Showing papers on "Gibberellic acid published in 1982"
TL;DR: The results together with those from other studies indicate that GA(3) differentially controls the expression of two alpha-amylase genes or groups of genes giving rise to two groups of alpha-AMylases with many different properties.
Abstract: The gibberellic acid (GA(3))-induced alpha-amylases from the aleurone layers of Himalaya barley (Hordeum vulgare L. cv Himalaya) have been purified by cycloheptaamylose-Sepharose affinity chromatography and fractionated by DEAE-cellulose chromatography. Four fractions (alpha-amylases 1-4) were obtained which fell into two groups (A and B) on the basis of a number of characteristics. Major differences in serological characteristics and in proteolytic fingerprints were found between group A (alpha-amylases 1 and 2) and group B (alpha-amylases 3 and 4). Also, the lag time for appearance of group B enzyme activity was longer than for group A, and the appearance of group B required higher GA(3) levels than group A. The components of each group behaved similarly, although differences in proteolytic fingerprints were detected.These results together with those from other studies indicate that GA(3) differentially controls the expression of two alpha-amylase genes or groups of genes giving rise to two groups of alpha-amylases with many different properties.
135 citations
TL;DR: It is concluded that both GA3 and ABA regulate protein synthesis both positively and negatively in aleurone cells largely by regulating levels of mRNA and in the case of α-amylase, possibly also by changing the efficiency of translation of its mRNA.
Abstract: Using in vivo pulse labeling, changes in the pattern of protein synthesis were detected in isolated barley aleurone layers treated with fibberellic acid (GA3). GA3 greatly altered the relative rates of synthesis of many polypeptides, increasing some, notably α-amylase, and decreasing others. α-Amylase synthesis increased until it was the major product (over 60%) of protein synthesis after 24h. The pulse-labeled pattern of secreted polypeptides was also changed by GA3. There was the expected increase in α-amylase together with a number of other polypeptides but there was reduced secretion of several polypeptides also.
107 citations
TL;DR: The application of gibberellic acid (GA3) at any time from early November until bud sprouting, resulted in a significant inhibition of flowering in the sweet orange and Clementine mandarins, suggesting the reversion of a floral to a vegetative apex.
Abstract: The application of gibberellic acid (GA3) at any time from early November until bud sprouting, resulted in a significant inhibition of flowering in the sweet orange [C. sinensis (L.) Osbeck] and the Satsuma (C. unshiu Marc.) and Clementine (C. reticulata Blanco) mandarins. Two response peaks were evident: the first occurred when the application was timed to the translocation of an unknown flowering signal from the leaves to the buds. The second occurred during bud sprouting, at the time the flower primordia were differentiating. From the pattern of flowering, it appears that the mechanism of inhibition was similar irrespective of the timing of GA3 application. There was an initial reduction in bud sprouting affecting selectively those buds originating leafless inflorescences. An additional inhibition resulted in a reduction in the number of leafy inflorescences with an increase in the number of vegetative shoots, suggesting the reversion of a floral to a vegetative apex. The inhibited buds sprouted readily in vitro but invariably vegetative shoots were formed. A continuous influence of the sustaining branch is necessary to keep the flowering commitment of the buds; irreversible commitment occurs when the petal primordia are well differentiated.
87 citations
TL;DR: The results support the hypothesis that ADC and polyamine content are important regulators of plant growth and reverses the red-light-induced inhibition of ADC activity in etiolated Alaska pea epicotyls.
Abstract: When gibberellic acid (GA 3 ; 5-35 micrograms per milliliter) is sprayed on 9-day-old light-grown dwarf Progress pea ( Pisum sativum ) seedlings, it causes a marked increase in the activity of arginine decarboxylase (ADC; EC 4.1.1.9) in the fourth internodes. The titer of putrescine and spermidine, polyamines produced indirectly as a result of ADC action, also rises markedly, paralleling the effect of GA 3 on internode growth. Ammonium (5-hydroxycarvacryl) trimethyl chloride piperidine carboxylate (AMO-1618; 100-200 micrograms per milliliter) causes changes in the reverse direction for enzyme activity, polyamine content, and growth. GA 3 also reverses the red-light-induced inhibition of ADC activity in etiolated Alaska pea epicotyls; this is additional evidence for gibberellin-light interaction in the control of polyamine biosynthesis. The enzyme ornithine decarboxylase (ODC; EC 4.1.1.17), an alternate source of putrescine arising from arginine, is not increased by GA 3 or by AMO-1618. The results support the hypothesis that ADC and polyamine content are important regulators of plant growth.
