bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties of (Sodium Potassium)‐Stimulated ATPases in English Ryegrass Roots and Implications in Ion Transport
Authors: NELSON P. V. , KUIPER P. J. C. 
Published: April 2006

AbstractMaximum ATPase activities in the cell wall fraction of English ryegrass (Lolium perenne L.) roots were stimulated by foru discrete millimole ratios of (Na++ K+); 40:0, 35:5, 5:35, and 0:40. The optimal pH for stimlation was found to be 6.5. Contrary to data in the literature, Mg2+ inhibited all stimulatory ratios of (Na++ K+) when plants were cultured on an adequate nutrient solution. When grown on a dilute solution, Mg2+ enhanced (Na++ K+)‐stimulated ATPase activity in this membrane preparation. The single optimal combined concentration of (Na++ K+) for all stimulatory ratios was 40 MM. The ratios of (Na++ K+) which stimulated ATPase activity in the cell wall fraction varied with position along the root axis such that all rarely existed simultaneously nor did any exist in the terminal millimetre of the root. Both cell wall and microsomal fractions showed stimulation by (Na++ K+) at all the above ratios indicating the possible presence of plasma membrane fragments in both fractions. Only the 35:5 ratio was stimulations were found in the supernatant. Implications of ion‐stimulated ATPase involvement in ion transport were drawn from the appearance of ATPase activity at a 40:0 ratio of (Na++ K+) and the disappearance of stimulations at 35:5, 5:35, and 0:40 ratios when plants were moved from a strong (35 mM total concentration) to a dilute (0.75 mM) nutrient solution.
Comparative Study of β‐Glucosidase from Cotyledons and Fruits of Cucumber, Cucumis sativus
Authors: McCREIGHT J. D. , PHARR D. M. , LOWER R. L. , SOX H. N. 
Published: April 2006

AbstractThis study was conducted to compare the β‐glucosidase of cotyledons and fruits of Cucumis sativus L. cv. Chipper. The concentration of the enzyme was followed throughout the growth period of each organ. The greatest concentration of the enzyme did not correspond with the most rapid period of growth. Each enzyme was characterized kinetically. The Michaelis constant of the cotyledon β‐glucosidase for p‐NO2‐phenyl‐β‐D‐gluco‐pyranoside was 1.57 mM, and was 0.35 mM for the fruit enzyme. The enzymes from the two sources also differed in affinity for glucono‐1,5‐lactone, a competitive inhibitor of β‐glucosidases, susceptibility to inhibition by saccharides, and heat stability. The two organs apparently contain different forms of β‐glucosidase.
Changes in Chloroplast Lipids during the Development of Photosynthetic Activity in Barley Etio‐Chloroplasts
Authors: SELLDÉN GUN , SELSTAM EVA 
Published: April 2006

AbstractThe content of monogalactosyl diglyceride, digalactosyl diglyceride, sulfoquinovosyl diglyceride and phosphatidyl glycerol of gel‐filtrated etio‐chloroplasts isolated from greening barley seedlings was determined. The development of photosynthetic electron transport, measured as anthraquinone autooxidation, was simultaneously determined with an oxygen electrode.During the first hour of irradiation of the etiolated seedlings the lipid content of the plastids decreased rapidly. The decrease is interpreted as a chlorophyll sensitized photooxidation of the fatty acids of the diglycerides.With artificial electron donors an oxygen uptake was detected after 10 min of greening. With no donors added, a DCMU sensitive oxygen uptake was detected after 2 h. The level of DCMU inhibition increased as the plastid developed and total inhibition was obtained after 5 h.Between 2 and 6 h of greening the lipid content of the plastids stayed constant. During this greening period there was a correlation between the appearance of a DCMU sensitive electron transport and the accumulation of the trans‐3‐hexadecenoic acid of phosphatidyl glycerol. The trans‐3‐hexadecenoic acid was present already in the dark‐grown seedlings but an increase in content did not occur until after 3 h.The lipid content increased after 6 h of greening. This increase coincided well in time with the formation of grana. The fatty acid composition of the individual lipids, with the exception of phosphatidyl glycerol, and the monogalactosyl diglyceride to digalactosyl diglyceride ratios did not change fundamentally during the greening.
Étude des activités photochimiques des étiochloroplastes isolés de plantules verdies en lumière intermittente
Authors: MATHIEU YVES 
Published: April 2006

