Diurnal Variation of Photosynthetic Parameters and Response Character of Cyclocarya paliurus Seedlings

Determinations were conducted on net photosynthetic rate(Pn), transpiration rate(Tr) stomatal conductance(Gs), intercellular CO2 concentration(Ci), and response of 1-year Cyclocarya paliurus seedlings. The result showed that diurnal variation of Pn, Tr, Gs had double peaks occurred at 9:30 and 13:00, while that of Ci topped in the morning and evening, the lowest at 11:30. Pn had extremely significant correlation with Gs (P < 0.01), significant correlation with Tr (P < 0.05). Light compensate point (LCP) was 14.63?mol/(m2?s), light saturation point (LSP) was 1 200?mol/(m2?s), maximum net photosynthetic rate (Pnmax) was 8.32 ?mol/(m2?s). The experiment demonstrated that photosynthetically available radiation (PAR) and atmospheric temperature (Ta) had effect on photosynthetic parameters of tested seedlings.