Effect of NaCl stress on tillering of rice (Oryza sativa L.) and mitigation regulation of prohexadione-calcium

Abstract

Salt stress inhibits crop quality and yields, and growth regulators are used to enhance salt tolerance of crops. Here, we report the effect of prohexadione-calcium (Pro-Ca) on rice tillering under salt stress. The results showed the malondialdehyde (MDA) levels and electrolyte leakage in leaves were increased as well as the expression of the antioxidant enzymes was induced under salt stress. Foliar application of Pro-Ca reduced seedling height, increased the stem base width, improved the lodging resistance of rice, decreased MDA content and electrolyte leakage, and alleviated the membrane damage of rice under salt stress. Exogenous Pro-Ca also increased the net photosynthetic rate (Pn) and the stomatal conductance (Gs) of rice, decreased the intercellular CO2 concentration (Ci), and increased the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) of rice at the tillering stage under salt stress. In conclusion, Pro-Ca improved the salt tolerance of rice at the tillering stage by enhancing the lodging resistance of rice, alleviating cell membrane damage of leaves caused by NaCl stress, and enhancing photosynthesis and antioxidant capacity. Effect of Pro-Ca on rice at the tillering stage under 0.3% NaCl stress was discussed, which provided a theoretical basis for revealing physiological changes at the rice tillering stage.