深圳地区桂花夏冬季光合生理特性的比较

在自然条件下使用LI-6400光合仪,分别在夏季和冬季,对深圳地区引进的4个桂花品种(‘日香桂’、‘小叶佛顶珠’、‘晚银桂’、‘万点金’)的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Cond)、光合有效辐射(PAR)、大气温度(Ta)等生理生态因子的日变化进行了测定,并对桂花Pn与各种因子的关系进行了比较分析,结果表明:在夏季,4个桂花品种Pn日变化均呈现不对称的双峰曲线,有明显的光合"午休"现象.在冬季,4个桂花品种Pn日变化均呈现单峰曲线,不存在"午休"现象.胞间CO2浓度(Ci)、Cond、PAR、Ta和叶片水压亏缺(VPD)是影响桂花Pn较大的几个因子,其中Ci和Ta在夏季的影响程度尤为突出,PAR在冬季的影响程度最为明显.

Comparison of Photosynthetic Characteristics of Osmanthus fragrans between Summer and Winter of Cultivars in Shenzhen City

To four cultivars of Osmanthus fragrans(O.fragrans ’Rixianggui’,’Xiaoye Fodingzhu’,’Wan Yingui’,’Wandian Jin’) introduced in Shenzhen,Pn,Tr,Cond,PAR,Ta and other physiological and ecological factors were measured during summer and winter using the LI-6400 in natural conditions,and photosynthesis and the relationship between factors were analyzed.The results showed that: four cultivars of O.fragrans showed a diurnal variation of net photosynthetic rate of asymmetric double-peak curve,with a clear photosynthetic "lunch break" phenomenon in summer.In winter,the diurnal change showed a single peak curve.Ci,Cond,PAR,Ta and VPD are the most important factors to affect the net photosynthetic rate.Ci and Ta have the greatest influence in the summer,and PAR effect is particularly prominent in the winter.