This study investigated the role of phytohormones in the mediating effect of cadmium on growth and metabolism of tomato plants. Micro-Tom plants and its hormone mutants, procera ( pro ), diageotropica ( dgt ), epinastic ( epi ), and notabilis ( not ) have been used. Tomato seedlings were grown for 5 weeks under controlled hydroponics condition and then treated with CdCl 2 concentration ranging from 0 to 100 μM for 2- to 6-week. Lipid peroxidation, leaf chlorophyll, elemental (Cd, Fe, Zn, Ca, Mg) content, and antioxidant enzyme activity were determined. Cd stress considerably altered the transcriptional level of the metal transport-related genes. Cadmium inhibited the uptake of iron (Fe) and zinc (Zn), whereas it has no noticeable effect on magnesium (Mg) and calcium (Ca) content, which might have been induced by the defense against Cd toxicity. The overall results demonstrated that not and epi mutants (with altered levels of ABA and ethylene, respectively) had a Cd-sensitive phenotype while dgt mutant (with reduced sensitivity to auxin) avoided damaging effects of Cd stress. This observation is explained by the lowest Cd accumulation in dgt roots. These results provide valuable information for the relative importance of auxin, ethylene, and abscisic acid in regulating plant responses to heavy metal toxicity.

中文翻译：

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将植物激素与番茄中镉的生长、运输活动和代谢反应联系起来

本研究调查了植物激素在镉对番茄植株生长和代谢的介导作用中的作用。已使用 Micro-Tom 植物及其激素突变体 procera ( pro )、diageotropica ( dgt )、epinastic ( epi ) 和 notabilis ( not )。番茄幼苗在受控的水培条件下生长 5 周，然后用浓度范围为 0 至 100 μM 的 CdCl 2 处理 2 至 6 周。测定了脂质过氧化、叶叶绿素、元素（Cd、Fe、Zn、Ca、Mg）含量和抗氧化酶活性。镉胁迫显着改变了金属转运相关基因的转录水平。镉抑制铁 (Fe) 和锌 (Zn) 的吸收，而它对镁 (Mg) 和钙 (Ca) 的含量没有明显影响，这可能是由抵御 Cd 毒性引起的。总体结果表明 not 和 epi 突变体（分别具有改变的 ABA 和乙烯水平）具有 Cd 敏感性表型，而 dgt 突变体（对生长素的敏感性降低）避免了 Cd 胁迫的破坏性影响。这一观察结果可以通过 dgt 根中最低的 Cd 积累来解释。这些结果为植物生长素、乙烯和脱落酸在调节植物对重金属毒性反应的相对重要性提供了有价值的信息。