外源8'-炔基脱落酸强化东南景天吸收重金属的研究

为探究脱落酸类似物8''-炔基脱落酸8''-（C₂H）ABA]强化东南景天富集重金属的效应，通过水培的方法研究了外源8''-（C₂H）ABA分别对Cd（20 mg·L^-1）、Zn（160 mg·L^-1）单一胁迫下东南景天Cd/Zn积累和生理特性的影响，以及初步探讨了8''-（C₂H）ABA在植物重金属胁迫响应中的作用.实验结果表明：与天然ABA相比，外源8''-（C₂H）ABA能达到与ABA类似的作用效果，且对Cd胁迫下东南景天促进效果好于Zn；在Cd胁迫下，与对照相比，外源8''-（C₂H）ABA能显著增加东南景天根、叶中的Cd含量（44.2%、27.5%），以及光合色素（10.7%）和叶中过氧化物酶（SOD）活性（52.9%）、超氧化物歧化酶（POD）（24.7%）和过氧化氢酶（CAT）活性（27.9%）抗氧化酶活性，使可溶性糖（SS）（13%）和游离脯氨酸（Pro）（37.4%）含量增加，而叶中丙二醛（MDA）（40%）含量明显降低.上述结果表明，一定浓度的8''-（C₂H）ABA可以提高东南景天抗氧化酶活性来增强其对重金属Cd的抗性及吸收和转运能力，在强化东南景天修复重金属污染方面具有应用潜力.

Exogenous 8'-(C2H)ABA strengthening Sedum alfredii to absorb heavy metals

We investigated the effect of exogenous addition of abscisic acid (ABA) and its analog 8''-(C₂H)ABA, on accumulation of cadmium ions (Cd²⁺) and zinc ions (Zn²⁺) and physiologic responses in the leaves of Sedum alfredii under Cd²⁺ (20 mg·L^-1) stress and Zn²⁺ (160 mg·L^-1) stress. The methods that we employed were based on hydroponic principles. The result showed that 8''-(C₂H) ABA had a similar effect to that of ABA in helping S. alfredii to repair heavy metals, especially Cd²⁺-contaminated soil. Cd²⁺ accumulation in leaves and roots increased remarkably, whereas the contents of malondialdehyde, soluble proteins, soluble sugars and proline synthesis decreased upon exogenous addition of ABA and 8''-(C₂H)ABA. Treatment with ABA or 8''-(C₂H)ABA enhanced the activity of peroxidase, superoxide dismutase and catalase significantly in leaves. Exogenous addition of ABA or 8''-(C₂H) ABA at certain concentrations increased Cd²⁺ accumulation, while reducing the content of osmoregulatory substances and regulatory activities of antioxidant enzymes. These results showed that ABA or 8''-(C₂H) ABA could be used as new exogenous substances for Cd²⁺ removal in Cd²⁺-contaminated soils, and make contributions to urban environmental management.