Abstract
The process of rice (Oryza sativa L.) seedling cultivation is often subjected to adverse environmental stress. Biostimulants regulate the robust growth of rice seedlings and play a crucial role in promoting the green and ecological development of agriculture. In this study, 1.0 and 2.0 g • m-2 of the biostimulant were applied to soil in rice seedbeds. Growth indicators of rice, antioxidant enzyme activities and soil physicochemical characteristics were assessed at the 2.5-leaf and 4-leaf stages of rice. The results indicated that applying 2.0 g • m-2 of the biostimulant at both the 2.5-leaf and 4-leaf stages had the most significant promoting effect on rice growth. At the 2.5-leaf and 4-leaf stages, the number of fibrous roots increased by 23.43% and 22.25%, stem base width increased by 19.05% and 19.58%, above ground dry weight increased by 18.09% and 16.47%, root dry weight increased by 19.67% and 18.28%, leaf peroxidase (POD) activity increased by 34.44% and 42.94%, superoxide dismutase (SOD) activity increased by 37.24% and 56.79%, malondialdehyde (MDA) content decreased by 18.60% and 27.67%, and chlorophyll content increased significantly by 28.31% and 34.24%, respectively. At the 4-leaf stage of rice, urease, phosphatase and cellulase activities in the seedbed soil increased by 42.13%, 25.96% and 33.59%, respectively, while soil alkaline nitrogen, available phosphorus and available potassium content decreased by 19.76%, 19.02% and 17.88%, respectively. The application of biostimulants played a crucial role in promoting the growth of rice seedlings and enhancing soil nutrient absorption.