Effects Of Branch Bending Angle On Carbon,Nitrogen And Endogenous Hormones Contents In Short Branch Terminal Buds Of Apple Trees

Apple is a deciduous fruit tree. It has high yield and high nutritional value. Fuji is themain planting variety in our country, because of strong growth of the tree, so it is difficult tobe flower and productions are affected. Branch bending can control the strong growth, adjustthe nutrient transportation and distribution and hormone balance, then promote into flowerand improve the output of orchard, it becomes one of the common method in fruit treetraining and pruning.In this paper, the Fuji and gala were tested to study the effects of three branch bendingangles(70°,90°and110°) on carbon, nitrogen and hormones’ contents in short branchesterminal buds. The main results were as following:1.Improve branch angle can increase soluble sugar and starch contents, C/N and reducenitrogen content on short branch terminal buds on apple trees in a certain range. The solublesugar, starch contents and C/N of short branch terminal buds in Gala are bigger than in Fuji,but nitrogen content is lower than in Fuji. When branch angle is110°, sugar content and C/Nis larger in Fuji, and some value of110°is smaller than90°in Gala, but no significantdifferences. Branch bending angle is too big, the tree is mechanical damaged and easy topremature aging. So the angle of Fuji should be110°and Gala should be90°.2.IAA and GA3contents of short branch terminal buds reduced with the angle of branchbending increasing, but ABA and ZR contents, ABA/IAA, ABA/GA3, ZR/IAA and ZR/GA3increased. During May and September, IAA and GA3contents in buds are gradually decreased,ABA and ZR contents are constantly increasing, ABA/IAA, ABA/GA3, ZR/IAA, ZR/GA3areslowly increasing, all reach maximum in late September. IAA, ABA and ZR, and ABA/IAA,ABA/GA3, ZR/IAA and ZR/GA3are significantly different, but the differences of GA3content of short branch terminal buds is irregular. Branch bending angle is relativelycomplicated impact on hormone balance in short branch terminal buds. GA3, ZR contents andZR/IAA, ZR/GA3of short branch terminal buds in Gala is smaller than in Fuji, but ABAcontent and ABA/IAA, ABA/GA3are bigger than in Fuji.Combination of effects of branch bending angle to carbon and nitrogen contents and C/N,the result can be obtained that the angle of Fuji should be110°and Gala should be90°. In this condition, the flower bud differentiation is advantageous, and the tree is not easy to prematureaging.