Objective To study the response of photosynthetic characteristics of different ecological tree species to light and nutrient supply for providing a scientific basis for plantation cultivation.

Method The seedlings of Quercus acutissima, Phoebe bournei, and Schima superba were used. This study included two light intensities (natural full light and 45% full light) and three N:P ratios (N:P=5, N:P=15, N:P=45). We measured the changes of Photosynthetic fluorescence parameters, and seedlings’ height, seedlings’ ground diameter to study the changes of plant photosynthetic characteristics in different environments, and analyze the relationship between seedling growth and photosynthetic parameters.

Result (1) Compared with the full light treatment, the shading treatment decreased the light saturation point (LSP) and the maximum net photosynthetic rate (P_nmax) of Q. acutissima, and increased the P_nmax of S. superba. but had no significant effect on P_nmax of P. bournei. Under the two light treatments, fertilization increased the LSP and light compensation point (LCP) of P. bournei and S. superba, but the effects of fertilization on the shading LSP and LCP of Q. acutissima were less. (2) Shading significantly reduced the quantum yield of regulated energy dissipation of PSⅡ Y(NPQ) of Q. acutissima, P. bournei and S. superba, and significantly increased the quantum yield of non-regulated energy dissipation of PSⅡ Y (NO) . Under the full light treatments, fertilization generally increased the effective quantum yield of PSⅡ Y(II) and ETR of Q. acutissima, P. bournei and S. superba, but decreased Y(NPQ) . Under the shading treatments, fertilization significantly increased Y(II) and ETR of P. bournei, while Y(II) and ETR of Q. acutissima increased significantly when the N:P supply ratio was 5. Y(II) and ETR of S. superba increased significantly when the N:P supply ratio was 15. (3) Compared with the full light treatment, shading significantly increased the contents of chlorophyll a, chlorophyll b, chlorophyll a + b and carotenoid of Q. acutissima, P. bournei and S. superba. Under the two light treatments, fertilization significantly increased the photosynthetic pigment content of Q. acutissima, S. superba and P. bournei (only full light treatment). (4) Regardless of light or shading, fertilization generally increased the relative growth rates of seedling’s height and ground diameter of the three tree species, and there was a positive correlation between the growth and photosynthetic pigment.

Conclusion Photosynthetic characteristics and growth of Q. acutissima, P. bournei and S. superba are affected by the interaction of light and fertilization. The effect of nitrogen and phosphorus fertilization on seedling growth under different light intensities depends on nitrogen and phosphorus supply ratio and tree species.