Comparative Study on Photosynthetic Characteristics of Two Ecotypes of Euhalophyte Suaeda Salsa L. Grown Under Natural Saline Conditions

Suaeda salsa L. grown in the intertidal zone and those in high salinity soils of the Yellow River Delta were used to investigate the category and characteristic of photosynthesis and fluorescence. Results showed that the water content, Na+ and Cl- contents of the high salinity soils were lower. The temperature on the surface of soil and in the depth of 10 cm from the surface, the content of K+ and Ca2+ of the high salinity soils were significantly higher than those in the intertidal zone soils. Pn, Gs, Fv/Fm, Phi PSII, the fresh weight and dry weight per plant of S. salsa grown in the high salinity soils were higher. However, Ci of S. salsa grown in the high salinity soils were lower. These suggested that S. salsa grown in the high salinity soils was mainly suffering from salt stress, while S. salsa in the intertidal zone soils was suffering from waterlogging, low temperature and salt stress together. S. salsa in the intertidal zone soils decreased light absorption and alleviated photoinhibition, but as a result the biomass was reduced.