采用LI-6400光合测定仪测定四季桂光响应曲线和光合特性的季节变化。结果表明,四季桂叶片的光响应曲线变化趋势基本一致,净光合速率和光补偿点由低到高依次为1月< 4月< 10月< 7月,光饱和点依次为7月< 10月< 4月< 1月。四季桂叶片Pn、Tr、VPD、Gs的日变化表现为1月和4月均为单峰曲线,10:00达到峰值;7月和10月均为"双峰型",具有明显的光合"午休"现象。1月,Ci持续下降;4月Ci先逐渐下降,15:00出现小峰值;10月和7月,Ci在10:00最低,15:00达到峰值。

The seasonal changes of light response curve and photosynthetic characteristics of Osmanthus fragrans var.semperflorens were determined by LI-6400.The results showed that the light response curve changes of O. fragrans var.semperflorens's leaves at different seasons were similar.The net photosynthetic rate and light compensation point were Jan< Apr< Oct< Jul,and the light saturation point was Jul< Oct< Apr< Jan.The day changes of Pn,Tr,VPD and Gs of O. fragrans var.semperflorens were single peak curve separately at January and April,while double peak curve and had photosynthetic "lunch-break" atmosphere at July and October.The seasonal change of Ci was that Ci decreased continuously at January,while decreased first and then reached a small peak value at 15:00 at April,and appeared the lowest point at 10:00 and the highest point at 15:00 at July and October.