bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Delimitation of Chlorophyll Formation after an Irradiation with a Sharply Defined Light Area
Authors: Virgin Hemming I. , Arvidsson Lars G. 
Published: April 2006

AbstractLeaves of dark grown wheat seedlings have been irradiated for a few minutes with a strictly defined beam of red light. After a stay in darkness for six hours the whole leaves were irradiated for three hours. The pre‐irradiated spot will then stand out greener than the rest of the leaf, due to accelerated formation of protochlorophyll, earlier described (22), and will consequently show a higher concentration of chlorophyll a. By scanning the leaf with a microphotometer it was shown that no spread whatsoever of the effect of the light impulse takes place, i.e. the phytochrome, which is one of the light absorbing systems, exerts its effect strictly locally. This is in contrast to many other red light effects on photomorphogenetic phenomena characterized by a rapid spread of the stimulus. The two kinds of phytochrome actions are discussed.
Effects of Soil Salinity and Growth Regulators on Germination and Seedling Metabolism of Wheat
Authors: Sarin M. N. , Narayanan A. 
Published: April 2006

AbstractGermination studies were carried out with the wheat varieties NP823, Karchia, Sonora 63, Sonora 64, Mayo 64 and Lerma Rojo in artificially salinized soil maintained at ECe 2, 8, 12 and 16 mmhos/cm at 25°C. Early seedling growth and metabolism of variety NP 823 was studied in salt solutions alone and with addition of the growth regulators GA3 and Cycocel (2‐chloroethyl trimethylammonium chloride). Soil salinity both depressed and delayed the germination. Among the varieties tested NP 823 and Karchia were relatively less susceptible to salt injury while Lerma Rojo exhibited a maximum susceptibility. Salt supply also brought about a reduction in the early seedling growth, the release of reducing sugar and the amylase activity. The adverse effect on amylase activity was not mediated through the synthesis of enzyme protein but by an inhibition of the enzyme activity. Exogenous supply of GA3 counteracted the adverse effect of salt on amylase activity and the release of reducing sugar but not on the early seedling growth.
Palmelloid Formation of Chlamydomonas
Authors: Iwasa Kozo , Murakami Shohachi 
Published: April 2006

AbstractOrganic acids such as citrate, oxalate, succinate, fumarate, malate, glutamate, aspartate, glycolate and phthalate induce palmelloid formation at neutral pH in liquid cultures of Chlamydomonas, while acetate hardly does it. The palmelloids consist of a minimum of four cells and are embedded in a jelly‐like material. The effective organic acids are generally not only unutilizable as respiratory substrates, but affect also slightly the respiration or photosynthesis and tend to inhibit growth. In a synchronous culture, an addition of citrate at an early stage of a light or dark period has little or no effect on cell growth and multiplication but inhibits the dissociation of divided daughter cells strikingly.
Changes in Nucleic Acid Metabolism of Excised Barley Leaves During Senescence and the Effect of Kinetin on these Changes
Authors: Atkin Roger K. , Srivastava B. I. Sahai 
Published: April 2006

AbstractThe changes in the amount, rale of synthesis and the nucleotide composition of different RNA fractions in excised barley leaves floated on water or kinetin (10 mg/l) in the dark were examined. In excised leaves floated on water all nucleic acid components declined and these declines were retarded by kinetin. Barley leaves floated on water showed a stimulation of 32P incorporation into various RNA fractions within 48 hours followed by a decline after 96–144 hours. The leaves floated on kinetin, however, showed an even higher incorporation of 32P into UNA by 48 hours which remained at a comparatively higher level throughout the experiment. In spite of the above changes in RNA synthesis significant differences in the 32P sucrose gradient profiles or in the 32P nucleotide composition of UNA from water and kinetin floated leaves were not noted.The results of this study show that important changes in nucleic acid metabolism occur during the early stages of leaf senescence and that alterations in nucleic acid metabolism during senescence and during kinetin treatment may involve quantitative and only subtle qualitative changes.
Sweetgum Dormancy Release: Effects of Chilling, Photoperiod, and Genotype
Authors: Farmer Robert E. 
Published: April 2006

AbstractIn Liquidambar styraciflua L., 1200 to 1600 hours of chilling (3°C) resulted in rapid resumption of growth under greenhouse forcing conditions. Long photoperiods were effective substitutes for chilling. Plants from southern Alabama (Lat. 31°) had a lower chilling requirement than those from western Tennessee (Lat. 36°). Growth rate of plants under long photoperiod varied directly with degree of previous chilling.
Transport Gradient of Indoleacetic Acid in Pine Seedlings
Authors: Zaerr J. B. 
Published: April 2006

