Pysiological effects of NaCl on Ceratophyllum demersum L., a submerged rootless aquatic macrophyte

In the present study, effects of NaCl concentrations (0, 20, 40 and 80 mM) were investigated on Ceratophyllum demersum. Macronutrients N, P and K and micronutrients Zn and Cu were significantly decreased by NaCl salinity. In general, however, Fe and Mn contents of macrophyte tissues increased. As a result, NaCl toxicity disturbed the uptake and translocation of macro and micronutrients in the macrophyte and induced its nutrient imbalance. Although proline, ascorbate and non-protein protein thiols amounts were increased with salinity, contents of photosynthetic pigments, total soluble carbohydrate, reducing sugar and protein were reduced. Observed increases in malondialdehyde contents, one of the most frequently used indicators of lipid peroxidation, showed that oxidative damage occurred in membranes resulting from NaCl. High salinity stress developed some toxicity symptoms. These symptoms probably occurred due to ionic toxicity, imbalance of macro and micronutrients and/or oxidative stress triggered by salinity.