bluuebunny/crossref_metadata_2025_split huggingface dataset:
Separation of Cytokinins from Danish Cabbage by Column Chromatography on Insoluble Polyvinylpyrrolidone
Authors: THOMAS T. H. , CARROLL J. E. , ISENBERG F. M. R. , PENDERGRASS ANN , HOWELL LYDIA 
Published: April 2006

AbstractChromatography of partially purified extracts of Danish cabbage (Brassica oleracea var. capitata L.) heads on polyvinylpyrrolidone columns using a weak phosphate buffer indicated a cytokinin complex containing nine components active in the modified Amaranthus betacyanin bioassay. Similar elution patterns were obtained with extracts of four different cabbage varieties but varietal differences occurred in the biological activity from each component peak. Paper and thin‐layer chromatography indicated the presence of both zeatin and zeatin riboside in the extracts but the other cytokinin‐active components were not identified. Separation of sweet‐corn extracts by this technique indicated that most of the cytokinin activity occurred in the elution volume where zeatin and zeatin riboside would normally occur.
Effects of Light on the Georeaction and Growth Inhibitor Content of Roots
Authors: PILET PAUL‐EMILE 
Published: April 2006

AbstractThe positive geotropic response of the apical segments prepared from the primary roots of Zea mays depends upon at least one growth inhibitor, produced by the root cap, moving basipetally into the extending zone of the root in which it accumulates in the lower part. Anjou maize reacts in both darkness and light while Kelvedon maize is, for the first few hours, geotropic only in light. The production (or activity) of the growth‐inhibiting substance — tested by using vertical half‐decapitated root segments — is quite similar to the georeaction. This finding provides strong evidence that, in the case of Kelvedon maize roots, the inhibitory substance may depend on light. Observations related to the root segment of Anjou and Kelvedon maizes of which the tips are exchanged, are in agreement with the above results.
Phenolic Content in Male and Female Carica papaya: A Possible Physiological Marker for Sex Identification of Vegetative Seedlings
Authors: JINDAL K. K. , SINGH R. N. 
Published: April 2006

AbstractThe phenolic composition was determined in the leaves, petioles and bark tissues of male and female plants of two papaya cultivars. The same kind of phenolics were isolated from the male and female plants. However, a marked difference was observed between the plant organs of different cultivars. The important free and bound phenolics extracted after acidic and alkaline hydrolysis were caffeic acid, gentisic acid, m‐coumaric acid, p‐coumaric acid, salicylic acid and quercetin. Four phenolic compounds were not identified. The amounts of free, acid‐hydrolysable and alkali‐hydrolysable phenolic compounds were considerably higher in male plants.
The Biosynthesis of 8‐Hydroxy‐6‐methoxy‐3‐methyl‐3,4‐dihydroisocoumarin and 5‐Hydroxy‐7‐methoxy‐2‐methylchromone in Carrot Root Tissues Treated with Ethylene
Authors: SARKAR SUBODH K. , PHAN C. TON 
Published: April 2006

AbstractBiosynthesis of ethylene‐induced isocoumarin and eugenin in carrots (Daucus carota L.) was studied. Radioactive isocoumarin eugenin was isolated from these carrots fed with 1‐14C‐acetate and was isolated from ethylene treated carrots fed with 1‐14C‐acetate, 2‐14C‐malonate, and 3‐14C‐acetoacetate. Also, radioactive G‐3H‐5,7‐dihydroxy‐2‐methylchromone. A trapping experiment with 5,7‐dihydroxy‐2‐methyl‐chromone as trapping agent indicated that this compound was synthesized in carrots from acetate. From the results obtained, it was inferred that the biosynthesis of isocoumarin and eugenin must proceed via the acetate pathway.
The Effect of Light Intensity on Total Photophosphorylation and the ATP Level in Scenedesmus
Authors: OKKEH A. , TILLBERG J.‐E. , KYLIN A. 
Published: April 2006

