bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photoassimilation of CO2 by Isolated Bundle‐Sheath Strands of Zea mays
Authors: FARINEAU JACK 
Published: April 2006

AbstractThe role of malate decarboxylation as a source of CO2 and NADPH for the evolution of photosynthesis of isolated maize bundle‐sheath strands has been investigated. The bundle‐sheath cells were supplied with malate plus NADP, in the presence of intermediates of the Calvin cycle to increase the rate of CO2 fixation.The effects of malate addition on the rate of 3 phospoglycerate synthesis, with non‐saturating concentrations of bicarbonate, can be explained by an increase of the cellular pool of CO2 in the cells due to malate decarboxylation. The CO2 reacting with RuDP to give phosphoglycerate corresponds effectively to carbon atom 4 of malate. Malate addition produces an enhancement of the rate of CO2 incorporation which is much more important when the reducing power is the limiting process for the evolution of the Calvin cycle (with phosphoglycerate as added substrate and/or in the presence of DCMU. These results demonstrate the utilization of NADPH produced by malate decarboxylation for the regeneration of RuDP. NADPH can also reverse the reaction of malate decarboxylation and gives rise to a synthesis of malate by carboxylation of pyruvate.In contrast, the pattern of 14C distribution among compounds is not strongly modified by malate addition. This result suggests that PGA reduction in the whole leaf must occur also in mesophyll cells to allow correctregeneration of the reduced compounds of the photosynthetic cycle.
Isolation and Partial Characterization of Globoids from Aleurone Grains of Arachis hypogaea Seed
Authors: SHARMA CHANDRA B. , DIECKERT JULIUS W. 
Published: April 2006

AbstractThe aleurone grains of the peanut (Arachis hypogaea) have been fractionated into the globoidal and nongloboidal components by homogenization in 0.5 M sucrose solution and differential centrifugation. The major components of the globoids are: protein, 35.1%; magnesium, 2.5%; potassium, 2.0%; myoinositol, 7.0%; total phosphorus, 7.4%; oxalic acid, 3.5%; and moisture, 8.6%. Small amounts of calcium (0.5%) and manganese (0.03%) are also present. Of the total phosphorus about 97% is present as organic phosphorus of which phytic acid (myoinositol hexaphosphoric acid) constitutes the major portion with only 0.1% orthophosphate and traces of lower phosphates of myoinositol. The globoidal fraction accounts for about 50% of the total magnesium, manganese, phytic acid, oxalic acid, and for 13% of the potassium and 80% of the calcium present in the aleurone grains. The remainder of these components are present in the matrix of the aleurone grain. There seems to be a cation deficit in the globoids and a cation excess in the aleurone grains and soluble fraction. The nature of the missing cation in the globoid and the missing anion in the aleurone grain or in the soluble fraction was not determined, but thought to be protein.
Uptake by Yeast: Interaction of Rb+, Na+ and Phosphate
Authors: BORST‐PAUWELS G. W. F. H. , THEUVENET A. P. R. , PETERS P. H. J. 
Published: April 2006

AbstractIt has been shown that addition of phosphate to phosphate deficient yeast gives rise to an immediate increase in the rate of Na+ uptake and an immediate decrease in the rate of Rb+ uptake. In addition, phosphate uptake is enhanced specifically by Na ions presumably by a process with a very high affinity for phosphate with a Km of about 2 × 10−6M at pH 7.2, whereas the Km for phosphate uptake of the Na+ independent process amounts to 1.3 × 10−4M.
Changes in Nitrogenous Compounds and Proteases during Germination of Vigna sinensis Seeds
Authors: PRISCO JOSÉ TARQUINIO , AINOUZ IRACEMA LIMA , MELO SIGEFRÊDO de C. 
Published: April 2006

AbstractSeedling growth, protein, soluble amino nitrogen, and proteolytic activity of serido beans (Vigna sinensis) were studied during the first 6 days of germination. Cotyledon dry weight decreased constantly with germination time, reaching at the 6th day 27% of the weight it had at day 0. Embryo‐axis dry weight increased during the same period, amounting to 79% of the total weight of the seedling at the 6th day of germination. Cotyledon proteins increased slightly during the 1st day of germination and then decreased until the end of the experimental period. Cotyledonary soluble amino nitrogen stayed constant for the 1st day of germination, increased up to the 3rd day, and then fell steadily until the 5th day. Embryo‐axis soluble amino nitrogen followed the same pattern as the embryo‐axis proteins, that is, a slight increase during the first 3 days, a pronounced increase from the 3rd to the 5th, and a leveling off from this day on. Proteolytic activity was studied at pH 3.5 and pH 6.0. Both proteases increased in activity during the first 3 days of germination, at which point they reached their maximum activities. From this day on their activities fell continuously, reaching on the 6th day values slightly higher than those of day 0. These observations appear to indicate that contrary to pea cotyledon proteases, serido bean protesaes are intimately associated with reserve protein degradation.
Allelopathy in Heracleum laciniatum: Inhibition of Lettuce Seed Germination and Root Growth
Authors: JUNTTILA OLAVI 
Published: April 2006

