Mechanisms of nickel uptake and hyperaccumulation by plants and implications for soil remediation

Abstract

Soil contamination by heavy metals like Ni was originally restricted to metalliferous soils but in modern time it has become a general problem due to increasing anthropogenic activities. Because of the characteristics of cost-effectiveness, environmental friendliness, and fewer side-effects, the development of plant based remediation technologies for the cleanup of Ni-contaminated soils has attracted much attention. Nickel is an essential micronutrient, but is toxic to plants at excessive levels. Some plant species can accumulate Ni in the shoots at a high concentration, these plants are called hyperaccumulators. In the past two decades, researchers have endeavored to understand the physiological and molecular mechanisms of Ni uptake, transport, and detoxification in the Ni-hyperaccumulator plants. This is the basis of creating ideal plants for phytoremediation through cell and genetic engineering technologies, which may subsequently improve phytoremediation efficiency for decontaminating Ni-contaminated soils. Both rhizosphere microorganisms and endophytes can play a role in phytoremediation. Optimizing plant and soil management practices, particularly the correction of soil pH and additions of amendments of exogenous chelates and fertilizers, can also enhance phytoremediation of Ni-contaminated soils. The primary objective of this review is to discuss the recent progresses in basic and applied research relevant to phytoremediation of Ni-contaminated soils. © 2012 Elsevier Inc.