Effect Of Approach Grafting On Growth And Physiological Characteristics In Trunk-Wounded Apple Trees

In this study,five-year-old 'Nagafu 2'/Mb[Malus baccata(L.)Borkh.]and 'Nagafu 2'/M9 apple trees were used as materials and their trunk were barked in early April of 2016 and 2017,respectively.Then approach grafted M9 and Baleng Crab(BC)with uniform growth which were transplanted besided the apple trees.To research the effect of the different degree of trunk wounding and approach grafting different number M9 on trunk-wounded apple trees.The results are as following:1.Trunk wounding reduced the annual growth of tree height,the length of annual shoots,the annual growth of trunk diameter,the flowering number,fruit set,leaf area and the number of new shoots in'Nagafu 2'/Mbapple tree.Approach grafted M9 or BC increased the flowering number,fruit set and leaf area.Trunk wounding in 'Nagafu 2'/M9 apple trees reduced the annual growth of tree height and leaf area;approach grafted M9 increased the annual growth of tree height and the leaf area,but approach grafting BC has no significant changes.Trunk wounding reduced significantly declined the leaf net photosynthetic efficiency,fruit size,peel colour and yield,and increased the fruit soluble solide content and fruit firmness in 'Nagafu 2'/Mband 'Nagafu 2'/M9 apple trees,and they were renewed by approach grafting M9 and BC.There was no significant difference in carbohydrates content of new shoot by approach grafting and trunk wounding treatment;Trunk wounding reduced the contents of IAA,GA and ZR in shoot,and increased the content of ABA,and IAA and ZR of new shoots were increased by approach grafting M9 or BC;Trunk wounding reduced leaf N,K,P contents in 'Nagafu 2'/Mband leaf N,K,Mg,Ca contents in 'Nagafu 2'/M9,approach grafting have no significance.2.With the increaseing of trunk-wounded area,the tree vigor,leaf net photosynthetic efficiency,fruit quality and yield were reduced in 'Nagafu 2'/Mband 'Nagafu 2'/M9,and all could be restored by approach grafting M9.The content of ZR,IAA and GA of 'Nagafu 2' apple trees were decreased with the increasing of trunk-wounded area,while ABA and soluble protein contents were increased.Approach graft increased the contents of ZR and IAA.The larger the barking area,the lower the N and K content in new shoots.3.Approach grafting on trunk-barked 'Nagafu 2' apple tree with one,two or three M9 rootstocks have similar recovery effect on the leaf area,photosynthetic efficiency and the soluble protein content in new shoots;the fruit maturity in 'Nagafu 2'/Mbis positively correlated with the number of grafted M9;the contents of ZR,Mg,K and P in 'Nagafu 2'/Mband 'Nagafu 2'/M9 were increased by approach grafting M9,and they were positively related to the number of grafted M9.