Effects Of Tree Shape On Photosynthetic Characteristics And Fruit Quality Of Sweet Cherry

Sweet cherry(Prunus avium L.),belonging to the Rosaceae family,and the Subgenus cerasus(Prunus)are very popular among the public because of their good flavor,sweet and sour taste and rich in a variety of nutritional elements.Since the selection of tree shape and variety plays a major role in the improvement of cherry quality and yield,it is of great significance for sweet cherry production to study the influence of tree shape structure on tree growth,fruit yield and quality formation.In this experiment,with ’Qinying No.1’,’Yan Yang’ and ’Red light’ as samples,the effects of three kinds of super slender spindle(control tree),slanting hedge wall and UFO(Upright Fruiting Offshoots)tree on photosynthetic characteristics,fruit quality of cherry trees were investigated.Nine sweet cherry varieties,including ’Zao Dacao’,’Brooks’,’ Lite ’,’Vanguard’,’Serbius’,’ Meizao ’,’Samito’,’Reni’ and ’13-33’,were selected as test materials to study the fruit quality of different varieties with uniform ultra-slender spindle tree shape,and to evaluate and analyze the fruit quality by principal component analysis.Specific research results are as follows:1.Among the three sweet cherry varieties,’Qinying No.1’,’Yan Yang’ and ’Red Light’,the one with the largest number of fruit branches per plant is super slender spindle shape,followed by UFO shape,and the one with the least number of fruit branches is inclined hedge shape.The highest yield per plant is super slender spindle shape,the lowest is inclined hedge wall shape,the difference between the two is 1.2times,but the yield per mu of inclined hedge wall shape is the highest among the three trees,UFO shape yield is the lowest.Among the three types of trees,the super-slender spindle shape has the highest trunk thickness and trunk height.Therefore,for production,the inclined hedge shape has more advantages in total output.2.The net photosynthetic rate(Pn)of the leaves of ’Qinying No.1’,’Yanyang’and ’Honghong’ of the three varieties of sweet cherry with inclined hedge shape was significantly higher than that of the control trees,and the diurnal variation curve of photosynthesis showed an obvious "double peak" phenomenon,with the two peaks at about 11:30 and 14:30,respectively,and the peak value showed the highest in inclined hedge shape.The most prominent chlorophyll fluorescence parameters and photosynthetic pigment content were the inclined hedge wall shape,and the net photosynthetic rate was correlated with the maximum photochemical efficiency.Compared with super slender spindle shape and UFO tree shape,inclined hedge wall showed better photosynthetic characteristics.3.The analysis and comparison of fruit quality of the three tree shapes showed that the surface color,single fruit weight,soluble solid content and sugar-acid ratio of the fruits were significantly higher in the tilted hedge shape than in the control ultra-slender spindle shape and UFO shape.There was little difference in the contents of soluble protein,anthocyanins,vitamin C,total phenols,total flavonoids and other internal qualities.The fruit quality of inclined hedges was better,but the difference was not significant.4.Among the 9 varieties of sweet cherry,such as’ Zao Da Guo ’,’Brooks’,’ Ritte ’,’Vanguard’,’Servia’,’Meizao’,’Samito’,’Reni’ and ’13-33’,the fruits are generally heart-shaped or kidney-shaped,and the edible rate ranges from 89.67 to 92.89%.The largest single fruit weight was’ Brooks’ at 12.06 g,and the smallest was’ Meizao ’at7.83 g.For fruit color,’13-33’ is yellow,’Renee’ is red-yellow,and the rest are red.’Brooks’ is the darkest,dark red.The highest hardness is’ 13-33 ’,the lowest hardness is’ Meizao ’.The highest content of solid acid ratio,sugar acid ratio,soluble protein,vitamin C,anthocyanins,flavonoids and total phenols is’ Brooks’,which has a significant difference compared with other varieties.5.A total of 5 principal components were extracted from 14 fruit quality indexes by principal component analysis,and the overall contribution rate was 84.32%.With the contribution rates of the five principal components as the weight,the comprehensive evaluation model was obtained:F=31.93%F1+18.41%F2+14.61%F3+10.95%F4+8.42%F5.According to the comprehensive score,the comprehensive quality of the nine sweet cherry varieties in descending order were: ’Brooks’,’ Ritte ’,’13-33’,’Zao Daguo’,’Serbia’,’Samito’,’Vanguard’,’Meizao’ and ’Reni’.