Ca^(2+)和CaM在IAA诱导小麦芽鞘伸长中的作用

Effect of Ca^(2+) and CaM on auxin-induced elongation of wheat coleoptiles

应用 Ca^(2+)抑制剂和 CaM(钙调素)拮抗剂,对 Ca^(2+)和 CaM 在 IAA诱导小麦芽鞘伸长中的作用进行了研究.结果表明,小于0.5 mmol/L Ca^(2+)可明显促进小麦芽鞘切段伸长,并能加强 IAA 对伸长的促进,1mmol/L 以上Ca^(2+)则有抑制伸长的作用.Ca^(2+)通道抑制剂 Co^(2+)和 La^(3+)、CaM 拮抗剂CPZ(氯丙嗪)明显抑制芽鞘切段伸长,也降低 IAA 促进伸长的效应.因而,可以认为 Ca^(2+)介入 IAA 诱导细胞的伸长过程,Ca^(2+)通过 CaM 发挥其生理功能.

Ca^(2+)at relatively low concentrations(≤0.5mmol/L)could enhance elongation of wheat coleoptiles and progress in the induced effect of auxin.On the other hand,Ca^(2+)in- hibited those processes at relatively high concentrations(≥1 mmol/ L).These results sup- ported the mechanism in which Ca^(2+)at low concentration interferes directly with the biochemical process of coleoptile elongation.Further evidences that Ca^(2+)couples the auxin stimulus to the respons came from observations showing that EGTA(chelating Ca^(2+)), La^(3+) and Co^(2+)(blocking Ca^(2+) transport from wall into cell)inhibited elongation,and that CaCl_2 could reverse La^(3+) and Co^(2+) effects.The results that CPZ,a CaM antagonist,in- hibited auxin-induced elongation suggested that CaM probably involved in the process of auxin-induced elongation in which Ca^(2+)played an important role.