Abstract:Seedlings of three subtropical forest species, Schima supeba, Cryptocarya concinna,and Castanopsis fissa, were grown under varied light conditions at 100%, 40% and 16% of nature sunlight intensity. During the winter time, the fully exmpding leaves in the top of the Plants were collected for determination of chlorophyll fluorescence,contents of chlorophyll, carotenoid, soluble protein and soluble sugar, as well as the permeability of cell membrane.All of the species exhibited acclimation to different irradiances and low temperature in winter. No considerable leakness of leaf electrolyte was observed, but the toeal electrolyte of leaf was declined at low irradiance.Chlorophyll fluorescence Fv/Fm ratio was slightly decreased (Scheime superba and Castanopsis fissa) or markedly decreased (Cryptocarya concinna) in leaves at 100% of irradinnce. Same trend of decreasing Fv/Fm value was found in three species after treatment for 9 hours with leaf discs at 5℃ and light intensity of 100μmol m-2s-1. The ratios of Chl a/b and soluble sub/protein and Fv/Fm were lower in Cryptocarya concinnathan in Schima superba and Schima superba and the former was susceptible to high light and low temperature, but the latter two species showed a higher ability of environmental acclimation.In comparision with 100% and 16% of irradiance, however, the similar ratio of soluble protein/Chl in three species, and more soluble sugar and plotein in leaves at 40% of irradiance showed that this light level favoured the normal synthesis of organic compounds durins winter season.