71 citations
70 citations
TL;DR: Because of relative ease of operation, great sensitivity and the short time required for assessing biological activity, this assay could be used in conjunction with the bean second internode bioassay for evaluating the activity of brassinolide and its analogs, as well as of other growth promoters.
Abstract: The growth rate of mung bean epicotyls was used for evaluating the effect of brassinolide on cell elongation. Growth above that of control plants was observed at 10−10M and above. Gibberellic acid showed an additivity relationship with low concentrations (10−9–10−8M) of brassinolide in this test system and the two growth promoters may therefore act independently at the cellular level. Because of relative ease of operation, great sensitivity and the short time required for assessing biological activity, this assay could be used in conjunction with the bean second internode bioassay for evaluating the activity of brassinolide and its analogs, as well as of other growth promotors.
69 citations
TL;DR: Viable, long-lived, gibberellic acid (GA3)-responsive protoplasts have, for the first time, been isolated from aleurone layers of mature wild oat (Avena fatua L.) grain and these respond to treatment with GA3 in essentially the same manner as the tissue from which they were derived.
Abstract: Viable, long-lived, gibberellic acid (GA3)-responsive protoplasts have, for the first time, been isolated from aleurone layers of mature wild oat (Avena fatua L.) grain. More than 90% of the cells of aleurone layers are recovered as protoplasts, and these respond to treatment with GA3 in essentially the same manner as the tissue from which they were derived. Protoplasts become vacuolate during incubation in vitro and, although not dependent upon GA3, vacuolation is markedly stimulated by the hormone. Amylase and ribonuclease (RNase) are produced and secreted only in the presence of GA3 and only after lag periods of 3 d and 4 d respectively. The amounts of amylase produced and secreted are proportional to GA3 concentrations as low as 1.61·10-13 M. With increasing concentrations of mannitol in the culture medium both vacuolation and the GA3-induced production and secretion of enzymes are inhibited progressively, the latter being precluded by 0.6 M to 0.7 M mannitol.
66 citations
TL;DR: Hormone levels of tomato fruits may be successfully, easily and reproducibly altered by inducing parthenocarpic fruit growth and thus eliminating development of seeds which are a major source of hormone synthesis.
Abstract: Ethylene, indol-3-acetic acid (IAA), gibberellin-like substances (GAs) and abscisic acid (ABA) were analysed in extracts from normal, seed-containing and parthenocarpic tomato fruits throughout fruit development. Parthenocarpic fruit growth was induced with an auxin (4-CPA), morphactin (CME) or gibberellic acid (GA3) and compared with that of pollinated control fruits. Fruit growth was only affected by the treatment with GA3, decreasing size and fresh weight by 60%. The peak sequence of hormones during fruit development was ethylene-GAs-IAA-ABA. Seeded fruits contained the highest levels of IAA and ABA but the lowest levels of GAs. Also, in seeded fruits, a high proportion of IAA and ABA was found in the seeds whereas this was not the case for GAs. Hormone levels of tomato fruits may be successfully, easily and reproducibly altered by inducing parthenocarpic fruit growth and thus eliminating development of seeds which are a major source of hormone synthesis. In spite of markedly changed hormone levels, there was no obvious relationship between fruit growth and extractable hormones per se. However, the results indicate that a high ratio of GAs: auxins is unfavourable for growth of tomato fruits.
59 citations
TL;DR: Aleurone layers from immature developing wheat grains, though normally insensitive, can be made to produce α-amylase in response to gibberellic acid by subjecting the grains to a period of enforced dehydration prior to introduction to the hormone.
Abstract: Aleurone tissue from undried immature developing wheat grains (Triticum aestivum L. cv. Sappo), normally insensitive to gibberellic acid, can be made to respond to the hormone by a series of temperature treatments. Incubation of the de-embryoed grains at temperatures above 27° C for at least 8 h causes the tissue to become sensitive. Prolonged incubation at temperatures below 27° C does not effect a change in sensitivity. In addition to the requirement for exposure to an elevated temperature for a period of several hours the tissue must also subsequently be subjected to a period at a lower temperature for just a few seconds for the response to be observed. Once sensitized, the tissue remains responsive to gibberellic acid for substantial periods of time. Exposure of the tissue to temperatures which induce sensitivity to gibberellic acid also results in an increased leakage of amino acids. It is suggested that the increase in sensitivity to gibberellin requires two separate processes to take place. One could be a homeoviscous adaptation of the cell membranes in response to elevated temperature, the other a subsequent, permanent change in conformation of membrane components.
50 citations
TL;DR: The development of the graft as measured by an increase in mechanical strength and the formation of vascular connections was similar to that observed in whole plant grafts; however, fewer differentiated wound vessel members (WVMs) were detected.
