bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytokinin Content of Pea Seeds during their Growth and Development
Authors: Burrows W. J. , Carr D. J. 
Published: April 2006

AbstractSeed development in Pisum arvense L. cv. New Zealand Maple has been studied in relation to changes in level of total endogenous cytokinins. Growth of both the whole seed and the embryo is diauxic, having two phases of active growth separated by a lag period. The two maxima in the growth rates of the whole seed and the embryo occur about the 23rd and 31st days after anthesis. The lag period occurs between days 26 and 28. Cell division is thought to have ceased prior to day 19 and the changes in total cytokinin content in pea seeds after this time are believed to be largely independent of cell division. The three maxima in the cylokinin content per gm. fresh weight of seed and per seed were found to be coincident with the maximum volume of endosperm per seed and the two maxima in the growth rates of the whole seed and the embryo.
Growth of Boletus variegatus in Surface and Shake Cultures
Authors: Pedersen T. A. , Lindeberg Göusta 
Published: April 2006

AbstractA method of growing the mycelium of Boletus variegatus Fr. (Suillus variegatus Kuntze) in shake cultures is described. The growth curves of the fungus in stationary surface cultures and shaken submerged cultures have been compared. Growth in stationary cultures comprised (1) an acceleration phase, characterized by an approximately linear cube root plot, (2) a linear phase of constant increase of dry weight per day, and (3) a deceleration phase. In the shake cultures, two growth periods, both characterized by linear cube root plots, were observed. The growth rate constant was higher for the first than for the second period. During the second period, enlarged rounded cells with dense contents but normal cell walls were formed. The carbon source was exhausted and growth stopped after nine days in the agitated cultures and after about three weeks in the stationary ones. The economic coefficient for glucose utilization was higher in the agitated than in the stationary cultures.
A Definition of Optimum Nutrient Requirements in Birch Seedlings. I.
Authors: Ingestad Torsten 
Published: April 2006

AbstractThe aim of the investigation was to find a method of growing birch seedlings with a constant optimum nutrient status. The studies in this paper have indicated important factors in such a growth method which must be comprised in a definition of nutrient requirements. The optimum nutrient proportions in the seedlings and the optimum total concentration in the solution must be known. Special attention must be paid to the ratio between NH4+ and NO3−in the solution and in the uptake. The amounts of nutrients taken up at optimum nutrition can be followed by measurement of pH and conductivity. Thus, the nutrients consumed may be replaced by titrations which may be automated by standard equipment. The nutrient proportions to be added are determined by the optimum internal proportions. It is not necessary to change the nutrient solution even if the volume is relatively small in relation to plant mass. There was no evidence of effects of accumulation of root exudates or infections. By using the system described, it is possible to attain considerably greater fresh and dry matter production in birch seedlings than when an optimum conventional solution is used.
Effects of Benzyladenine on Bean Leaf Senescence and the Translocation of 14C‐Assimilates
Authors: Fletcher R. A. , Hofstra G. , Adedipe N. O. 
Published: April 2006

AbstractTreating primary leaves of bean plants with benzyladenine (BA) greatly increased the retention of photosynthetic assimilates in the treated leaves. Within 24 hours of treatment, the BA treated primary leaves retained 70 % of their assimilates and maintained this high level throughout the period studied. In contrast, the primary leaves of control plants retained 30 % at week 2, increased retention to 80 % between week 4 and 5 and dropped to 50 % during senescence at week 6. When the trifoliate leaves of 5 week old plants were fed 14CO2, less than 1 % of the total activity was recovered from the BA treated leaves. It is concluded that the retardation of leaf senescence by BA on intact plants is not due to mobilization of metabolites from other plant parts, but is associated with a high retention of photosynthates.
Differential Responses to Environmental Conditions by Fungal Cells Sensitized by Heat Shock or UV Irradiation
Authors: Fries Nils 
Published: April 2006

AbstractCells of the ascomycele Ophiostoma multianulatum were sensitized to the supra‐optimal temperature of 30°C either by heat shock or by UV irradiation. At this incubation temperature the death rate of the heat‐shocked cells was higher than that of the irradiated cells. This difference was increased if hydrolysed casein was added to the incubation medium. The heat‐shocked cells were also killed faster at 30°C, if nitrogen instead of air was bubbled through the cell suspension. Heat shock, in contrast to UV irradiation, strongly increased the sensitivity to a high concentration of sodium chloride.
Evolution de I'amidon et des sucres solubles chez des feuilles isoléaes d' Aster tripolium et de Cochlearia tniglica. Action du NaCI Par
Authors: Binet P. 
Published: April 2006

