مرکز منطقه ای اطلاع رساني علوم و فناوري - Heavy Metals and Phytoremediation: Physiological and Molecular Mechanisms

Abstract :

Heavy metal pollution is a significant environmental problem with a negative potential impact on agriculture and human health. The physical remediation technologies have been in use to remove and destroy toxic elements. However, phytoremediation is widely viewed as the alternative to the environmentally destructive physical remediation methods. Phytoremediation, the use of plants to remove heavy metals, is an effective, environmentally friendship and cheap method. Some plants possess a range of potential mechanisms that may be involved in the detoxification of heavy metals, and they manage to survive under metal stress. Metal hyperaccumulator plants can accumulate and detoxify extraordinarily high concentra”tions of metal ions in their shoots. High tolerance to heavy metal toxicity could rely either on reduced uptake or increased plant internal sequestration, which is manifested by an interaction between a genotype and its environment. The molecular genetic technologies have led to an increased understanding of mechanisms of heavy metal tolerance/accumulation in plants. The use of genetic engineering to modify plants for metal uptake, transport and sequestration may open up new avenues for enhancing efficiency of phytoremediation. Metal chelators, metal transporters, metallothionein and phytochelatin genes have been transferred to plants for improved capacity of metal uptake and sequestration. A better understanding of the mechanisms of uptake, transport and sequestration of metals in hyperaccumulator plants will lead to designing novel transgenic plants with superior phytoremediation traits. In this review, the molecular and physiological mechanisms involved in the improving plant with superior phytoremediation capability are discussed.