Department of Botany and Plant Pathology, Michigan State University, East Lansing, Michigan 48824.
Plant Physiol. 1976 Mar;57(3):347-50. doi: 10.1104/pp.57.3.347.
The ionic specificity of IAA-induced acidification by Avena coleoptiles was studied, using zwitterionic, presumably impermeant buffers. The acidification was almost totally dependent on divalent cations with an order of effectiveness of Ca(2+) >/= Sr(2+) > Mn(2+), Mg(2+); whereas other polyvalent cations tested were ineffective. The Ca(2+) response was IAA-dependent. The CaCl(2) concentration was optimal at 0.3 to 1 mm and inhibitory at higher concentrations. Sr(2+) inhibited Ca(2+)-dependent acidification and monovalent cations such as K(+) did not induce additional acidification in the presence of optimal CaCl(2). These data are consistent with a mechanism for IAA-induced acidification involving a Ca(2+) -H(+) exchange.
采用两性离子、可能不可渗透的缓冲液研究了 IAA 诱导的燕麦 coleoptiles 酸化的离子特异性。酸化几乎完全依赖于二价阳离子，其有效性顺序为 Ca(2+)>=Sr(2+)>Mn(2+)>Mg(2+)；而其他测试的多价阳离子则无效。Ca(2+)反应是 IAA 依赖性的。CaCl(2)浓度在 0.3 至 1 mM 时最佳，在较高浓度时具有抑制作用。Sr(2+)抑制 Ca(2+)-依赖性酸化，并且在存在最佳 CaCl(2)的情况下，单价阳离子如 K(+)不会诱导额外的酸化。这些数据与涉及 Ca(2+) -H(+)交换的 IAA 诱导酸化的机制一致。