AbstractMovement of indoleacetic acid (IAA‐1‐14C) through 5‐min segments from stems and roots of Pinus taeda L., P. jeffreyi Gtrev. and Balf., and P. ponderosa Laws, seedlings was measured. All three species showed the same general pattern of IAA‐1‐14C transport. Predominantly downward movement occurred at all points along the stem and root; least IAA‐1‐14C transport occurred in segments obtained near the shoot apex; and most occurred in segments obtained near or just below the cotyledons. This pattern of transport gradient is different from that reported in other plants. These results could be interpreted in either of two ways: (1) that transport limitations may control movement of the growth‐regulator, or (2) that the transport gradient may be an indication of endogenous growth‐regulator levels.
The Effect of Gibberellin on Tryptophan Conversion and Elongation of the Avena Coleoptile
Authors: Valdovinos Jack G. , Sastry K. S. Suryanarayana 
Published: April 2006

AbstractGibberellic acid (GA3) enhanced directly the release of 14CO2 from tryptophan‐1‐l4C by cell free preparations of Avena coleoptile tips. The rate of tryptophan metabolism in the presence of GA3 was increased by approximately 100 per cent. The addition of auxin synthesis inhibitors to incubation flasks nullified the enhancement effect of GA3 on elongation of the coleoptile tips. These studies implicate tryptamine as an intermediate in the formation of auxin from tryptophan. The possibility of GA3‐IAA interaction in the elongation processes was also investigated. Combination treatments of these growth‐promoting substances did not induce a synergistic growth response by the coleoptile tissue.
Cytokinin Reversal of Abscisic Acid Inhibition of Growth and α‐Amylase Synthesis in Barley Seed
Authors: Khan A. A. , Downing R. D. 
Published: April 2006

AbstractThe effect of cytokinin, kinetin, on abscisic acid (dormin) inhibition of α‐amylase synthesis and growth in intact barley seed was investigated. Abscisic acid at 5 × 10−5M nearly completely inhibited growth response and α‐amylase synthesis in barley seed. Kinetin reversed to a large extent abscisic acid inhibition of α‐aniylase synthesis and coleoptile growth. The response curves of α‐amylase synthesis and coleoptile growth in presence of a fixed amount of abscisic acid (6 × l0−6M) and increasing concentrations of kinetin (from 5 × l0−7M to 5 × 10−5 M) showed remarkable similarity. Kinetin and abscisic acid caused synergistic inhibition of root growth. Gibberellic acid was far less effective than kinetin in reversing abscisic acid inhibition of α‐amylase synthesis and coleoptile growth. A combination of kinetin and gibberellic acid caused nearly complete reversal of abscisic acid inhibition of α‐amylase synthesis but not the abscisic acid inhibition of growth. The results suggest that factors controlling α‐amylase synthesis may not have a dominant role in all growth responses of the seed. Kinetin possibly acts by removing the abscisic acid inhibition of enzyme specific sites thereby allowing gibberellic acid to function to produce α‐amylase.
Biochemische Differenzierungen bei Mais unter Mineralstoff mangel
Authors: Horovitz C. T. , Brad I. , Enescu Ioana , Niculescu S. , Jokl Elisabeta 
Published: April 2006

Abstract Biochemical Differences in Maize as Related to Mineral Deficiencies. I. Changes in the Activity of some Enzymes. — The enzymatic systems in the different organs of corn seedlings are variously affected in the first growing stages by deficiency in nitrogen, phosphorus or potassium, according to the specific physiological functions of the organs. Deficiency in nitrogen causes an increase in peroxidase and catalase activity and inhibition of pyruvic and glutamic decarboxylase. Deficiency in phosphorus causes an activation of peroxidase and catalase in leaves and an inhibition of acid phosphatasc, invertase, pyruvic and glutatnic decarboxylase in roots. Deficiency in potassium, as compared to deficiency in nitrogen and phosphorus, leads to the severest disturbances of the different enzymatic systems. This deficiency causes a strong increase in leaf invertase, catalase and peroxidase activity, a stimulus in respiration intensity in the roots, and an inhibition in pyruvic and glutaniic decarboxylase in leaves and roots. The activation and inhibition changes in the enzymatic processes, appearing as a consequence of nitrogen, phosphorus and potassium deficiency have different significance and intensity.
Effect of Phosphorus Deficiency on Carbohydrate Metabolism of Mentha arvensis
Authors: Singh J. N. , Singh D. P. 
Published: April 2006

