Mechanisms of selenium mitigating stress and accumulation of heavy metals in plants.

Selenium (Se) plays an important role in improving plant stress resistance, mitigating heavy metal stress and reducing heavy metal uptake. This paper reviewed mechanisms involved with Se for mitigation of heavy metal stress and accumulation. Se could alleviate heavy metals stress because of the combined physiological and biochemical effects of the relevant products, including GSH-Px which could change toxic peroxides to non-toxic substances and remove free radicals induced by heavy metals. Se could activate phytochelatins synthase and increase the amount of precursors to phytochelatin (PC), and make plant produce more PC, and form more heavy metal-PC complexes. The formation of Se-heavy metal complexes reduced the biotoxicity of heavy metals. Se could produce antagonistic effect with a variety of heavy metals, and reduce the uptake of heavy metals.