Study On Canopy Structure、Light Interception Efficiency And Photosynthesis Of Sweet Cherry With Different Tree Shapes Based On Three-dimensional Model

With the application of new dwarf close planting cultivation technology,there are many new tree shapes in the production of sweet cherry.In order to accurately study the canopy structure,light interception efficiency and photosynthesis of different tree shapes of sweet cherry,in this study,the super slender spindle and hedgerow one-side down of 7-year-old sweet cherry cultivar‘Jimei’were used as the research objects.The three-dimensional digital technology was used to measure the leaf spatial angle and the spatial coordinates of the branch endpoints of each tree form on the spot,analyze the relationship between the abnormal growth of branches and leaves,construct the canopy models of different tree forms of sweet cherry,study the canopy structure and light interception efficiency of different tree forms,and analyze the leaf photosynthetic characteristics of different tree forms of sweet cherry.Exploring the effects of different tree shapes on fruit quality and yield has important theoretical guiding significance for high-yield cultivation of sweet cherry.The main research results are as follows:1.Using three-dimensional digital technology,Vege STAR4.0 software was used to build the canopy model of sweet cherry’Jimei’super slender spindle and hedgerow one-side down.It was found that the 1-year-old total number of branches,total leaf number and total leaf area of the canopy of the super slender spindle were higher than those of the hedgerow one-side down,and the proportion of spur branches in the two shapes was significantly higher than that of other types of branches,reaching 53.81%and 49.28%,respectively.The proportion of flower-bunched branches in the super slender spindle canopy was significantly higher than that in the hedgerow one-side down（P<0.05）.2.The analysis of Vege STAR4.0 software found that the light interception efficiency values of hedgerow one-side down and super slender spindle canopy were 0.43 and 0.29（PLA/TLA）,respectively.The super slender spindle was significantly higher than that of super slender spindle.The azimuth distribution range of‘super slender spindle’canopy blade（-45°,45°）,and the azimuth distribution range of‘hedgerow one-side down’crown blade（-105°,105°）.The results showed that tree shape had significant effect on the light interception efficiency of spur branches（P<0.05）.The light interception efficiency of hedgerow side was 0.53,and that of super slender spindle was only 0.20.The light interception efficiency of hedgerow one-side down was higher than that of super slender spindle.3.The photosynthetic characteristics and chlorophyll content of the super slender spindle leaves were significantly higher than those of the hedgerow one-side down leaves.The net photosynthetic rates of the super slender spindle and hedgerow one-side down leaves were 20.56/μmol·m^-2·s^-1 and 14.80/μmol·m^-2·s^-1,respectively.The chlorophyll content of super slender spindle and hedgerow one-side down were 17.10 mg·g^-1 and 12.97 mg·g^-1,respectively.Photosynthesis and chlorophyll content of leaves in middle（1-2m）were significantly higher than those in upper（2-3m）and lower（0-1m）canopy.4.There were differences in fruit quality among different tree types.The single fruit weight of super slender spindle fruit was 11.05 g,and that of hedgerow one-side down was8.11 g,and the former was significantly higher than the latter;the soluble solids content of super slender spindle fruit was 18.33%,which was significantly higher than that of the hedgerow one-side down by 15.64%.The fruit quality of the two kinds of trees shapes reached the level of high quality fruit（single fruit weight>8 g and soluble solids content>15%as the standard）.5.The total leaf area per plant of‘super slender spindle’tree was 21.41 m²,and the total yield per plant was 31.94 kg;the total leaf area per plant of the?hedgerow one-side down?tree was 13.91 m²,and the yield per plant was 22.70 kg.The production efficiency of?super slender spindle?was significantly lower than’hedgerow one-side down’.’super slender spindle’needed 1.32 m² leaf area to produce 1 kg fruit with weight more than 8 g,but’hedgerow one-side down’only needed 0.88 m².74 plants per 667m² can be planted in’super slender spindle’,while 126 plants can be planted in’hedgerow one-side down’;the yield per 667m² of the‘super slender spindle’was 2450 kg,and the yield per 667m² of the‘hedgerow one-side down’was 2718 kg,6.There was no significant difference in leaf area per 667m² between the two tree types,but the yield per 667m² of hedge type was significantly higher than that of super slender spindle due to higher light interception efficiency,and increased with the increase of leaf area per 667m².’Super slender spindle’has higher yield per plant and stronger photosynthesis,but its planting number per 667m²,yield per 667m² and light interception efficiency of canopy are lower than that of hedgerow.Both flat and sloping fields of?super slender spindle?can be cultivated,with less investment in the early stage of the tree,but higher requirements for pruning.’Hedgerow one-side down’need to build a frame,early investment is bigger,but each 667m² can be planted more,higher yield per 667m²,simple pruning technology,suitable for dwarf close planting and facility cultivation.