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以耐Al性明显差异的 2个小麦基因型为材料 ,采用溶液培养试验和动力学方法研究了根际 pH变化、NH+ 4和NO-3 的吸收以及NO-3 还原与其耐Al性的关系。结果表明 ,A1胁迫下鉴 86 4(耐性基因型 )比扬麦 5号 (敏感基因型 )能维持较高的根际 pH值 ,当溶液 pH值下降到最低时 ,前者比后者高 0 2 3个pH单位。吸收动力学研究表明 ,鉴 86 4在无Al和有Al胁迫时对NO-3 的吸收速率和亲和力大于扬麦 5号 ;而对NH+ 4的吸收速率和亲和力却小于扬麦 5号。Al还降低叶片和根系的硝酸还原酶活性 ,但鉴 86 4的叶片和根系硝酸还原酶活性均高于扬麦 5号。此外 ,在Al胁迫下 ,植株体内游离脯氨酸含量迅速提高 ,但扬麦 5号积累量高于鉴 86 4。鉴 86 4具有较高的耐Al能力可能与其在Al胁迫下对NO-3 的吸收速率、亲和力以及硝酸还原酶活性较高 ,而对NH+ 4的吸收速率和亲和力较低 ,从而能维持较高的根际 pH值有关
Two wheat genotypes with significant Al tolerance were used as materials to study the relationship between rhizosphere pH changes, NH + 4 and NO-3 uptake and NO-3 reduction and Al tolerance by solution culture and kinetic methods. The results showed that under stress A1 864 (tolerant genotype) could maintain higher rhizospheric pH value than Yangmai 5 (sensitive genotype). When the pH value of solution decreased to the lowest, the former was higher than the latter 3 pH units. Absorption kinetics studies showed that the absorption rate and affinity of NO-3 in Jin 864 was higher than that of Yangmai 5 in the absence of Al and Al stress, while the absorption rate and affinity to NH + 4 was less than that of Yangmai 5. Al also decreased the nitrate reductase activity of leaves and roots, but the activity of nitrate reductase in leaves and roots of Jian 86 4 was higher than that of Yangmai 5. In addition, the content of free proline in plants increased rapidly under Al stress, but the accumulation of Yangmai 5 was higher than that of Jian 864. The higher Al-tolerant ability of 864 may be related to its higher absorption rate, affinity and nitrate reductase activity under Al stress, while its absorption rate and affinity to NH + 4 are lower, Rhizosphere pH