Photosynthetic Characteristics Research And Fruit Quality Determination Of The High Light Use Efficiency Tree Shape On ’Yuluxiang’ Pear

In this research,16 years old’Yuluxiang’pear (Pyrus sinkiangensis’Yuluxiang’) was the test material, researched on photosynthetic characteristics and fruit quality of different Canopy Structures, the three-bough, the four-bough, and the five-bough open-centre,and the free spindle. The results were as follows:1. In the four processing of’Yuluxiang’pear leaves, there were differences in light response curve of the east and west sides at morning and afternoon. With the increased of photosynthetically active radiation, the biggest change was the comparison leaf temperature, The three-bough centre leaf temperature was lower, fluctuations was the minimum, It had remained between 30 ± 2 ℃, the best performing of Pn at all day is the east side at morning, the Pn values of three, four, five-bough open-center and the check were 24.36μmol·m-2·s-1、25.19μmol·m-2·s-1、22.06μmol·m-2·s-1.16.52μmol·m-2·s-1, the best comprehensive performance in photosynthetic rate were the three-bough open-center, LCP was in the range of 28.01-38.07μmol·m-2·s-1, LSP was in the range of 1298.86-1912.41μmol·m-2·s-1, apparent quantum efficiency was in the range of 0.033～0.053μmol·m-2·s-1, the lowest Pn value was check, LCP was in the range of 31.9～51.99μmol·m-2·s-1, LSP was in the range of 950.1～1294.37μmol·m-2·s-*1, apparent quantum efficiency was 0.032-0.044μmol·m-2·s-1. The response curves of transpiration rate and stomata stomatal conductance to PAR were similar. Among other parameters of photosystem at different treatment had little difference, but the ability of photosynthetic in three, four, five-bough open-center shape leaves was better than that of the free spindle.2. With the increase of CO2, the Pn of four treatments were all rise, from high to low was three-bough, four-bough, five-bough, and check, the CCP was 41.53 μmol·mol-1,41.56 μmol·mol-1,41.81μmol·mol-1,60.53μmol·mol-1,the CSP was about 1200μmol·mol-1; the average value of transpiration rate from high to low was three-bough, four-bough, five-bough, and check,6.43mmol·m-2·s-1、6.17 mmol·m-2·s-1、 5.18 mmol·m-2·s-1、3.15 mmol·m-2·s-1. Transpiration rate, stomatal conductance, and intercellular CO2 concentration from high to low all were four-bough, three-bough, five-bough, and check. Among other parameters of photosystem in the different treatment had little difference, but the ability of photosynthetic in three, four, five-bough open-centre shape leaves was better than that of the free spindle.3. Fruit quality determination of four tree shapes indicated that some important quality index was different. The average single fruit weight, soluble solids, total soluble sugar and anthocyanin increased with the decrease of the number of branches, the open-center shape tree were higher than that of the free spindle shape tree; There was no different of the fruit shape index and total chlorophyll between the four treatments; The hardness, titratable acid decreased with the increasing number of branches. On the whole, the fruit quality of open-center shape tree was better than that of the free spindle, and the quality was improved when the main branch was increased.