植物对土壤重金属镉抗性的研究进展

摘要

In recent years, human activities, such as mining, industrial activities, caused the serious pollution of the heavy metal cadmium in soil. It’s harmful to plants and human beings.This study describes the physiological mechanisms and inhibition performances when plants are facing the heavy metal stress such as cadmium stress, and we analyze plant adaptive strategies under the heavy metal stress from the cellular and molecular aspects. Heavy metal element, cadmium, is not essential for plants. The process that plants transport and detoxify cadmium is precision, which is a very complex mechanism. Heavy metal transporters play a key role in the regulatory process involved in absorption, chelation, compartmentalization and metabolic utilization. Non-essential heavy metal transporter protein contains two types, absorption protein and transpiration protein. Absorption protein include AtNRAMP, ZNTand OsIRT etc. It can transport heavy metal into plant by one or several cationic transporter protein. Transpiration potein contain HMA family, CDF family, ABC transporter protein, whose main function is to discharge heavy metals in the cytoplasmic matrix, or transported cadmium to the vacuole and other organelles. Heavy metal transporter protein plays a very active defensive role in plant tolerance when plants facing heavy metal stress. It mainly discussed the study of plant cadmium resistance, and provided theoretical basis and application guide for plant remediation of heavy metal in this paper.%各种人类活动，如采矿、制革、冶炼、污水灌溉等引起土壤和水体重金属污染，严重威胁着植物生长和人类健康。重金属镉污染是其中最常见的一种。该文描述了受重金属镉胁迫时植物的生理机制及各种抑制表现，如线粒体的裂解，细胞的生长分裂、水分的吸收、光合作用受到抑制等；同时也从微生物和细胞分子生物学方面分析了植物对重金属胁迫的应对策略，它依赖于植物本身和周围生存微环境的通力合作，主要包括降低对重金属的利用、控制重金属的吸收、螯合重金属、促进重金属的排出、区室化重金属和对重金属诱导的活性氧基团进行解毒等几条途径。另外，植物体对土壤环境中重金属镉的吸收、转运和解毒是一个精密的调控过程，参与重金属吸收和排出的转运蛋白在整个调控过程中发挥关键作用，参与了吸收、螯合、区室化和代谢利用等关键步骤。非必需重金属转运蛋白分重金属吸收蛋白和重金属排出蛋白2大类，吸收蛋白主要有AtNRAMP、ZNT和OsIRT等，能够通过某一种或几种阳离子转运载体蛋白运输至植物体内；排除蛋白主要包括P1B型ATP酶、阳离子转运促进蛋白家族（CDF）和三磷酸结合盒转运蛋白（ATP-binding cassette transporter，ABC转运蛋白）3大蛋白家族，主要将重金属转运出细胞质或者将重金属转运进入植物体内的细胞器，转运蛋白在植物耐受重金属胁迫中起着积极的防御作用。该文探讨了植物对重金属镉胁迫的各种抗性机制，可为土壤重金属镉污染的修复如微生物修复、植物修复等提供一定的理论依据和应用指导。