连翘光合特性研究

用Li-6400光合作用测定系统对连翘的光合特性进行了测定。结果表明:连翘叶片的净光合速率Pn日变化呈"单峰型"曲线,无"午休"现象,12:00时Pn出现高峰,峰值为13.54μmol/(m2.s),叶片蒸腾速率Tr和气孔导度Gs的变化趋势与Pn一致,胞间CO2浓度Ci与之相反。Pn与Tr、Gs极显著正相关;影响连翘叶片光合作用的主导环境因子为光合有效辐射PAR和相对湿度RH。连翘光合作用的光饱和点LSP和光补偿点LCP分别为1 360μmol/(m2.s)和26.06μmol/(m2.s),表观量子效率为0.049 5;CO2饱和点较高,在2000μmol/mol范围内未达到饱和,CO2补偿点为81.79μmol/mol,羧化效率为0.036 3。以上结果表明,连翘是一种典型的阳性C3植物。

Photosynthetic characteristics of Forsythia suspensa

The photosynthetic characteristics of Forsythia suspensa were examined by means of Li-6400 Portable Photosynthesis System.The results indicated that the diurnal curve of photosynthes' rate(Pn) in F.suspensa presented a single peakcurve without mid-depression.The peak occurred at about 12:00 and the peak value was 13.54 μmol/(m2·s).The diurnal curves of leaf transpiration rate and stomatal conductance were identical to Pn,but negatively with internal CO2 concentration.Pn was significantly positively related with transpiration rate and stomatal conductance.The principal environmental factors affecting Pn were photosynthetic active radiation and relative humidity.The light saturation point and light compensation point of F.suspensa were 1 360 μmol/(m2·s) and 26.06 μmol/(m2·s) respectively,while the apparent quantum yield was 0.049 5.The CO2 saturation point was higher than 2 000 μmol/mol and CO2 compensation point was 81.79 μmol/mol,while the carboxylation efficiency was 0.036 3.These results indicated that F.suspensa is a C3 plant.