Chromium detoxification mechanism induced growth and antioxidant responses in vetiver (Chrysopogon zizanioides(L.) Roberty)

This study investigated the chromium (Cr) detoxification mechanism-induced changes in growth and antioxidant defence enzyme activities in Chrysopogon zizanioides. Plant growth decreased by 36.8% and 45.0% in the shoots and roots, respectively, in the 50 mg/L Cr treatment. Cr accumulation was higher in root (9807 μg/g DW) than in shoots (8730 μg/g DW). Photosynthetic pigments and malondialdehyde content increased up to the 30 mg/L Cr treatment, whereas they declined at higher doses. The activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) were increased significantly with increasing of Cr dose but slightly declined at higher doses. Isozyme banding patterns revealed the expression of multiple bands for SOD, CAT and POX enzymes, and the band intensity decreased at high doses of Cr exposure. These results indicate that higher Cr doses increased the oxidative stress by over production of reactive oxygen species (ROS) in vetiver that had potential tolerance mechanism to Cr as evidenced by enhanced level of antioxidative enzymes, photosynthetic pigments, MDA contents. Therefore, vetiver has evolved a mechanism for detoxification and accumulates higher concentration of toxic Cr. This study provides a better understanding of how vetiver detoxifies Cr.
本文研究了鉻(Cr)對香根草(Chrysopogon zizanioides)生長以及抗氧化防禦酶活性的影響，探討其對Cr 的解毒機制。在50 mg/L Cr 處理條件下，植物地上部分和地下部分的生長量分別降低了36.8%和45.0%；Cr 在植物地下部分的積累量(9807 μg/g 幹重)大於地上部分的積累量(8730 μg/g 幹重)。隨著Cr 添加量的增加,光合色素和丙二醛含量增加，在30 mg/L Cr 處理條件下含量達到最高，之後，隨著Cr 處理濃度的增加略有下降；同時，抗氧化防禦酶(超氧化物歧化酶、過氧化氫酶和過氧化物酶)的活性顯著提高，在較高濃度Cr 處理下略有下降。同工酶結果顯示在高濃度Cr 處理下，超氧化物歧化酶、過氧化氫酶和過氧化物酶的條帶強度降低。目前研究結果表明，高濃度Cr 導致活性氧過量產生，從而增加了對香根草的氧化損傷，而光合色素、丙二醛、抗氧化酶含量的增加表明香根草對Cr 有潛在的耐性機制。結果表明，香根草具有對Cr 的解毒機制，並可以積累高濃度的Cr。本文為更深入地研究根草對Cr 的解毒機制提供了依據。 Copyright © 2019 Central South University Press and Springer-Verlag GmbH Germany, part of Springer Nature.