AbstractPhotochemical Activities of Etiochloroplasts Isolated from Plants Greened under Intermittent Light. I. Absorption of Oxygen.Oxygen exchange by isolated etiochloroplasts from wheat leaves (Triticum sativum Lam. cv. Florence Aurore) has been studied with an oxygen electrode. The etiochloroplasts lack an oxygen evolving mechanism and show a light induced oxygen uptake with two components. One component, sensitive to 3‐(4‐chlorophenyl)‐1,1‐dimethylurea, results from electron flow through an active photosystem II and is suppressed by photosystem II electron donors. The other component is inhibited by quinones suggesting that it might represent some mechanism to trap and dissipate excitation energy from chlorophyll in competition with that produced by the presence of artificial traps. The results are discussed in order to explain the apparent lack of coupling between photosystem II, through which some electron flow is operating, and the active photosystem I present in these plastids.
Étude des activités photochimiques des étiochloroplastes isolés de plantules verdies en lumière intermittente
Authors: MATHIEU YVES 
Published: April 2006

Abstract Photochemical Activities of Etiochloroplasts Isolated from Plants Greened under Intermittent Light. II. Photobleaching of Pigments.Etiochloroplasts were isolated from wheat leaves (Triticum sativum Lam. cv. Florence Aurore) greened under repeated flashes with intervals of 15 min of darkness. These plastids are unable to evolve oxygen and show a light‐induced bleaching of chlorophyll and carotenoids. This bleaching is inhibited by 3‐(4‐chlorophenyl)‐1,1‐dimethylurea and partially results from the presence of an active photosystem II.Pigment stabilization can be achieved after giving additional repeated flashes with short intervals of darkness (5 s) to the seedlings; but stabilization is then much lower than that obtained by continuous light when plastids with similar photochemical activity (Hill reaction) are compared.Pigment bleaching in etiochloroplasts is thus not only due to their inability to use water as photosystem II electron donor but results also from other structural or functional deficiencies.
The Potassium Requirement for Growth and Embryogenesis in Wild Carrot Suspension Cultures
Authors: BROWN SUSAN , WETHERELL DONALD F. , DOUGALL DONALD K. 
Published: April 2006

AbstractA requirement for potassium for growth and forembryogenesis in suspension cultures of wild carrot (Daucus carota L.) was demonstrated. The concentration of K+ required for maximal growth (1 mM) was less than that required for maximal embryogenesis (20 mM). Neither Na+ nor NH4+ could replace K+. Ammonium ion enhanced embryogenesis when K+ was present at suboptimal levels greater than 1 mM. Nitrogen sources strongly influenced growth and embryogenesis, but the effects of nitrogen were separable from those of K+. Subline differences were noted. Subline CSC‐29 produced nearly half the maximum embryo number in 1 mM K+ while CSC‐31 produced no embryos at that K+ concentration. Growth of CSC‐29 was slightly repressed by Na+, but no more than by similarconcentrations of K+. Growth of CSC‐31 in 1 mM K+ was strongly repressed by Na+. Embryogenesis in CSC‐29 was unaffected by Na+. In CSC‐31, Na+ repressed embryogenesis at lower concentrations of K+.
Anthurium andraeanum Plantlets Produced from Callus Tissues Cultivated in vitro
Authors: PIERIK R. L. M. 
Published: April 2006

AbstractDuring the last 3 years a method has been developed to reproduce Anthurium andraeanum Lind. through callus cultures. The procedural sequence is as follows: callus induction on excised leaf fragments, callus subculture on solid and in liquid media, adventitious sprout formation in callus on solid media, and rooting of excised sprouts. Recently 20 adult genotypes were propagated by this method.
The Inhibitory Action of Cycloheximide on Respiration of Coleoptiles is Relieved by Light
Authors: DHEIDAH M. , BLACK M. 
Published: April 2006

AbstractConcentrations of cycloheximide which are frequently used for the specific purpose of inhibiting protein synthesis also reduce oxygen uptake in Triticum and Avena coleoptiles in darkness by up to 50%. Except at high concentrations of the chemical diffuse daylight almost completely relieves this inhibitory effect provided the coleoptiles are not submerged. In darkness oxygen consumption is rapidly affected when cycloheximide is supplied to coleoptiles; the relief by light is also fast. These observations raise questions concerning the use of cycloheximide in studies with coleoptiles.
Photochromic Pigments from Blue‐Green Algae: Phycochromes a, b, and c
Authors: BJÖRN G. S. , BJÖRN L. O. 
Published: April 2006

