Abstract: Pinus koraiensis is an ecologically important tree species in Northeast China. To explore its light adaptation characteristics and related eco-physiological mechanisms, the 3-, 5-, and 7-year old P. koraiensis seedlings were transplanted under the conditions of 100%, 60%, 30%, and 15% of full sunlight (marked as FI, II, LI, and WI, respectively), and sampled from forest gap, understory, and edge (marked as G, U and E, respectively) under actual light. The study on the changes of net photosynthetic rate (Pn), chlorophyll (Chl) content per unit leaf area, and specific leaf mass (LMA) showed that the Pn of 3- and 5-year old P. koraiensis in treatments II and LI was similar, and higher than that in treatment FI. 7 years old P. koraiensis had the highest Pn in treatment FI. In all treatments, P. koraiensis had a mono-peak change of Pn, with the peak at 13:00. The dark respiration rate (Rd) and maximum photosynthetic rates (Amax) of 3- and 5-year old P. koraiensis were higher in treatment LI than in treatment FI. The LMA decreased with decreasing light intensity, suggesting that P. koraiensis could effectively adapt to the changes of light condition in this way. No significant differences were observed in the photosynthetic characteristics of 3- and 5-year old P. koraiensis between treatments II and U, and between treatments LI, WI, and E, which suggested that the simulated light conditions matched well with the actual one. The plasticity index of eco-physiological parameters of 3 years old P. koraiensis was the highest. It was concluded that 1) the light requirement of P. koraiensis increased with its increasing age, 2) the optimal light condition for 3- and 5-year old P. koraiensis was 30%〖KG-*2〗-〖KG-*7〗60% of full sunlight, and that for 7 years old P. koraiensis was full sunlight, and 3) the favorable age of P. koraiensis seedlings for transplanting was 3 years old.

Key words: Plant ethanol extracts, Plutella xylostella, Life table, Interference index of population control, Index of population trend