Study On The Formation Mechanism And Regulation Of Fruit Shape Of Fuji Apple In Akesu

Fuji apple in Aksu has been broadly recognized by consumers due to its traits such as delicate flesh,sweet taste. However, Fuji apple has a serious deviating problem of fruit shape during its development,andthis “appearance” problem,currently,,has become a bottleneck in this business.In order to research seriousproblem,a series of field experiments and laboratory tests were carried out,and the formation mechanism ofFuji apple shape was studied in aspects of the process of pollination and fertilization and the developmentcondition of seeds, endogenous hormones and so on.Meanwhile, some regulating measures such as sprayexogenous hormone, artificial supplementary pollination were conducted in this experiment to researchFormation Mechanism of the Fruit Shape of Fuji Apple, and the conclusions are as follows:1. In its dynamical development, Aksu Fuji apple has a slightly larger vertical diameter than transverseone,and fruit shape index is1.239. After that, the growth of transverse diameter is always greater than thatof vertical diameter until its maturation, and development curve shows "S" type.The reseach on dynamicaldevelopment of iopsided fruits indicates that fruit deviation appears at early stage and in many fruits.Unsymmetrical rate was measured to be22.4%ten days after anthesis, and then slightly lowers down, yetthe overall change is not significant. In different directions of the crown, the fruit shewed rates in west andsouth are slightly lower than those in east and north.In different parts of the crown, the fruit shewed rate atthe top of the tree trunk is larger than those in the central and bottom of the crown.2．By analyzing the structure characteristics of fruit peel of normal and deform fruits, we found that there isno significant difference in peel anatomic structure between them.The flesh cell in small part of deformfruit is78.828um2, this size can only reaches about half of the normal fruit cell, therefore,the dysplasia insmall part of fruit is because cell elongation is not enough,and cell area is very small.3．Comparing with natural pollination,artificial pollination has a better effect on fruit shape development,fruit setting, fruit shape index increased by255.8%and6.52%respectively, and Unsymmetrical ratedecreased35.98%; IAA, GA₃and ZT are higher in young fruits in which is the critical period of cellexpansion and division, this effect increases Endogenous hormones that improve fruit qualities such as theimprovement of fruit shape index and reduction of deviation rate.Namely, insufficient pollinationfertilization is the fundamental reason that causes fruit shape deviation.4．The condition of seed development is closely related to the Fuji apple shape. Seed number and seeddistribution in the ventricles have significant negative correlation with deviation index,this means the moreseeds and ventricles exist in fruit, the lower deviation index fruit has. Most of seeds in deformed fruit havedysplasia that causes seeds abortion in more than two ventricles. Fruit setting rate has little relationshipwith the number of stigmas. In fact, the condition of pollinated seeds development in ventricle make no significant difference when the number of stigma is larger than3.5．Research on dynamic of endogenous hormone contents in seeds from normal, deformed fruits and pulpsuggests that the contents of endogenous hormones are the internal cause for deviation shape. the dynamictrends of IAA, ZT and GA₃are similar in seeds from normal, deformed fruits and pulp Normal fruit, themain trend of these hormones increases rapidly and peaks in young period, and decreases in the longprocess of growth period. IAA and ZT, GA₃peak later in seeds than they do in pulp.but the contents ofthem are far higher in seeds.the contents of IAA and ZT, GA₃, IAA, GA₃andZT/ABA in deformed seedsand pulp,particularly in young period,are all lower than those in normal ones. Sufficient endogenoushormones of IAA, GA₃and ZT in young fruit period improves pulp development, therefore, the majorreason for the formation of deformed fruit is lack of hormones at early development of friut.6．Exogenous hormones has certain effect on Fuji apple shape.Spraying GA₃at blossom has the best effecton of fruit setting rate,49%higher than that under water treatment,and79.45%higher than that under notreatment. Spraying exogenous hormones can reduce deviation index of Fuji apple, mixture （BA100ppm+IAA20ppm+GA₃300ppm） performs best. A series comparations, According to effects,could be made asblossom periodï¹¥blossom+young periodï¹¥young period. Blossom period,blossom+young period,youngperiod spraying6-BA and spray in florescence GA₃can increase the contents of soluble solids,mixedhormone can reduce titratable acid content in fruit.7．Spraying exogenous hormones has certain effect on endogenous hormones. spraying the mixedhormones of IAA,6-BA, GA₃has improving effect on endogenous hormones of IAA and GA₃at blossomstage, furturemore,the contents of IAA and GA₃in fruit trees which under the measurement are all largerthan the contrasts in the whole growing season, spraying the mixed hormones of6-BA, GA₃has improvingeffect on the content of endogenous hormone ZT, especially,at young and enlargement periods. but sprayIAA in young period,has lower ZT content than contrasts, shows that IAA has inhibitory effect on ZT inthe pulp; Spraying GA₃, mixed hormones in young fruit period, ABA content, compared with the contrast,significantly decreases, spraying IAA in young fruit period, ABA content is higher than the contrast, andthe difference disappears after enlargement period.8．the number of kept fruits is positively correlated with shape deviation rate, the more fruit kept, thehigher deviation index gets; Although Bagging has no effect on fruit shape index, it can reduce the shapedeviation index; Different fertilizers have certain effects on shape development, Tianwu company producesbiological fertilizer that has the best effect, other companies,Tianhai Tenghui and Fuzhou Junding are theseconds.