AbstractThe dependence of in vivo photophosphorylation on light intensity was studied in the unicellular green alga Scenedesmus obtusiusculus. By selective use of the inhibitor DCMU, phosphorylation in (I) the complete system, (II) the pseudocyclic system alone, and (III) the true cyclic system alone, were followed. When the total binding of phosphate was studied, all reaction types became light saturated in about the same manner. The effect of DCMU on the level of ATP varied according to light intensity. As for the specific systems of photophosphorylation, the following ATP data were found: (I) In the complete system the level of ATP decreases with light intensity. (II) Under pseudo‐cyclic conditions light first increases and then decreases the ATP level. Under the atmospheric conditions used (i.e. CO2‐free nitrogen) this indicates a regulation between photophosphorylation and glycolysis, for which possible explanations are discussed. (III) In the true cyclic conditions light has little effect on the ATP level. The possibility is indicated that there is a structural difference between the non‐cyclic (site 1) and the pseudocyclic (site 2) sites of photophosphorylation on the one hand and the true cyclic site (3) on the other.
Tissue Culture of Maize I. Callus Induction and Growth
Authors: SHERIDAN WILLIAM F. 
Published: April 2006

AbstractCallus induction and subculture was successful with mature embryos and stem sections of seedlings of Zea mays L. on Linsmaier and Skoog's medium modified to contain 4 mg/I of 2,4‐D and 1 g/I of casamino acids. — 2,4‐D was superior to NAA and IAA for both callus induction and growth. Callus subcultured on NAA formed abundant roots on agar‐solidified media and numerous root‐like primordia in liquid cultures. — Kinetin had no effect on callus induction in the presence of 2,4‐D and neither kinetin nor gibberellic acid stimulated callus growth during subculture. — Callus grew equally well on the medium of Linsmaier and Skoog, that of Schenk and Hildebrandt, and the B‐5 medium of Gamborg and Eveleigh containing 2% sucrose, 4 mg/I of 2,4‐D and 1 g/I of casamino acids. — The callus grew more rapidly at 25°C than at 30°C or 35°C. Little difference was noted at any temperature in callus growth in alternating light (16 h) and dark (8 h) or continuous dark. — Sucrose was superior to glucose and maltose in both liquid and agar‐solidified cultures. Lactose and galactose failed to support callus growth.
Studies on Auxin Protectors XII. Auxin Protectors and Polyphenol Oxidase in Developing Coffee Fruit
Authors: GRIFFIN BARBARA , STONIER TOM 
Published: April 2006

AbstractThe fruit of the coffee plant (Coffea arabica) was analyzed for auxin protector content. Ripe coffee berries were separated into pit and pulp, ground in buffer, and assayed for auxin protectors. The extracts were then subjected to gel filtration in order to determine the molecular weight of the protector(s). In the pit, a single protector was found with a molecular weight approaching 5000 daltons, while the pulp contained several auxin protectors, the largest of which appeared to be about 1000 daltons. Chromato‐graphic studies of various gel filtration fractions showed that protector activity was always associated with spots which exhibited a light blue fluorescence under UV.The changing patterns during coffee fruit development were also investigated. Auxin protector production, and polyphenol oxidase (E.C. 1.10.3.1), an enzyme related to protector metabolism, were assayed at weekly intervals. In the unripe berry, an auxin protector was found with a molecular weight exceeding 200,000 daltons; as the berry ripened the amount of this protector gradually decreased until almost none was present in the ripe berry and the pattern changed to the pattern described above. Polyphenol oxidase content decreased as the berry ripened.Commercially roasted pits, i.e., coffee “beans”, contained very high levels of protector activity. However, gel filtration studies showed this activity to be associated entirely with low molecular weight compounds.
The Role of Glumes and Gibberellic Acid in Dormancy of Themeda triandra Spikelets
Authors: MARTIN COLIN C. 
Published: April 2006

AbstractSpikelets of Themeda triandra are dormant when mature and require an after‐ripening period in dry storage of approximately 12 months before full germination potential is realized. Successful germination of spikelets entails the splitting of the tough upper glumes by radicles. Dormany appears to result from a combination of embryo dormancy and mechanically resistant glumes. Glume removal from dormant spikelets increases germination while glume removal plus gibberellic acid increases germination even more.During the after‐ripening period, the growth potential of spikelets and caryopses increases as measured by their ability to germinate in the presence of the osmoticum polyethylene glycol 6000. The inhibition of germination by decreasing osmotic potential of the germination medium significantly interacts with the promotion caused by gibberellic acid indicating that both factors affect germination by altering the growth potential of the embryos. The increase in growth potential during after‐ripening is probably related to the synthesis of gibberellin‐like substances. It is hypothesized that dormancy breaking during after‐ripening occurs because the growth potential of embryos increases and this consequently increases the ability of radicles to split the upper glumes during germination.
Comparison of Isocitrate Dehydrogenase Activity, Pyruvate Kinase Activity, and Polyphenol Content in Physiologically Different Pine Callus Tissue
Authors: COWLES JOE R. , FOWLER JO ANN , WALKINSHAW C. H. 
Published: April 2006

