Suaeda salsa is an annual euhalophyte in estuarine wetlands. Soil properties of wetlands have an important influence on S. salsa growth. Therefore, the soil ecological thresholds is valuable for the restoration of degraded S. salsa wetlands. The objectives of this present study were to analyze the soil physicochemical properties and evaluate the soil ecological thresholds in the typical degraded areas for S. salsa growth. Soil text components became coarser with increased sand contents and less clay contents, as the higher degree of wetland degradation. Meanwhile, the salt contents in different soil depths gradually increased with the increased degree of degradation of wetlands. Evident changes in soil water content, organic matter content, and cations concentrations were not observed, while the concentrations of these factors were higher in the soil layer of 0–10 cm than those in the 20–30 cm. The soil pH in the 0–10 cm soil layer was lower than that in the 20–30 cm. The content of the three available nutrients did not change evidently with the increasing degree of degradation. The optimum thresholds of soil salinity and water content were 7.073–16.613 g/kg and 31.8–63.2%, respectively.

In order to explore the bioaccumulation of heavy metals by Suaeda salsa and its ecological restoration capacity in the tidal flat of the Liaohe estuary, the absorption and reduction effect of Suaeda salsa on heavy metals was determined via a combination of on-site monitoring and experimental tests. The results showed that, under a high-salt environment, Suaeda salsa had a decreasing effect on heavy metals zinc, copper and lead, and the bioaccumulation coefficient BCF_Ss–Zn > BCF_Ss–Cu > BCF_Ss–Pb. When the concentration of heavy metal ions was high, Suaeda salsa could still survive, but the absorptivity was low, reducing its ability to repair heavy metal pollution. By correlating the research data with the population density of Suaeda salsa, the total removal of heavy metals was obtained, about 2008.6 kg Zn²⁺, 347.5 kg Cu²⁺, 376.1 kg Pb²⁺. This paper could provide a theoretical basis and technical support for the promotion and application of ecological restoration via Suaeda salsa.

To explore the ecological degradation of Suaeda Heteroptera in Panjin Red Beach wetland, the effects of Atrazine on the growth and physiological effects of Suaeda Heteroptera seedlings were studied by indoor hydroponics. Experimental results show that the leaves and roots of the Suaeda Heteroptera seedlings are very sensitive to Atrazine. And the LD₅₀ of the number of leaves of Suaeda Heteroptera seedlings were 34.2 μg/L. At low concentrations (3.8-11.4 μg/L), Atrazine promoted the growth of seedling leaves; at higher concentrations (22.8-34.8 μg/L), it inhibited leavse growth and had a significant dose-effect relationship Atrazine had different effects on height and root length of Suaeda Heteroptera, but had no effect on seedlings stem length. The formation of chlorophyll b in leaves of Suaeda Heteroptera treated by Atrazine was inhibited. Also, the main factor for the decrease of total chlorophyll consent is Atrazine.