Influence of Different Fertilization Treatments on Photosynthetic Characteristics of Fruit Enlargement Stage of Korla Fragrant Pear

The diurnal variation curves of photosynthetic characteristics of fruit enlargement stage of korla fragrant pear under different fertilization treatments were measured by portable photosynthesis system CIRAS-2 under the field conditions.The results showed that the diurnal variation curves of Pn of Korla Fragrant Pear presented double-apex curves,double-apex was weak or not obvious,and had a phenomenon of photosynthetic 'noon breaking'.The diurnal variation curves of Gs and Ls were same as Pn,they also showed double-apex curves,but the double-apex of Gs was obvious,the double-apex of Ls was weak.The diurnal variation curves of Ci were contrary with Pn,they showed double-valley curves.The diurnal variation curves of Tr presented single-apex curves,but the diurnal variation curves of WUE showed single-valley ones.It could cause obvious impacts on chlorophyll content,LAI and photosynthetic characteristics of Korla Fragrant Pear.Under different fertilization treatments,the roles of fertilizer N,P and K to chlorophyll content and LAI of Korla Fragrant Pear were in the order of NPK.The photosynthetic characteristics were different,the roles of fertilizer N,P and K in Pn and WUE of Korla Fragrant Pear leaves were in the order of KPN,Tr of Korla Fragrant Pear leaves was in the order of PNK,and Gs of Korla Fragrant Pear leaves was in the order of KNP.