AbstractAqueous extracts of blue‐green algae were fractionated by electrofocusing. In all algae investigated, fractions with iso‐electric points at or near 4.6 showed photochromic behaviour analogous to that of phytochrome, although they were sensitive to light of shorter wavelength. Three main types of photochromic pigments were found: Phycochrome a (in Tolypothrix distorta, Phormidium luridum, Nostoc muscorum 1453/12, and Anacystis nidulans) has one form absorbing maximally at about 590 nm (formed under red light) and one absorbing maximally at about 630 nm (formed under green light). Phycochrome b (in Tolypothrix distorta) has one form absorbing maximally near 510 nm and one form absorbing maximally at 570 nm (formed in yellow‐green and blue‐green light, respectively). Phycochrome c (in Nostoc muscorum A and probably in Tolypothrix tenuis) has one form absorbing maximally at 650 nm (formed under green light) and one absorbing very weakly in the green region (formed under red light). The conversion of Phormidium phycochrome a from its red‐absorbing form to its green‐absorbing form causes the same spectral change as if an f‐chromophore of phycocyanin were transformed into an s‐chromophore. The quantum yield for this conversion is estimated to be 0.1, while the quantum yield for the reversion is estimated to be 0.4 on the assumption that the absorption coefficients are those of f‐ and s‐chromophores. Phycochrome c is less light‐sensitive than phycochromes a and b.
Light‐Induced Absorption Changes in Etiolated Coleoptiles
Authors: WIDELL S. , BJÖRN L. O. 
Published: April 2006

AbstractBlue (or green) light induced reversible and irreversible absorption changes in etiolated wheat (Triticum aestivum) coleoptiles. Immediately after a 10 s pulse of blue light there was an absorbance increase at 440 nm and a decrease at 420 nm. The absorbance at 440 nm returned to the original level in a biphasic way, with first‐order rate constants of 0.05 s−1 and 0.006 s−1 at 25°C. The change at 440 nm was partly, but not completely, inhibited by iodide. In the 500–600 nm region complex changes occurred, indicating the participation of at least two different cytochromes, one of which was oxidized during a 10 s light pulse and the other oxidized more slowly during the following dark period.
Seed Germination and Bolting in Red Beet as Affected by Parent Plant Environment
Authors: HEIDE OLA M. , JUNTTILA OLAVI , SAMUELSEN RAGNAR T. 
Published: April 2006

AbstractLow temperature and long day regimes applied during seed development and maturation of red beet (Beta rulgaris var. rubra L.) increased the proportion of empty seed balls and reduced the germination ability of normally developed seeds. Low seed development temperatures also greatly increased the bolting susceptibility of seedlings grown at low temperatures or temperatures which are marginal for bolting, but were not able to bring about bolting under conditions which are not themselves inducive to flowering. In a field experiment a significant reduction of the root tuber yield was associated with these effects.
The Influence of 8‐Hydroxyquinoline on the Accumulation of Porphyrins in Dark‐Grown Wheat Leaves Treated with δ‐Aminolevulinic Acid
Authors: RYBERG MARGARETA , SUNDQVIST CHRISTER 
Published: April 2006

AbstractDark‐grown wheat leaves treated with δ‐aminolevulinic acid and 8‐hydroxyquinoline accumulated porphyrins, most of which were protochlorophyllide and magnesiumprotoporphyrin monomethylester. The ratio between these two components was dependent on the concentration of 8‐hydroxyquinoline. Small amounts of other porphyrins could also be detected. The treatment with 8‐hydroxyquinoline and the presence of large amounts of porphyrins other than protochlorophyllide did not influence the photoreduction of protochlorophyllide or the Shibata shift. 8‐Hydroxyquinoline caused an inhibition of protochlorophyllide biosynthesis, which could be reversed by rinsing the leaves several times with phosphate buffer. Magnesiumprotoporphyrin monomethylester was then converted to protochlorophyllide. The reversal induced by washing was increased if the buffer contained iron. The possible function of iron in the chlorophyll metabolism and its role in the inhibition reactions with 8‐hydroxyquinoline are discussed.
Gibberellin and Inhibitor Content during Iris Bulb Development
Authors: ALPI A. , CECCARELLI N. , TOGNONI F. , GREGORINI G. 
Published: April 2006

