Effect of salinity on four freshwater macrophytes

The sublethal effects of salinity on four freshwater macrophyte species commonly found in floodplain wetlands in north-eastern Victoria (Myriophyllurn crispaturn, Eleocharis acuta, Potarnogeton tricarinatus and Triglochin procera) are reported. These species taken from the same freshwater wetland showed a wide range of salt sensitivities; P. tricarinatus was the most sensitive followed by M. crispatum and then E. acuta and T. procera. A progressive depression of growth rate and plant size was observed for each species when grown at salinities greater then 1000 mg L-1. The onset of these changes in growth pattern occurred earlier at the higher salinities. Both sexual and asexual reproduction were blocked in M. crispatum at salinities greater than 1000 mg L-1, even though 52% of plants survived after 72 days growth in water of salinity 7000 mg L-1.