小麦的铝毒及耐性

为探明Al的毒性和忍耐机理 ,比较了Scout 66和Atlas 66Al敏感和抗性的 2个小麦品种的根对Al的积累模式、根细胞壁对Al的吸附以及Al诱导的有机酸的分泌。结果表明 ,Al对Scout 6 6根伸长的抑制作用较Atlas 66明显。根系吸收的Al主要积累于 0至 5mm根尖处。Scout 6 6的根尖及Al处理后分离的根尖细胞壁对Al的积累量大于Atlas 6 6。但是 ,Al处理前分离根尖细胞壁 ,Al处理后细胞壁对Al的吸附量两品种间无显著差异。Al可诱导Atlas 6 6的根系分泌苹果酸 ,而Scout 6 6的分泌物中未发现Al诱导的有机酸。这些结果表明 ,Atlas 6 6的根尖及其细胞壁较Scout 66积累较少的Al,这种差异与Al诱导的有机酸分泌有关 ,而与根尖细胞壁固有的吸附Al的能力无关

Aluminum toxicity and tolerance of wheat

To elucidate aluminum (Al) toxicity and Al-tolerant mechanism, the pattern of Al-accumulation in roots of wheat (Triticum aestivum L.), absorption of Al to cell walls and Al-induced secretion of organic acids from roots were compared in Al-tolerant cultivar, Atlas 66, and Al-sensitive cultivar, Scout 66, of wheat. After exposed the roots to Al solution, more inhibition of root elongation was found in Scout 66. Al was mainly accumulated in the terminal 0 to 5 cm of roots. Scout 66 accumulated more Al in root apices and cell wall separated from root apices after Al treatment. However, after Al treatment difference in Al absorption to the cell walls separated from root apices before Al treatment between the cultivars was not found. In other hand, Al-induced malate acid was found in root exudates of Atlas 66, while no organic acid was found in that of Scout 66. These results indicated that less Al was accumulated in the roots of Atlas 66 than that of Scout 66. This difference seems related to the Al-induced secretion of organic acids from roots, but not to the capacity of cell walls itself to Al-accumulation.