Abstract Starch and soluble sugars in leaves of Aster tripolium L. and Cochlearia angliea L. Effect of NaCI. ‐ The limbs or foliar disks of Aster tripolium L. and Cochlearia anglica L. synthelize starch when exposed to light at 25°C, and in the presence of glucose or saceharose together with 0.25 to 0.61 % of NaCI.
Changes in the Activity of Certain Enzymes of Acer pseudoplatanus L. Cells at four Stages of Growth in Suspension Culture
Authors: Kaarina Simola Liisa , Sopanen Tuomas 
Published: April 2006

AbstractThe activities of twelve enzymes were studied in Acer psendoplatanum L. cells grown in suspension cultures for 6, 12, 19 and 22 days. The enzyme activities of cells (6 and 12 days) in the phase of rapid cell division were rather different from that of cells in the stationary phase (19, 22 days). The activity of aldolasc was highest at the first two stages of growth, when the amount of RNA and protein per cell was highest, and after this decreased steeply. The curves of specific activities of several phosphatases (glucosc‐6‐phosphatasc, α‐glycerophosphatase, acid phosphatase and ATPase) and ribonuclease were almost the reverse of the curve of aldolase, showing a minimum in 12‐day‐old cells and a maximum in cells 19 and 22 days old. The activity of peroxidase was also high in ageing cells. Glutamate: oxaloacetate transaminase and aminopeptidases (leucine and alanine) had synchronous maxima (6 and 19 days) of specific activity but the activity of aminopeptidases decreased gradually during ageing of the suspension, if the enzyme activities are calculated per 107 cells. Glutamate: pyruvate transaminasc activity was very low and no dcoxyribonuclease activity could be detected.
Influence of Auxin on Young's Modulus in Stems and Roots of Pisum and the Theory of Changing the Modulus in Tissues
Authors: Burströum H. G. , Uhrströum Inger , Olausson B. 
Published: April 2006

AbstractThe effect of auxin on elastic extensibility has been investigated by means of the resonance frequency melhod in Pisum, sativum. The time lag for the decrease in Young's modulus E, caused by IAA, was between 2 and 3 minutes in etiolated stem internodes. The time lag for growth was about 7 minutes. The measurements of E in root segments were only qualitative owing to the structural characteristics; IAA decreases E in roots as it does in stems, but only in the region where IAA is assumed to enhance elongation. The connexion between elastic modulus and growth is discussed with reference to other investigations. The assumption has been made that a decrease in elastic modulus indicates a change in the cell wall which in some way is conducive to growth (induction of elongation). The theoretical possibilities of changing E have been discussed with reference to the formula for water fluxes. Both a change in a cell wall properly and a change in the cytoplasmic permeability are able to cause a change in E in the same way as auxin does. An early action of auxin must be located in the cell‐wall‐plasmalemma region.
The Starch Statolith Hypothesis and the Optimum Angle of Geotropic Stimulation
Authors: IVERSEN TOR‐HENNING , LARSEN POUL 
Published: April 2006

AbstractWhen roots of cress seedlings (Lepidium sativum L.) are stimulated for 10 min at an angle of 135° (i.e. the root tips are pointing obliquely upward), the resulting geotropic curvatures become larger than after 10 min stimulation at 45°. This well‐known behavior has been explained by the better conditions for statoliths, initially located in the floor end of the statocytes, to slide along the cell walls when root tips are pointing upward at 135° than when pointing downward at 45°. Accepting this explanation, one would predict the optimum angle of stimulation to be near 45° when roots had first been kept inverted long enough for their statoliths to accumulate in the opposite end of each functional statocyte. This prediction has been verified in experiments with cress seedlings which were first kept inverted for 16 min, then stimulated for 10 min at given angles, and subsequently rotated parallel to the horizontal axis of the klinostat at 2 rpm. Under these conditions, roots stimulated at 45° curve faster during a 20 to 30 min period on the klinostat than roots stimulated at 135°, but thereafter they stop curving. Roots stimulated at 135°, on the other hand, although initially curving slower than those at 45°, continue curving for at least a whole hour, and attain larger curvatures than the others after 40 min. The optimum shifts from near 45° to near 135° during the course of the klinostat rotation. The behavior of normal and pre‐invertcd roots is interpreted as the result of at least two effects: (1) a stimulation due to the movement of amyloplasts, which is enhanced if these are allowed to slide along the cell walls, and (2) a modification of the development of the resulting curvatures by tonic effects, which are inhibitory between stimulation angles 0° and 90°, and absent or enhancing between 90° and 180°.
De novo Synthesis of Polyglucans by a Phosphorylase Isoenzyme in Algae
Authors: FREDRICK JEROME F. 
Published: April 2006

