Abstract: We evaluated the ecological adaptability of Polygonatum cyrtonema Hua to different light conditions and determined the photosynthetic, fluorescence characteristics and growth performances of P.cyrtonema Hua. The survival rate was 100%, when the light intensity was equal or greater than 75% of full light, and the survival rate of P.cyrtonema Hua significantly reduced with the decreasing of the light intensity. Leaf area, basal diameter, and height of individual of P.cyrtonema Hua reached peak value at 45%-75% of full light, and specific leaf weight was the highest under 75% of light transmittance. When decreasing the light intensity, the contents of Chl a, Chl b and Chl contents increased firstly and then decreased, while the rate of Chl（a/b）and Car content changed in the inverse trend. Light had significant effect on T_r of P.cyrtonema Hua, while it showed no significant effect on P_n diurnal progress. When light intensity increased, Pmax decreased firstly and then increased. LCP and LSP decreased, while AQY changed insignificantly. Light intensity had significant effect on fluorescence parameters, while light intensity showed insignificant effect on F_v/F_m. Low light intensity influenced fluorescence parameters more obviously than that of high light intensity. Therefore, P.cyrtonema Hua is tolerant to low light environments which had high utilization efficiency in blue light, and it can grow well under 45%-75% of full light.

Key words: Polygonatum cyrtonema Hua, light intensity, growth characteristics, chlorophyll content, chlorophyll fluorescence parameters