Effect of elevated atmospheric CO₂ concentrations on photosynthesis light response characteristics of three coniferous tree species seedlings

Potted seedlings of Pinus koraiensis, Picea koraiensis, and Larix olgensis, the dominant coniferous tree species in Changbai Mountain, were grown under elevated CO₂ concentration (700 μmol·mol^-1) and ambient CO₂ concentration (400 μmol·mol^-1) for two year, and their photosynthesis light response curves were determined with Cl-301PS CO₂ gas analysis system under a series of light intensity from 0 to 2500 μmol·quanta·m^-2·s^-1. The comparison of dark respiration rate (DRR), maximum net photosynthetic rate (A_max), quantum use efficiency (QUE), light compensation point (LCP), light saturation point (LSP) and photo inhibition point (PP) for the seedlings of these coniferous tree species under different CO₂ concentration showed that Larix olgensis, which had better adaptation of photosynthesis to elevated CO₂ concentration, was heliophilous species. The shade-tolerant species Picea koraiensis showed the least adaptation of photosynthesis to elevated CO₂ concentration. Furthermore, the relationship between photosynthetic physiological character of tree species and their succession status was also discussed in this paper.