Effects of uniconazole on physiological characteristics and microstructure under waterlogging stress at seedling stage in soybean

To explore the effects of waterlogging stress on the physiological characteristics and microstructure of soybean and the mitigation effect of S3307, the physiological characteristics of soybean leaves and roots, the microstructure of hypocotyls and the regulation effect of S3307 were investigated using Kenfeng 14 as the experimental material with S3307 sprayed on the leaves of soybean at V1 stage and five days after waterlogging stress in a pot experiment. The results showed that waterlogging stress increased the number of ventilated tissues in soybean hypocotyl, and the area of ventilated tissues increased gradually with the prolongation of waterlogging stress. S3307 could improve soybean adaptability to waterlogging adversity, increase the number of ventilated tissue and cope with the hypoxia stress by waterlogging stress on plants. Compared with CK, waterlogging stress increased the accumulation of ROS and membrane lipid peroxidation in leaves and roots, and gradually increased with the prolongation of stress time. Meanwhile, the activity of enzymatic antioxidant defense system was enhanced at early stage under waterlogging stress, resulting in an increase in the content of osmotic regulatory substances, which decreased with the prolongation of stress time. S3307 can promote the activity of antioxidant enzyme in leaves and roots, inhibit the excessive accumulation of ROS and MDA content, maintain a high content of osmotic regulation substances, and alleviate the damage caused by waterlogging stress. In summary, there were differences in response to different organs under waterlogging stress. S3307 can alleviate the damage to soybean plants caused by waterlogging stress to a certain extent.