Effects Of Salinity And Waterlogging On Salt-tolerance Of Suaeda Salsa L. From An Intertidal Zone And Saline Inland Soil

The effects of salinity and waterlogging on seedling emergence and salt-tolerance of euhalophyte Suaeda salsa L. from an intertidal zone and saline inland soil were investigated. Seedlings of S. salsa from the intertidal zone emerged more rapidly than those for the second population under both waterlogged and drained conditions. Waterlogging and NaCl had no adverse effect on seedling emergence in S. salsa from the intertidal zone, but markedly inhibited those in S. salsa from saline inland. Salinity had no adverse effect on survival seedling percentage in waterlogged treatment, but high salinity (600 mM NaCl) decreased those in drained treatment in S. salsa from the intertidal zone, and the opposite trend presented in S. salsa from saline inland. Shoot dry weight of young seedlings markedly decreased in high salinity for both populations under both waterlogged and drained conditions, especially for S. salsa from saline inland. In conclusion, the population of S. salsa in the intertidal zone is more waterlogging tolerant than the saline inland population during the seedling emergence stage.S. salsa from both the intertidal zone and saline inland can survive the combined stresses of salinity and waterlogging. The biomasses of both populations were lower under waterlogged conditions compared to those in drained treatment. High salinity decreased the biomasses of shoots and roots of S. salsa from both the intertidal zone and saline inland in both drained and waterlogged treatments. The biomasses of shoots and roots of S. salsa from saline inland were higher than those of S. salsa from the intertidal zone, but the opposite trend was found for the root/shoot ratio in all treatments. Waterlogging had no effect on the Cl- concentration in leaves of S. salsa from saline inland. The Cl- concentration in leaves of S. salsa from the intertidal zone was lower compared with that of S. salsa from saline inland in all treatments, but the opposite trend was found in the roots at a salinity concentration of 600 mM NaCl. Waterlogging decreased the K+/Na+ ratio in leaves of S. salsa from saline inland, while the opposite trend was shown in S. salsa from the intertidal zone. The concentrations of Na+ in roots of S. salsa from the intertidal zone were higher than those in the second population in all treatments. Adventitious roots emerged under waterlogged condition in S. salsa from saline inland at a range of NaCl concentrations, especially at 1 mM NaCl. Adventitious roots were not found in S. salsa from the intertidal zone in all treatments. Aerenchyma was observed in roots of both populations under both drained and waterlogged conditions. Adventitious roots and aerenchyma in roots (including adventitious roots) enhanced the oxygen-utilization capacity for S. salsa from saline inland, which may be an important strategy for the saline inland population to endure combined salinity and waterlogging conditions. Aerenchyma in roots of S. salsa from the intertidal zone indicates that the population is well adaptated to waterlogging conditions.