Enhancement of polyribosome formation and RNA synthesis of gibberellic Acid in wounded potato tuber tissue

As part of a more detailed study on plant tumorigenesis, the action of gibberellic acid (GA₃) in wounded potato tuber tissues as a model system has been evaluated. GA₃ stimulates total RNA synthesis in wounded tissues, the optimal concentration being 0.1 micromolar. The responsiveness of the tissue toward the hormone develops with time after wounding. Whereas freshly wounded tissue does not respond at all to the hormone, it becomes competent after about 6 hours, the competence being maximal after 1 day of wound healing.     

Enhancement of somatic embryogenesis frequency by gibberellic acid in fennel

The effect of GA₃ on somatic embryogenesis from petiole fragments excised from micropropagated fennel plantlets was studied. Explants were maintained for 4 weeks on an induction medium containing, 2,4-d and kinetin and were then transferred to a medium devoid of these growth regulators to allow embryo development. The addition of autoclaved or filter-sterilized GA₃ to the induction medium or to the embryo development medium increased the number of embryogenic explants. No positive effect was observed when GA₃ was added to the micropropagation medium of the mother plantlets. Gibberellic acid also counteracted the inhibiting effect of continuous light on the number of embryogenic explants. Moreover, the embryogenic frequency of petiole explants from several genotypes previously considered as poorly reacting was highly enhanced by GA₃.Abbreviations BA 6-benzyladenine - 2,4-d 2,4-dichlorophenoxyacetic acid - GA₃ Gibberellic acid - IAA Indole-3-acetic acid - IBA Indole-3-butyric acid     

Enhancement by gibberellic acid and asymmetric distribution of lysophospholipase in germinating barley

Germination of whole barley seeds for 4 and 6 days followed by measurement of lysophospholipase (lysolecithin acyl hydrolase, LAH) in the embryo-containing and embryo-free halves revealed a gradient of activity between the two halves of the seed. Most of the activity appeared in the embryo-containing half. This gradient decreased slightly in the aleurone and dramatically in the starchy endosperm during the 2 day germination interval. Embryo-containing and embryo-free half seeds of surface sterilized barley were placed separately on sterile agar plates. After 4 and 6 days LAH was observed in both the aleurone and starchy endosperm of the embryo-containing halves. In the embryo-free halves, LAH appeared at low levels in the aleurone and was virtually absent in the starchy endosperm. The scutellum of germinating seeds contains LAH activity. Exposure of embryo-free half seeds to GA₃ for 24 hr showed enhancement of acidic and alkaline LAH activities in the aleurone fraction and in the GA₃-medium in which the half seeds were treated. The LAH activity of the starchy endosperm of these half seeds was little changed by GA₃ treatment. Exposure of isolated aleurones to GA₃ for 24 hr resulted in substantial enhancement of acidic and alkaline LAH activities in the bathing medium and in fractions prepared from the aleurone. The physiological significance of the influence of GA₃ on LAH activity during barley germination is discussed.     

Control of carbohydrase formation by gibberellic acid in barley endosperm

α-Amylase, limit dextrinase and α-glucosidase were induced by gibberellic acid in barley grain from which the embryos had been excised. The responses to different concentrations of gibberellic acid were similar for the three carbohydrases. However α-glucosidase activity increased before the other two enzymes, and a low level of α-glucosidase was found in ungerminated grain. Experiments with cycloheximide and density-labelling in deuterium oxide suggest that the observed increases in activity are the result of de novo protein synthesis. The induction of these enzymes was reduced by pre-incubation in actinomycin D.     

Floral induction by gibberellic acid in Impatiens balsamina,a qualitative short-day plant

Summary In the qualitative short-day plant Impatiens balsamina, gibberellic acid (GA₃) not only promoted the formation of floral buds in response to suboptimal photoinductive conditions and reduced the number of SD cycles that are required for their development into flowers, but also caused initiation of floral buds under non-inductive photoperiods. In plants treated with repeated applications of GA₃, the floral buds developed into flowers irrespective of whether the apex was left intact or was removed. In those that received a single application of GA₃ the floral buds developed into flowers only in decapitated plants.     

Nucleic acid contents and polyribosome formation in wheat embryos during germination and vernalization

The contents of RNA and DNA in wheat embryo, determined by theSTS method, were higher during cold treatment than the periodof germination. The ratios of sRNA and IRNA to DNA and thatof sRNA to total RNA for both periods were similar accordingto MAK column chromatography. The polyribosome contents werehigher during cold treatment than germination. However, monosomecontents were identical for both periods. During germination,the polyribosome content was the highest in embryos germinatedfor two days and continuously decreased thereafter. During coldtreatment, polyribosome content was maximum in embryos cold-treatedfor 10 days then and decreased slowly for 60 days. (Received August 12, 1977; )     

Floral induction by gibberellic acid in Zinnia elegans jacq. under non-inductive long days

Summary Flowering was induced in Zinnia elegans under non-inductive 24-h photoperiods by the application of gibberellic acid, although later than under inductive 8-h photoperiods. Gibberellic acid also enhanced extension growth and leaf differentiation under both photoperiods.     

