Structural and metabolic responses of Ceratophyllum demersum to eutrophic conditions

Eutrophication in water bodies affects the growth of aquatic plants. In this study, we conducted static experiments to better understand the structural and metabolic responses of Ceratophyllum demersum under eutrophication conditions. The anatomical structure, nitrogen (N) and phosphorous (P) levels in tissue, malondiadehyde (MDA), and activities of three antioxidases (peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT)) of C. dermersum cultured at different nutrient levels (oligotropher, mesotropher, eutropher, and hypertrophics) were investigated. The results showed that with nutrient concentration increase, disordered anatomical structures and a cavity in stem of C. demersum existed; there was also an increase in the N and P contents of C. demersum. The MDA content improved with nutrient increase while POD and SOD activities initially increased and later decreased. CAT activity also increased during the experimental period. These finding suggested that changes in stem anatomical structure and the increase in antioxidant enzyme activity can be served as the indicators of the response of C. demersum to eutrophication conditions.