硅对减轻水稻的铝胁迫效应及其机理研究

通过分析溶液中Al离子形态变化和根内Al的分布 ,探讨Si对减轻水稻Al胁迫的效应及其机理。结果表明 ,pH4.5的溶液培养条件下Al在短时间内即可明显地抑制水稻根系的生长 ,加入不同形态的硅酸可有效地减轻Al对水稻的胁迫 ,根的伸长量接近或达到对照处理的水平。加Si降低了溶液中单质态Al离子的浓度 ,改变了溶液中Al的形态。分子筛柱层析分离和离子交换树脂吸附分析发现 ,溶液中产生了新的Al化合物 ,阳离子交换态Al的比率由 78%降低到 48% ,而交换态Si的比率由 0 %增加到 20%。Al主要聚集于根质外体特别是细胞壁中 ,加入低分子态硅酸增加了根全Al和质外体Al的含量 ,但是却降低了细胞壁Al的含量 ,而加入高分子态硅酸明显地降低了根全Al、质外体、共质体和细胞壁Al的含量

Effect of silicon on alleviation of aluminum toxicity and corresponded mechanisms in rice

The effect of silicon (Si) on alleviation of aluminum (Al) phytotoxicity and corresponded mechanisms were investigated in this study by analyzing Al chemical forms in solutions and the distribution of Al in rice roots. The results indicated that the root growth was inhibited quickly and remarkably by Al treatment at pH 4.5,while this inhibition was alleviated by addition of Si in different forms and the elongation of root was approached or come up to those of control plants without Si addition. Al forms in the solution changed because of Si addition. A new Al-complex was found by investigating Al-forms in the solution with molecular-sieve chromatography and cation exchange resin, while the monomer Al concentration decreased. The ratio of exchangeable Al reduced from 78% to 48%, while the ratio of exchangeable Si increased from 0% to 20% with Si addition. Al in the roots was mainly accumulated in apoplastic tissues, especially in cell walls. In other hands, total Al content and Al content in the apoplast of roots increased, while Al content in the cell wall fraction decreased with the low molecular Si addition in the Al solutions. However, in the case of the high molecular Si addition to the Al solution, the contents of total Al, Al in the apoplast, in symplast fractions, and in cell wall decreased markedly.