Quantitative estimation of gibberellic acid by paper chromatography

Метод для количественного определения от gibberellic кислоты в процессе брожения средства массовой информации, с использованием бумаги по убыванию хроматографии в butylacetate воды описана. Образца корректируется, чтобы рН 2.5-3.0, добыто с н-бутанола, и 0,05 мл. органического слоя пятнами на Хроматографический бумагу. После equilibration от Атмосфера в банке, chromatogram Разработана в butylacetate насыщенных с водой, за 7 часов, и растворитель разрешено покинуть капельного нижней части листа. Обнаружение осуществляется путем опрыскивания с 3% раствор серной кислоты в метаноле и после сушки бумаги, пятна с синий u.v. флуоресценции наблюдается. Определенный артикль площадь пятна оценивается с помощью калибровочной кривой, заговор с ценностей, стандартов, соответствующих 20, 60 и 120 μ g. gibberellic кислоты. Погрешность оценки составляет ± 10-15% когда оценки выполняются тщательно. Низкий предел чувствительности 5 μg.     

Determination of femtomol quantities of gibberellic acid by radioimmunoassay

A highly sensitive and specific radioimmunoassay which allows the detection of as little as 5 fmol (2 pg) of gibberellic acid (GA₃) in crude plant extracts is described. Antisera of high affinity and titer were obtained by immunizing rabbits with a conjugate of carboxyl-coupled GA₃ and bovine serum albumin. [¹²⁵I]Gibberellic acid-[N-(p-hydroxybenzyl) putrescine]amide of high specific activity, used as the immunotracer, is readily displaced by gibberellic acid methyl ester but not by free gibberellic acid. Thus, methylation of extracts prior to analysis is required. The assay is very specific; besides GA₃, only the closely related GA₇ is highly immunoreactive. Various gibberellins, related compounds, as well as other classes of plant hormones do not interfere with the assay. Levels of immunoreactive gibberellins (GA₃, GA₇) in actively growing tissues, among them cell suspension cultures of 33 different species, were determined.Abbreviations ABA abscisic acid - GC-MS gas chromatography-mass spectroscopy - TLC thin-layer chromatography - GA gibberellin Part 17 in the Series: Use of Immunoassay in Plant Science     

Hormonal control of polyribosome formation in barley aleurone layers

The addition of abscisic acid to barley (Hordeum vulgare L. cv. Himalaya) aleurone layers at the same time as gibberellic acid completely prevents the gibberellin-induced increases in the percentage of polysomes, the formation of polyribosomes, and the synthesis of α-amylase, even when the molar concentration of gibberellic acid is four times greater than the concentration of abscisic acid. The addition of abscisic acid to aleurone cells producing α-amylase (midcourse addition) inhibits the further synthesis of α-amylase and decreases the percentage of polysomes but does not change the number of ribosomes per cell.     

Effect of gibberellic acid and salicylic acid on the activity and electrophoretic pattern of IAA-oxidase during floral induction inImpatiens balsamina

IAA-oxidase activity increased in the stem as well as in the leaves of plants treated with GA₃, SA and GA₃ + SA during the early stages under inductive and non-inductive photoperiods, the activity being the highest in GA₃ + SA-treated plants. An isoenzyme of IAA-oxidase with Rm 0.15 developed in the stem as well as in the leaves subsequent to 1 or 2 inductive treatments. As this band persisted till the end of the experiment, it may be associated with the initiation as well as development of floral buds. Another band (Rm 0.30) appears to be associated with the phenol (SA) as it developed in the stem as well as in the leaves of SA- and GA₃ + SA-treated plants under both photoperiods. A band with Rm 0.60 developed in the leaves but not in the stem of GA₃-, SA- and GA₃ + SA-treated plants under both photoperiods.     

Stimulation of germination ofimmature bean embryos by gibberellic acid

Summary Bean embryos excised from seeds 15–18 days after anthesis germinate, but do not develop into seedlings unless gibberellic acid is included in the culture medium.     

Laboratory fermentation of gibberellic acid

При изучении условий ферментации пригодные для gibberellic кислоты 6 коллекция штаммов Fusarium moniliforme и Gibberella fujikuroi были использованы Используется штамм имеет решающее значение за урожайностью и состав эффективный метаболит. После проверки методов, описанных в литературе нового средства массовой информации для gibberellic кислоты был разработан, которые будут использоваться для брожения на шейкер и в лабораторных fermentors, средних содержащие сахарозы и кукуруза крутых спиртными напитками. С помощью взаимных шейкер, максимум производство gibberellic кислота была получена после 14 дней, используя три этапа propagations по истечении 12 дней после брожения Максимальные значения, достигнутые в ходе ферментации из наиболее подходящие штаммы составил 150-240 μ g. / мл. Максимум производства в лаборатории fermentors достигло 212 μ g. / мл Метаболит изолированных после брожения в рамках описанных условиях определены в качестве gibberellic кислота     

Regulation of swelling of etiolated-wheat-leaf protoplasts by phytochrome and gibberellic acid

The effect of light on the size of intact protoplasts isolated from the primary leaves of etiolated Triticum aestivum was studied. A 2-min red-light irradiation in the presence of 1 mM KCl was sufficient to cause a swelling of protoplasts compared with those maintained in darkness. The effect was photoreversible by far-red light over two light cycles, indicating the involvement of phytochrome. At 4°C, escape from reversibility occurred between 2 and 5 min after the exposure to red light. In exposure-response experiments, 20 s red light at 27 μmol m^-2s^-1 was sufficient to saturate the response. Exogenous gibberellic acid added in darkness in the presence of KCl also induced protoplast swelling. Gibberellins may act as an intermediate in the phytochrome-induced swelling of protoplasts.