为了了解缺苞箭竹的气体交换对短期CO2浓度升高的响应,用Li-6400光合测定系统测定了缺苞箭竹叶净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)和叶面饱和水汽压亏缺(Vpdl)随光照强度的变化。结果表明:缺苞箭竹Pn、Gs和Tr随光强增强先增大并维持在一定水平然后又呈现下降趋势,水分利用效率(WUE)随光照强度增强先增大然后维持在一个较高水平,Vpdl呈现先减小后增大的规律;Pn和WUE随CO2浓度升高先增大然后减小,Gs和Tr随CO2浓度升高先减小后增大,Vpdl以随CO2浓度升高而增大。随CO2浓度升高光饱和光合速率提高20%-61%,气孔导度降低36%-57%,蒸腾速率降低30%-53%,水分利用效率提高120%-215%,饱和水汽压亏缺提高4%~11%。
To determine bamboo (Fargesia denudata) response on short-term elevated CO2 concentrations under 400,800,1 200 and 1 500 μmol · mol^-1 ,LI- 6400 Portable Photosynthesis System was used to examine the changes of the net photosynthetic rate(Pn), transpiration rate (Tr), stomatal conductance (Gs) and vapor deficit at the leaf surface (Vpdl) of bamboo (Fargesia denudata) leaf with light intensity under different CO2 concentration. The results showed that with enhanced light intensity, Pn, Gs and Tr increased first and sustained at a high level then decreased, WUE(water use efficiency) increased first and sustained at a high and WUE increased first and then decreased, Gs and Tr decreased first and then increased and Vpdl increased. Under elevated CO2 ,the light saturation photosynthetic rate increased by 20-61%, Gs and Tr decreased by 36%-57% and 30%-53% separately,WUE increased by 120%-215%, while Vpdl increased by 4%-11%.