Effect of Saline-alkali Stress on Seed Germination of the Halophyte Halostachys caspica

Abstract The process of soil salinization and the preponderance of saline water sources all over the world represent one of the most harmful abiotic stresses to plant growth. In nature, soil salt and alkali coexist, and the interaction of salt and alkali is an important feature of saline-alkali stress. Halostachys caspica is a salt-tolerant halophyte belonging to Amaranthaceae and widely distributed in arid and saline-alkali areas in Xinjiang, Northwest China. This paper studied the response of the germination of the desert halophyte Halostachys caspica to different types of salt stress, aiming to provide a theoretical basis for development and utilization of halophytes growing in saline-alkali soils. The results showed that the seed germination of Halostachys caspica was not significantly inhibited when the salt concentration was low (≤ 200 mmol/L), but with the increase of salt concentration, the germination rate of seeds dropped sharply, and the recovery germination rate at high concentration was higher than that at low concentration, when salt was removed. Step-by-step regression analysis showed that at the same concentration, the alkaline salt inhibited seed germination more severely than the neutral salts; the inhibitory effect of the mixed salt and mixed alkali on seed germination is heavier than that of the mono-salt and mono-alkali; under mixed salt alkali stress, the higher the alkaline salt content, the higher the degree of inhibition on seed germination; indicating that alkaline salt play a major role in mixed saline-alkali stress.