AbstractConcentrations of gibberellin‐like substances and inhibitors were determined in different organs from Iris hollandica cv. Prof. Blaauw during cold treatment and during growth in the greenhouse. Barley‐aleurone, dwarf pea and Avena coleoptile straight growth bioassays were used to determine the activity. Developing bulblets contained the highest level of gibberellin activity followed by that in floral organs. During the development of the plants quantitative changes occurred both in the non‐acidic, free, and bound pools of gibberellins.Two kinds of inhibitors, “acidic” and “non‐acidic”, have been found in the extracts. Most of the non‐acidic type were present in the roots. The acidic inhibitors were present in scales and sheath‐leaves and disappeared with cold treatment.
Glumatic‐Oxaloacetic Transaminase in Leaves of Phosphorus‐Deficient Citrus Plants
Authors: ACHITUV MIRIAM , BAR‐AKIVA A. 
Published: April 2006

AbstractPhosphorus deficiency in citrus leaves resulted in reduced glutamic‐oxaloacetic transaminase (GOT) activity and low pyridoxal‐phosphate (PLP) content. GOT activity was estimated in crude enzyme extracts by spectrophotometry PLP content was detected colorimetrically in water‐alcoholic extracts.K and Cu deficiencies increased; ‐N, ‐S and ‐Zn decreased and ‐Mg, ‐Fe and ‐Mn did not affect GOT activity in citrus leaves.Experiments were conducted to restore enzyme activity either by direct addition of PLP to the reaction mixture or by infiltration of PLP or KH2PO4 to detached, intact leaves. The infiltration was carried out in vacuo and the leaves were incubated on wet paper for 26 h, after which enzyme activity was estimated. Transamination activity of ‐P leaves more restored by PLP than by KH2PO4 treatments. In zinc‐deficient leaves the enzyme activity was not restored by infiltration of KH2PO4.
Allelopathic Inhibitors in Seeds of Hevacleum laciniatum
Authors: JUNTTILA OLAVI 
Published: April 2006

AbstractBiological inhibitors present in the dry seeds of Heracleum laciniatum Horn have been studied by means of thin layer chromatography and various bioassays. The ethylacetate fraction of methanol extracts contained three main groups of inhibitors having the following R values when chromatographed on silica gel with chloroform: (1) 0.60–0.80; (2) 0.20–0.40; (3) 0.0–0.10.The group (1) inhibited lettuce seed germination and root growth, elongation of Avena first internode segments, growth of the fungus Cladosporium cucumerinum, and it caused leakage of betacyanin from red beet tuber slices. The groups (2) and (3) had no activity in red beet betacyanin leakage test, but they were inhibitory in the other bioassays used. The group (3) were generally less active than the group (2). The group (2) contained the furanocoumarins pimpinellin, bergapten, isobergapten and angelicin. Inhibitors present in the groups (1) and (3) have not been identified. Effects of five synthetic furanocoumarins (pimpinellin, bergapten, isobergapten, isopimpinellin, sphondin) on lettuce seed germination and Cladosporium growth were investigated. Pimpinellin was inhibitory to Cladosporium growth, and lettuce seed germination was inhibited by pimpinellin and sphondin.
Simultaneous Appearance of C‐550 and Cytochrome b559HP (High Potential Form) in Barley Leaves Greened under Intermittent Light
Authors: FARINEAU JACK 
Published: April 2006

AbstractCytochrome b559HP has been detected by spectrochemical assays in plastids of barley leaves greened under intermittent light (flashed leaves). The amount of cytochrome b559HP in these plastids was nearly 10‐fold lower than in normal chloroplasts when the results were expressed on plastid number. The amount of cytochrome b559HP phototransformable at ‐170°C was similar, on a C‐550 basis, in the plastids of flashed and normal green leaves. The appearance of the 2 components was simultaneous during the greening process under intermittent light and it is suggested that it was parallel to the increase of appressed regions in thylakoids.The illumination of flashed leaves under continuous light for 5 minutes allowed the appearance of a normal Photosystem‐II activity, but had no effect either on the cytochrome b559HP content of the plastids or on the photoreactivity of this component at low temperature.
Wachstum und N‐Stoffwechsel sowie Anderungen des Isoenzymspektrums der Glutamatdehydrogenase (GDH) in batchvermehrten, licht‐ und dunkelkultivierten Zellsuspensionen von Pisum sativum
Authors: PRIESS H. HARMS. I. , PAHLICH E. 
Published: April 2006

