摘要
Cytokinins and Ca 2+ singly retarded senescence of detached rice leaves.When Ca 2+ was applied together with cytokinins,the effectiveness of cytokinins was significantly reduced.Ca 2+ and cytokinins did not stimulate ethylene production synergistically,ruling out the possibility that ethylene was involved in the inhibition of cytokinin induced senescence retarding effect by Ca 2+ .The experiment with specific compounds known to increase (Ca ionophore A23187),or decrease (EGTA,LaCl 3,Verapamil,chlorpromazine) cytosolic Ca 2+ level indicated that the elevated cytosolic Ca 2+ retards senescence.
单独使用细胞分裂素 (BA和 Zeatin,1 0 -9～ 1 0 -5 mol/ L和 Ca2 + (1 0 -3 mol/ L)处理水稻离体叶片时 ,二者均对叶片衰老有延缓作用。但当用 Ca2 +和细胞分裂素同时处理叶片时 ,细胞分裂素延缓衰老的作用受到 Ca2 + 的明显抑制。进一步研究表明 ,细胞分裂素和 Ca2 + 并未协同刺激水稻离体叶片的乙烯生成 ,这样排除了通过乙烯促进叶片衰老的可能性。用可提高细胞质 Ca2 + 浓度的钙通道载体 A2 31 87处理叶片时 ,可延缓叶片衰老 ;而用可降低胞质 Ca2 +浓度的试剂 ,如 EGTA、La Cl3 、Verapamil、氯丙嗪等(1 0 -3 mol/ L)处理叶片时 ,可促进叶片衰老 ,进而排除了细胞分裂素促进 Ca2 +的吸收而加快衰老的可能性。
基金
Supported by the N tional Natural Science Foundation of China
