Ecological Responses of Betula Platyphylla Suk and Pinus Tabulaeformis Carr.Seedlings to Controlled Light Instensity Conditions
Betula Platyphylla Suk and Pinus Tabulaeformis Cart.are two main pioneer tree species among the mountain forest system in North China.One-year-old Betula Platyphylla Suk and Pinus Tabulaeformis Carr.seedlings were selected in this study to be treated with four light intensities (100％,50％,25％,and 12.5％ relative transmittance levels) in a common garden experiment.After one growing season,the differences in photosynthetic traits of these two seedlings were measured.Results showed that after shade treatments,light compensation point of one-yearold Betula Platyphylla Suk and Pinus Tabulaeformis Carr.decreased significantly,but stomatal conductance significantly increased,showing consistent response trend.At 50％ relative transmittance level,the maximum net assimilation rate (Amax) and light saturation point decreased significantly,but the contents of chlorophyll a,b and overall chlorophyll of Betula Platyphylla Suk seedlings increased as the light intensity decrease.Meanwhile,the photosynthetic plasticity index of Betula Platyphylla Suk was greater than that of Pinus Tabulaeformis Carr.In addition,their photosynthetic plasticity index was greater than their morphological plasticity index.The above results indicated that both Betula Platyphylla Suk and Pinus Tabulaeformis Carr.seedlings had stronger light response and plasticity with regard to photosynthetic traits,corresponding to their ecological traits as pioneer tree species.At the same time,the highlight environment adaptability of Betula Platyphylla Suk was greater than that of Pinus Tabulaeformis Carr.
国家科技期刊平台
NSTL
万方数据
维普
