Response of Soil Microalgae to Salt Stress and Its Improvement Effect on Salinized Soil

Soil salinization has become a worldwide environmental problem. In order to explore the new biological technology for salinized soil improvement, laboratory simulation experiments were carried out in this study, in which an indigenous microalgae isolated from the biological soil crust of salinized soil in Xinjiang was used to explore the salt tolerance of the algae and its effect on saline-alkali soil. The results show that the microalgae had high salt tolerance to grow in 1 mol/L NaCl solution. The synthesis of algal photosynthetic pigments was inhibited by salt stress with obvious gradient effect. After 18 d incubation, the contents of the soluble salts in 0.5 mol/L, 1.0 mol/L, 1.5 mol/L NaCl treatment groups decreased by 16.99%, 9.23%, and 3.27%, respectively. The soil microalgae were inoculated and cultivated on the surface of high saline-alkali soil. The experimental groups with initial chlorophyll a of 3 μ g/cm2, 5 μ g/cm2 and 8 μ g/cm2 soil, the soil moisture content increased by 29.41%, 38.29% and 39.54%, and extracellular polymers (EPS) increased by 82.84%, 86.04%, and 116.06%, respectively. These results indicate that soil microalgae can reduce soluble salt, control soil salt transport, and maintain soil moisture. This study provides an important theoretical basis for saline soil improvement by soil microalgae. © 2023 China University of Geosciences. All rights reserved.