Studies On Jun-jujube Fruit Drop Mechanism And Dropping Regulation

The phenomenon of Jun jujube fruit drop is serious in Aksu region, so this experiment selects8yearsold of Jun jujube as test material, using field trials and laboratory test method in order to conclude the fruitdrop law and regulate it by sprying foliar fertilizer and exogenous hormone, root application ofbiologicalorganic fertilizer and thinning flower and fruit. The results are as follows:1. Young fruit began to fall off at10d after fruit setting and this phenomenon continued to fruit maturity.There were two fruit drop peaks during young fruit period and fruit enlargement period and its cumulativenumber accounted for total were respectively47.1%,78.7%. Jun jujube fruit drop rate was as high as90.4%.2. The abscission layer of Jun jujube fruit and fruit stalk is gradually differentiated. During the process offruit drop medulla abscission layer firstly isolated and formed into cracks, then extended to xylem andformed a big gap with phloem, but the catheter and companion cells in the vascular bundle tissues did notseparate, the junction between fruit and fruit stalk finally detached by the external force.3. The formation of Jun jujube first physiological drop peak associated with the low content of IAA andZT, and the second drop peak occurred in the fruit enlargement period, which related with the reduction ofGA3, IAA, and ZT, while the sharp rise of ABA. The value of ABA/(GA3+IAA+ZT) had certaininstruction function to Jun jujube physiological fruit drop in the Jun jujube development process.4. Spraying urea, potassium dihydrogen phosphate and boric acid before fruit setting period had the bestprevention effect. Spraying5different kinds of foliar fertilizer before the young fruit could alleviate thefruit drop. On the stage of fruit enlargement, the effect of spraying zinc sulfate was not obvious, while othertreatments were obvious, however the drop rate related to other periods are relatively high. Five kinds oftreatments failed to meet expectations to prevent fruit drop.5. Spraying gibberellin during flowering phase reduced fruit drop effectively, while such effect did notexist in the stage of young fruit and fruit enlargement. Spraying naphthylacetic acid also could prevent fruitdrop especially during fruit setting and yong fruit period.While spraying gibberellic acid and naphthylaceticacid during fruit enlargement period and crisp ripe stage did not mitigate the fruit drop and the fruit droprate exceeded70%6. Root application of biological organic fertilizer could reduce fruit drop to a certain extent. Differentfertilizers in different periods had the different effects, and the effect of biological organic fertilizer3wasrelatively well.7. Thinning flower and fruit could reduce the fruit drop during different fruit development stage, and theaverage fruit drop rate of flower thinning was21.09%, fruit thinning was only18.42%.