Abstract: Summary
A novel method is described in which the two halves of an explanted internode of Lycopersicon esculentum, Datura stramonium or Nicandra physaloides may be grafted together successfully in sterile culture. An absolute requirement for the formation of a successful graft is the application of indole-3-acetic acid (IAA at 0.2 to 2.0 mg l−1) to the apical end of the internode. The addition of kinetin (0.2 mg l−1) to the culture medium stimulated graft development but gibberellic acid (GA3 at 0−5 mg l−1) was inhibitory. The development of the graft as measured by an increase in mechanical strength and the formation of vascular connections was similar to that observed in whole plant grafts; however, fewer differentiated wound vessel members (WVMs) were detected. This technique should provide a powerful tool for the further study of graft development in compatible and incompatible combinations.
TL;DR: It is proposed that the mechanism which controls and determines the early stages of fiber differentiation is based on an interaction of three major hormonal signals: indoleacetic acid plus gibberellic acid from the leaves with zeatin from the root apices.
Abstract: The differentiation of secondary xylem fibers was studied in cultured hypocotyl segments of Helianthus annuus L. It is shown that cytokinin is both a limiting and controlling factor in the early stages of fiber differentiation. In the absence of kinetin or zeatin, there was no fiber differentiation. However, cytokinin could induce fiber differentiation only in the presence of indoleacetic and gibberellic acids. First fibers were observed in the tissue after 12 days in culture, and their number increased linearly during the following 2 weeks. At low cytokinin levels, there was a positive correlation between cytokinin concentration in the medium and the number of fibers formed in the explants. A similar correlation was also found at low gibberellic acid concentrations. At high concentration, zeatin was more effective than kinetin. It seems that later stages of fiber differentiation can occur in the absence of cytokinin. It is proposed that the mechanism which controls and determines the early stages of fiber differentiation is based on an interaction of three major hormonal signals: indoleacetic acid plus gibberellic acid from the leaves with zeatin from the root apices.
TL;DR: Aleurone layers from immature developing wheat grains (Triticum aestivum L. cvs. Sappo) can be made to produce α-amylase in response to gibberellic acid by subjecting the grains to a period of enforced dehydration prior to introduction to the hormone.
Abstract: Aleurone layers from immature developing wheat grains (Triticum aestivum L. cvs. Sappo. and Champlein), though normally insensitive, can be made to produce α-amylase in response to gibberellic acid by subjecting the grains to a period of enforced dehydration prior to introduction to the hormone. The change in sensitivity appears to depend upon the water content of the tissue, water levels of below approximately 25% being critical for the effect. Grain detachment or duration of drying apparently do not qualitatively influence the development of sensitivity to gibberellic acid. Enhanced sensitivity resulting from drying is not caused by changes in gibberellic acid uptake. A possible mechanism for the change in sensitivity of aleurone cells might be through structural alterations in cell membranes.
TL;DR: The application of Amo 1618 retards the production of isocitrate lyase activity but also retards protein synthesis in general, suggesting that endogenous gibberellins also act non-specifically in the regulation of protein synthesis during castor bean germination.
Abstract: Gibberellic acid (GA3) stimulates isocitrate lyase activity of the endosperm during germination of castor bean seeds. Isocitrate lyase from castor bean was purified and an antibody to it was prepared from rabbit serum. This antibody was used to measure the amounts of isocitrate lyase-mRNA using an in vitro translation system. No specific stimulation of isocitrate lyase-mRNA by application of GA3 was detected. The stimulation of isocitrate lyase activity by exogenous GA3 may be accounted for by the action of the growth substance in advancing the overall production of rRNA and mRNA which accelerates the rate of total protein synthesis during germination. The application of Amo 1618 retards the production of isocitrate lyase activity but also retards protein synthesis in general. This suggests that endogenous gibberellins also act non-specifically in the regulation of protein synthesis during castor bean germination.
TL;DR: The regenerated plants were generally shorter and less vigorous than the original donor material, but the majority of those examined had the expected euploid chromosome number indicating that their altered morphology had a physiological rather than a genetic basis.
TL;DR: In this article, the effects of different osmotic stresses (from 0 to -8× 105 Pa) obtained with NaC or polyethylene glycol 6000 solutions on the germination of flax, sesame and onion seeds were investigated.
Abstract: The effects of different osmotic stresses (from 0 to –8× 105 Pa) obtained with NaC or polyethylene glycol 6000 solutions on the germination of flax, sesame and onion seeds were investigated. The effect of presoaking with gibberellic acid (GA3) on the germination of the above mentioned seeds was also studied.
