中文摘要：

对19个大豆（Glycine max）品种进行了筛选试验，选择耐铝性不同的2个大豆品种（铝耐性品种：浙春2号和敏感品种：浙春3号）作为实验材料，设置5个铝处理水平和3个平行组（根际、非根际和外源根系分泌物组），测定了大豆根系分泌物中柠檬酸的含量；在处理30d后用浸提法提取3种类型土样中的各种形态的铝并测定其含量，同时检测了相应土样的pH值变化．实验结果显示，铝胁迫下，耐铝品种浙春2号根系分泌大量的柠檬酸，比铝敏感品种浙春3号显著；随着铝处理量的增加，浙春2号根际土壤相对于非根际土壤而言，Al^3＋、（AIOH）^2＋、Al（OH）^2＋等形态铝的含量均有所降低，单聚体羟基铝（（Al0H）^2＋、Al（OH）^2＋）含量的降低尤为显著，而腐殖酸铝（HA-Al）的含量有所升高；外源根系分泌物组的实验结果和根际土壤组相似，显示出耐铝性大豆根系分泌物具有一定的铝毒缓解效应．实验结果还表明，根系分泌物对根系土壤具有一定的酸化作用，而铝的形态与pH值有直接的关系，所以根系分泌物对铝形态存在一定的间接影响．

英文摘要：

19 soybean （Glycine max） cultivars were analysed and found to differ considerably in aluminum （ AI ） resistance. The cuhivars Zhechun No. 2 （M-resistant） and Zhechun No. 3 （M-sensitive） were selected for further analysis ; At the same time, 5 different concentration of aluminium （ Al^3 ＋ ） and 3 parallel treatments were set up. The different forms of aluminum and the pH of the soils were both determined after 30 d. The results indicated that secretion of citric acid became most under treatment of Al^3＋ in Zhechun No. 2, and the efflux of Zhechun No. 2 was much more than Zhechun No. 3; Exchangeable aluminum （ Al^3＋） and （ （AlOH）^ 2 ＋, Al （ OH ）^ 2＋ ） of Zhechun No. 2 decreased, while （ HA-Al） increased compare to non-rhizosphere soils. The effect of exogenous exudation was similar to that of the exudation from rhizosphere soil of soybean, which indicated the root exudate play an important role in the detoxification of aluminum. The results also showed that root exudation had something to do with the acidification of soil, and the form of aluminiumhad a direct relationship with pH, so the root secretion also had a certain impact on the form of aluminum indirectly.