AbstractDuring the growth of callus tissue of slash pine (Pinus elliottil Engelm.) several physiologically different types of tissue can be observed, often within the same culture. Different tissues were selected, based on color appearance, and used to determine isocitrate dehydrogenase and pyruvate kinase activity, and total polyphenol content. Isocitrate dehydrogenase and pyruvate kinase activity in yellow tissue was 3‐ to 5‐fold greater than in brown tissue, whereas the polyphenol content in yellow tissue was approximately 5‐fold less than in brown tissue. Dark brown callus, which also contained large amounts of polyphenols, did not have detectable enzyme activity. The differences in optimal concentrations of substrate and cofactors for the isocitrate dehydrogenase and pyruvate kinase reactions in yellow and brown tissues were very minor and therefore cannot account for the 3‐ to 5‐fold difference in enzyme activity between these tissues. Also, the addition of brown or dark‐brown tissue extract to the yellow tissue extract did not inhibit isocitrate dehydrogenase or pyruvate kinase activity in the yellow tissue extract.
Changes in Root Resistance as a Function of Applied Suction, Time of Day, and Root Temperature
Authors: SHIRAZI G. A. , STONE J. F. , CROY L. I. , TODD G. W. 
Published: April 2006

AbstractWater uptake rate of decapitated root systems of cotton (Gossypium hirsutum L.), tomato (Lycopersicon esculentum L. cv. Rutgers), and kidney bean (Phaseolus vulgaris L.) plants shows an exponential increase with applied suction up to about —1 bar. The water uptake rate was higher on the descending path of applied suction than on the ascending path, indicating a hysteresis effect in the roots. The root resistance in a cotton plant increased between 3‐to 5‐fold during the photoperiod of 12 hours. The water uptake rate increased with increasing temperature of the root medium up to 30°C in cotton and 25°C in tomato and bean plants.
Effect of Growth Regulators and Herbicides on Photosynthetic Partial Reactions in Isolated Leaf Cells
Authors: KULANDAIVELU G. , GNANAM A. 
Published: April 2006

AbstractThe effect of indoleacetic acid, gibberellic acid, 2,4‐dichloro‐phenoxyacetic acid and amitrole at various concentration levels ranging from 0.05 to 1.0 mM on the photosynthetic evolution of O2 and 14CO2 fixation by isolated leaf cells was studied. The plant growth regulators enhanced O2 evolution and 14CO2 fixation at low concentrations and were inhibitory beyond a critical level. The amitrole had an inhibitory effect at all the concentration levels used. All the substances exhibited similar patterns of effect on the ferricyanide reduction by isolated chloroplasts and on the electron transport rates of sub‐chloro‐plast particles containing PS‐I and PS‐II independently, under non‐phosphorylating conditions. As was seen from the response in all the three electron transport systems of the chloroplast studied, the electron transport chain connecting PS‐II and PS‐I could be considered as a possible site of action at least for the growth regulating substances as it is the only part that is common to all the three reactions. The phosphorylation associated with this part of the electron transport was “inhibited” by the substances even at the lowest concentration used. The stimulation of non‐phosphorylating electron flow, with a simultaneous reduction in the rate of ATP synthesis, at low concentration levels indicated that these substances played a possible uncoupling role. The amitrole on the other hand appeared to have a generalized non‐specific inhibitory action on all the partial reactions of photosynthesis.
Enhancement of Gibberellin Activity by Ethylenediaminetetraacetic Acid in Celery Seeds and Embryoless Barley Seeds
Authors: PALEVITCH D. , THOMAS T. H. 
Published: April 2006

AbstractThe phytochrome‐controlled dormancy of celery seeds (Apium graveolens L.) can be broken by exogenously applied growth regulators. Gibberellins, especially the mixture of GA4 and GA7 appeared to be the primary stimuli for germination of darkincubated seeds. However, concentrations less than 1 mM were ineffective in replacing the light requirement in one celery cultivar (cv.Utah), and in another cultivar (cv.Lathom Blanching), concentrations above 1 mM were insufficient. The addition of ethylenediaminetetraacetic acid (EDTA) to gibberellins, increased markedly their activity and reduced by several orders of magnitude the gibberellin concentrations needed to stimulate a light treatment. This synergistic activity is similar to the effect of benzyladenine (BA) or Succinic acid‐2,2‐dimethylhydrazide (SADH) when added to gibberellins. In a diverse plant system, the mixture of gibberellin with EDTA increased significantly the amount of reducing sugars released by embryoless barley seeds.
Phase Change in Hedera helix: Induction of the Mature to Juvenile Phase Change by Gibberellin A3
Authors: ROGLER CHARLES E. , HACKETT WESLEY P. 
Published: April 2006