Abstract Growth, N‐metabolism and isoenzyme pattern of glutamate dehydrogenase in batch‐cultures of Pisum sativum cells under light and dark conditions.Cell suspension cultures of Pisum sativum L. derived from root and shoot sections of seedlings have been prepared and cultured in defined nutrient medium. Both the cells and the media were analysed daily for the N‐fractions and carbohydrates during the growth period.The data obtained indicate specific correlations between growth and nitrogen and carbohydrate metabolism. At the beginning of the growth cycle ammonia as compared to nitrate was favoured in uptake. An increased uptake of nitrate occurred at the end of the linear growth phase when carbohydrate in the media was depleted. The uptake of sucrose was rapid during the whole growth cycle, only in the range of the linear growth phase the uptake stagnated for 3 or 4 days. During increased biosynthesis of nitrogenous compounds at the beginning of the growth cycle up to seven isoenzymes of the glutamate dehydrogenase could be separated by polyacrylamide gel electrophoresis. The isoenzyme pattern changed during the stationary growth phase, especially when the carbohydrate content in the medium decreased. There is some evidence that the isoenzyme pattern is influenced by carbohydrate metabolism.
Extracellular Alkaline Phosphatase in Multicellular Marine Algae and Their Utilization of Glycerophosphate
Authors: WALTHER KRISTINA , FRIES LISBETH 
Published: April 2006

AbstractThe production of extracellular alkaline phosphatase by multicellular marine algae in axenic culture has been investigated. The algae studied were five species of Rhodophyta: Asterocytis ramosa, Goniotrichum elegans, Nemalion helminthoides, Polysiphonia urceolata and Rhodosorus marinus; and one species of Phaeophyta: Ecrocarpus confervoides. The extent of enzyme activity varies from one species to another. It also varies with the phosphorus conditions under which the alga is grown. The pattern of glycerophosphate utilization suggests that this type of compound is not taken up directly by the alga but split by the external enzyme before uptake of the phosphate‐ion only. The enzyme performs its action outside the organism and appears both associated with the cells and free in the surrounding water. Assays with culture filtrate of Asterocytis and Ectocarpus show that the enzyme is an unspecific phosphomonoesterase with optimum activity far to the alkaline side. It is activated by Zn2+.
Acetylcholine and Synthesis of Ethylene in Etiolated Bean Tissues
Authors: PARUPS E. V. 
Published: April 2006

AbstractAcetylcholine chloride inhibited ethylene production in etiolated bean tissues and prevented to some extent the IAA‐promoted opening of the bean hypocotyl hooks. The results were interpreted on the basis of acetylcholine mimicking the effects of red light on auxin content and ethylene production.
Changes in the Reactivity of the Photosynthetic Apparatus in Heterotrophic Ageing Cultures of Scenedesmus obliquus
Authors: KULANDAIVELU G. , SENGER H. 
Published: April 2006

AbstractDark grown cultures of Scenedesmus aged for 2, 10 and 30 days, when transferred into light for 2 hours showed about 1.5, 10 and 80 fold increases, respectively, of their oxygen evolving capacity. The presence of Mg2+ and Mn2+ accelerated the reactivation; neither cell growth nor cell division was apparent during reactivation. An action spectrum for this reactivation process showed essentially the same absorption spectrum of that of chlorophyll in vivo which indicates the energy dependence of the process on photosynthesis. Kinetics of cytochrome f photo‐oxidation, 520 nm absorbance changes and fluorescence induction demonstrate that the immediate recovery of the photosynthetic capacity is mainly due to a reestablishment of a balanced electron transport system. Light periods as short as 30 minutes were found to be sufficient to reestablish an efficient coupling between the two photosystems.
Effect of Lincocin Treatment on the Greening Process in Bean (Phaseolus vulgaris) Leaves
Authors: SÁRVÁRI ÉVA , HALÁSZ G. , NYITRAI P. , LÁNG F. 
Published: April 2006

AbstractThe effect of lincocin (a plastid protein synthesis inhibitor) treatment on the greening process of bean (Phaseolus vulgaris L.) leaves have been studied.In comparison with control leaves treated ones had a decreased rate of chloroplast development. They had a marked chlorophyll deficiency and a decreased chlorophyll a/b ratio. Some long and short wavelength forms of chlorophyll a were lacking as evidenced from the absorption spectra at 25°C and the fluorescence spectra at 77°K. The –14CO2 fixation was inhibited by 80–90% in treated leaves. The fluorescence induced by the measuring light was greater in the treated leaves than in the control ones, and the kinetics of the decline of the relative fluorescence intensity were also different. Electron microscopic studies showed macrogranum‐like structures and incomplete membrane vesicles in the treated plastids. After longer treatment a destruction of membranes was observed.The results indicate some structural and functional membrane deficiencies and instability of the membranes.