Compare on Photosynthetic Characteristics Among Provenances of Pinus yunnanensis

The photosynthetic characteristics were compared for twoyearold seedlings of Pinus yunnanensis sampled five provenances by using the Li6400 to reveal the difference of photosynthetic characteristics among provenances.The results indicated that all photosynthetic parameters studied were significant difference (p<001) among provenances of P.yunnanensis except the light use efficiency (LUE).There were light differences in the net photosynthetic rate (Pn) among provenances when the illumination intensity increased initially based on light response curve fitting,but significant differences came to light when the illumination intensity increased progressively. There were significant (p<005) and extremely significant (p<001) correlations most of pairwise photosynthetic indexes.The extremely positive correlations existed in pairwise Pn,stomatal conductance (Gs) and transpiration (Tr).The correlations were relatively heavy between Pn and Gs as well as photosynthetically active radiation (PAR), which indicated that Pn was a main photosynthetic capacity factor.There were the highest maximum net photosynthetic rate (Pmax),light saturation point (LSP) and water use efficiency (WUE),and the minimum Tr,Gs and light compensation point (LCP) in Baoshan (BS) provenance.The provenance has the high potential photosynthetic capacity and the strong drought resistance ability,which further illustrated Baoshan provenance has the strong potential to adaptable to the light environment.