Physiological Responses of Halophyte Suaeda salsa to Water Table and Salt Stresses in Coastal Wetland of Yellow River Delta

摘要

Soil salinity and waterlogging are two major environmental problems in estuarine wetlands. The objective of this study was to investigate the effects of salt stress, water table, and their combination on growth, chlorophyll content, antioxidant system, and ion accumulation in Suaeda salsa plant, which is the pioneer plant in coastal wetland of the Yellow River Delta (YRD). The results showed that plant height, number of branches, and biomass were significantly affected by water table and salt stress. With enhanced salt stress, the ratio of leaf to total biomass increased and the ratio of root to total biomass decreased. The contents of Chl-a, -b, Chl-a + b, and carotenoids (Car) decreased significantly with increasing soil salinity and the water table level. Salt stress enhanced the activity of superoxide dismutase (SOD) and catalase (CAT), but reduced the content of protein. With the lowering water table level, the activity of CAT and protein content increased, and activity of SOD decreased. Na~+ and Cl~- content were up-regulated with increasing salt stress (NaCl), whereas, the contents of other cations (K~+, Ca~(2+), and Mg~(2+)) and anions (SO~(2-)_4 and NO~-_3) were decreased. In summary, the results indicated that the S. salsa plants could adapt to the adverse soil environments through modifying their growth and physiology status at the highly saline and intertidal zone, such as the YRD estuarine wetlands, and also could be used as a bio-reclamation plant to decline the high salt in saline soils.