Abstract: Two-year-old red pine seedlings were grown in pots to study the effects of different soil water contents (including aridity, waterlogging stress and stress relief) on the chlorophyll fluorescence parameters of red pine seedlings in order to provide theoretical foundation for the expansion of cultivation and management of red pines. The results were as follows: (1)Dramatic responses in fluorescence origin (F_o), fluorescence maximum (F_m), fluorescence variety (F_v), maximal photochemical efficiency (F_v/F_m) and quantum yield of PSⅡ electron transport (Φ_PSⅡ) were detected under different soil water stress (p<0.05); (2)Under both aridity and waterlogging stress, F_v/F_m decreased with the increasing of the stress intensity and the extending of the stress time, presenting as FC60>FC80>FC>FC40>FC20>FL, and the F_v/F_m in all treatments had risen with various extents (recovery speed of aridity treatment was faster than that of waterlogging treatment); (3)The chlorophyll fluorescence parameters under the condition of FC60 were optimal. Therefore, the moderately and mildly arid sites are more suitable for the growth of red pine seedlings.

Key words: Red Pine, water stress, relief stress, chlorophyll fluorescence