Toxicological effects of bisphenol A on growth and antioxidant defense system in Oryza sativa as revealed by ultrastructure analysis

- BPA stress induces morphological changes in both roots and leaves of rice seedlings.
- Oxidative stress on rice seedlings was established.
- Antioxidant enzyme response to BPA exposure was studied.
- Changes in cellular organelles were observed.

The present study was conducted to evaluate the effect of bisphenol A (BPA) on rice seedlings grown in a hydroponic system. The obtained results demonstrated that at lower concentration (up to 10 µM) BPA had some stimulatory effects on the growth of rice seedlings but at higher doses it significantly inhibited seedlings growth. The photosynthetic pigments were significantly decreased by high doses of BPA. Exposure to BPA caused increased membrane permeability in root cells and resulted in increased concentration of reactive oxygen species (ROS) and increased lipid peroxidation as revealed by thiobarbituric acid reactive substances (TBARS) assay. In leaves, superoxide dismutase (SOD) activity exhibited an increase at lower concentrations of BPA but was inhibited at the highest dose (200 µM) of BPA. At 100 µM of BPA, a significant increase in antioxidant activities in leaves was observed but at 200 µM this activity was inhibited. In roots, a significant decrease in enzymes activity was recorded at the highest concentration of BPA (200 µM); however, ascorbate peroxidase (APX) and catalase (CAT) activities were significantly increased at the concentrations of 10 and 50 µM in comparison to the control. Moreover, the present results revealed that BPA severely affected cell organelles in rice seedlings. It can be concluded that the observed adverse effects in rice seedlings by BPA in the present study could be attributed to the oxidative stress caused by BPA.