中文摘要：

以3个铝耐性不同的小麦品种为材料，研究了Al胁迫下小麦幼苗根系质外体和共质体抗坏血酸含量以及抗坏血酸氧化酶和过氧化物酶活性的变化。结果显示，Al耐性品种‘Atlas 66’质外体中抗坏血酸总含量随着处理Al浓度的增加显著升高，而在Al敏感品种‘Scout 66’和‘扬麦9号’中显著降低。同时，‘Atlas 66’质外体中还原型抗坏血酸含量在高浓度Al处理下显著升高，2个敏感品种则在低浓度Al处理下还原型抗坏血酸含量略有升高。耐性品种‘Atlas66’根系共质体还原型抗坏血酸和抗坏血酸总量在5～40 μmol·L-1 AlCl3处理下无显著变化，而在2个敏感品种中则随处理Al浓度的增加显著下降。80μmol·L-1 AlCl3处理下‘Atlas66’根系质外体和共质体抗坏血酸氧化酶以及抗坏血酸过氧化物酶活性与对照相比均无显著变化，而在‘Scout66’和‘扬麦9号’中则均显著降低。因此Al胁迫下‘Atlas66’根系质外体抗坏血酸含量的升高和共质体抗坏血酸含量的维持以及Al毒害下抗坏血酸利用率较高可能是其Al耐性的一个重要机制。

英文摘要：

Three wheat varieties with different aluminum tolerances were used to study ascorbic acid contents,and ascorbic oxidase and APX activities in root apoplast and symplasm of wheat seedling under aluminum stress. The results revealed that as the Al concentration increased,the ascorbic acid content in root apoplast of the Al-tolerant variety ‘Atlas 66＇ significantly increased and those of the Al-sensitive varieties ‘Scout66＇ and ‘Yangmai 9＇ significantly declined. In the meantime,the reductive ascorbic acid content in root symplasm of ‘Atlas 66＇ significantly increased in the treatments with a high Al concentration and those of the two Al-sensitive varieties slightly increased in the treatments with a low Al concentration. In root symplasm of the Al-tolerant variety ‘Atlas 66＇ the total content of reductive ascorbic acid and ascorbic acid did not vary in the treatments with the AlCl3 concentration ranging within 5-40μmol·L-1 but in the root symplasm of the two Al-sensitive varieties the total content of reductive ascorbic acid and ascorbic acid significantly declined as the Al concentration increased. In the treatment with 5-40 μmol·L-1 AlCl3, compared with ascorbic oxidase and APX activities in the control ,the ascorbic oxidase and APX activities in root apoplast and symplasm of ‘Atlas 66＇ did not significantly vary,but those of ‘Scout66＇ and ‘Yangmai 9＇ significantly declined. Therefore,that under Al stress, ‘Atlas 66＇ had increased ascorbic acid content in its root apoplast and a stabilized ascorbic acid content in its root symplasm and a low use efficiency of ascorbic acid while its suffering Al damage was probably one important mechanism by which it tolerated Al.