Showing papers on "Gibberellic acid published in 1971"
TL;DR: The treated cotyledons of cucumber plants grown in the dark for 7 days were treated with various concentrations of cytokinins for 14 h and then moved into light and had up to 450% more chlorophyll than the water controls.
Abstract: Cotyledons of cucumber plants grown in the dark for 7 days were treated with various concentrations of cytokinins for 14 h and then moved into light. After 3 h the treated cotyledons had up to 450% more chlorophyll than the water controls. This suggests that cytokinins have an important role in the formation of chlorophyll. The increase in chlorophyll level was proportional to cytokinin concentration and was apparent at concentrations as low as 0.001 mg/l. Sensitivity to cytokinins depended on the age of the cotyledons and the time of exposure to light. Gibberellic acid, indoleacetic acid, adenine and sucrose did not cause a similar increase in chlorophyll levels. This effect of cytokinins on chlorophyll formation is valuable as a simple, rapid bioassay for cytokinins.
145 citations
TL;DR: Isolated epidermal strips of Commelina communis L. showed progressively smaller stomatal openings when incubated in abscisic acid solutions ranging in concentration from 10-8 to 10-4 M.
Abstract: Isolated epidermal strips of Commelina communis L. showed progressively smaller stomatal openings when incubated in abscisic acid solutions ranging in concentration from 10-8 to 10-4 M. The effects were reproducible and did not appear to be affected by the presence of auxin, gibberellic acid or kinetin. This specificity suggests that this method may prove valuable as a quick, sensitive bioassay for abscisic acid and other related compounds which might be used as antitranspirants on field crops. The fungal toxin fusicoccin, previously reported to cause increased stomatal opening on intact leaves, partially reversed the closure induced by abscisic acid.
86 citations
TL;DR: The rate of synthesis of the endoplasmic reticulum in barley aleurone cells after treatment with gibberellic acid was determined by measurement of [(14)C]-choline incorporation into acid-insoluble material in a semipurified fraction containing the endplasmic Reticulum.
Abstract: The rate of synthesis of the endoplasmic reticulum in barley aleurone cells after treatment with gibberellic acid was determined by measurement of [14C]-choline incorporation into acid-insoluble material in a semipurified fraction containing the endoplasmic reticulum. 94% of the 14C incorporated into this fraction is extractable by lipid solvents and only 9% is removed by procedures for nucleic acid extraction. Gibberellic acid increases the rate of synthesis of the endoplasmic reticulum 4- to 8-fold, starting about 4 hr after addition of the hormone (at about the same time as polysome formation). Abscisic acid inhibits this gibberellic acid-enhanced increase in the rate of synthesis of endoplasmic reticulum.
84 citations
TL;DR: It is proposed that hydrolysis products which accumulate in the starchy endosperm of germinating seeds function to regulate the production of hydrolytic enzymes by the aleurone layer.
Abstract: α-Amylase levels in intact seeds of barley (Hordeum vulgare L. cv. Himalaya) reach a maximum at 3 to 4 days of germination while gibberellin levels continue to increase beyond 6 days of germination. In contrast to its effect on half seeds, gibberellic acid does not increase the total amount of α-amylase produced in germinating seeds. The inability of gibberellic acid to stimulate α-amylase production is not related to its availability; rather, evidence suggests that a factor(s) in whole seeds prevents further enhancement of α-amylase formation and accumulation. Hydrolysis products accumulate in the subaleurone space of the endosperm of germinating seeds up to concentrations of 570 milliosmolar. Chromatography of these hydrolysis products indicate the presence of maltose and glucose. Calculations based on reducing sugar determinations show that glucose accounts for as much as 57% of the solutes present in the endosperm fluid. Both maltose and glucose in the range of 0.2 to 0.4 M effectively inhibit the production of α-amylase by isolated barley aleurone layers. This inhibition is quantitatively similar to that brought about by solutions of polyethylene glycol and mannitol. On the basis of these data we propose that hydrolysis products which accumulate in the starchy endosperm of germinating seeds function to regulate the production of hydrolytic enzymes by the aleurone layer.
80 citations
TL;DR: It is suggested that one of the first effects of flooding is to reduce GA levels and so inhibit stem elongation and at a later stage of waterlogging GA3 is less effective and other factors appear to inhibit shoot growth.
