Department of Plant Sciences, Texas A&M University, College Station, Texas 77843.
Plant Physiol. 1972 Dec;50(6):756-8. doi: 10.1104/pp.50.6.756.
Abscission of cotyledonary leaves from cotton (Gossypium hirsutum L. cv. Stoneville 213) seedlings occurred following relief from water stress. The amount of abscission was related to the magnitude of the plant water deficit. Leaf abscission promoted by exogenous ethylene was enhanced in seedlings subjected to water stress. Treatment with ethylene (2.0 to 3.2 microliters of ethylene per liter of air for 24 hours) raised the threshold plant water potential required to induce abscission from -17 to -7 bar, indicating that the stress caused the tissue to become predisposed to ethylene action. Based on the abscission response curve for seedlings treated with ethylene while under water stress, this apparent predisposition was developed as the plant water potentials reached the -7 to -10 bar range. The abscission-promoting effects of ethylene in combination with water stress were reversed with 15% CO(2) at plant water potentials above -12 bar, but the CO(2) reversal was lost at lower water potentials. These results are compatible with the concept that ethylene plays a regulatory role in leaf abscission induced by water stress.
棉籽（Gossypium hirsutum L. cv. Stoneville 213）幼苗在解除水分胁迫后，子叶会脱落。脱落的数量与植物水分亏缺的程度有关。外源乙烯促进的叶片脱落，在遭受水分胁迫的幼苗中增强。用乙烯（2.0 至 3.2 微升乙烯/升空气处理 24 小时）将诱导脱落所需的植物水势阈值从-17 提高到-7 巴，表明胁迫使组织容易受到乙烯的作用。基于在水分胁迫下用乙烯处理的幼苗的脱落反应曲线，这种明显的倾向性是在植物水势达到-7 到-10 巴范围时发展起来的。在植物水势高于-12 巴时，乙烯与水分胁迫的协同作用促进脱落，但在较低的水势下，CO2 会失去逆转作用。这些结果与乙烯在水分胁迫诱导的叶片脱落中起调节作用的概念是一致的。