TL;DR: It is suggested that salicylhydroxamic acid-sensitive process(es), presumably alternative respiration, is necessary for the stimulation of germination in the presence of azide, but not in the germination of genetically nondormant, gibberellic acid-treated dormant, or afterripened seeds.
Abstract: The dormancy breaking effect of sodium azide was studied in seeds of several genetically pure lines of Avena fatua L. isolated from field populations. Sodium azide (0.8 and 1 mM) induced germination in several dormant lines (characterized by long term dormancy) after two weeks of treatment. By about five weeks, germination was nearly complete in azide treated seeds as compared to little or no germination in controls. (2-chloroethyl) trimethylammonium chloride (an inhibitor of gibberellin biosynthesis) completely inhibited the azide effect suggesting that stimulation of germination by azide requires gibberellin biosynthesis. Azide was very effective in breaking dormancy in lines AN-51, AN-86, AN-127 and AN-265, but failed to induce germination in Montana 73. In this line there was a synergism between azide and gibberellic acid in promotion of germination. Thus, at least two metabolic blocks are involved in the stimulation of germination in this line. Salicylhydroxamic acid (an inhibitor of alternative respiration) at 3 mM completely inhibited the germination induced by 1 mM azide. At this concentration, salicylhydroxamic acid did not inhibit germination in 1) genetically nondormant seeds (line SH-430), 2) afterripened seeds of a dormant line (AN-51), and 3) gibberellic acid-treated dormant seeds. These findings suggest that salicylhydroxamic acid-sensitive process(es), presumably alternative respiration, is necessary for the stimulation of germination in the presence of azide, but not in the germination of genetically nondormant, gibberellic acid-treated dormant, or afterripened seeds.
TL;DR: It is proposed that coumarin may represent in part the unknown inhibitor responsible for tuber initiation with reference to the inhibitor/gibberellic acid ratio theory of tuberization.
Abstract: Coumarin readily stimulates tuberization of cultured axillary shoots obtained from etiolated potato sprouts. Adequate concentrations of coumarin must be continuously present in the medium to effect tuber initiation. High nitrogen, gibberellic acid, abscisic acid, indole acetic acid, or naphthalene acetic acid reduced or inhibited coumarin-induced tuberization. Gibberellic acid and high concentrations of nitrogen in medium inhibited the uptake of coumarin-3-14C by the. axillary shoot. Based on the data of physiological activities by coumarin in other plant species and our data on tuberization, we propose that coumarin may represent in part the unknown inhibitor responsible for tuber initiation with reference to the inhibitor/gibberellic acid ratio theory of tuberization.
TL;DR: It was observed that the plastids which were isolated from tissues, and incubated in a cofactor-fortified medium, under a repetitive light-dark regime were capable of synthesizing chlorophyll(ide) a from exogenous δ-aminolevulinic acid at a rate about twice as high as the highest rates observable in greening tissues in vivo.
TL;DR: There is a close relationship between callus, plantlet regeneration and added growth regulator in rice cultured on a modified MS medium supplemented with 2,4-D, naphthyleneacetic acid, and indole-3-acetic Acid.
TL;DR: Findings indicate that synthesis of polyuronides, xyloglucans and cellulose, which occurs during extension growth of the apical region of the epicotyl, is regulated chiefly by auxin whereas synthesis of xylans and Cellulose during cell maturation in the basal area of the Epicotyl is regulated by GA.
Abstract: The effects of auxin and gibberellic acid on cell wall composition in various regions of epicotyls of azuki bean (Vigna angularis Ohwi and Ohashi cv. Takara) were investigated with the following results. (1) Young segments excised from apical regions of the epicotyl elongated in response to added 10−4M indole-3-acetic acid (IAA). When the segments were supplied with 50 mM sucrose, the IAA-induced segment growth was accompanied by enhanced overall synthesis of cell wall polysaccharides, such as xyloglucans, polyuronides and cellulose. This IAA effect on the cell wall synthesis is a consequence of extension growth induced by IAA. Gibberellic acid (GA) at 10−4M synergistically enhanced the IAA-induced cell wall synthesis as well as IAA-induced extension growth, although GA by itself neither stimulated the cell wall synthesis nor extension growth. In the absence of sucrose, cell wall synthesis was not induced by IAA or GA. (2) In mature segments excised from basal regions of the epicotyl, no extension growth was induced by IAA or GA. GA enhanced the synthesis of xylans and cellulose when the segments were supplied with 50 mM sucrose. IAA had no effect on the cell wall synthesis. These findings indicate that synthesis of polyuronides, xyloglucans and cellulose, which occurs during extension growth of the apical region of the epicotyl, is regulated chiefly by auxin whereas synthesis of xylans and cellulose during cell maturation in the basal region of the epicotyl is regulated by GA.
