Morphological and Physiological Responses of Suaeda salsa under Drought and Salt Stress

Abstract

Abstract Drought and salt stress are major constraints for agricultural survival and development. Suaeda salsa is one of the hot spots plants in the study of drought- and salt-tolerant with important soil improvement and ecological restoration roles. Therefore, it is significant to understand the effects of water shortage and salt stress on physiological and biochemical properties of plants. In the study, two different horizontal gradients were set up to measure the phenotype, physiological and biochemical characteristics of S. salsa under drought and salt stress. The results showed that drought and salt stress inhibited the growth of S. salsa. Different salt concentrations significantly increased the activities of catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD). With increasing concentration of salt stress, malondialdehyde (MDA), soluble protein and soluble sugar contents showed an upward trend, while chlorophyll b and carotenoid contents first decreased, and then increased by 28.21% and 45.45% due to the accumulation of proline. As drought stress concentration increased, the POD activity first decreased and then increased, while soluble protein contents showed an opposite trend. Under severe drought, chlorophyll a/b and carotenoid contents decreased by 52.0%, 57.01%, and 20.00%, respectively. Our results indicated that drought and high salinity inhibited the growth, morphology, and most physiological and biochemical characteristics of S. salsa, while the activities of antioxidant enzymes, content of osmotic adjustment substances and photosynthetic pigments might be related to the accumulation of proline.