Metal hyperaccumulation in plants: A review focusing on phytoremediation technology

Abstract

Metal hyperaccumulation is a characteristic present in over 500 plant species and approximately in 0.2% of all angiosperms. Hyper accumulators are model plants for phytoremediation as they are tolerant to heavy metals. Metals hyperaccumulation and tolerance are genetically inherited traits. Plants possess a range of potential cellular mechanisms that may be involved in the detoxification of heavy metals and thus tolerance to metal stress. Recent discovery have given first insights into the molecular basis of metal hyperaccumulation and metal hypertolerance in some plants. However, the ecological and biological significance of hyperaccumulation is not clear yet. The recent progress of molecular techniques has helped to improve the performance of phytoremediation technology as well as plant adaptation to extreme metallic environments. The knowledge of metal hyperaccumulation physiology has recently developed as a result of the advancement of molecular biology. Molecular technique help to understand the gene regulations system and plant metal homeostasis. This study reviews the recent advances of phytoremediation technology using hyperaccumulator plants addressing both potential and limitations, physiological and molecular aspects and provides a broad overview of most important genes which have been correlated to metals hyperaccumulation and tolerance, evidence of the effect of heavy metal on biomass productions, plant biochemical, antioxidant defence system and discusses the prospects of transgenic plants in phytoremediation of heavy metals. © 2011 Asian Network for Scientific Information.