Analysis On The Effect Of Girdling And Constriction Of Armeniaca Vulgaris ‘Suletan’

‘Suletan’is a characteristic early maturing local apricot species in tuokesun County,Turpan,Xinjiang.However,due to its short fruit development period,and in order to achieve the purpose of early marketing and long-distance transportation,it was picked when the fruit reached its recoverable maturity,resulting in less accumulation of fruit content,low sugar content and insufficient flavor.In this experiment,the four-year-old fruiting branch group of‘Suletan’apricot was treated by girdling and constriction.The effects of the two methods on regulating shoot growth,fruit development,light and characteristic photosynthetic assimilation product distribution and improving the content of main flavor substances in fruit were compared.The purpose of this study was to explore an effective method to improve the fruit flavor of‘Suletan’apricot,in order to further improve the market competitiveness and industrial benefits of‘Suletan’apricot.The main research results are as follows:（1）After girdling and constriction treatment on the base of fruiting branches of‘Suletan’apricot,the growth and thickening of new shoots could be effectively inhibited,from 21 d after full bloom to 56 d after full bloom,the lengths of new shoots of control,girdling and constriction increased by 26.8 cm,5.7 cm and11.4 cm,respectively,new shoots diameter increased:1.74 mm,0.8 mm,1.03 mm.Girdling inhibited shoot growth more obviously.The chlorophy II content of functional leaves after girdling and constriction was 3.20%and 5.43%higher than that of control,respectively.The net photosynthetic rate,stomatal conductance,transpiration rate and intercellular CO₂concentration of the functional leaves after girdling and constriction treatments increased by 13.25%and 24.40%,7.83%and 27.61%,16.58%and 37.81%,and 18.84%and 8.61%,respectively,compared with the control.By comparing the control,girdling and constriction treatments,it can be seen that constriction treatment can more effectively inhibit the vegetative growth of‘Suletan’apricot and improve the net photosynthetic rate of leaves.At the same time,only the girdling and constriction treatment had a slight flow phenomenon in the same year,the flow rate was 10%,and the flow rate of the next year was 20%.There was no flow in the control and hanging treatment.（2）After girdling and constriction treatment,the fruit maturity was 2-3 days earlier than the control.Both girdling and constriction treatments could increase the longitudinal,transverse,lateral diameters and single fruit weight at different degrees.On the 56th day after full bloom,the single fruit weight of girdling and constriction treatments increased by 10.78%and 15.94%compared with the control,respectively.The longitudinal diameters increased by 3.52%and 6.93%compared with the control,respectively.The transverse diameters increased by 2.93%and 8.41%compared with the control,respectively.The lateral diameters increased by 2.69%and 4.69%compared with the control,respectively.The fruit lateral diameter and single fruit weight increased more significantly under constriction treatment.（3）The total sugar content of‘Suletan’apricot increased rapidly in the second rapid growth period.girdling and constriction can increase the total sugar and total acid content of fruit.When the fruit matures 56 days after full bloom,the sugar components in the pulp are mainly sucrose,fructose,glucose and sorbitol,accounting for 66.5%-68.6%,5.2%-6.5%,18.9%-21.7%and 3.7%-6.2%of the total sugar,respectively.After girdling and constriction,the sucrose content of the fruit was 8.43%and12.69%higher than that of the control,and the total sugar content was 10.96%and 12.78%higher than that of the control,respectively.Malic acid content was the highest at maturity of‘Suletan’apricot fruit,accounting for about 85%of the total acid content.The malic acid content of girdling treatment was 6.06%lower than control treatment,the malic acid content of constriction treatment was 7.88%higher than control treatment,the total acid content of girdling treatment was 5.90%lower than control treatment,the total acid content of constriction treatment was 6.92%higher than control treatment.The sugar-acid ratio of the fruits after girdling and constriction increased,so the flavor of the fruits after girdling and constriction was better than that of the control.The total sugar content and total acid content of the flesh treated by constriction are higher,and the fruit flavor is better.（4）Sorbitol is the main form of carbohydrate export and transport in the leaves and phloem of‘Suletan’apricot.After girdling and constriction treatment,the sorbitol content in the leaves of girdling treatment was 0.95%higher than that of the control treatment,and that of constriction treatment was2%lower than that of the control treatment.The sorbitol content in phloem of the girdling treatment was 27.29%lower than that of the control,and the sorbitol content of the constriction treatment was26.30%lower than that of the control.The difference of sorbitol concentration between control,girdling and constriction from leaf to fruit was 11.42 mg/g FW,12.72 mg/g FW and 13.10 mg/g FW,respectively.The concentration difference of sorbitol between leaves and fruits increased after girdling and constriction treatment,which effectively promoted the transportation of sorbitol to fruit end.The effect of constriction treatment on the transportation of sorbitol to fruit end was more significant.（5）The constriction treatment can effectively slow down the vegetative growth of new shoots,increase the single fruit weight of fruit,increase the content of total sugar and total acid in fruit,improve the ratio of sugar to acid,and promote the early maturity of fruit without damaging the tree,which is a more safe and effective control method to improve the fruit quality of‘Suletan’apricot.