Abstract: Flooding of tomato roots results in decreased stem growth. We have shown that flooding will reduce levels of gibberellins (GA) in the roots, shoots, and bleeding sap of tomato plants. The adventitious roots that appear on the third day of waterlogging may be responsible for the production of GA that accumulate in the shoot after 3 to 4 days of flooding. The endogenous GA of tomato will stimulate stem growth of tomato plants. Initially, application of gibberellic acid (GA3) will stimulate the growth of flooded plants to a greater extent than that of non waterlogged plants. It is suggested that one of the first effects of flooding is to reduce GA levels and so inhibit stem elongation. At a later stage of waterlogging GA3 is less effective and other factors appear to inhibit shoot growth.
79 citations
TL;DR: In this paper, a metabolic disturbance was revealed by impaired seedling growth on germination of wheat irradiated with 60 Co gamma rays at 20-200 krad dose levels, and the relative permeability of 14 C-leucine in wheat was not changed due to radiation treatment.
74 citations
TL;DR: Abscisic acid inhibits stomatal opening in isolated abaxial epidermal strips of Vicia faba and appears to act directly on the guard cells, rather than by influencing water potentials throughout the leaf.
Abstract: Abscisic acid inhibits stomatal opening in isolated abaxial epidermal strips of Vicia faba. Kinetin, benzyladenine, and gibberellic acid, which can enhance stomatal apertures in intact leaves, are ...
72 citations
TL;DR: From a comparison of the effects of seven growth retardants and abscisic acid (ABA) on various growth systems, it was found that the gibberellin-regulated growth of lettuce hypocotyls was uniquely inhibited by the growth retardant, alpha-cyclopropyl-alpha-(4-methoxyphenyl)-5-pyrimidine methanol (EL-531).
Abstract: From a comparison of the effects of seven growth retardants and abscisic acid (ABA) on various growth systems, it was found that the gibberellin-regulated growth of lettuce hypocotyls was uniquely inhibited by the growth retardant, alpha-cyclopropyl-alpha-(4-methoxyphenyl)-5-pyrimidine methanol (EL-531). Auxin-regulated growth of coleoptile sections was inhibited by Phosfon and only slightly by EL-531 and Alar. Cytokinin-regulated growth of Xanthium cotyledons showed little or no inhibition by any of the retardants. ABA was inhibitory in all three types of tests. The distinctive effects of EL-531 against gibberellin-stimulated growth and the general ability of gibberellic acid to relieve EL-531 inhibition suggest that this retardant acts in part against the gibberellin-stimulated growth system, but at a locus which discriminates between growth and nongrowth functions of gibberellic acid. It shows little or no antagonism of gibberellin actions which do not involve growth: the barley endosperm test and the Rumex leaf senescence test.
59 citations
TL;DR: It is concluded that gibberellic acid functions primarily to enhance glucanase release rather than its formation, and does not markedly affect the total amount ofglucanase obtained from these cells when compared with water controls.
Abstract: A beta-1, 3-glucanase of barley (Hordeum vulgare) aleurone cells accumulates when half-seeds are imbibed on water, and accumulation continues when the aleurone layers are incubated in buffer solution. The release of the enzyme is a gibberellic acid-dependent process, however. Although gibberellic acid stimulates glucanase release, it does not markedly affect the total amount of glucanase obtained from these cells when compared with water controls. beta-1, 3-Glucanase release from aleurone cells is a function of gibberellic acid concentration and commences after a 4-hour lag period. Processes occurring during this lag period are also dependent upon gibberellic acid concentration. Removal of gibberellic acid from the incubation medium at the end of the lag period, however, does not affect subsequent release of glucanase. The release of glucanase from aleurone cells is an active process with a Q(10) greater than 3. Inhibitors of respiration and protein and RNA synthesis effectively inhibit the formation and release of glucanase. It is concluded that gibberellic acid functions primarily to enhance glucanase release rather than its formation.
50 citations
TL;DR: Abscisic acid reduced the senescence retarding effect of GA more than that of cytokinin or GA to which given amounts of ABA were added, and a high concentration of cytkinins nullified thesenescence enhancing effect of low concentrations of A BA.
