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Background: Low temperatures during flowering severely affect crop growth and yield. Methods: This experiment was conducted under potted conditions with LXD 4 and TJH as test materials and pre-sprayed with exogenous ABA at a concentration of 20 mg·L-1 at flowering stage, respectively and then with an average of 15℃ condition for 5 days. Result: The results showed that foliar spraying exogenous ABA effectively inhibited the increase of MDA content and relatively significantly improved the photosynthetic parameters such as Gs and Tr and alleviated the loss of yield factors caused by chilling stress. Compared with spraying water, spraying exogenous ABA can significantly increase the yield per pot of LXD 4 by 6.72~17.77% and TJH by 6.41~37.04% under low temperature conditions. In summary, foliar spraying exogenous ABA ameliorated the effects of chilling stress on the physiological characteristics of adzuki bean leaves and improved yield as a result of improved antioxidant defense mechanisms which impeded lipid peroxidation. Thus, we conclude that foliar spraying exogenous ABA could decelerate the damages caused by chilling stress to some extent. [ABSTRACT FROM AUTHOR]

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 pro-longation 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. S33Q7 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. [ABSTRACT FROM AUTHOR]

In order to explore the difference on the resistance physiology and yield and the mitigation effect of uniconazole (S3307) pretreatment under waterlogging stress, the pot experiment was conducted using Longxiaodou 4 (LXD 4) and Tianjin-hong (TJH). The anti-stress physiological indexes and yield were measured on 5th day after waterlogging stress and foliar spraying S3307 at seedling stage, and samples were taken every day. The results showed that leaf physiological indexes in waterlogging stress were changed during seedling stage, the content of H2O2, MDA, proline and soluble protein were significantly increased, as the same as the content of ABA, IAA, and SA, and the activities of SOD, POD, and CAT. Waterlogging treatment for five days resulted in a significant decrease in the output of LXD 4 in a single pot by 8.40% to 12.61%, and that of TJH decreased by 9.91% to 10.01%. S3307 had the effect of resisting waterlogging stress, and could effectively increase the content of proline and soluble protein in the leaf of adzuki bean, significantly reduced the content of H2O2 and MDA, significantly increased the activity of SOD and POD, the value of SOD/POD and SOD/CAT, significantly increased the ABA and SA content, and significantly inhibited the increase in IAA content. Foliar spraying S3307 significantly increased the output of LXD 4 by 2.85% to 6.18% under waterlogging treatment for four days, and significantly increased the yield of TJH by 2.85% to 3.95%, respectively. This study concluded that there were significant differences under physiological stress in reactive oxygen species accumulation, membrane lipid peroxidation, antioxidant enzyme activities and hormone levels among different varieties of adzuki bean under waterlogging stress. Spraying S3307 could effectively alleviate the effects of waterlogging stress on the physiology and yield in adzuki bean. The results provide a theoretical basis for further studying the physiological mechanism of adzuki bean resistance to waterlogging at the seedling stage and improving the yield of adzuki bean under waterlogging stress. [ABSTRACT FROM AUTHOR]