Figure 9. The proposed model illustrating the amplification loop involving CDF4, ABA, and ROS.

CDF4 is a senescence‐associated gene with expression induced by ABA and ROS, two well‐known leaf senescence inducers. CDF4 further promotes ABA biosynthesis by activating the transcription of NCED2 and NCED3 and repressing H₂O₂ scavenging by inhibiting CAT2 transcription. At the same time, CDF4 can bind to the PGAZAT promoter region, thus promoting the floral organ abscission process. Given that ABA and ROS also mutually promote each other's accumulation, CDF4, ABA, and ROS form a tripartite amplification loop to accelerate leaf senescence and floral organ abscission. As a result, the levels of CDF4, ABA, and ROS undergo a gradual increase driven by their interlinking positive feedback loops during the leaf senescence and floral organ abscission process. In the legend, the solid and dotted lines represent the direct interaction obtained in this research and indirect interaction, respectively. And the arrow‐ and T‐ending lines represent positive and negative regulatory pathways, respectively.