厚壁毛竹光合作用对CO_2浓度倍增的短期响应

采用Li-6400P光合测定仪对比测定了大气CO2浓度和短期CO2浓度倍增下不同季节厚壁毛竹的光合特性,结果表明:CO2浓度加倍促使最大净光合速率、净光合速率、水分利用率、光合量子效率和光饱和点升高,年平均增幅分别为62.79%、48.74%、94.41%、8.70%和16.67%;CO2浓度加倍促使蒸腾速率、暗呼吸速率和光补偿点下降,年平均降幅分别为17.60%、37.25%和40.50%。不同季节厚壁毛竹光合生理特性参数在CO2浓度加倍后的增加幅度或降低幅度与叶片生理活性和气候变化密切相关。CO2浓度的倍增并未明显改变厚壁毛竹光合特性的季节变化规律,除光补偿点外,其它光合参数的季节大小顺序仍与大气CO2浓度下的相同。厚壁毛竹光合作用对短期CO2浓度升高的响应特征与C3植物光合作用对短期CO2浓度升高响应的普遍规律相符。

Photosynthetic responses of Phyllostachys edulis'Pachyloen' to doubled CO2 concentration

Phyllostachys edulis'Pachyloen',a cultivar of Ph.edulis,has the advantages over bamboo shoots and wood. In order to explore the physio-ecological response and acclimation of Ph.edulis'Pachyloen'to high CO2 concentration,the photosynthetic characteristics under atmospheric CO2 concentration and doubled CO2 concentration were determined in four seasons by Li-6400P. The results showed that the doubled CO2 concentration promoted the maximal net photosynthetic rate(Pmax),net photosynthetic rate(Pn),water use efficiency(WUE),apparent quantum yield(AQY)and light saturate point(LSP). The increments were 62.79%,48.74%,94.41%,8.70% and 16.67% respectively. Transpiration rate(Tr),dark respiration rate(Rd)and light compensate point(LCP)were decreased under the doubled CO2 concentration,and their decrements were 17.60%,37.25% and 40.50% respectively. After CO2 concentration doubled,the photosynthetic parameters'variation range of Ph.edulis'Pachyloen'in four seasons were closely related to its leaf physiological activity and climate change. The order of photosynthetic parameters'value was same with that of atmospheric CO2 concentration except LCP. It indicated that the seasonal variation tendency of photosynthetic characteristics had not been changed by the doubled CO2 concentration. On the whole,the photosynthetic response of Ph.edulis'Pachyloen'to short-term elevated CO2 concentration accorded with the general law for C3 plant.