To study the effects of indole-3-acetic acid (IAA) on cadmium (Cd) accumulation and the physiological responses of the Cd hyperaccumulator Solanum nigrum and non-hyperaccumulator Solanum melongena, a pot experiment was conducted in soil containing 2 mg kg-1 Cd in which different concentrations of IAA (0, 10, 20, or 40 mg L-1) were sprayed on plant leaves. The results showed that Cd accumulation in shoots of S. nigrum was significantly increased by 30% after the addition of 10 mg L-1 IAA under 2 mg kg-1 Cd stress compared to that in the control, but shoot Cd accumulation showed no significant change in S. melongena after this IAA treatment. Additionally, the growth and the proline content in the two species were significantly increased by 20 mg L-1 IAA. The activities of peroxidase and catalase in leaves of S. nigrum and the activity of superoxide dismutase (SOD) in S. melongena were significantly increased and their malondialdehyde content was significantly decreased compared to those in the control. The root activity of S. nigrum was significantly improved after 10 and 20 mg L-1 IAA treatments, but no significant difference was observed in S. melongena. The correlation analysis results showed that the Cd concentration in leaves of S. nigrum was significantly and positively correlated with the carotenoid and proline contents, and there was also a significant positive correlation between the Cd concentration and SOD activity in leaves of S. melongena. Therefore, S. nigrum is an ideal plant for the phytoextraction of Cd-contaminated soil assisted by IAA. IAA promotes Cd accumulation in plant shoots by enhancing the accumulation of carotenoids and proline in S. nigrum and maintaining a high leaf SOD activity in S. melongena.

中文翻译：

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吲哚-3-乙酸通过不同的生理反应促进镉（Cd）在镉超蓄积和非镉超蓄积中的蓄积。

为了研究吲哚-3-乙酸（IAA）对镉（Cd）积累的影响以及镉超蓄积龙葵和非超级蓄积龙葵的生理响应，在含2 mg kg-1的土壤中进行了盆栽试验在植物叶片上喷洒不同浓度的IAA（0、10、20或40 mg L-1）的Cd。结果表明，与对照相比，在2 mg kg-1 Cd胁迫下，添加10 mg L-1 IAA后，黑麦草芽中Cd的积累显着增加了30％，但芽中Cd的积累无明显变化。 IAA处理后，黄粉病菌发生了变化。另外，两个物种的生长和脯氨酸含量显着增加了20 mg L-1 IAA。烟草叶片中过氧化物酶和过氧化氢酶的活性 与对照组相比，黑麦草中的黑质和超氧化物歧化酶（SOD）活性显着增加，丙二醛含量显着降低。10和20 mg L-1 IAA处理后，黑链霉菌的根系活性得到显着改善，但在黑链霉菌中未观察到显着差异。相关分析结果表明，黑芥中Cd含量与类胡萝卜素和脯氨酸含量呈显着正相关，而黑麦中Cd浓度与SOD活性也呈显着正相关。因此，黑葡萄球菌是IAA辅助植物提取镉污染土壤的理想植物。