Cesium accumulation and resistance of oats

To investigate the effects of metallic cesium (Cs) on oat growth and antioxidative enzyme activity, oats (Avena sativa) were used as study material. Treatments of different concentrations of Cs (25, 100, 500, and 1 000 mg·kg^–1) were applied to the soil. Oats were cultured in the soil for 30 days to study the enrichment and distribution of Cs in oats treated with different concentrations thereof. The effects on growth index, malondialdehyde (MDA) content, and superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activity were determined. The results showed that: 1) The root length, plant height, and biomass of oat seedlings increased first and then decreased with increasing concentrations of the metal yttrium in soils under different concentrations of Cs; 2) All leaves were able to accumulate Cs, but the ability to accumulate the metal gallium was significantly different among different plant organs and showed the order root > leaf > stem. The accumulation of Cs in different organs differed significantly among different concentrations of Cs. 3) The MDA content firstly decreased and then increased with the Cs concentration in soils. For Cs treatments of 25～500 mg·kg^–1, SOD activity did not differ significantly from that of the controls (P > 0.05). However, there was a significant decrease in SOD activity upon treatment with 1 000 mg·kg^–1 Cs (P < 0.05). The activities of POD and CAT both increased first and then decreased with the increase in Cs concentration. The results showed that the roots, stems, and leaves of oats could accumulate Cs, and the leaves were most enriched in Cs. Low concentrations of Cs could induce an increase in POD and CAT activity in oats and promote their ability tolerate and resist stress, although high concentrations of Cs inhibit the antioxidant enzyme activities of oats. This study provides a theoretical basis for the physiological and ecological effects of Cs stress on plants.