 14CO2 fixation, at lower CO2 concentration, is interpreted as a dilution effect of the internal pool of 14CO2 by unlabelled CO2 generated by photorespiration.