Abstract:In this study, the expression of CELL GROWTH DEFECT FACTOR 1 (CDF1)like protein encoding gene P1 was detected in different developmental stages of Arabidopsis thaliana leaves by realtime PCR. The results showed that P1 is expressed in all developmental stages of rosette leaves, but its expression was the highest in senescent leaves. GUS staining showed that P1 promoter has high driven activity in leaves. In seedlings and the vegetative stage plants (4-5 weeks old), GUS staining can be detected in all rosette leaves, but after the plants entered into reproductive stages (after 6 weeks old), the rosette peripheral leaves began to yellowing and GUS staining was centralized to the senescing leaves and increased with leaf senescence progress, but the stain in younger leaves was weaker. GUS fluorescent quantitative analyses further confirmed the staining results. By searching cisacting elements in P1 promoter, the elements related to MeJAresponsiveness, heat stress responsiveness, droughtinducibility and salicylic acid responsiveness which have been previously proved to induce leaf senescence reactions were found. These results indicate that P1 as a membrane protein in leaves is possibly participate in the cell response to leaf senescence signals. This study lays a foundation for the molecular function verification of P1 during leaf senescence process in future.