Abstract: The interrelation between the effects of abscisic acid (ABA) and the effects of cytokinins and gibberellic acid in retarding leaf senescence was investigated. Leaf discs from plants of Taraxacum megallorrhizon, Rumex pulcber and Tropaeolum majus were floated on solutions of cytokinin or GA to which given amounts of ABA were added. After five days, chlorophyll was extracted and the amount estimated spectrophoto-metrically. The interrelation between the effects of abscisic acid and cytokinins differed from that between the effects of ABA and gibberellic acid. Abscisic acid reduced the senescence retarding effect of GA more than that of cytokinins. A high concentration of cytokinins nullified the senescence enhancing effect of low concentrations of ABA. GA did not reverse the effects of ABA.
49 citations
TL;DR: It is proposed that the over-all effect of gibberellic acid on enzyme development is to provide more substrate (particularly glucose) for general cell metabolism and wall synthesis within elongating internodes.
TL;DR: The most sensitive assay reported in this paper, for the determination of indole-3-acetic acid and gibberellic acid, is the inhibition of inactivation of modifed bacteriphage, which was inhibiteid by the free hormone.
Abstract: Specific antibodies to two plant hormones, namely indole-3-acetic acid and gibberellic acid, were producd in rabbits which were immunized with conjugates of either hormone to hemolocyanin. The Specific antiboddies obtained were used for assaying the hormones by several immunological assays. The most sensitive assay reported in this paper, for the determination of indole-3-acetic acid and gibberellic acid, is the inhibition of inactivation of modifed bacteriphage. For this assay conjugates of either hormone with bacteriophage T4 were prepared and characterized. Such chemically modified bacteriophahges were completely inactivated by the respective specific antiserum and this inactivation was inhibiteid by the free hormone.
The specificity of the antibodies produced was tested by a series of cross-reactions. There was no immunological cross-reaction between the two hormones which can, therefore, be determined independently. However, antibodies to indole-3-acetic acid cross-reacted with chemically related compounds such as indoelcetyl-ɛ-amino carporic acid, tryptamine and truyptophan. The immunological specificity of different gibberellins tested was found to bne in good correlation with the biological specificity.
TL;DR: Dormant and non-dormant embryos have respiratory quotients near unity supporting the hypothesis that starch degradation occurs before germination, and release from dormancy is associated with a shift in metabolism from the glycolytic pathway to the pentose phosphate pathway.
Abstract: The rates of oxygen consumption of dormant and non-dormant excised embryos of Avena fatua L. before germination are similar. Gibberellic acid (GA) treatment stimulates germination of dormant embryos without affecting oxygen consumption. Thus dormancy is not the result of restricted oxygen uptake. The fat content of dormant and non-dormant caryopses remains constant during germination. Dormant and non-dormant embryos have respiratory quotients near unity supporting the hypothesis that starch degradation occurs before germination. 6-Phosphogluconate dehydrogenase, a key enzyme of the pentose phosphate pathway, is present in dormant and non-dormant dry embryos but the pre-germination C6/C1 ratio of non-dormant embryos is markedly lower than that of dormant embryos, indicating a greater participation of the pentose phosphate pathway in the respiratory metabolism of non-dormant embryos. Release from dormancy is associated with a shift in metabolism from the glycolytic pathway to the pentose phosphate pathway. ...
TL;DR: Benzyladenine applied directly to inhibited buds initiates growth in 16-day-old intact plants and this growth is further enhanced when GA is applied 48 h after BA trea...
Abstract: Growth of cotyledonary buds in soybean plants is controlled by an interaction between hormones and is dependent on age of the plant and meristematic activity of the buds. Indoleacetic acid (IAA) applied to the cut surface of decapitated 7-day-old plants does not inhibit the growth of buds which are actively undergoing mitosis. Growth is inhibited, however, when IAA is applied in combination with benzyl-adenine(BA) and this inhibitory effect is minimized by gibberellic acid (GA). In 16-day-old plants where mitosis in the buds has ceased IAA alone inhibits bud growth. In both 7- and 16-day-old decapitated plants, application of GA, alone or in combination with BA promotes growth of the buds. Inhibited buds have two peroxidase isoenzymes with pronounced activity. The activity of one of these decreases when the buds are released from dominance. Benzyladenine applied directly to inhibited buds initiates growth in 16-day-old intact plants and this growth is further enhanced when GA is applied 48 h after BA trea...
TL;DR: In addition to releasing hydrolytic enzymes, isolated barley aleurone layers release large amounts of reserve protein, which is only partially dependent on gibberellic acid (GA3).
