Study on Diurnal Change Characteristics of Photosynthesis of Twenty-five Cut Chrysanthemum Cultivars

Taking 25cut chrysanthemum major cultivars from Guangdong as test materials,using potable LI-6400XT photosynthetic system,the net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr) and intracellular CO 2 concentration(Ci) of diurnal change characteristics of photosynthesis were studied.The results showed that the diurnal changes of net photosynthetic rate(Pn) of 11cultivars showed unimodal type while the other 14cultivars bimodal type which indicated a midday depression phenomenon.The midday depression phenomenon was found to be caused by non-stomatal factors.The Pn of 10cultivars(‘Bayuehuang’,et al.) were highly consistent with stomatal conductance(Gs) and transpiration rate(Tr),while negatively related to intracellular CO 2 concentration(Ci).The daily mean Pn values varied among different seasons,and their order were 2009/092010/032009/122009/112010/01 2009/10.Six cultivars(‘Shijiushaonan’,‘Bayuehuang’,‘Baifenchi’,‘Xintaihong’,‘Hongmeiren’,‘Shibaxiaojie’) possessed high photosynthetic capacity.