岩黄连光合与蒸腾特性及其对光照强度和CO_2浓度的响应

采用LI-6400便携式光合测定系统(Li-CorInc.,USA)对岩黄连叶片的气体交换进行了测定。结果表明(1)岩黄连叶片的光饱和点(LSP)为329.18μmol.m-2.s-1左右,光补偿点(LCP)为12.76μmol.m-2.s-1,最大净光合速率为2.96μmol.m-2.s-1,暗呼吸速率(Rd)为0.17μmol.m-2.s-1。光饱和点和光补偿点都比效低,表明岩黄连对光照的要求不高,属于阴生植物。(2)4月份,岩黄连Pn随CO2浓度升高而逐渐增大。当CO2浓度由50μmol.mol-1增加到600μmol.mol-1,Pn几乎呈直线上升,600~1000μmol.mol-1范围内逐渐缓和,到1000μmol.mol-1以后Pn变化平稳。由曲线估算CO2饱和点(CSP)大约在1000μmol.mol-1左右。CO2的补偿点为68.80μmol.mol-1。羧化效率为0.0308μmol.m-2.s-1。(3)岩黄连叶片水分利用率(WUE)随有效光辐射强度(PAR)的增强呈抛物线状变化,PAR在200μmol.m-2.s-1内呈直线上升,到200μmol.m-2.s-1时WUE达最大值,大于200μmol.m-2.s-1后WUE呈逐渐下降趋势。

Photosynthetic and transpiration characteristics of Corydalis saxicola and its response to light intensity and concentration of CO2

The gas exchange of Corydalis saxicola was measured in the field with Li-6400 Portable Photosynthesis (Li-Cor Inc., USA). The results were as follows:The light saturation point, light compensation point, maximum photosynthetic rate, and respiration rate for the leaf of Corydalis saxicola were 329.18 μmol·m -2 ·s -1 , 12.76 μmol·m -2 ·s -1 , 2.96 μmol·m -2 ·s -1 and 0.17 μmol·m -2 ·s -1 , respectively. The light saturation and compensation point were low. This indicated that C.saxicola was adapted to weak light, it's a shade plant. The net photosynthetic rate of C.saxicola increased with the raising of the concentration of CO_2 in April. The net photosynthetic rate increased linearly when the concentration of CO_2 was in 50 μmol·mol -1 to 600 μmol·mol -1 , after that, it increased slowly while the concentration of CO_2 increased to 1 000 μmol·mol -1 . It could be estimated from the A-Ci curve that the CO_2 saturation and compensation point and the maximum carboxylation rate were 1 000 μmol·mol -1 , 68.80 μmol·mol -1 and 0.030 8 μmol·m -2 ·s -1 respectively. The water use efficiency (WUE) of C.saxicola varied with the parabola model while the PAR increased. It increased linearly with the increasing of PAR till the PAR was 200 μmol·m -2 ·s -1 and then decreased gradually.