重金属铜、锌、镉复合胁迫对麻疯树幼苗生理生化的影响

Effects of combined stress of heavy metals Cu, Zn and Cd on physiology and biochemistry of Jatropha curcas seedlings

关键词:  重金属胁迫, 麻疯树, 生理生化特性

Key words:  heavy metal stress, Jatropha carcas, physiological and biochemical characteristics

摘要:

该研究以Cu²⁺、Zn²⁺、Cd²⁺单一胁迫为对照,探讨不同浓度的Cu²⁺、Zn²⁺、Cd²⁺复合胁迫对麻疯树幼苗生理生化指标的影响。结果表明:随着Cu²⁺、Zn²⁺、Cd²⁺浓度的增加,麻疯树幼苗叶片中的蛋白质(Pro)、丙二醛(MDA)含量均逐渐增加,其叶片叶绿素含量随着Zn²⁺胁迫浓度的增加呈现出先降后升的趋势,在中等浓度(100 mg·L^-1)的Zn²⁺胁迫时含量最低、随着Cu²⁺胁迫浓度的增加叶绿素含量先升高后降低,在Cu²⁺浓度为200 mg·L^-1时含量最高,达到1 200 mg·g^-1 FW; Cd²⁺胁迫对叶绿素含量和根系活力无明显影响。根系活力在Zn²⁺浓度为100 mg·L^-1 时最强,随着Cu²⁺浓度的增加而减弱。低浓度的Cu²⁺、Zn²⁺、Cd²⁺对过氧化物酶活性和可溶性糖含量都具有促进作用。Cu²⁺、Zn²⁺、Cd²⁺复合胁迫时对可溶性蛋白、叶绿素和丙二醛含量均无明显影响,随着复合胁迫时浓度的增加,可溶性糖含量和根系活力先增后减。这表明麻疯树对三种重金属的胁迫具有一定的抗性,过高浓度的胁迫会影响麻疯树幼苗生理生化的一些指标,但是麻疯树可以通过自身的防御系统使伤害降到最小。此外,重金属复合胁迫可以在一定程度上减轻单一胁迫对麻疯树幼苗造成的毒害作用。

Abstract:

Cu²⁺, Zn²⁺ and Cd²⁺ single stress were used as controls to study the effects of different concentrations of Cu²⁺, Zn²⁺ and Cd²⁺ on physiological and biochemical indexes of Jatropha curcas seedlings. The results showed that the contents of protein(Pro)and malondialdehyde(MDA)in leaves of J. curcas seedlings increased gradually with the increase of Cu²⁺, Zn²⁺ and Cd²⁺ concentrations, and the chlorophyll content of leaves increased with the increase of Zn²⁺ stress concentration. The post-reduction trend was the lowest at the medium concentration(100 mg·L^-1)Zn²⁺ stress, and the chlorophyll content increased first and then decreased with the increase of Cu²⁺ stress concentration. The highest content was obtained when Cu²⁺ concentration was 200 mg·L^-1, reaching 1 200 mg· g^-1; Cd²⁺ stress had no significant effects on chlorophyll content and root activity. The root activity was the strongest when Zn²⁺ concentration was 100 mg·L^-1, and it decreased with the increase of Cu²⁺ concentration. Low concentrations of Cu²⁺, Zn²⁺ and Cd²⁺ promoted both pero-xidase activity and soluble sugar content. The contents of soluble protein, chlorophyll and malondialdehyde were not significantly affected by Cu²⁺, Zn²⁺ and Cd²⁺ stresses. The soluble sugar content and root activity increased first and then decreased with the increase of concentration during complex stress. The results showed that J. curcas had certain resis-tance to stress of the heavy metals. Excessive concentration of stress could affect some physiological and biochemical indexes of J. curcas seedlings, but J. curcas could reduce damage through its own defense system. In addition, heavy metal complex stress could alleviate the toxic effects of single stress on J. curcas seedlings to some extent.