Showing papers by "Abraham H. Halevy published in 1972"
TL;DR: It was suggested that ethylene affects senescence in rose petals by inducing an increase in abscisic acid activity, which in turn may control ethylene evolution, via a feedback mechanism.
Abstract: The role of abscisic acid and ethylene in the senescence of rose petals cv. Golden-Wave was examined. A rise in ethylene evolution, followed by an increase in the level of abscisic acid was observed. The presence of abscisic acid in rose petals was established, using different chromatography systems, several bioassays, and immunoassay. External application of ethylene accelerated senescence and induced a rise in endogenous abscisic acid-like activity. Application of abscisic acid promoted senescence, but suppressed ethylene production. The data suggest that the participation of these two hormones in the control of senescence is via the same pathway. The possibility of interrelationship between abscisic acid and ethylene was tested and experimental evidence in favor of this hypothesis is presented. It was suggested that ethylene affects senescence in rose petals by inducing an increase in abscisic acid activity, which in turn may control ethylene evolution, via a feedback mechanism.
116 citations
TL;DR: The data suggest that ethylene participates in the endogenous regulation of sex expression by promoting femaleness.
Abstract: Ethylene evolved from monoecious and gynoecious cucumber (Cucumis sativus) plants grown under short and long day conditions was determined. More ethylene was evolved from floral buds and apices bearing buds than from whole seedlings of comparable weight. More ethylene also was evolved from apices of the gynoecious than from those of the monoecious type. Furthermore, quantities evolved from female buds were greater than from male ones and plants grown under short day conditions which promote femaleness evolved more ethylene than those grown under long day conditions. The data suggest that ethylene participates in the endogenous regulation of sex expression by promoting femaleness.
111 citations
TL;DR: The endogenous levels of auxin, gibberellin, and inhibitors were followed in monoecious and gynoecious cucumber plants, and in plants treated with the ethylene-releasing compound Ethephon, and higher auxin inhibitor and lower gibb Berellin levels were associated with female tendency.
Abstract: The endogenous levels of auxin, gibberellin, and inhibitors were followed in monoecious and gynoecious cucumber (Cucumis sativus L.) plants, and in plants treated with the ethylene-releasing compound Ethephon (2-chloroethyl phosphonic acid). Higher auxin inhibitor and lower gibberellin levels were associated with female tendency. The endogenous level of gibberellin and auxin decreased in Ethephon-treated plants. Application of Ethephon induced a rise in abscisic acid. Root application of abscisic acid promoted female tendency of gynoecious cucumbers grown under conditions which increase maleness. High CO(2) levels, which are known to antagonize ethylene, increased maleness of gynoecious cucumbers. The possibility of interrelationship between gibberellin, auxin, ethylene, and abscisic acid on sex expression are discussed.
65 citations
TL;DR: In this article, Abscisic acid (ABA), succinic acid-2,2-dimethylhydrazide (SADH), or 2 chlorethyl phosphonic acid (ethephon) treatments were used to promote the tuberization of Dahlia plants in long days.
Abstract: Treatments with abscisic acid (ABA), succinic acid-2,2-dimethylhydrazide (SADH), or 2 chlorethyl phosphonic acid (ethephon) promoted the tuberization of dahlia plants in long-days. This effect was smaller, however, than the effect short days have on tuberization. In contrast, gibberellic acid (GA) treatments inhibited tuberization. SADH and ethephon treatments of budless leaf-cuttings inhibited tuberization whereas ABA treatments slightly enhanced it. Evolution of endogenous ethylene reached a peak between the second and third week after the start of short-day treatments, and then decreased to the low level found in plants growing under long days. The peak in ethylene evolution occurred one week before the onset of tuberization.
26 citations
TL;DR: The level of dehydrogenase activity was determined in different parts of gladiolus corms and cormels during various stages of dormancy by a refined triphenyl tetrazolium chloride (TTC) method, in which tissue is considered to be active if the red formazan derivative is produced.
Abstract: SummaryThe level of dehydrogenase activity was determined in different parts of gladiolus corms and cormels during various stages of dormancy by a refined triphenyl tetrazolium chloride (TTC) method, in which tissue is considered to be active if the red formazan derivative is produced. A negative correlation between the depth of dormancy and the rate of TTC reduction was found. In corms the terminal bud was found suitable for determining the state of dormancy, but in cormels samples of the whole structure were taken.
4 citations
TL;DR: In this paper, the authors used various combinations of ethephon and the fungicides methylethyl mercury benzoate, benomyl, thiobendazole and methylmercury dicyandiamide either before or after storage at 10 °C and 30 °C for 6 weeks.
Abstract: SUMMARYGladiolus corms and cormels were treated with various combinations of ethephon and the fungicides methylethyl mercury benzoate, benomyl, thiobendazole and methylmercury dicyandiamide either before or after storage at 10 °C and 30 °C for 6 weeks. The treated corms were examined for germination, splitting and rot symptoms caused by Fusarium oxysporum f. sp. gladioli.Ethephon increased corm splitting in all treatments; it also increased germination in corms stored at 30 °C, and it increased the proportion of corms showing typical Fusarium rot symptoms by stimulating the growth of latent internal Fusarium. The effectiveness of the fungicides tested against F. oxysporum f. sp. gladioli was enhanced by the addition of ethephon. Permeability of corms to methylethyl mercury benzoate was increased by ethephon, and it is concluded that ethephon improves the efficiency of this fungicide, and probably of other fungicides as well, by increasing their penetration into gladiolus corms.
4 citations
01 Jan 1972
TL;DR: Root application ofabscisic acid promoted femaletendency ofgynoecious cucumbers grown underconditions whichincrease maleness and highC02levels, which are known toantagonize ethylene, increased maleness ofgy noeciously cucumbers.
Abstract: Theendogenous levels ofauxin, gibberellin, andinhibitors werefollowed inmonoecious andgynoecious cucumber(Cucumissativus L.)plants, andinplants treated withtheethylene-releasing compoundEthephon (2-chloroethyl phosphonic acid). Higher auxininhibitor andlowergibberellin levels were associated withfemaletendency. Theendogenous level ofgibberellin andauxindecreased inEthephon-treated plants. ApplicationofEthephon induceda riseinabscisic acid.Root application ofabscisic acidpromoted femaletendency ofgynoecious cucumbers grownunderconditions whichincrease maleness. HighC02levels, whichareknowntoantagonize ethylene, increased maleness ofgynoecious cucumbers. Thepossibility ofinterrelationship betweengibbereilin, auxin, ethylene, and abscisic acidonsexexpression arediscussed.