Insight into citric acid-induced chromium detoxification in rice (Oryza sativa. L)

High content of chromium in plants hampers plants' metabolism, disrupts plant growth and development. Therefore, improving plants' tolerance to Cr toxicity is very essential. In our present study, we investigated the role of citric acid (CA) on chromium detoxification in terms of stress tolerance in rice. Application of CA under Cr stress restore the growth parameters, total protein content and membrane stability confirming that CA plays important role in Cr detoxification in rice. However, supplementation of CA under Cr stress caused no significant change in root Cr content but increased shoot Cr concentration (97 mu g/g) compare with Cr stressed plant (24 mu g/gm), suggesting that CA alleviates Cr toxicity by its chelating properties. Moreover, Fe content showed no significant changes due to CA supplementation under Cr stress, implying that Fe regulation is not involved with CA-mediated mitigation of Cr toxicity in rice. Furthermore, increased CAT, POD, and GR activity along with raised metabolites (glutathione and proline) indicates active participation in ROS scavenging and palliate the Cr toxicity in rice.