A hydroponic experiment with two different cadmium (Cd) accumulating rice lines of Lu527-8 (the high Cd accumulating rice line) and Lu527-4 (the normal rice line) was carried out to explore the links among Cd stress, root exudates and Cd accumulation. The results showed that (1) Cd stress increased quantities of organic acids, but had no effect on composition in root exudates of the two rice lines. In Cd treatments, the contents of every detected organic acid in root exudates of Lu527-8 were 1.76–2.43 times higher than those of Lu527-4. Significant positive correlations between organic acids contents and Cd contents in plants were observed in both rice lines, except that malic acid was only highly relevant to Lu527-8, but not to Lu527-4. (2) Both composition and quantities of amino acids in root exudates changed a lot under Cd stress and this change differed in two rice lines. In control, four amino acids (glutamic acid, glycine, tyrosine and histidine) were detected in two rice lines. Under Cd stress, eight amino acids in Lu527-8 and seven amino acids in Lu527-4 could be detected, among which phenylalanine was only secreted by Lu527-8 and alanine, methionine and lysine were secreted by both rice lines. The contents of those four newly secreted amino acids from Lu527-8 increased significantly with the increase of Cd dose and each had a high-positive correlation with Cd contents, but the same change did not appear in Lu527-4. The difference between two rice lines in secretion of organic acids and amino acids may be related to their different Cd uptake properties.

以Lu527-8（高镉累积水稻系）和Lu527-4（正常水稻系）两种不同的镉累积水稻系为对象，进行了水培试验，探讨了镉胁迫，根系分泌物和镉之间的联系。积累。结果表明：（1）镉胁迫增加了两种水稻系的有机酸含量，但对根系分泌物的组成没有影响。在镉处理中，Lu527-8根系分泌物中检测到的每种有机酸的含量是Lu527-4的1.76–2.43倍。在两个水稻品系中均观察到植物中有机酸含量和镉含量之间的显着正相关，只是苹果酸仅与Lu527-8高度相关，而与Lu527-4高度相关。（2）在镉胁迫下，根系分泌物的氨基酸组成和数量均发生了很大变化，并且在两个水稻系中这种变化有所不同。在对照中，在两个水稻品系中检测到四个氨基酸（谷氨酸，甘氨酸，酪氨酸和组氨酸）。在镉胁迫下，可以检测到Lu527-8中的八个氨基酸和Lu527-4中的七个氨基酸，其中苯丙氨酸仅由Lu527-8分泌，而两个水稻系均分泌丙氨酸，蛋氨酸和赖氨酸。Lu527-8中这四个新分泌的氨基酸的含量随Cd剂量的增加而显着增加，并且各自与Cd含量呈高正相关，但Lu527-4中未出现相同的变化。两个水稻系在有机酸和氨基酸分泌方面的差异可能与它们对镉的吸收特性不同有关。