铝诱导大豆根系有机酸分泌的能量消耗定量研究  

Quantitative study of energy consumption for Al-induced secretion of organic acids from soybean roots

作　　者：沈春鹏[1] 赖勇林[1] 吴道铭[1] 杨旭健[1] 龙新宪[1] 王宏斌[2] 沈宏[1] 

机构地区：[1]华南农业大学资源环境学院,广州510642 [2]中山大学生命科学学院,广州510275

出　　处：《植物营养与肥料学报》2014年第1期205-212,共8页Journal of Plant Nutrition and Fertilizers

基　　金：国家自然科学基金项目(30771294;31172026);博士点基金(20104404110016);留学回国择优基金项目([2010]412号);广东省高层次人才项目(粤教师函[2010]79号);国际科学基金(C/3042-3)项目资助

摘　　要：铝诱导大豆根系有机酸分泌是其解铝毒的一种重要机制,该过程需要消耗能量,然而有关能量消耗的定量研究还未见报道。本文比较了铝胁迫条件下,两个大豆品种根尖有机酸分泌、腺苷酸、无机磷、细胞质pH值等指标的变化。结果表明,铝处理(25μmol/L)明显诱导大豆根系苹果酸和柠檬酸的分泌。与对照相比,铝胁迫条件下中豆32和本地2号的根尖ATP含量分别降低40.1%和13.2%,根系细胞质子跨膜电化学势差分别增加1711.8和570.6 J/mol,然而,根尖无机磷浓度变化差异不大。运用Nernst-Gibbs方程定量计算自由能变化,发现中豆32和本地2号根尖细胞自由能分别消耗16.13 kJ/mol和14.59 kJ/mol,中豆32分泌单位苹果酸和柠檬酸的能量消耗分别为0.96 kJ/mol和3.15 kJ/mol,本地2号则为2.01 kJ/mol和5.68 kJ/mol。这表明不同耐铝性大豆品种分泌有机酸消耗的能量存在差异,该结果为筛选耐铝作物品种提供了新思路。Aluminum （Al）-induced release of organic acids from soybean roots has been regarded as one of important Al resistant mechanisms. The process is associated with energy consumption. However, the quantitative study of energy consumption remains to be elucidated in the process of Al-induced efflux of organic acids. In this study, two soybean （Glycine max） cultivars, Zhongdou 32（ZD 32） and Bendi 2（BD 2）, were selected to study the mechanism of this process. The changes of secreted organic acids, cytoplasmic pH, adenylate, and inorganic phosphate concentration were examined in roots of soybean seedlings. The results indicate that Al of 25 μmol/L could induce the secretion of malate and citrate from both cultivars’ roots significantly. Compared to the control, Al stress decreases the ATP contents by 40.1% and 13.2% in roots of ZD 32 and BD 2 respectively, and as well as increases the proton transmembrane electrochemical potential differences by 1711.8 and 570.6 J/mol. However, the inorganic phosphorus concentrations are not changed significantly in roots of both cultivars. Based on the above results, the Nernst-Gibbs equation is used to calculate energy consumption of organic acids secretion induced by Al. It is found that the gibbs free energy consumption amounts are 16.13 kJ/mol and 14.59 kJ/mol in ZD 32 and BD 2 roots, respectively. The energy consumption amounts for malate and citrate exudation are 0.96 kJ/mol and 3.15 kJ/mol in ZD 32, and 2.01 kJ/mol and 5.68 kJ/mol in BD 2 respectively. These finding suggests that different Al-tolerant soybean cultivars consume different energy in the process of Al-induced secretion of organic acids. This study provides a new way to screen Al-tolerant crop varieties.

关 键 词：铝胁迫 大豆 有机酸 无机磷 跨膜电化学势差 腺苷酸 能量消耗 

分 类 号：S565.1[农业科学—作物学]