【摘要】 由于工业“三废”和机动车尾气的排放、污水灌溉及农药、除草剂和化肥的使用，严重地污染了土壤、水质和大气，其中土壤中的重金属（Ｈｇ、Ｃｄ、Ａｓ、Ｃｕ和Ａｌ）污染更为严重［１］。重金属在植物根、茎、叶及籽粒中的大量累积，不仅严重地影响植物的生长和发育［１～...更多还原

【Abstract】 Heavy metals impact on the cytoplasmic function in a number of different ways, principally by their binding to protein sulfhydryl groups, by producing a deficiency of essential ions and, eventually, by substituting the essential ions. Other modes of toxicity are possible, including disruption of cell transport processes and oxidative damage by free radicals generated by metal redox cycling. Plants have developed a variety of biochemical defense strategies to prevent heavy metal poisoning. The possible defense mechanism in plant may involve: metal binding to cell walls, avoidance of uptake these toxic metal ions, reduction of heavy metal transport across the cell membrane, active efflux, compartmentalization and metal chelation. Phytochelatins that can tightly bind and sequester metals may play an important role in the accumulation of heavy metals and preventing them from entering the cell metabolic pathway, the rates of high molecular weight (HMW) metal phytochelatin complexes (Cd S 4 complex) formation may be an important determinant of the plant tolerance. In addition, plants possess several antioxidant defense systems to protect themselves from the oxidative stress by heavy metals.更多还原