β-Pinene partially ameliorates Cr(VI)-inhibited growth and biochemical changes in emerging seedlings

The present study investigated the potential role of exogenous β-pinene (non-oxygenated monoterpene) in ameliorating the toxic effects of Cr(VI) (hexavalent chromium) in Zea mays, Oryza sativa and Triticum aestivum. Cr(VI) reduced the root and coleoptile growth of test plants, decreased the amount of chlorophyll and proteins, affected the respiratory mechanism, and altered the specific activity of enzymes—proteases, peroxidases (PODs) and polyphenol oxidases (PPOs). However, β-pinene supplementation caused a decrease in toxic effects of Cr(VI). The addition of β-pinene resulted in better root and coleoptile growth, greater chlorophyll content and protein content, lesser accumulation of Cr in plant tissues, and modulation of activities of proteases, PPOs and PODs in Cr(VI) + β-pinene treatments over that in Cr(VI) alone. The increased activity of proteases and PPOs, and decreased activity of PODs in test plants under Cr(VI) alone treatment was recuperated with the supplementation of β-pinene. The study concludes that β-pinene has a potential to ameliorate the inhibitory effect of Cr(VI) on the early growth and biochemical processes in plants experiencing Cr toxicity, and thus provides protection against Cr(VI) toxicity.