AbstractThe α2 phosphorylase isoenzyme of Oscillatoria princeps, Rhodymenia pertusa and Chlorella pyrcnoidosa has been found to be capable of the synthesis of amylose‐like polyglucans without the necessity for addition of primers. This enzyme differs in this respect from the a1 isoenzyme of blue‐green and green algae. The a2 enzyme appears to be a glyco‐protein and synthesis of linear polyglucans appears to occur by the apposition of glucosyl residues from glucose‐1‐phos‐phate directly to the glycosyl moiety of its molecule.
Investigations of the Geotropic Curvature of the Avena Coleoptile
Authors: JOHNSSON ANDERS 
Published: April 2006

AbstractThe geotropic reaction in Avena coleoptiles is studied as a function of the stimulation time. The direction of the stimulation with respect to the vascular bundles must be defined when studying geotropic responses.It is found that the threshold time to evoke geotropic response is less than half a minute, i.e., at least ten times lower than the presentation time usually reported in the literature. An extrapolation procedure can be used to give a so‐called extrapolated presentation time tb, which is intimately related to the logarithmic part of the geotropic response curve and has a physical meaning in the reciprocity rule.The problem of the duration of the true threshold time for stimulation with 1 g is discussed.An experiment indicates that it is not necessary for mass particles (“statoliths”) to settle on the lateral cell wall in order to start the geotropic reaction chain.The slope of the logarithmic part of the geotropic response curve is independent of the transverse force applied to the coleoptiles. Support is given to the view that the slope is determined by the number of sedimenting mass particles.
A New Tomato Mutant Inefficient in the Transport of Iron
Authors: BROWN J. C. , CHANEY R. L. , AMBLER J. E. 
Published: April 2006

AbstractAn Fe‐inefficient tomato mutant, T3238fe (Lycopersicon esculentum) was identified by growing the plants in solution cultures containing different concentrations of FeHEDTA. Approach grafts of T3238Fe (Fe‐efficient) top on T3238fe rootstock and vice versa, located the cause of Fe inefficiency in T3238fe roots. The T3238Fe tomato takes up more Fe than T3238fe and it responds favorably to Fe‐stress by releasing hydrogen ions from its roots, increasing reduction of Fe3+ to Fe2+ at its roots, and increasing the citrate concentration in its roots. T3238fe showed very little response to Fe stress; it was unable to absorb and transport adequate Fe from PeEDDHA to support growth.
The Contribution of Photosynthesis to Chlorophyll Formation in Etiolated Mung Bean Leaves
Authors: DODGE A. D. , ALEXANDER D. J. , BLACKWOOD G. C. 
Published: April 2006

AbstractChlorophyll formation in seven day old etiolated mung bean leaves was inhibited by CMU. The inhibition was reversed by feeding sucrose, or by leaving the cotyledons attached to the leaves. Photosynthesis appeared to contribute substrates for further chloroplast development soon after its commencement. When sucrose was fed in the presence of CMU at a range of light intensities, there was a distinct light induced promotion of chlorophyll formation at light intensities of 500–2000 lux. Treatment of the leaves with salicyl‐aldoxime, an inhibitor of cyclic photophosphorylation indicated that this process could play an important part in chloroplast development.
Control of Tryptophan Biosynthesis in Plant Tissue Cultures: Lack of Repression of Anthranilate and Tryptophan Synthetases by Tryptophan
Authors: WIDHOLM JACK M. 
Published: April 2006

