Background: Rice (Oryza sativa L.) is a food crop for humans worldwide. However, temperature has an effect during the vegetative and reproductive stages. In high-latitude regions where rice is cultivated, cold stress is a major cause of yield loss and plant death. Research has identified a group of plant-specific transcription factors, DNA binding with one zinc fingers (DOFs), with a diverse range of functions, including stress signaling and stress response during plant growth. The aim of this study was to identify Dof genes in two rice subspecies, indica and japonica, and screen for Dof genes that may be involved in cold tolerance during plant growth. Results: A total of 30 rice Dofs (OsDofs) were identified using bioinformatics and genome-wide analyses and phylogenetically analyzed. The 30 OsDOFs were classified into six subfamilies, and 24 motifs were identified based on protein sequence alignment. The chromosome locations of OsDofs were determined and nine gene duplication events were identified. A joint phylogenetic analysis was performed on DOF protein sequences obtained from four monocotyledon species to examine the evolutionary relationship of DOF proteins. Expression profiling of OsDofs from two japonica cultivars (Longdao5, which is cold-tolerant, and Longjing11, which is cold-sensitive) revealed that OsDof1 and OsDof19 are cold-inducible genes. We examined the seed setting rates in OsDof1- and OsDof19-overexpression and RNAi lines and found that OsDof1 showed a response to cold stress. Conclusions: Our investigation identified OsDof1 as a potential target for genetic breeding of rice with enhanced cold tolerance.

Seedling cultivation of rice (Oryza sativa L.) is a critical initial step in rice production. This study investigated the effects of sowing methods and strigolactone (GR24) on rice seedlings under salt stress. Results showed that drill-sown seedlings exhibited superior quality under normal conditions compared to broadcast-sown seedlings. Salt stress significantly increased the contents of Cl⁻, Na⁺, reactive oxygen species (ROS), and malondialdehyde (MDA), disrupted chloroplast structure and hormonal balance, and reduced gas exchange parameters and chlorophyll fluorescence parameters. Notably, drill-sowing conferred stronger salt tolerance than broadcast-sowing. Exogenous application of GR24 enhanced activities of antioxidant enzymes—including superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD), and catalase (CAT)—and elevated non-enzymatic antioxidant contents such as ascorbic acid (ASA), glutathione (GSH), total phenolics, and flavonoids, alongside related enzyme activities. Concurrently, GR24 reduced Na⁺ and Cl⁻ accumulation, lowered the Na⁺/K⁺ ratio, and increased the contents of K⁺, Ca²⁺, Mg²⁺, and hormones. Consequently, GR24 decreased MDA and ROS levels, protected membrane integrity, reduced electrolyte leakage, repaired chloroplast structure, and improved gas exchange and chlorophyll fluorescence parameters. Due to their superior spatial distribution and photosynthetic efficiency, drill-sown seedlings synergized with GR24 to enhance antioxidant capacity under salt stress, enabling more effective scavenging of peroxidative radicals, stabilization of the photosynthetic system, and mitigation of salt-induced growth inhibition. Ultimately, this combination demonstrated greater stress alleviation than broadcast-sown seedlings.

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 Tianjinhong (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.