铝胁迫对小麦根尖细胞蛋白质及苹果酸分泌的影响

以一对近等位基因小麦品系(ET8和ES8)为材料,研究了铝胁迫条件下根系生长情况,根尖铝含量,根尖细胞质蛋白组分以及铝胁迫下两个小麦品系苹果酸分泌的差异。结果表明,小麦品系ET8的耐铝性明显高于ES8;而ET8根尖铝含量则明显低于ES8;50mol/L铝处理24h后ES8小麦的细胞质蛋白组成受到明显影响,而ET8则无明显影响。由于铝胁迫条件下ET8分泌的苹果酸的量明显高于ES8,因此可以认为,分泌的苹果酸一方面与铝结合使其无毒化;另一方面将铝排斥于根尖细胞外,从而阻止铝进入细胞质内对细胞产生毒害作用。

Effects of aluminum stress on wheat root tip cytoplasmic proteins and malate efflux

In the present study, a pair of near iso-genic wheat line, ET8 and ES8, was used to investigate the effects of aluminum (Al) stress on root growth, root tip Al content, root tip cytoplasmic protein, and malate efflux from their roots. Root elongation was decreased with increasing Al concentrations applied, but it was always higher in ET8 than in ES8, indicating high Al tolerance in ET8. Total Al content in root tips was significantly lower in ET8 than in ES8 suggesting the role of Al exclusion mechanism in Al tolerance of ET8. After 50 μmol/L Al exposure for 24 h, SDS-PAGE cytoplasmic protein profiles in root tips were severely affected in ES8 but not in ET8. Furthermore, Al-induced malate efflux was significantly higher in ET8 than in ES8, indicating that exclusion of Al from root tips is due to efflux of malate from wheat roots. Although ET8 was higher in Al tolerance than ES8, the root growth was still inhibited by 50 μmol/L Al exposure for 24 h. We hypothesise that Al may inhibit root elongation apoplastically rather than cytoplasitically.