AbstractTobacco (cv. Xanthi and cv. Wisconsin 38), rice, carrot, tomato, and soybean tissue cultures were grown in liquid media containing L‐tryptophan. The addition of tryptophan increased the cellular tryptophan levels greatly (12–2500 fold), but did not lower appreciably the levels of two tryptophan biosynthetic enzymes, anthranilate synthetase and tryptophan synthetase. However, the addition of 50 μM tryptophan to the crude enzyme extract completely inhibited the anthranilate synthetase activity while 1 mM tryptophan inhibited the tryptophan synthetase activity by only 10–20°/o. This information indicates that tryptophan biosynthesis is controlled by the feedback inhibition of anthranilate synthetase by tryptophan and not by repression of enzyme synthesis.All of the species had significant enzyme levels. Anthranilate synthetase activity could not be detected in extracts from cells grown on tryptophan unless the extracts were first passed through two G‐25 Sephadex columns with a short 30 °C warming step in between, a procedure shown to remove an inhibitor of the enzyme.
Changes in Indoleacetic Acid Oxidase Activity Associated with Plant Water Potential
Authors: DARBYSHIRE B. 
Published: April 2006

AbstractThe effect of plant water potential on the activity of indoleacetic acid oxidase was examined. It was found that with increasing plant water deficit the activity of indoleacetic acid oxidase increased. Higher activies of this enzyme are known to be associated with older tissues and lower endogenous auxin levels. It is suggested that while water stress may adversely affect a variety of physiological processes, increases in the activity of indoleacetic acid oxidase may provide plants with a drought adaption mechanism.
Phytochrome Effects in Night‐break Illuminations on Flowering of Chrysanthemum
Authors: KADMAN‐ZAHAVI AVISHAG , YAHEL HERUT 
Published: April 2006

AbstractThe inhibition of flowering in chrysanthemum by cyclic or continuous illuminations in the middle of the night was studied with mixed red/far red (incandescent) and pure red light at different intensities. Although cyclic lighting greatly enhanced the flower‐inhibitory capacity of mixed red/far red light, no such effect was obtained with pure red light. It is argued that the “dark reversion” hypothesis is not adequate to explain the differential effectiveness of cyclic lighting. A possible mechanism is suggested by which mixed red/far red light may produce more Pfr by interrupted than by uninterrupted illuminations.Contribution from The Volcani Institute of Agricultural Research, Bet‐Dagan, Israel. 1970 Series No. 1826‐E.
Light, Seed Coat and Gibberellic Acid in Relation to the Amylase Activity in Germinating Scots Pine Seeds (Pinus silvestris)
Authors: NYMAN BENGT 
Published: April 2006

AbstractThe amylolytic activity in homogenates from both embryos and endosperms of Scots pine seeds depends on the presence of α‐amylase. The activity of this enzyme has been studied in relation to the light factor during the first 24 hours of the germination process. No positive correlations have been found between the observed activities and earlier observed enhancement of the starch degradation in light. The endosperm activities have been shown to be affected both by the presence of an intact coat and the presence of the embryo. The embryo influence could not be restored by gibberellic acid. The results have been discussed in relation to the physiology of gibberellin and ethylene.The author wishes to express his thanks to the Swedish Natural Science Research Council for financial support and to Miss Brigitte Thierbach for skilful, technical assistance.
Indole‐3‐acetic Acid Levels and the Role of Indole‐3‐acetic Acid Oxidase in the Normal Root and Club‐root of Cabbage
Authors: RAA JAN 
Published: April 2006

AbstractThe auxin content of club‐root (Plasmodiophora brassicae Wor.) is 50–100 times higher than that of normal cabbage root. The importance of this difference in the disease development is discussed. Both normal root and club‐root of cabbage contain allosteric IAA oxidase and IAA oxidase with ordinary kinetic properties. In normal cabbage root the allosteric one is associated with cell fractions sedimenting at 20,000 × g and 105,000 × g, in club‐root it remains in the supernatant after 105,000 × g centrifugation. IAA oxidase with conventional kinetic properties is present in both these tissues in the cell fraction sedimenting at 10,000 × g, which contains mainly cell wall fragments. It is concluded that IAA oxidase is not primarily involved in regulation of the endogenous IAA level.
Uptake and Incorporation of 14C‐labelled Maleic Hydrazide into the Roots of Salix viminalis
Authors: COUPLAND D. , PEEL A. J. 
Published: April 2006

AbstractLabelled maleic hydrazide (MH) was shown to be accumulated preferentially into the root‐tips of young Willow roots by radiochemical analysis. A large proportion of the activity incorporated into the cell constituents was associated with RNA. MH was also bound in some way to the cell wall material. The greatest proportion of the activity was easily removed from the root tissue and thus probably occurred free within the cytoplasm and free‐space.The incorporation of MH into RNA and its subsequent effects on cell metabolism via abnormal protein and enzyme synthesis is given as an explanation of the mode of action of MH.
Effects of Benzyladenine on Photosynthesis, Growth and Senescence of the Bean Plant
Authors: ADEDIPE N. O. , HUNT L. A. , FLETCHER R. A. 
Published: April 2006