AbstractA sensitive and reproducible method to obtain GA3 induced morphological reversion of mature Hedera helix to the juvenile form has been developed. Dose response experiments indicate that GA3 stimulates reversion over a 50–100 fold range with a half maximal response at approximately 0.5 μg GA3 per plant. The individual characteristics involved in phase change revert to the juvenile form in a sequential manner as GA3 dose is increased. Variations in light intensity from 1.2–3.6 × 104 lux and temperature from 15 to 26°C do not affect this hormonal response. Other growth regulators including indoleacetic acid, kinetin, abscisic acid and (2‐chloroethyl)phosphonic acid (Ethephon) are inactive but other gibberellins (GA1 and a mixture of A4–A7) are active in stimulating reversion. Therefore, the response is specific for gibberellins as a class of hormones but non‐specific for a particular form of gibberellin. The significance of this response in relation to juvenility in woody plants is discussed.
Redistribution of Endogenous Indoleacetic Acid, Abscisic Acid and Gibberellins in Geotropically Stimulated Ribes nigrum Shoots
Authors: EL‐ANTABLY HAMED M. M. 
Published: April 2006

AbstractThe presence of IAA, ABA and gibberellins in extracts of shoots of Ribes nigrum was demonstrated by gas‐liquid chroma‐tography (GLC) for both IAA and ABA and by the lettuce hypocotyl assay for gibberellins. Quantitative estimation of the three substances in extracts from upper and lower halves of shoots which had been kept horizontal, and which showed negative geotropic response after 4 h, indicated a redistribution of hormones during the geotropic stimulation. The ratio of the hormones in lower and upper halves was 3.8:1 and 2.8:1 for IAA and giberellins respectively, whereas the ratio of ABA in upper and lower halves was 2.1:1. There is, however, no evidence for the participation of gibberellins and ABA in the early development of negative geotropic curvatures, since shoots of intact Vicia faba seedlings treated with 100 mg/1 solution of GA3, ABA and 10 mg/1 IAA for 30 min prior to geotropic stimulation, developed negative geotropic curvatures, although shoots pretreated with 50 and 100 mg/1 IAA did not develop curvature.
Influence of UV‐B Radiation on Early Seedling Growth and Translocation of 65Zn from Cotyledons in Cotton
Authors: AMBLER J. E. , KRIZEK D. T. , SEMENIUK P. 
Published: April 2006

AbstractThe influence of UV‐B radiation from filtered or unfiltered fluorescent sunlamps on early seedling growth and translocation of 65Zn from cotyledons to the shoot was examined in two cultivars of cotton, Acala and Gregg. Ten‐day‐old seedlings which had been irradiated in the greenhouse for 6 h continuously each day for 14 days with 0.81 or 1.61 W × m‐2 UV‐B radiation under two unfiltered FS‐40 sunlamps, showed pronounced phytotoxic damage. This was characterized at first by bronzing and glazing of the cotyledons and later by upward curling of the leaves and abscission. Leaf expansion, dry matter accumulation, and mobilization of 65Zn from the cotyledons was severely impaired in the young developing shoot under unfiltered UV‐B radiation. A significant stress response also was observed in seedlings exposed to 0.61 W × m‐2 UV‐B radiation through a polystyrene filter and 0.73 W × m‐2 UV‐B radiation through a cellulose‐acetate filter. This stress response was characterized by the formation of a red pigment in the petioles of the cotyledons, reduced leaf expansion, and reduced transport of 65Zn. Control seedlings exposed to 0.03 W × m‐2 UV‐B radiation through a mylar filter were green, had maximum leaf size and dry‐matter accumulation, and had the greatest percentage of 65Zn translocated from the cotyledons.
Influence of Ultraviolet Radiation on Germination and Early Seedling Growth
Authors: KRIZEK DONALD T. 
Published: April 2006

