Drought and rewatering practices improve adaptability of seedling maize to drought stress by a super-compensate effect

Abstract

Periodic drought adversely affects the growth and yield of summer crops in the Huang-Huai-Hai Plain. Drought-rewatering practice as one of the important agronomic measures to improve crop drought resistance. A field experiment was conducted to investigate practice physiological, biochemical, and molecular responses of maize seedling after two rounds of repeated drought and rewatering treatments. The results demonstrated that rewatering following repeated drought events had a compensatory effect on the photosynthetic rate (Pn) and on osmotic and antioxidant regulation. Specifically, the Pn and stomatal conductance (Gs) increased by 10.12% and 5.61%, respectively, compared to the control (CK) during the second round of treatment. Additionally, soluble protein (sPro) and proline (Pro) content rose significantly, with increases of 26.12% and 343.49% observed on day 5 of the second round, leading to a gradual reduction in leaf water content and osmosis. Following drought exposure, the activities of superoxide dismutase (SOD) and peroxidase (POD) contributed to the decreased levels of malondialdehyde (MDA), with both enzymes recovering during rewatering. In contrast, plant height, leaf area, and biomass were significantly reduced in the CK group. Notably, root length increased by 21.05% after the drought-rewatering practice, enhancing the maize seedlings' ability to adapt to drought stress. Overall, maize seedlings exhibited enhanced adaptability to drought conditions following two cycles of drought-rewatering treatments.