Effects of light intensity on the growth, photosynthetic characteristics, and secondary metabolites of Eleutherococcus senticosus Harms.

In this investigation, we used the growth, photosynthetic physiological parameters, and targeted metabolite analysis to evaluate the responses of Eleutherococcus senticosus in different shading treatments. The results showed that the moderate shading treatment (Z1) promoted the growth and inhibited photosynthesis of plants. The severe shading treatment (Z2) inhibited both the growth and photosynthesis of the plants. Besides, Z1 had no significant effect on the PSII, while Z2 inhibited the PSII. Most of the eight medicinal metabolites accumulated in the Z1. The C6C1- and C6C3-type phenolics accumulated in the Z1, and the C6C3C6-type in the Z2. In conclusion, the moderate shading treatment accumulated more defensive phenolics; this might be the reason for this shading condition promoting the growth and the accumulation of medicinal metabolites of the plant. The result of this study laid a theoretical foundation for the further study of shading treatments on the secondary metabolism of Eleutherococcus senticosus. [ABSTRACT FROM AUTHOR]