毛细管电泳法对铝胁迫下小麦根部有机酸的直接测定

Determination of organic acids by capillary electrophoretic in root of wheat cultured under aluminum-stress

在进行植物抗铝逆性研究中,从植物的培养液中发现从根部分泌出的有机酸与铝结合从而实现无毒化是其抗铝逆性机理的重要依据,但是其分析需繁杂的前处理过程。而本文用毛细管电泳法直接测定了铝胁迫下培育的小麦根中的铝和有机酸,确认了主要积累的是苹果酸和柠檬酸。发现随着提高培养液中的铝浓度,根部的铝量也相应增加。同时,虽然根中的柠檬酸量无明显变化,但苹果酸被诱导增加。在pH7.8的Na3PO4缓冲溶液中加入表面活性剂溴化十六烷基三甲铵作为电泳溶液体系,紫外检测波长214nm,可以有效地分离检测以阴离子形式存在的上述有机酸。探讨了植物抗铝胁迫研究中简便易行的植物根部有机酸的直接测定方法。

Recently, for some species of higher plants, a mechanism has been proposed that organic acids secreted from the roots has been shown to play an important role in the external Al detoxification. In that case, Al ions in culture solution can be chelated to detoxification. In present work, the contents of Al and organic acids in root of wheat cultured under Al-stress were determined by capillary electrophoresis. It is found that the malic and citric acids are mainly accumulated. Simultaneously, the amount of malic acid accumulated in root increased with increasing external Al concentration, whereas this tendency was not observed remarkably for citric acid. Furthermore, the binding properties of organic acids to Al ion were investigated and their relations with plant Al-tolerance were illustrated. Organic acids existing in the anionic form in a pH 7.8 phosphate buffer containing hexadecyl trimethyl ammonium bromide were separated effectively and detected at 214 nm.