AbstractThe effects of phosphorus deficiency on carbohydrate fractions of Mentha arvensis L. var. piperascens were studied. Mint plants were grown in sand cultures under full nutrition and phosphorus deficiency conditions. Component organs, viz., leaf, stem and root, were sampled at four different stages of the growth cycle and analysed for various sugar fractions.In leaf and root phosphorus deficiency brought about a definite increase in all sugar fractions whereas in stem a reduction was noticed. The stem appeared to be the principal storage organ throughout the growth. Maximum sugar concentration was recorded at the age of 70 days, which represents the full maturity stage, and coincided with maximum essential oil accumulation.
Relationship of IAA‐oxidase Activity to Gibberellinand IAA‐induced Elongation of Light‐grown Cucumber Seedlings
Authors: Katsumi Masayuki , Sano Hiroshi 
Published: April 2006

AbstractThe growth and IAA‐oxidase activity of light‐grown cucumber seedlings (cv. Aonagajibae) were investigated in response to GA3 and IAA.Both GA3 and IAA induced significant elongation of the hypocotyl. The fresh and dry weights of the hypocotyl increased due to GA3 or IAA treatment, whereas no significant change was observed in the cotyledons of GA3‐treated seedlings as compared with the controls. The fresh and dry weights of IAA‐treated cotyledons were both lower than those of controls.Treatment with GA3 or IAA resulted in retardation of IAA‐oxidase activity in the hypocotyl and cotyledons. The degree of retardation was less in the cotyledons than in the hypocotyl. An inverse relationship was recognized between GA3‐ or IAA‐induced elongation and IAA‐oxidase activity in the hypocotyl.The auxin‐mediated mechanism for gibberellin action was discussed.
Interactions between Plants and Epiphytic Bacteria Regarding Their Auxin Metaholism
Authors: Wichner Siegfried 
Published: April 2006

AbstractDuring an ether extraction (20 h, 4°C), nonsterilc pea epicotyls deliver at least 5 times more auxin than sterile ones. A great part of the additional auxin originates from a bacterial auxin production during the extraction. Presence of chloramphenicol or streptomycin during the extraction lowers the auxin amount extractable from nonsterile epicotyls. In extraction conditions (i.e. covered with ether, 20 h, 4°C), epiphytic bacteria contained in homogenates of nonsterile plant parts produce IAA from added tryptophan.Furthermore, first results are presented underlining the fact that epiphytic bacteria already produce auxin at the surface of nonsterile plant parts (before an extraction).
On the Adaptation of Aphanomyces astaci as a Parasite
Authors: Unestam Torgny 
Published: April 2006

AbstractThe crayfish plague parasite Aphanomyces astaci was compared with some other species of Aphanomyces in several physiological respects to detect signs of specialization in the plague fungus which could be connected with its life as a parasite.Thus, A. astaci showed good growth in crayfish serum in contrast to the other species. Zoospore germination showed a similar hut not so distinct pattern. Chemo‐taxis in zoospores was weak and restricted in its substrate range in A. astaci but was stronger and less restricted in the saprophytic species. Electrotaxis was quite apparent in A. astaci.Virulence in A. astacin was correlated to linear growth rate of individual hyphae in crayfish serum but neither to spore germination percentage in serum of resistant or susceptible crayfishes nor to motility of the zoospores. The saprophytic Aphanomyces strains did not penetrate the soft cuticle of crayfish in vitro but A. astaci strains did, regardless of virulence.Zoospore production in A. astaci was restricted to lower concentrations of mineral salts Mum in the other fungi.No sexual or other resting structures were found in infected crayfish but thick walled as well as gemmae‐like hyphal portions were formed in some media in vitro.Infection of crayfish can take place between 2 and 25°C and zoospores are able in survive at least a week in an aquarium of redistilled water at 14°C and still infect the animals, but in highly bacterium‐contaminated water they do not cause infection.The results were discussed with respect to the origin of the “abnormal” parasite. Together with those of earlier experiments they suggest Unit A. astaci is physiologically adapted as a parasite on fresh water arthropods.This investigation was supported by a grant from the Swedish Natural Science Research Council and by funds paid to the Swedish state by the Swedish water power industry.The author is deeply indebted to the head of this institute Professor Nils Fries, for his encouragement. advice, and support, let Mr Andrew Watson for help in carrying out the electrotaxis experiment, to Docent Karin Aschan‐Aberg for criticizing the manuscript, to Mrs. Linda Fryktund for revising the English text, and to Mr. Can Wihma for skilful technical assistance.
Retention and Passage of Calcium and Strontium in Stems of Phaseolus vulgaris as Mediated by Xylem Stream Flow Rate and Dinitrophenol
Authors: Emmert Fred H. 
Published: April 2006

