Department of Plant Sciences, Texas A&M University, College Station, Texas 77843.
Plant Physiol. 1975 Feb;55(2):308-11. doi: 10.1104/pp.55.2.308.
Gibberellic acid (GA(3)) promoted leaf abscission from cotton (Gossypium hirsutum L.) plants exposed to ethylene. With mature plants, only the rate of abscission was increased, but when vegetative plants were exposed to ethylene for 4 days or less, the amount of abscission was increased markedly. Promotion of abscission occurred at near saturating ethylene levels (10 mul/liter), over a wide range of GA(3) concentrations, and with both GA(3) and GA(7).GA(3) promoted abscission when Ethephon was substituted for ethylene and at locations not receiving direct application of GA(3). The magnitude of the abscission promotion by GA(3) was greater than that resulting from auxin transport inhibitors or abscisic acid. The characteristic inhibition of abscission by auxin occurred. The responses suggest that endogenous gibberellins may be involved in rapid abscission of apical leaves from vegetative cotton plants exposed to ethylene. Application of GA(3) may offer an additional option in agricultural manipulation of abscission and dehiscence.
赤霉素（GA（3））促进了暴露于乙烯的棉花（Gossypium hirsutum L.）植株的叶片脱落。对于成熟植株，仅增加了脱落的速度，但当营养植物暴露于乙烯 4 天或更短时，脱落的数量明显增加。在接近饱和的乙烯水平（10 微升/升）下，在 GA（3）浓度的广泛范围内，以及 GA（3）和 GA（7）的作用下，促进了脱落的发生。当用乙烯利代替乙烯和在未直接施用 GA（3）的位置时，GA（3）促进了脱落。GA（3）促进脱落的幅度大于生长素运输抑制剂或脱落酸的脱落促进幅度。生长素的特征性抑制脱落作用发生。这些反应表明，内源赤霉素可能参与了乙烯暴露的营养棉植株顶叶的快速脱落。GA（3）的应用可能为农业中脱落和开裂的控制提供了另一种选择。
