Relationship between delta 13C and photosynthetic parameters and their responses to leaf nitrogen content in six broadleaf tree species.

摘要

Stable carbon isotope composition ( delta 13C), net photosynthetic rate (PN), actual quantum yield of photosystem 2 (PS2) electron transport ( Phi PS2), nitrogen content (Nc), and photosynthetic nitrogen use efficiency (PNUE) in the leaves of six broadleaf tree species were determined under field environmental conditions. The six tree species were Magnolia liliiflora Desr., M. grandiflora Linn., M. denudata Desr., Prunus mume (Sieb.) Sieb. et Zucc. cv. Meiren Men, P. mume (Sieb.) Sieb. et Zucc. f. alphandii (Carr.) Rehd., and P. persica (L.) Batsch. var. rubro-plena. The relationships among delta 13C, Phi PS2, PN, and PNUE, as well as their responses to Nc in the six species were also studied. Both PN and delta 13C negatively correlated with Nc, but Phi PS2 positively correlated with Nc. This indicated that with Nc increase, PN and delta 13C decreased, while Phi PS2 increased. There were weak negative correlations between delta 13C and PNUE, and strong negative correlations (p<0.01) between Phi PS2 and PNUE. According to the variance analysis of parameters, there existed significant interspecific differences (p<0.001) of delta 13C, PN, Phi PS2, PNUE, and Nc among the tree seedlings of the six tree species, which suggests that the potential photosynthetic capacities depend on plant species, irradiance, and water use capacity under field conditions..