Effects Of Trunk Tree Structure On Canopy Microenvironmental Factors And Leaf And Fruit Traits Of Fragrant Pear

In order to optimize the suitable trunk tree structure for improving the fruit quality of fragrant pear,the experiment studied the different trunk tree structures of fragrant pear from the perspective of tree phase index,canopy environmental factors,leaf traits,fruit quality and opening.The effects of trunk structure on tree body,environmental factors,leaf and fruit traits were studied.The main results are as follows:(1)The trunk-shaped cultivation density and the number of small main branches affect the growth of the tree.The trunk-shaped tree structure of Korla fragrant pear : trunk height 70 ～ 79 cm,crown width 2.21～ 2.53 m,trunk circumference 39.75 ～ 43.5cm,small main branch length 1.22 ～ 1.34 m,crown volume 5.77～ 7.42m3,canopy projection area 4.23 ～ 5.03m2;under the same planting density,the number of small main branches is small,and the stem height,crown width,stem circumference,length of small main branches,crown volume and canopy projection area are large,which is convenient for pruning management.Under the same number of small main branches,the planting density is small,the stem height and crown width are large.(2)There were significant differences in the vertical and horizontal distribution of light intensity in different canopy layers of the trunk shape of Korla Fragrant Pear.The upper layer > middle layer > lower layer,external > middle > internal,and the number of small main branches had a significant effect on light intensity.The diurnal variation of light intensity in vertical and horizontal directions in May and June showed ’ single peak ’ or ’ double peak ’ curve changes,while the diurnal variation of light intensity in vertical and horizontal directions in July and August only showed ’ single peak ’ curve changes.The vertical temperature change of the canopy was significantly higher in the upper layer than in the middle and lower layers,and the horizontal distribution difference was not significant.The relative humidity was lower >middle > upper,internal > middle > upper.From May to September,the diurnal variations of temperature and relative humidity at different levels and parts of the canopy were similar,showing a ’ single peak ’curve and a ’ U-shaped ’ curve.(3)From May to September,under two different plant row spacing,when the opening angle is 90 °,the leaf length and width and dry and fresh weight reach the maximum value.From May to August,the leaf pigment content is the highest when the opening angle is 90 °.When the opening angle is 75 ° ～ 90 °,the content of N,P,IAA and GAin the leaves is the highest,and the content of ABA is the lowest.(4)Under different densities,1.5m × 4.0m orchard had low fruit hardness and stone cell content,high soluble sugar content and soluble solids content,and good taste.Under the same row spacing,the fruit size of 15 small main branches was uniform,and the fruit soluble solids content and soluble sugar content were high.The upper and outer fruits in the canopy are large,the fruit shape is good,the color is red,the hardness is small,and the soluble sugar content is high.(5)In the 1.5m × 4.0m orchard,the single fruit weight of the fruit with an opening angle of 75 ° ～ 90° was 129 g,which was significantly higher than that of other opening angles.The lowest peeling hardness was 6.13 N,and the soluble solids and soluble sugar content were high.The soluble sugar content was significantly higher than that of 90 ° ～ 105 °,the titratable acid content was low,and the taste was the best.In the 2.0m × 4.0m orchard,the single fruit weight of 75 °-90 ° fruit was 130.89 g,the fruit was the brightest,the color was yellowish green,but the internal quality was poor.The peel hardness of 90 ° fruit was low,the soluble solids content was 10.11 %,the soluble sugar content was 8.55 %,and the stone cell content was low.The internal quality of the fruit outside the main branch is better than that in the middle and inside.Based on the above conclusions,the fruit quality of 1.5m × 4m and 15 small branches was better.In the orchard of 1.5m × 4.0m,the leaf growth index and pigment content were high when the opening angle was 90 °.The opening angle of 75 °-90 ° was not only beneficial to leaf nutrient accumulation and hormone distribution,but also had good fruit quality.In the orchard of 2.0 m × 4.0 m,the leaf growth index and pigment content were high and the fruit quality was good when the opening degree was 90 °.Therefore,the opening angle of 1.5 m × 4.0 m orchard is 75 ° ～ 90 °.The best opening angle is 90 ° for 2.0m × 4.0m orchard.