This experiment studied the effect of the chloroplasts ultra-structure and photosynthesis characteristicsin different amount of fertilizer with10years-old and20years-old Korla Fragrant Pear as material. In theexperiment, we treated the plants in four levels, e.g.30kg each tree,50kg each tree,80kg each tree,100kgeach tree. And we treated the plants in three fruit load processing, for high, medium and low. The leaf netphotosynthetic rate, stomata conductance,intercellular CO2concentration, transpiration rate,...