Abstract: In addition to releasing hydrolytic enzymes, isolated barley aleurone layers release large amounts of reserve protein. This protein release is only partially dependent on gibberellic acid (GA3). The addition of GA3 causes a shift in molecular weight distribution to lower molecular weight, and a change in the N-terminal profile of the released protein. Inhibition of proteolysis reduces protein release. When proteolysis is inhibited, amylase production can be made partially dependent on added amino acids.
TL;DR: Eleven growth substances were tested for their bud producing capacity in Funaria hygrometrica and the cytokinins: benzylaminopurine, kinetin and mercaptopurine showed a quantitative relationship while methylaminipurine did not and there existed a linear relationship between reduction in buds and abscisic acid added.
Abstract: Eleven growth substances were tested for their bud producing capacity in Funaria hygrometrica. IAA and gibberellic acid showed no response, neither did inositol, abscisic acid and adenine. The cytokinins: benzylaminopurine, kinetin and mercaptopurine showed a quantitative relationship while methylaminopurine did not. When different amounts of abscisic acid were added together with 10 μg kinetin (which gave maximal production of buds), there existed a linear relationship between reduction in buds and abscisic acid added. Results are obtained in two weeks and it is therefore a fairly quick method for assaying certain cytokinin and also abscisic acid.
TL;DR: In this paper, the effect of various plant growth regulators on the conformation of treated pea seedlings was evaluated using the thermal denaturation transition profiles and the melting temperature (Tm), and it was shown that IBA and IPA caused an upward shift of the Tm, but at higher concentrations both compounds caused a downward shift.
TL;DR: Particulate fractions isolated from the growing region of the epicotyl of Pisum sativum L. var Alaska are capable of transferring glucose from uridine or guanosine diphosphate glucose-14C to buffer-insoluble products which are partly alkali-soluble and partly alkaline- insoluble.
Abstract: Particulate fractions isolated from the growing region of the epicotyl of Pisum sativum L. var Alaska are capable of transferring glucose from uridine or guanosine diphosphate glucose-14C to buffer-insoluble products which are partly alkali-soluble and partly alkali-insoluble. Cellobiose activates the reaction; carboxymethylcellulose and cellodextrins act as competitive acceptor molecules.When the epicotyl is decapitated, glucan synthetase activity disappears from particulate fractions of the growing region within 3 days unless the hormone indoleacetic acid (IAA) is added to the tissue, in which event activity is retained. Other growth regulators (gibberellic acid, benzyladenine) have no such effect. Loss of activity is not due to a change in solubility of enzyme or product or to the absence of substrate, activator, or acceptor molecules, nor is it accompanied by comparable losses in total protein or cellulase activity from the particulate fraction. It is concluded that IAA is needed for the formation and...
TL;DR: Some amino acids, bases of nucleic acids, and gibberellic acid partially alleviated the alantolactone-induced inhibition of the seed germination.
TL;DR: It is postulated, however, that cyclic AMP does not substitute entirely for the growth factor by probably acts by potentiating the responses that are initiated by the hormone.
TL;DR: Arditti and Knauft as discussed by the authors showed that combining ABA and NAA can induce post-pollination phenomena in orchid flowers, but lower anthocyanin content than treatments with ABA only.