AbstractBoth dark and red light germination of lettuce seeds (cv. “Maikönig”) as well as their root and hypocotol elongation were inhibited when the seeds were sown in petri dishes together with a few seeds of Heracleum laciniatum Horn. This inhibition was not significantly counteracted by the presence of gibberellic acid (GA3) or/and 6‐benzylaminopurine (BA). However, a large proportion of the lettuce seeds germinated abnormally (only cotyledons emerged) when treated with BA in the presence of Heracleum seeds. GA3 had alone no significant effect on abnormal germination, but it counteracted the effect of BA to some extent.The inhibitory effect of Heracleum seeds gradually disappeared during a moist incubation period of one to seven days in darkness at 25°C.When lettuce seeds were pre‐incubated together with Heracleum seeds for one to five days the remaining, non‐germinated lettuce seeds had lost their ability for subsequent germination in darkness in distilled water. This induced dark dormancy was to a great extent broken by red light, but not by GA3 or/and BA.H. laciniatum seeds inhibited the germination of Salix pentandra seeds and to some extent also the germination of radish but had no effect on the germination of spruce.
Changes in Some Enzyme Activities and Respiration in the Early Stage of Callus Formation in a Carrot‐root Tissue Culture
Authors: KOMAMINE ATSUSHI , SHIMIZU TOMIKO 
Published: April 2006

AbstractThe respiratory rate increased in two phases during early stages of callus formation in carrot (Daucus carota)‐root phloem slices cultured in vitro, showing separate peaks at about 24 and 96 h of culture. In the first phase (within 24 h of culture), the activities of phosphoglucose isomerase, phosphofructokinase and succinate dehydrogenase did not increase, but active syntheses of RNA and protein, indicated by experiments with incorporation of [14C]‐uracil and ‐leucine, resulted in an active turnover of ATP, to which the first increase in the respiratory rate may be attributable. On the other hand, the activity of phosphoribosylpyrophosphate synthetase, an enzyme related to nucleic acid synthesis, increased in the first 24 h of culture. In the second phase (24–96 h of culture), the activities of the respiratory enzymes investigated increased. This increase was repressed by cycloheximide, indicating de novo syntheses of the respiratory enzymes during this time, which may result in an enlargement of the respiratory capacity, to which the second increase in respiration may be mainly attributable. In the first phase, exogenous supplied 2,4‐dichlorophenoxyacetic acid had little or no effect on the respiratory rate and the activities of the respiratory enzymes, but it enhanced synthesis of RNA and the activity of phosphoribosylpyrophosphate synthetase. In the second phase, it increased all the activities of enzymes investigated as well as the respiratory rate and RNA synthesis.
Effect of Abscisic Acid on the Transpiration of Zea mays
Authors: TALHA MAHMOUD , LARSEN POUL 
Published: April 2006

AbstractIntact plants of Zea mays L. were treated with foliar sprays of cis‐trans‐abscisic acid (ABA) at concentrations from 10−9 to 10−4M. Even the lowest concentration caused a reduction of the transpiration rate as measured between 1 and 33 h after spraying. With increasing ABA concentrations, there was a nearly linear relationship between the logarithm of the ABA concentration and the (decreasing) transpiration rate within that period. Subsequently a partial recovery of the transpiration rate set in, beginning progressively later as the ABA concentration was increased. After 5 1/2 days the transpiration rate of plants treated with 10−9 and 10−8M was nearly back to normal, whereas plants treated with 10−4M transpiration at only about 2/3 their normal rate.In experiments with detached maize leaves supplied with water or ABA solutions (10−8 to 10−5M) through their cut bases, the transpiration of control leaves decreased gradually to a low level in 24 h. ABA caused a marked and rapid reduction of the transpiration rate compared to that of the controls. After a few hours, the transpiration of the treated leaves decreased at a slower rate than that of the controls, thus approaching the control values. After 35 h, the transpiration of leaves treated with 10−5M ABA was nearly the same as in untreated leaves. Exchanging the ABA solution for distilled water after 24 h had little effect on the subsequent course of the transpiration rate.
The Effect of Temperature on Growth and Mineral Nutrition of Fruits of Apple, with Special Reference to Calcium
Authors: TROMP J. 
Published: April 2006

