Effects of Different Loading Capacity on Photosynthetic Efficiency and Chloroplasts Ultra-structure in Korla Fragrant Pear

The leaf net photosynthetic rate,stomatal conductance,intercellular CO2 concentration,transpiration rate,chlorophyll content,starch content and chloroplast ultrastructure were observed under the treatments of different fruit loading capacity,by using 10 year-old and 20 years-old Korld Fragrant Pear as the test materials,also the comprehensive analysis was carried out on the effect of different loading capacity on photosynthetic efficiency of Korla Fragrant Pear.The results showed that the leaf photosynthetic rate,stomatal conductance,transpiration rate and starch content were bigger in high fruit loading capacity than in low fruit loading capacity in 10 years-old and 20 years-old Korla Fragrant Pear.Both the quantity and volume of the chloroplast in high fruit loading capacity were higher than that in low fruit loading capacity under the conditions of high loading capacity of the fruit.So,the appropriate addition of loadjing capacity of Korla Fragrant Pear was conductive to improving the leaf photosynthetic efficiency.