Influence of Photosynthetic Characteristics on Fruit Setting Stage of Korla Fragrant Pear Under Different Element Deficiency Treatments

The diurnal variation curves of photosynthetic characteristics of fruit setting stage of Korla fragrant pear under different element deficiency were measured by portable photosynthesis system CIRAS-2 in the field conditions.The results showed that the diurnal variation curves of Pn of Korla fragrant pear presented double-apex curves,and had a phenomenon of photosynthetic 'noon breaking'.The diurnal variation curves of Gs and Ls were the same as Pn,they also showed double-apex curves.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 Chl content,LAI and photosynthetic characteristics of Korla fragrant pear.Under different element deficiency,the roles of fertilizer N,P and K to Chl content and LAI of Korla Fragrant Pear were in order of NPK.The photosynthetic characteristics were different,the role of fertilizer N,P and K to Pn of Korla Fragrant Pear leaves was in order of KPN,Tr of Korla Fragrant Pear leaves was in order of NPK,Gs of Korla Fragrant Pear leaves was in order of KNP,WUE of Korla Fragrant Pear leaves was in order of NKP.