The role of exogenous proline in amelioration of lipid peroxidation in rice seedlings exposed to Cr(VI)

- Accumulation of MDA in roots was positively related to Cr(VI) concentrations.
- Cr(VI) induced damage of root cell viability was significantly evident.
- Exogenous proline significantly increased Cr accumulation in roots.
- Decreases in MDA content and root cell viability was observed in Pro-treated rice seedlings.
- Exogenous proline is able to effectively reduce Cr(VI)-induced lipid peroxidation in rice seedlings.

Lipid peroxidation was hydroponically investigated in rice seedlings (Oryza sativa L. cv. XZX 45) treated with different doses of hexavalent chromium (Cr(VI)) in the presence or absence of exogenous proline. Results showed that Cr(VI) induced lipid peroxidation was observed as indicated by higher accumulation of malondialdehyde (MDA) in roots of rice seedlings without application of proline. Cr(VI) also caused inhibition of relative growth rate and increase of root cell death of rice seedlings compared with control. Additionally, changes of roots phenotype traits were evident in roots of rice seedlings under Cr(VI) stress. Exogenous proline significantly increased Cr accumulation in roots, compared with rice seedings without proline treatment. However, less lipid peroxidation was detected in proline-treated rice seedlings as displayed by decreases in MDA content and root cell viability. Hierarchical cluster analysis was also performed using varieties of Cr accumulation, MDA content, root viability and root phenotype traits to further elucidate the role of exogenous proline in amelioration of lipid peroxidation. It is suggestive from the present study that exogenous proline is able to effectively reduce Cr(VI)-induced lipid peroxidation in rice seedlings.