AbstractThe influence of the stem on delivery of Ca Sr to the plant top was studied by noting the extent to which the stem interfered with through passage of these elements. Tagged Ca Sr solutions were forced through bean stem sections, and solute which completed passage to the exudate was considered indicative of the nutrition normally available to the plant top. Tests were conducted over two widely different xylem stream flow rates, and with or without the addition of dinitrophenol to the source solution. Approximately identical amounts of cation were introduced into the stem for all test situations.In all cases, the stem retained the bulk of introduced cation and allowed only a fraction (ca 25 percent) to complete passage to the exudate. Within this pattern, less stem retention and greater through passage occurred at the high (versus the low) stream flow rate, and also where dinitrophenol was present in the source solution.In all cases, the stem preferentially retained Sr over Ca so that the exudate was relatively dilute in Sr. Such discrimination was less at the high (versus the low) stream flow rate. It was enhanced by the presence of dinitrophenol.
Occurrence of Plant Growth Inhibitors in Tropical and Subtropical Vegetation
Authors: Bovey R. W. , Diaz‐Colon J. D. 
Published: April 2006

AbstractAcetone, ethanol and water extracts of mature fruits of yaupon (llex vomitoria Ait.) inhibited germination of mesquite (Prosopis juliflora Swartz DC. var. glandulosa (Torr.) Cockerell and sorghum (Sorghum bicolor (L.) Moench). Extracts of guava fruit (Psidium guajava L.) inhibited cucumber (Cucumis sativus L.) seed germination. Water soluble inhibitors were found in fruits, leaves, roots and bark of several tropical species representing 10 different families.Strong inhibition of cucumber seed germination and growth did not occur in sand when water extracts containing inhibitors were applied. Growth of corn, sorghum, cucumber and bean was reduced in soils collected beneath Malay apple (Eugenia malaccensis L.) trees. Plant growth‐inhibitors occurred in all species studied in various plant parts, and some apparently affect the growth and ecology of other plant species.
Rhizosphere Oxidation in Rice: An Analysis of Intervarietal Differences in Oxygen Flux from the Roots
Authors: ARMSTRONG W. 
Published: April 2006

AbstractThe polarographic technique (Armstrong 1967) has been found suitable for the detection of significant intervarietal differences in oxygen diffusion from rice roots. All the evidence obtained supports the thesis that intervarietal differences in oxygen diffusion rate occur and the varieties tested may be arranged in order of increasing oxygen flux as follows N 36 < N 22 < N 29 < N 32 < Yubae. The lowest oxygen flux rates are found in those varieties (N 22 and N 36) susceptible to Akagare disease of rice while the flux rates of varieties resistant to Akagare (N 29 and N 32) are higher. On the basis of these results one would also expect Yubae to be resistant to Akagare.The results are discussed with reference to previous work which has shown the oxidising activity and carbohydrate exudation properties of rice roots to be similarly correlated with resistance or susceptibility to Akagare.Attention is drawn to what it is felt are the shortcomings in existing techniques for measuring the oxidising activity of roots.It is suggested that with certain provisions the polarographic technique may he found useful in any effort to build up high oxidising power into the new plant type proposed for the tropics.
Wechselwirkung von Riboflavin, Isoriboflavin und 2‐Thiouracil auf die Induktion zweidimensionalen Wachstums von Farnprothallien
Authors: Schraudolf H. , Legler K. 
Published: April 2006

Abstract Action of riboflavin, isoriboflavin and 2‐thiouracil in the induction of 2‐dimensional growth of fern prothallia.—The inhibition of cell division induced by 2‐thiouracil in prothallia of Dryopteris filix‐mas and Anemia phyllitidis is reversed by riboflavin as well as by its physiological inactive analogue isoriboflavin. This antagonism is not due to an in vivo interaction as stated by Yeoh and Raghavan, but is rather caused by an in vivo sensibilisation of photo destruction of the inhibitor during early phase of spore germination.Riboflavin as well as isoriboflavin strongly inhibit cell divisions in the prothallia of Anemia phyllitidis.In spite of a significantly reduced growth rate NO retardation of the onset of the 2‐diniensional differentiation, as related lo a critical cell number, can be slated in the Anemia prothallia.
Comparisons of Phosphate, Carbohydrate, and Kjeldahl Nitrogen Content of Normal and Xantha Mutant Leaves of Helianthus annuus
Authors: Habermann Helen M. 
Published: April 2006