AbstractGrowth and mineral composition of fruits in potted trees were studied at two temperatures (19 and 24°C) in two experiments with Golden Delicious and one with Cox's Orange Pippin under a controlled environment. In Golden Delicious the high temperature promoted fruit growth markedly, but in Cox's Orange Pippin the stimulation was much less pronounced.The levels of K, N, Mg, and P (expressed as amounts per fruit) were increased at the higher temperature. This increase was almost completely the result of differences in fruit growth. With respect to Ca the high temperature reduced Ca influx in one Golden Delicious experiment and had hardly any effect in the other, but favoured influx in Cox's Orange Pippin. In one Golden Delicious experiment the temperature was raised 7 weeks after blossoming, which resulted in a temporary drop of Ca. When the same temperature change was applied 4 weeks earlier, Ca continued to increase.It is assumed that mineral influx occurs via the xylem during the first few weeks after fruit set and via the phloem throughout. The results are discussed in terms of differences in mobility in the phloem for the various minerals and of a shift in the ratio between xylem and phloem movement induced by differences in the growth rate of the fruits.
Activity of Antheridiogen from the Fern Anemia phyllitidis in Three Flowering Plant Bioassays
Authors: SHARP PAMELA B. , KEITT GEORGE W. , CLUM HAROLD H. , NÄF ULRICH 
Published: April 2006

AbstractPure samples of the antheridiogen of Anemia phyllitidis (AAn) were tested for their ability to affect the growth of dwarf corn (d5) and lettuce seedlings, and to influence α‐amylase production by barley half‐seeds. Stimulation of dwarf corn growth and barley amylase production was, on a molar basis, from 1/2 to 1/250 that given by GA3. In lettuce, AAn had a synergistic effect with low levels of GA3; alone, AAn was inhibitory or ineffective. Therefore, in addition to having a close chemical resemblance to gibberellin, AAn induces similar, but not identical physiological responses in flowering plants as well as ferns.
Identification of Zeatin and Zeatinriboside in Coconut Milk
Authors: STADEN J. VAN , DREWES S. E. 
Published: April 2006

AbstractZeatin and zeatinriboside were identified from the milk of mature Cocos nucifera fruits. It would appear as if the two compounds are present in roughly equal proportions. Ethyl acetate extraction in a liquid‐liquid extractor at an alkaline pH (8.0) proved to be a very efficient method of extracting zeatinriboside. Partitioning with water‐saturated n‐butanol proved to be the best way of extracting zeatin.
Effect of Indoleacetic Acid on the Abscisic Acid Level in Stem Tissue
Authors: ELIASSON LENNART 
Published: April 2006

AbstractExcised stem sections from growing plants of Populus tremula L. and Pisum sativum L. including lateral buds were treated with indole‐3‐acetic acid in a phosphate buffer solution. In control sections the level of the abscisic acid‐like inhibitor decreased strongly during 24 h as did the level of the endogenous auxin. Exogenous indoleacetic acid counteracted the decrease in the inhibitor level to a considerable extent. Implications of this auxin effect in relation to apical dominance are discussed.
Chlorophyll Accumulation, CO2 Fixation Enzymes, and Hill Activity, in Greening Roots of Lens culinaris
Authors: NATO A. , DELEENS E. 
Published: April 2006

AbstractThe carboxylation of ribulose‐1,5‐diphosphate was demonstrated in vitro with extracts of ctiolated seedling roots. The presence of ribulose‐1,5‐diphosphate carboxylase was characterized in the subcellular fraction enriched in amyloplasts.Synthesis of chlorophyll, development of CO2 fixation capacities and of Hill activity upon illumination have been studied with roots of Lens culinaris seedlings. The marked increases in CO2 fixation with ribulose‐1,5‐diphosphate as the substrate and in Hill activity that occur after a lag phase seem to be related to cytological changes during the greening of roots.
Cultivation in the Dark of the Blue‐green Alga Fremyella diplosiphon. A Photoreversible Effect of Green and Red Light on Growth Rate
Authors: DIAKOFF STEPHEN , SCHEIBE JOSEPH 
Published: April 2006

