Chromium toxicity and cellular responses in plants

28103

The extensive use of various chromium (Cr) compounds in numerous industries has caused increasing concern about environmental contamination with this element. The uptake and phytotoxic effects of Cr depends on its oxidation state. Both hexavalent [Cr(VI)] and trivalent [Cr(III)] forms of Cr are phytotoxic, but Cr(VI) is more toxic than Cr(III). Since plants lack a specific transport system for Cr, it is taken up by carriers of essential ions such as sulfate or iron. Cr phytotoxicity inhibits seed germination and seedling growth, disrupts nutrient and water balance, degrades the pigments, reduces the activities of heme enzymes, and induces accumulation of various metabolites. Chromium causes deleterious effects on plant physiological processes such as photosynthesis and respiration. Chromium induces formation of reactive oxygen species, resulting in oxidative damage. The reactive oxygen species have the capacity to initiate lipid peroxidation. Organic acids, antioxidant enzymes, proline accumulation, metallothioneins, alternative oxidase pathway and stress proteins are important in plants as components of tolerance mechanisms and are also involved in detoxification of toxic metals. In this review, the effects of Cr toxicity and possible mechanisms of Cr detoxification and tolerance in plants are discussed.

163

Chromium toxicity , Growth , Chlorophyll biosynthesis , Reactive oxygen species , Lipid peroxidation , Detoxification mechanisms

Erciyes University Journal Of The Institute Of Science an‎d Technology

176

Erciyes University Journal Of The Institute Of Science an‎d Technology