Vol. 4, Issue 3 (2019)
In order to determine the feasibility of using Salix matsudana to repair wastewater contaminated by 2, 4-dichlorophenol, we investigated the physiological response of Salix matsudana to 2, 4-dichlorophenol and the effects of exogenous selenium (Se) application on the tolerance of Salix matsudana to 2, 4-dichlorophenol stress. The clonal plants of Salix matsudana were cultured in Hoagland solution supplied with 2, 4-dichlorophenol (0, 5, 10, 12.5, 15 mg·L-1) and Se (2 μmol·L-1), separately or simultaneously. It was shown that the exposure to 2, 4-dichlorophenol led to signiﬁcant changes in the photosynthetic physiological parameters of Salix matsudana: net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (E), chlorophyll content decreased, and superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity increased first and then decreased. The addition of Se increased Pn, maximum photochemical calibration rate (Fv/Fm), chlorophyll content and decreased the coefficient of photochemical quenching (NPQ), SOD, CAT activities. But Se enhanced POD activities and decreased E and Gs at low concentration of 2, 4-dichlorophenol. The results imply that with the increase of the concentration of 2, 4-dichlorophenol, the toxicity will be strengthened, and the plant will make corresponding reaction mechanism, such as the increase of initial antioxidant enzyme activity, and the degree of disturbances caused by 2, 4-dichlorophenol could be partially ameliorated by Se supplementation. However, the effect of Se on the 2, 4-dichlorophenol-stressed plants depended on the concentration of Se and application of Se may be a risk factor in low concentration 2, 4-dichlorophenol.
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