TL;DR: Cordycepin and actinomycin-D counteracted induction of “floating” leaves by ABA, which suggests that new RNA synthesis is required for this ABA effect.
01 Jan 1982
TL;DR: The results suggest that the study of this unique juice vesicle system may contribute to a better understanding of fruit development.
Abstract: Actively growing juice-vesicle explants, established from small lemon ( Citrus limon L. Burm. f. var. `Eureka9) fruits, were cultured in vitro on defined media. The juice vesicles continued to enlarge in culture for several months, without callus proliferation, and their initial growth was promoted by indoleacetic acid, gibberellic acid, and N 6 -benzyladenine. The metabolic competence of the explants, and its relevance to whole fruit development, was further investigated. Juice vesicles continued to accumulate protein on all media, for at least 16 days, but sugars did not change much during culture. Acid invertase increased dramatically during the first days of culture, and its specific activity was markedly promoted by indoleacetic acid, and to a lesser degree by gibberellic acid. Total peroxidase of juice vesicles increased progressively up to the 11th day of culture, and its specific activity was promoted by all three hormones, especially by N 6 -benzyladenine. Explant growth was accompanied by appearance of several cathodic and anodic isoperoxidases. The results suggest that the study of this unique juice vesicle system may contribute to a better understanding of fruit development.
TL;DR: Two aspects of the normal pattern of tiller bud development were mimicked by GA3 application: intensification of the inhibition of bud outgrowth before anthesis and acceleration of buds outgrowth occurring after anthesis.
Abstract: The hormonal control of apical dominance (inhibition of lateral bud formation and development) in sorghum [Sorghum bicolor (L.) Moench] was studied by applying plant growth regulators to two cultivars—SM100 (weak apical dominance) and BT×378 (strong apical dominance). In the field, SM100 produced an average of 1 tiller per 2 plants before anthesis and BT×378 produced none. Following anthesis, apical dominance diminished in both cultivars. Spray applications of 0.2 mM gibberellic acid (GA3) during the initial 7 weeks of seedling growth completely inhibited bud outgrowth before anthesis in SM100. Bud outgrowth increased rapidly in both cultivars after termination of GA3 applications. This rapid increase in bud outgrowth was similar to the normal release from apical dominance ocurrlng in untreated plants following anthesis except that it was earlier, occurred at a more rapid rate, and a larger final number of buds was released. Thus, two aspects of the normal pattern of tiller bud development were mimicked by GA3 application: i) intensification of the inhibition of bud outgrowth before anthesis and ii) acceleration of bud outgrowth occurring after anthesis. In plants grown hydroponically in the greenhouse, GA3 again inhibited bud outgrowth in SM100 plants during the vegetative period. A role for gibberellin(s) in sorghum apical dominance is suggested because bud outgrowth was promoted in BT×378 plants by a gibberellin synthesis inhibitor, ancymidol. Evidence for the participation of auxins and cytokinins in sorghum apical dominance was also obtained. The auxin naphthaleneacetic acid inhibited bud outgrowth in SM100. In BT×378 the auxin transport inhibitor naphthylphthalamic acid and the cytokinin benzyladenine caused bud outgrowth which resembled that obtained by apical bud removal.
TL;DR: The development of xylanase activity by isolated barley aleurone layers exposed to gibberellic acid was enhanced by Ethylene, whereas the rate of glucanase synthesis was unaffected by ethylene, suggesting that elevated xylan enzyme activity expressed in ethylene-treated tissue may be responsible for enhanced release of amylase in response to ethylene.
Abstract: The development of xylanase activity by isolated barley ( Hordeum vulgare cv. Himalaya) aleurone layers exposed to gibberellic acid was enhanced by ethylene, whereas the rate of glucanase synthesis was unaffected by ethylene. The elevated xylanase activity expressed in ethylene-treated tissue may be responsible for enhanced release of amylase in response to ethylene. The redistribution of ionic species in response to gibberellic acid and ethylene was explored. The release of calcium was much more sensitive to ethylene than the release of any of the other ions investigated (potassium, magnesium, and phosphate). Ethylene induced a 101% increase in the release of calcium from gibberellic acid-treated aleurone layers. The possible relevance of this observation to the ethylene-enhanced release of amylase is discussed.
TL;DR: A single GA 3 -spray at petal-fall to the entire tree enhanced initial set in the ‘Navelate’ sweet orange, but this effect was transient and in most cases final yield was not increased.