AbstractThe net photosynthetic rate of attached primary bean leaves treated with benzyladenine (BA) decreased from 35 nano‐grams carbon dioxide per square centimetre and second (ng cm−2 s−1) at week 2 to 17 ng cm−2 s−1 at week 4, and thereafter increased to 24 at week 6. By contrast the net photo‐synthetic rate of the water‐treated leaves decreased to 4–5 ng cm−2 s−1 at weeks 5 and 6. The stomatal resistance was not markedly affected by BA treatment.The BA‐treated primary leaves had higher dry and specific weights, and the chlorophyll and carotenoid contents were greater than for the water controls. The pigment content of the BA‐treated leaves steadily increased from week 2 to 6, whereas in the water controls it remained constant till week 4 and thereafter decreased.It is concluded that retardation of leaf senescence by BA is assoclatcd with a mnintenance of photosynthetic activity.
Infrared Energy as a Factor in Controlled Environments
Authors: PALLAS J. E. , MICHEL B. E. 
Published: April 2006

AbstractThe proportion of visible to infrared radiation varies in different growth chambers. Whether this might affect leaf temperature and plant growth was investigated in chambers with equal visible radiation. In one chamber infrared energy was half the total, while in two chambers it was 75% of the total. Photoperiods were 14 hours and day and night temperatures 25° and 20°C, respectively. Warm weather species tested were Zea mays, Phaseolus vulgaris, Gossypium hirsutum, Glycine max, and Sorghum vulgare.High infrared did not increase the leaf temperatures of Sorghum vulgare, but growth was better than under low infrared. In the other 4 species, slightly higher leaf temperatures were observed, but growth was not significantly increased by high infrared. Of the cool weather species, Pisum sativum L. (Alaska and Wando) and Vicia faba L., grew less; Avena saliva L. grew equally; and Brassica oleracea L. var. capitata grew better in high infrared. Leaf temperatures of these cool weather species were generally below ambient and were not appreciably affected by the proportion of infrared. The CO2 was uncontrolled in one high infrared chamber and was 400 μl CO2 liter or more. Except for G. max and P. vulgaris, the growth of the warm weather species was not significantly affected; however, all cool weather species grew best in this chamber. A sparing effect from infrared damage is induced by high CO2.
The Effect of Fruiting upon Transpiration Rate and Stomatal Opening in Apple Leaves
Authors: HANSEN POUL 
Published: April 2006

AbstractThe uptake of water by apple trees (Malus × domestica‘Golden Delicious’) was measured in a pot experiment and was found to be much greater in apple trees carrying many fruits than in comparable specimens without fruits. The main reason seemed to be differences in the transpiration rates of the leaves. This was corroborated by microscopic investigations which showed a higher degree of stomatal opening in the fruiting trees. In some cases minor reductions in water uptake per tree were caused by reducing the supplies of potassium and nitrogen.
Triterpeneglycosides as Inhibitors of Fungal Growth and Metabolism
Authors: OLSEN ROLF A. 
Published: April 2006

AbstractA venacin, the resistance factor in oat roots against Ophio‐bolus graminis var. graminis, and a related triterpeneglycoside, aescin, induced a rapid release of K+ from mycelia of Opbio‐bolus graminis and Neurospora crassa, suspended in phosphate buffer. N. crassa also released Mg2+ whereas no outflux of Mg2+ was found from O. graminis.The inhibitors induced a release of inorganic phosphate into acetate buffer from Neurospora crassa. The amount of inorganic phosphate in the mycelia decreased when O. graminis and N. crassa were treated with the inhibitors in phosphate buffer. In other media the inhibitors had weak or no effects on the ion contents of the mycelia.The effect of aescin was low in Aspergillus niger and nil in Pythium irregulare. However, high amounts of K+, Mg2+, and phosphate ions were lost to the medium when the mycelium of P. irregulare, washed with distilled water, was suspended in different buffers. The ions lost were reabsorbed during the experimental period. The leakage of ions indicates that the plasma membrane of the growth sensitive fungi is severely affected by the inhibitors, while a corresponding effect on the growth insensitive fungi does not take place.