中亚热带常绿阔叶林优势树种幼树光合特性季节动态

基于指数改进模型估算了亚热带常绿阔叶林优势树种米槠(Castanopsis carlesii)、丝栗栲(Castanopsis fargesii)和木荷(Schima superba)生长旺盛期(春、夏、秋季)的光合参数特性。结果表明:米槠、丝栗栲、木荷光饱和点春季最小,分别为1 241.25、1 245.93、1 366.49 μmol/(m²·s); 最大净光合速率夏季均最大,分别为3.78、5.39、7.20 μmol/(m²·s)。木荷春季的光饱和点、光补偿点、最大净光合速率、暗呼吸速率均大于米槠和丝栗栲。在夏季和秋季,木荷和丝栗栲光饱和点均大于米槠; 木荷最大净光合速率均大于米槠和丝栗栲,且在秋季其最大净光合速率仍大于米槠。综合比较得出:木荷具有较强的光合能力和光环境适应能力,其次是丝栗栲,米槠较差。

Seasonal dynamic study on photosynthetic characteristics of dominant evergreen broadleaved forest

Based on modified exponential model, we estimated photosynthetic parameters of Castanopsis carlesii, C. fargesii and Schima superba during their vigorous growth period(spring, summer, autumn), which were dominant tree species in evergreen broad-leaved forest. The light saturation points of Castanopsis carlesii, C. fargesii and S. superba in spring were lest in three seasons, were 1 241.25, 1 245.93, 1 366.49, μmol/(m²·s)respectively, and their maximum net photosynthetic rates in summer were most in three seasons, were 3.78, 5.39, 7.20 μmol/(m²·s)respectively. The light compensation point, light saturation point, maximum net photosynthetic rate, dark respiration rate of Schima superba were all more than Castanopsis carlesii and C. fargesii in spring. In summer and autumn, the light saturation points of Castanopsis fargesii and S. superba were both more than Castanopsis carlesii. Furthermore, the maximum net photosynthetic rates of S. superba were more than Castanopsis carlesii and C. fargesii, and also more than C. carlesii in autumn. The result of comprehensive comparison was that the photosynthetic capacity and adaptability to light environment of Schima superba were strong, and then that was C. fargesii, and C. carlesii was last.