LAUSR

Abstract The long-term utilization of brackish water for irrigation in arid areas will decrease the oxygen content required for root growth, leading to the deterioration of soil environment in the root zone and the inhibition of plant growth. This study investigated the effects of oxygenated brackish water on the physiological characteristics of seed germination and seedling growth characteristics of spring wheat. The dissolved oxygen (DO) of 20 mg·l−1 in brackish water had a significant promotion effect on the seed germination and seedling growth. Specifically, at this DO concentration of 20 mg·l−1, the germination rate, germination potential, germination index, vigor index, and plant height on the 23rd day after sowing of wheat seeds were significantly higher than those of brackish water treatment (CK). Furthermore, compared with CK, the α-amylase activity in wheat seeds was significantly increased. Germination rate could be used as the quantitative evaluation index for wheat seed germination under the condition of oxygenated brackish water irrigation. According to the relationship between germination rate and DO concentration, the DO concentration with the maximum germination rate was 19 mg·l−1. During the wheat seedling growth period, compared with CK, the oxygenated brackish water with DO concentration of 20 mg·l−1 significantly increased the contents of soluble sugar and soluble protein in the leaves, whereas significantly decreased the proline content. Soluble sugar content was selected as the quantitative evaluation index for wheat seedling growth. The electrical conductivity and the activities of alkaline phosphatase and nitrate reductase in the root zone soil were significantly influenced. Thus, the oxygenation of brackish water with appropriate DO concentration could effectively improve the salt stress caused by brackish water irrigation. These results provide an effective method for the safe and efficient utilization of brackish water.