外源IAA增强丹波黑大豆抗铝性的生理机制

Physiological Mechanism of Exogenous IAA Increasing Aluminum Resistance of Tamba Black Soybean

以铝耐受型丹波黑大豆(RB)幼苗为供试材料,考察了不同浓度铝胁迫下添加外源IAA对RB根尖内源IAA、H2O2、MDA、铝含量、柠檬酸分泌量以及质膜H+-ATPase活性的影响,探讨外源IAA增强RB抗铝能力的生理机制。结果显示:(1)经25、50和200μmol·L-1 AlCl3胁迫处理24h后,RB根尖IAA含量、柠檬酸分泌量和质膜H+-ATPase活性均表现为先上升后下降的趋势,而H2O2、MDA和根尖铝含量却随着铝处理浓度的增加呈显著上升趋势。(2)与单独25、50和200μmol·L-1 AlCl3胁迫处理相比,添加50μmol·L-1外源IAA后使得RB根尖铝、MDA和H2O2含量均显著降低,同时使RB根尖柠檬酸分泌量分别相应增加到单独处理的2.39、1.73和6.85倍,且其相应的质膜H+-ATPase活性也增加了1.09、1.74和1.45倍。研究表明,外源IAA能通过增强丹波黑大豆根尖柠檬酸的分泌量和质膜H+-ATPase活性来提高其对铝胁迫的抗性,明显缓解铝毒害作用。

In this study,the Tamba Black soybean （RB） was used as the experimental material to analysis the physiological mechanism of exogenous IAA increasing AI resistance by investigation the e/lect ot exogenous IAA on the contents of endogenous IAA, H2 02, MDA, Al, citrate exudation and the activities of the plasma membrane （PM） H＋-ATPase under Al stress. The results showed that after exposure to 25,50 and 200 /~mol ~ L-1 AlCla for 24 h,the contents of endogenous IAA,citrate exudation and the activities of the PM H＋-ATPase in RB roots were firstly promoted, then decreased. However, the contents of H202 and MDA were increased significantly with Al concentrations increasing. Additionally, the contents of Al, MDA and H2O2 in RB roots were significantly decreased while 50 μmol.L^-1 IAA was added to 25,50 and 200 μmol . L^- 1 Al treatment solutions. Furthermore,the citrate exudation increased approximately 2.39,1.73 and 6.85-fold and the activities of the PM H＋-ATPase enhanced approximately 1.09,1.74 and 1.45-fold than that of only Al treatment in RB roots,respectively. Taken together,our results indicated that exoge- nous application of IAA significantly enhanced Al resistance of RB by enhancement of citrate exudation and the PM H^＋-ATPase activity under Al stress.