摘要
通过对 1 7a生杉木人工林小枝的活体测定 ,研究了大气 CO2 增长对杉木中龄林净光合、呼吸、气孔导度和水分利用效率等生理生态特性的影响。结果表明 ,在 CO2 浓度为 4 5μmol/ L左右时 ,杉木针叶净光合速率比正常大气 CO2 下提高 1倍以上 ,气孔导度和蒸腾速率有不同程度的降低 ,水分利用效率提高约 1～ 2倍 ;同时使光补偿点降低 ,饱和点和光抑制点提高 ,光量子效率提高 4 0 %～ 2 95%且阳枝大于阴枝 ,针叶暗呼吸降低 2 0 %～ 72 %。随着 CO2 浓度的增加 ,针叶净光合速率和水分利用效率呈线性上升 ,约到 4 5μmol/ L以后 ,增加速率减慢 ,但 CO2 饱和点可达 1 1 6μmol/ L以上。杉木针叶对CO2 增长的这种反应 ,对大气 CO2 不断增长的条件下杉木生长是有利的 ,但对其长期反应还有待进一步研究。
The net photosynthesis (Pn) ,transpiration( TR) ,stomatal conductance( COND ),water use efficiency( WUE )and dark respiration( DR )of 17 year old Chinese fir shoots under ambient and elevated CO 2 conditions were measured with LiCor 6200 Photosynthesis system,and their responses to elevated CO 2 were discussed.It was suggested that compared to the ambient air CO 2 concentration. Pn under 45μmol/L CO 2 was doubled and COND and TR decreased to some extent,leading to the increase of WUE by 100%～200%;at the same time. DR reduced by 20%～72% and quantum efficiency increased by 40%～295%;light compensation point deereased while light saturation point and light inhibition point elevated.It was also found that with the increase of CO 2 concentration. Pn and WUE increased linearly until around 45μmol/L CO 2,the increasing rates reduced,but the CO 2 saturation point for Pn was higher than 117μmol/L.It was concluded that the increasing CO 2 concentration in the atmosphere would be beneficial to Chinese fir in a short term,but its long term responses are not determined and need to be further studied.
出处
《生态学报》
CAS
CSCD
北大核心
2000年第3期390-396,共7页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目!"杉木人工林光合作用尺度转换研究 (编号 :3 9770 596)
和林业部重点资助课题"江西大岗山森林生态系统定
关键词
CO2增长
杉木净光合速率
气孔导度
WEU
暗呼吸
elevated CO 2
net photosynthesis
transpiration
stomatal conductance
water use efficiency
dark respiration