Abstract: New Phytol. ( 1971) 70, 333- 341. POST-POLLINATION PHENOMENA IN ORCHID FLOWERS II. INDUCTION OF SYMPTOMS BY ABSCISIC ACID AND ITS INTERACTIONS WITH AUXIN, GIBBERELLIC ACID AND KINETIN* BY JOSEPH ARDITTI, BRIGITTA FLICK AND DAVID JEFFREY Department of Devewpmental and Cell Biowgy, University of California, Irvine, California 92664, and Division of Natural Sciences, Universi.ty of California, Santa Cruz, California 95060, U.S.A. (Received 15 June 1970) SUMMARY Applications of ABA to Cymbidium flowers induce some, but not all, po.st-pollination symptoms. Anthocyanin levels in sepals, petals, columns and labella are raised; flowers wilt; dorsal sepals become hooded; caJli develop colouration while losing turgidity; columns do not swell, lose very little curvature; and stigmas do not close. Combinations of ABA and NAA induce all post-pollination phenomena, but lower anthocyanin content than treatments with ABA only. ABA plus GA 3 have effects which are similar to those of ABA alone, except that anthocyanin levels are reduced. The same is essentially true of ABA-kinetin mixtures but intensities of the effects are different and with some concentration ratios, stigmatic closure also occurs. The effects of ABA and its interactions with GA 3 , kinetin or NAA are explained in terms of the roles these hormones may play in synthesis of nucleic acids and enzymes. INTRODUCTION Orchid flowers, including those of Cymbidium, undergo remarkable changes following pollination. The perianth wilts or some of its segments may become green and leaf-like. Stigmas close while columns swell and lose their curvature. Both columns and labella produce 'anthocyanins whereas the usually yellow calli (in Cymbidium) turn red or orange and lose their turgidity. Within the ovary, ovule development is initiated, con- tinues at a rate commensurate with pollen tube growth and climaxes in fertilization 26-45 days later (Wirth and Withner, 1959). Applications of auxins to the stigma initiate most of these changes, although ovule development is aborted (for a short review see Arditti and Knauft, 1969). This is of particular interest since either pollination or auxin initiate events of such diversity that they would seem to be normally unrelated. Wilting of the perianth is an aspect of senescence; closing of the stigma and swelling of the column represent growth due to cell enlargement; greening and persistence of the column are modifications in function; changes in segments of the perianth involve organogenesis; ovule development is morphogenesis; synthesis of anthocyanins results from newly expressed biochemical capabilities; and the reduced turgidity of the calli implies changes in water relations. * See Arditti and Knauft (1969) for part I. D
TL;DR: Activity of endogenous gibberellin-like substances was not substantially different between flowering and non-flowering field-grown Geneva plants when sampled in long day lengths of August and the implications of these findings on hormonal balance in the strawberry are discussed.
TL;DR: Treatment of an elongating internode with the hormones resulted in an increase in inhibition of bud growth by IAA in the presence of GA3, and all possible combinations of IAA and GA3 within the concentration range 101 to 105 μg/g lanolin were antagonistic.
Abstract: Indole-3-acetic acid (IAA) applied to the fully elongated second internode of decapitated Phaseolus multiflorus plants always inhibited axillary bud elongation at concentrations down to 100 μg/g lanolin, whereas gibberellic acid (GA3) enhanced bud elongation at concentrations down to 1000 μg/g lanolin. Lower concentrations than these of either IAA or GA3 were without significant effect. All possible combinations of IAA and GA3 within the concentration range 101 to 105 μg/g lanolin were antagonistic; IAA tending to inhibit, and GA3 promote, axillary bud elongation growth. Treatment of an elongating internode with the hormones resulted in an increase in inhibition of bud growth by IAA in the presence of GA3.
Journal Article•
TL;DR: Evidence is presented which indicates that only the monomer form exists in vivo in the pea epicotyl tissue and that the oxidized dimer is an artifact of extraction.
Abstract: Histones from the epicotyls of light-grown dwarf peas (Pisum sativum L. cv. Little Marvel) which had been treated with gibberellic acid were compared to histones from control dwarf peas by the method of polyacrylamide gel electrophoresis. The histone complements were found to be unaltered in the electrophoretic mobility and relative quantity of the individual fractions. The ratio of histone to DNA was also unaffected by treatment with gibberellic acid. The investigation confirmed earlier reports that over 95% of the histone of peas is contained in seven molecular species and that one of these can exist both as an oxidized disulfide dimer and as a reduced monomer. Evidence is presented which indicates that only the monomer form exists in vivo in the pea epicotyl tissue and that the oxidized dimer is an artifact of extraction. The implications of the data concerning the mechanism of action of gibberellic acid are discussed.
TL;DR: Chilling and treatment with GA3 break dormancy by increasing the expansive force of the embryo; thus, chilled or GA3-treated embryos exert enough expansive force to break through the seed coat, whereas nontreated embryos do not.
Abstract: Dormancy in intact seeds of Ruellia humilis is broken by chilling or by treatment with gibberellic acid (GA3). Embryos are nondormant and will grow when the seed coat is removed completely. Embryos from chilled or GA3-treated seeds have more growth potential than embryos from nontreated seeds. Dormancy is ascribed to the mechanical restriction of the embryo by the seed coat. Chilling and treatment with GA3 break dormancy by increasing the expansive force of the embryo; thus, chilled or GA3-treated embryos exert enough expansive force to break through the seed coat, whereas nontreated embryos do not.