AbstractThe influence of UV‐B radiation (280–320 nm) from filtered and unfiltered FS‐40 fluorescent sunlamps on germination and early seedling growth was examined for a range of vegetables (tomato, radish, cucumber, lettuce, and bean) and field crops (wheat, cotton, soybean, and millet). Continuous exposure of seeds for 3 days to 26.9 × 10−2 W × m−2 UV‐B radiation (280–320 nm) at 25°C, had a slight effect on fresh weight of seedlings but no appreciable influence on germination percentage, or dry weight of seedlings. Extending the time of exposure to 6 days, however, resulted in abnormal seedling growth in all species but wheat. Typical responses were short, stubby roots, bronzing of the cotyledons, increased pigmentation, and abnormal curvature of the shoots.
Abscisic Acid Analysis in Vitis vinifera in the Period of Endogenous Bud Dormancy by High Pressure Liquid Chromatography
Authors: DÜRING H. , BACHMANN O. 
Published: April 2006

AbstractIn buds and nodes of Vitis vinifera L. cv. Riesling, the content of abscisic acid (ABA) was measured by high pressure liquid chromatography and related to bud dormancy. In the period of endogenous bud dormancy (rate of bud break is low or zero under favourable climatic conditions) the ABA content increased twelvefold. This indicates a causal relationship between endogenous bud dormancy and ABA.
Simulation of Hormone Transport in Petiole Segments of Coleus
Authors: VEEN H. , FRISSEL M. J. 
Published: April 2006

AbstractTranslocation and distribution of abscisic‐(1‐14C) acid and of (5‐3H)indol‐3yl‐acetic acid in agar cylinders and in boiled and fresh petiole segments of Coleus scutellarioides Bentham have been studied by liquid scintillation counting. The hormones were simultaneously applied in donor blocks of agar. Transport and distribution data of the two compounds were compared with those of (36Cl‐)chloride in the same systems. From the data on movement in agar cylinders, diffusion coefficients of the transported compounds were approximated using a simulation model in which it was assumed that the movement was controlled by diffusion only. Movement in boiled tissue segments fitted the model if a correction factor was included in the equation for diffusion. Acropetal movement of indol‐3yl‐acetic acid in fresh petiole segments can be entirely explained in terms of passive transport and for basipetal transport it seems to be a major component. Movement of abscisic acid and of chloride in fresh petiole segments fit also a model based on diffusion. The limitations of the simulation model are discussed.
Emergence and Seedling Growth of a Cultivated and a Wild Strain of Safflower under Various Amounts of Simulated Rainfall
Authors: BASSIRI ABDOLLAH , SIONIT NASSER 
Published: April 2006

AbstractTwo separate experiments were conducted to investigate the effects of different planting depths and irrigation regimes on the emergence and seedling heights of a cultivated (Carthamus tinctorius L. cv. Arak 2811) and a wild strain (C. oxyacantha Bieb.) of safflower. In the first experiment, three planting depths (0.5, 2.0 and 3.5 cm) and four water levels (6,9,12, and 15 mm) were used. Water was applied only once at the start of the experiment. For Arak 2811, the highest emergence percentage and seedling height were obtained when seeds were planted 0.5 cm deep in the soil and irrigated with the equivalent of 12 mm of rainfall.In the second experiment, five water levels (3, 6, 9, 12 and 15 mm) were applied at 3‐day intervals for a period of 25 days and the planting depth was 0.5 cm. For Arak 2811, the seedlings emerged within 4 to 7 days after the first watering while for the wild strain, the emergence started on the 4th day and continued up to the 17th day. The emergence percentage of the wild safflower was almost half of that of the cultivated strain. However, the emerged wild seedlings were much more resistant to low available water than the seedlings of the cultivated variety of safflower.
Freeze Preservation of Cultured Plant Cells
Authors: NAG K. K. , STREET H. E. 
Published: April 2006

AbstractA basic technique for successful freeze preservation and storage at ‐196°C of cultured plant cells and an assay of percentage survival following the freezing‐storage‐thawing procedure are described. These techniques have been applied to suspension cultures of carrot (3 cell lines), belladonna and sycamore. Dimethyl sulfoxide (DMSO) and glycerol, when appropriately applied, were the most effective cryoprotectants tested. Although these cryoprotectants were of low toxicity and did not cause alterations in the cytology and growth potential of the recovered cells, the cell lines differed in their sensitivity to the toxicity of these cryoprotectants. Small meristematic cells survived the freezing‐thawing procedure better than larger more highly vacuolated cells. Specific differences in survival are in part explained in terms of differences in cell morphology.