AbstractTissues of the xantha mutant of Helianthus annuus have an abnormally high phosphorus content compared to normally pigmented tissues of comparable age and position on the plant. A major portion of the observed differences can be accounted for in the acid‐insoluble “7‐minute” phosphate fraction, a fraction thought to be composed primarily of polyphosphates. Although this suggests that the xantha mutant may possess a mechanism for immobilizing excess phosphates as insoluble polymers, all qualitative tests for polyphosphates in extracts of mutant leaves have been negative.Carbohydrate levels in the mutant are lower than in wild type leaves due to the absence of photosynthesis in the mutant and its inability to form starch. Differences between mutant and wild type in Kjeldahl nitrogen appear to be a consequence of aging effects resulting from propagation by grafting onto physiologically older stocks.
Studies in Stomatal Behaviour: The Effects of Moving, Normal and Carbon Dioxide‐Free Air on the Stomata of Some Plants
Authors: Hafez M. G. A. , Younis M. E. 
Published: April 2006

AbstractA series of experiments were conducted to investigate the effects of moving, normal and carbon dioxide‐free air on the stomata within porometer cups attached to the illuminated leaves of Datura stramonium, Pelargonium zonale, Duranta plumieri and Clerodendron inerme.A marked opening stomatal response was obtained in Datura and Pelargonium on changing to carbon dioxide‐free air. In general no such response was established in Duranta and Clerodendron. Indications of even an opposite closing effect were shown in the case of Duranta.The present results seem to disprove the reduction of carbon dioxide by photosynthesis as the major factor controlling the wide stomatal opening within a porometer cup. The possibility of a humidity effect is also suggested.
Cellulase Induction and Wall Extension in the Water Mold Achlya ambisexualis
Authors: Thomas D. des S. , Mullins J. T. 
Published: April 2006

AbstractBranching of the coenocytic hyphae in the water mold Achlya ambisexualis Raper is always accompanied by a rise in cellulase activity. Branching and the cellulase response can be induced either by the sexual hormone atheridiol or by casein hydro‐lysate. Only those strains which branch in response to the inducer show a concomitant rise in cellulase. The peak of induced mycelial cellulase corresponds in time with the appearance of branch primordia.
The Relative Contributions of Sugars from Assimilating Leaves and Stem Storage Cells to the Sieve Tube Sap in Willow Cuttings
Authors: Ho L. C. , Peel A. J. 
Published: April 2006

AbstractA method is described for the measurement of the relative contributions of sugars from the assimilating leaves and stem storage cells to the sieve tube sap in leafy cuttings of Salix viminalis L. In these experiments sieve tube sap was collected as honeydew from a small colony of aphids, Tuberolachnus salignus (Gmelin).Using this method it has been shown that in cuttings maintained under continuous illumination prior to experimentation, the leaves contribute about 75 per cent of the total sugars in the sieve tube sap. With cuttings which have been stored by keeping them in darkness, the level of labile carbohydrates in the stem storage cells decreases, in comparison with those growing in light, and the percentage of sugars in the sieve tube sap supplied by the leaves rises to 90 per cent.
Freezing of Conifer Xylem and the Cohesion‐Tension Theory
Authors: Sucoff Edward 
Published: April 2006

AbstractThe research explored the apparent contradiction between the cohesion‐tension theory and the lack of blockage following freezing in conifers.Five to ten cm lengths of the main stem of actively transpiring Thuja occidentalis, Picea glauca and Pinus sylvestris were frozen. On thaw, there was no evidence of blockage in the formerly frozen xylem. Microscopic examination of frozen wood and hydrodynamic considerations showed that air was present in the xylem water and that bubbles were probably present upon freezing. On freezing about 9 per cent of the water irreversibly migrated into the unfrozen plant parts.Lack of blockage in the presence of air bubbles was reconciled to the cohesion‐tension theory by a model in which only the largest bubble in a number of interconnected cells expands. As this bubble expands tension is released allowing all bubbles in adjoining tracheids to redissolve. Potential rate of resolution of unexpanded bubbles following release of tension was calculated to be less than 0. 1 second.