The impact of selenium treatment on some physiological and antioxidant properties of Apium repens

- Lower Se(IV) concentrations (0.01, 0.1, 1 mg L−1) promoted growth of Apium repens.
- Higher Se(IV) concentrations increased amount of carotenoid and anthocyanins.
- Photochemical efficiency decreased in plants exposed to high Se(IV) concentrations.
- High Se(IV) concentrations caused degradation of both total glutathione and cysteine.
- Results demonstrated the antioxidant and pro-oxidant properties of Se.

Studies are scarce regarding the physiological effects of selenium treatment on antioxidant capacity of plants. In the presented in vitro experiment, Apium repens was used to investigate its ability to absorb Se(IV) at different concentrations (0.01, 0.1, 1, 10 and 50 mg L−1) and its physiological response to treatment. These plants possessed a high affinity to take up Se(IV), since Se concentration measured in plants reached 730 μg g−1 DM in 50 mg L−1 treated plants. Lower Se(IV) concentrations (0.01-1 mg L−1) promoted growth, while higher Se(IV) concentrations (10 and 50 mg L−1) affected it negatively. The photochemical efficiency decreased significantly in plants treated with higher Se(IV) concentrations compared to control plants. In the roots, total cysteine and glutathione content increased gradually from 0.01 to 10 mg L−1 Se treatment, when compared to the control. Enhanced total glutathione levels were also determined in the above ground parts when the plants were treated with lower Se(IV) concentrations (0.01-1 mg L−1). In both roots and above-ground parts, 50 mg L−1 Se(IV) treatment caused a significant degradation of total cysteine and glutathione, which was accompanied by a significantly larger oxidized glutathione pool. By applying five different concentrations of Se(IV), it was possible to identify a threshold Se content for A. repens, above which the nature of the effects induced changes from antioxidant to pro-oxidant.