AbstractThe blue‐green alga Fremyella diplosiphon Drouet can be grown in the dark on a medium consisting of mineral salts, glucose, and casein hydrolysate. A variety of organic substances was tested for effectiveness as a carbon or nitrogen source. The most effective individual compounds were glucose and citrulline, respectively. A daily irradiation of 5 min green light depresses the dark growth rate. The effect of green is reversible by brief irradiation with red light, and multiple photoreversibility was demonstrated.This green, red‐reversible effect on dark growth rate may be related to other photomorphogenic responses to brief irradiation with green and red in the Cyanophyta. A master photoreversible pigment similar to phytochrome is a possible photoreceptor for these effects.
Phase Change in Hedera helix: Stabilization of the Mature Form with Abscisic Acid and Growth Retardants
Authors: ROGLER CHARLES E. , HACKETT WESLEY P. 
Published: April 2006

AbstractApplications of ABA to the mature form of Hedera helix stabilize its morphological characteristics and prevent GA3 induced reversion to the juvenile form. Plants treated with GA3 reverted to the juvenile form whereas those supplied with ABA in conjunction with GA3 remained mature. When mature plants were treated with 5 nanomoles of GA3 and 5 micromoles of ABA, reversion did not occur, but when the GA3 dose was raised to 25 nanomoles with the same level of ABA, reversion did occur. This implies that the relative amounts of GA3 and ABA applied are important in controlling growth form and not the absolute levels of these hormones. Applications of growth retardants (Chlormequat, Ancymidol, and SADH) stabilize the mature form by preventing spontaneous reversions induced under low light intensity. These two lines of evidence support the hypothesis that the mature morphological form can be stabilized by regulating the effective level of gibberellins in the plant and this can be accomplished by inhibition of gibberellin action or gibberellin biosynthesis.
Effects of Anions on Swelling, Respiration, and Phosphorylation of Isolated Corn Mitochondria
Authors: MILLER J. E. , KOEPPE D. E. , MILLER RAYMOND J. 
Published: April 2006

AbstractThe effects of a series of anions on swelling, respiration, and oxidative phosphorylation of corn mitochondria were studied. Active mitochondrial swelling similar to that found with HPO4−2 was demonstrated in the presence of IO3−, NO2−, MoO4−2, SO4−2, HAsO4−2, acetate, S2O3−2, SeO4−2, CrO4−2, and WoO4−2. In general, those anions which caused active swelling also released respiration and reduced the efficiency of oxidative phosphorylation with exogenous NADH as substrate. The degree of passive swelling in the presence of certain of the monovalent anions was found to approximate the order of the lyotropic series (SCN− > CIO4− > I− > NO3− > CI−).
Partial Reversal by Cytokinin and (2‐Chloroethyl)‐Trimethylammonium Chloride of Near‐Ultraviolet Inhibited Growth and Morphogenesis in Callus Cultures
Authors: FRIDBORG GUNNAR , ERIKSSON TAGE 
Published: April 2006

AbstractCallus cultures of Haplopappus gracilis, Nicotiana tabacum and Allium cepa var. proliferum were in varying degrees inhibited by blue to near‐UV light obtained from fluorescent tubes. The inhibition was considerably reduced for Haplopappus cultures by 6‐(3‐methyl‐2‐buten‐1‐ylamino)‐purine (2 iP) and (2‐chloro‐ethyl)‐trimethylammonium chloride (CCC) in combination. Even separately these compounds stimulated growth in blue but not in white light. A high concentration of 2 iP reduced the inhibiting effects of near‐UV on tobacco tissue cultures, and a synergism was observed between 2 iP and CCC in respect to shoot formation in blue light. Allium callus was not significantly affected by CCC. It was also observed that the concentration of indol‐3‐acetic acid (IAA) was more important for the growth of tobacco cultures in blue than in white light. It is believed that the light‐inhibition of growth is partly due to a photoinactivation of IAA and that 2 iP and CCC might be active through processes controlling the levels of IAA and other growth hormones.
Effects of SO2 on Photosynthesis and Nitrogen Fixation
Authors: HÄLLGREN JAN‐ERIK , HUSS KERSTIN 
Published: April 2006

