铝对大豆根系柠檬酸合成与分泌的影响  

Effect of aluminum on synthesis and secretion of citrate in soybean roots

作　　者：莫丙波[1] 沈春鹏[1] 于智卫[1] 沈宏[1] 

机构地区：[1]华南农业大学资源环境学院根层调控实验室,广东广州510642

出　　处：《生态环境学报》2009年第3期1037-1041,共5页Ecology and Environmental Sciences

基　　金：国家自然科学基金项目((30771294);国际科学基金(C/3042-2;3)资助

摘　　要：铝诱导有机酸分泌是作物解铝毒的一种重要机制,然而铝如何诱导有机酸分泌的机理并不清楚。以不同铝耐性大豆(Glycine max)(BX10和BD2)为材料,研究了铝对柠檬酸合成与分泌的影响。结果发现,在0.5mmol·L-1CaCl2溶液中,铝处理明显抑制大豆根系伸长,BX10比BD2具有较大的主根伸长率。铝处理明显诱导大豆根系分泌柠檬酸,BX10的柠檬酸分泌量比BD2高出32.3%～64%。铝处理降低根系内源柠檬酸含量,但不影响柠檬酸合酶活性,BX10比BD2具有较高的柠檬酸合酶活性,表明铝诱导的柠檬酸合成与其分泌关系密切。另外,在pH4.5的完全营养液中进行铝、磷间隔处理发现,供磷明显增加大豆铝吸收,而且BX10比BD2具有较大生物量与铝吸收,这表明,磷对铝的吸收具有重要作用,大豆磷效率可能影响其铝耐性。Al-induced secretion of organic acid is regarded as an important mechanism for plant root to detoxify A1 toxicity. However, it is not clear how A1 induces secretion of organic acid. In this study, two soybean cultivars with different AI tolerance （BX10 and BD2） were used to investigate the effect of AI on the synthesis and secretion of citrate. Results indicated that treatment with 50 ~tM of A1C13 inhibited root elongation of both two cultivars. BX 10 had a longer root elongation than BD2 did. AI could trigger the secre- tion of citrate significantly. Secretion of citrate in BX10 was 32.3%-64% higher than that of BD2. A1 decreased the endogenous concentration of citrate, but did not affect the activity of citrate synthase. BX 10 had a higher activity of citrate synthase than BD2 did suggesting the synthesis of citrate was related to its secretion. In addition, A1 ＆ phosphate interaction experiments in nutrient solution （pH4.5） indicated that phosphate supply increased AI uptake in soybean, and a higher biomass and A1 uptake was observed in BX10 rather than BD2, suggesting that phosphate nutrition influenced A1 uptake and A1 tolerance.

关 键 词：铝胁迫 大豆 柠檬酸合成与分泌 

分 类 号：S565.1[农业科学—作物学] S158.3