Abstract: To understand responses and adaptation of 2-needled pine photosynthesis to environmental changes, we conducted a provenance experiment on Pinus densiflora Sieb. et Zucc(5 provenances),Pinus sylvestris var. sylvestriformis(1 provenance),and Pinus sylvestris var. mongolica(3 provenances) respectively. Seeds, collected from 9 provenances with significantly different geographical and climatic conditions, were planted and grew up in greenhouse of Northeast Forestry University. Measurement of the seedlings was conducted after two years. Significant diffrence of lightsaturated net photosynthetic rate(P_max)(p=0.18), dark respiration rate(R_d)(p=0.15) and apparent quantum yield(AQY)(p=0.18) was not be found among the three species, but was found among the 9 provenances. AQY from Xingkaihu showed the highest (0.084 5±0.002 4 mol CO₂·mol^-1 photons), which was higher 13.10%~159.23% than that of other provenances. R_d was high from Heihe and Xingkaihu provnences(1.62±0.18 μmol CO₂·m^-2·s^-1, 1.52±0.30 μmol CO₂·m^-2·s^-1 respectively) and lower from Antu and Dongning provenances(0.40±0.01 μmol CO₂·m^-2·s^-1, 0.34±0.03 μmol CO₂·m^-2·s^-1 respectively). There are significant diffrence of P_max among the 9 provenances(p=0.02) averaging 18.36±1.81 μmol CO₂·m^-2·s^-1 from Xingkaihu, Dongning, Korea, Jidong, Erdaobaihe and Honghuaerji, which higher than that of from Antu, Mohe and Heihe averaging 12.57±0.86 μmol CO₂·m^-2·s^-1. Significant difference was found among the populations in height of seedlings and base stem diameter. Among thises populations, the height of seedlings is highest for Korean population, and lowest for Heihe population. The base stem diameter of seedlings is highest for Xingkaihu population and lowest for Antu population. The maximum of these two characters is 3 times higher than the minimum. The significant variations in the photosynthetic capacity and some related factors from the nine 2-needled pine provenances suggest an evident of ecophysiological adaptation of photosynthesis to their original environmental conditions.

Key words: 2-needled pine, provenance, photosynthetic capacity, growth characters