AbstractResponses of photosynthesis and nitrogen fixation to NaHSO3 (10−5−5 × 10−3M) were investigated in the lichen Stereocaulon paschale (L.) Fr. and the blue‐green alga Anabaena cylindrica Lemmermann. The treatments were performed in buffered media with varying pH (5.8–8.1) and light conditions (0–32 W × m−2). The activities of the intact organisms were investigated, under the same environmental conditions, with 14C liquid scintillation and acetylene reduction techniques respectively.The nitrogen fixation proved to be more susceptible than photosynthesis, in both organisms, and in all cases treatments at pH 5.8 were more inhibitory than at higher pH‐values. Treatment with 5 × 10−4M NaHSO3 at pH 5.8 caused no reduction of photosynthesis in S. paschale, while the inhibition of nitrogen fixation was 97%. For A. cylindrica the corresponding values were 40% and 75% respectively. Short‐time treatments of A. cylindrica showed that the nitrogen fixation was more rapidly affected than photosynthesis. The inhibition of nitrogenase activity and CO2‐fixation was smaller in the dark and increased at higher light intensities. Both processes showed a good capacity for recovery after removal of the NaHSO3 solution. Also the clumping ability of A. cylindrica was disturbed by NaHSO3 treatments.
Soluble and Insoluble Protein Patterns during Induction of Freezing Tolerance in Black Locust Seedlings
Authors: BROWN GREGORY N. , BIXBY JAMES A. 
Published: April 2006

AbstractProtein metabolism plays a major role in the development of freezing tolerance in plants. Soluble and insoluble protein concentrations were followed during induction of freezing tolerance in black locust (Robinia pseudoacacia L.) stem tissues. Soluble proteins were fractionated using two‐dimensional polyacrylamide gel electrophoresis and examined for the presence of glycoprotein fractions. Soluble protein concentration remained relatively constant during early stages of induction of freezing tolerance but increased significantly during later stages, while insoluble protein concentration remained relatively constant throughout induction. A new soluble protein component appeared during later stages of induction and was identified as a glycoprotein. Some glycoproteins are known to have a high water‐binding capacity, which could play a role in intracellular resistance to ice formation during development of freezing tolerance.
An Abscisic Acid‐like Substance in Dry and Soaked Phaseolus vulgaris Seeds Determined by the Lemna Growth Bioassay
Authors: TILLBERG ELISABETH 
Published: April 2006

AbstractAn acid inhibitor, probably abscisic acid (ABA) in low concentrations was found to be present in bean seeds. The evidence is based on data from paper electrophoresis, chromatography, UV absorption and growth inhibition in the Lemna bioassay, sensitive down to a concentration of 10‐11M ABA or 0.02–0.03 ng/flask.The inhibitor level as measured by this bioassay decreases considerably with increasing soaking time. Acid ether‐soluble inhibitors could even be detected in the soaking water from the soaked seeds.
Cytokinins: A Rapid Extraction and Purification Method
Authors: HAHN HEINZ 
Published: April 2006

AbstractA method is described for the isolation, purification and quantitation of free cytokinin bases and ribosides using ethyl acetate at pH 7.7 for the extraction. The extraction is almost complete (97.7%) as determined by using N6‐(Δ2‐isopentenyl)adenine‐8‐14C. The subsequent fast purification by chromatography on a standardized silica gel column in chloroform‐methanol (7:3 v/v) is followed by thin layer chromatography (silica gel 60 F254) in chloroform‐acetic acid (8:2 v/v). The recovery of N6‐(Δ2‐isopentenyl)adenine‐8‐14C after this two step purification was 78–82%. The efficiency of the method was determined by applying this procedure to N6‐(Δ2‐isopentenyl)adenine and N6(Δ2‐isopentenyl)adenosine. Using gas liquid chromatography the recovery for N6‐(Δ2‐isopentenyl)adenosine was determined to be 61% and compared to 43% for N6‐(Δ2‐isopentenyl)adenosine, showing the suitability of the described method for gas liquid chromatography.
Effets d'un Sejour à l'Obscurité sur le Pouvoir Germinatif et sur L'Evolution de l'Appareil Photosynthétique des Spores de Funaria hygrometrica
Authors: CHEVALLIER D. 
Published: April 2006

AbstractIn Funaria spores fine structural changes occur, especially in the plastids, during prolonged incubation in darkness on an inorganic liquid medium, although under these conditions germination cannot take place. If then exposed to illumination, these spores germinate rapidly and synchronously. Chloroplasts formed in darkness have thicker grana, absorb more CO2, have a higher reducing power, and give a more intense paramagnetic resonance signal than chloroplasts formed in light.