Physiological Mechanisms of Delaying Leaf Senescence in Maize Treated with Compound Mixtures of DCPTA and CCC

At the beginning of silking, maize production began to form, but leaves started senescence and photosynthetic capacity decreased at this time, all of those severely restricted the formation of the production. In order to study the effects of exogenous substances on the process of leaf senescence, 40 mg
• L−1 DCPTA and 20 mg
• L−1 CCC were mixed in the research. When the maize grew to the six expanded leaves stage, 10 mL compound mixtures (TR) were sprayed on both sides of leaves for per plant, and the control was treated with water (CK). Three plants were selected randomly for determination of physiological index at the 10, 20, 30, 40 and 50 days after silking. The results showed that TR could increase the chlorophyll content significantly, Fv/Fm, Fv/F0 and Y(II) values of TR were higher than those of CK while F0 values were opposite. Compared with CK, TR increased SOD and POD activity and soluble protein content, reduced MDA content. Correlation analysis showed that chlorophyll content had negative correlation with F0, and MDA content had negative correlation with other indexes. Compared with CK, TR reduced the negative correlation effect between chlorophyll content and MDA, increased the positive correlation effect between chlorophyll content and Fv/Fm, SOD, POD, soluble protein. The study provided theoretical and experimental evidence for the application of the compound mixtures of DCPTA and CCC to the production.