The Effect of Jingdusha on Cucumber Chlorophyll Fluorescence Parameters under Corynespora cassiicola Stress

Aims: The paper aimed to clarify the effect of Jingdusha on chlorophyll fluorescence parameters of cucumber seedlings under Corynespora cassiicola stress.

Study Design: We applied the method of artificial inoculation in the pot and analyzed the changes in the content of chlorophyll and chlorophyll fluorescence parameters.

Place and Duration of Study: In 2018, these experiments were conducted in the College of Bioscience and Biotechnology of Shenyang Agricultural University (Lab 240).

Methodology: The seedlings in the two-leaf period were induced by 2.0 mL·L-1 of Jingdusha, then inoculated C. cassiicola for 24 h. Cucumber seedlings of each treatment group were randomly selected for the content of chlorophyll and chlorophyll fluorescence parameters determination. The leaves of cucumber seedlings in each treatment group were randomly collected at 1 d, 3 d, 5 d, 7 d and 9 d after inoculation for the determination of the content of chlorophyll and chlorophyll fluorescence parameters.

Results: When C. cassiicola infects cucumber, Jingdusha can effectively increase the energy conversion efficiency of the PSII central response and the potential activity of PSII, besides, the photosynthetic reaction activity did not change significantly in the early stage, but increased significantly in the later stage and rescure the degree of photosynthetic structural damage.

Conclusion: In conclusion, under C. cassiicola stress, plant immune resistant inducer Jingdusha can effectively increase the capacity of PSII and the efficiency of PSII operation under the light in cucumber seedlings, reduce the damage of photosynthetic structure, increase the ability of PSII to accept and transfer electrons, as well as reduce the degradation of chlorophyll and the dissipation of light energy under C. cassiicola stress.