Effects Of Spraying Hormones On Fruit Quality Characteristics Of Centennial Seedless Grape Under Different Cultivation Environments

The fruit quality of Centennial Seedless grape is easily affected by high temperature environment,and hormones can regulate the fruit quality,but there are few studies on the effects of hormones on the growth and development of grape fruit under high temperature and dry environment.Therefore,this study took Centennial Seedless grape as the experimental object,sprayed hormones in different cultivation areas,and carried out experiments around the hormone concentration to improve fruit quality in high-temperature areas.The experimental sites were Shanshan County,Turpan City（high-temperature area）and Anningqu Town,Urumqi City（suitable temperature area）,with a total of 9 d hormone concentrations of H1-H9 and CK water as the control,Determine and analyze the differences of appearance indexes and internal quality indexes such as sugar,acid,VC,phenolic substances and aroma substances of grape fruit dipped in hormone under different temperature environmental conditions,and explore the effects of hormone on sensory quality and internal quality of Centennial Seedless grape,so as to provide reference for the use of hormone in the cultivation of Centennial Seedless grape in high temperature area,It provides a theoretical basis for the production of high-quality Centennial Seedless grape in high-temperature areas.The main results are as follows:1.In 2021,the daily maximum temperature in Turpan（high temperature area）is up to 43℃,and that in Urumqi（moderate temperature area）is up to 38℃.The days exceeding 35℃are 86 d and 20 d respectively.The maximum temperature and time exceeding 35℃in Turpan are significantly higher than that in Urumqi.2.The stronger adaptability of Centennial Seedless grape to light is that in the high-temperature area,the daily change of leaf net photosynthetic rate showed a typical bimodal curve,and the maximum peak appeared around 10:00.The light saturation point and apparent quantum efficiency of Turpan are higher than that of Urumqi178.92μmol·m^-1·s^-1 and 0.01μmol·m^-1·s^-1;The light compensation point of Turpan is 11.94μmol·m^-1·s^-1,17.94%higher than Urumqi.Turpan（high temperature area）Centennial Seedless grape flowering period is about 9 d earlier than Urumqi（moderate temperature area）,which seriously affects the fruit size.The grain weight of Centennial Seedless grape in high temperature area is 2.0 g lighter than that in moderate temperature area.3.Continuous high temperature will reduce the enzyme activity of Centennial Seedless grape.Hormone treatment increased the activities of SOD,POD and CAT in the fruit,reduced the content of MDA,and significantly reduced the impact of high temperature stress on various physiological indexes of grape.With the increase of hormone concentration,the activities of SOD,POD and CAT increased.The treatment of hormone 70 mg/L GA₃+1 mg/L CPPU had the most significant effect on the activities of SOD,POD and CAT in fruit.Compared with CK,the activities of SOD,POD and CAT increased by 0.706 U/g,0.796 U/g and 1.077 U/g in Turpan（high temperature area）and 0.476 U/g,0.096 U/g and 1.134 U/g in Urumqi（suitable temperature area）respectively.4.High temperature stress affects the improvement of fruit quality.Hormone treatment has a significant effect on increasing fruit grain size and improving fruit quality such as nutrients and phenols.Compared with CK,70 mg/L GA₃+1 mg/L CPPU treatment had the best effect on fruit enlargement,fruit nutrient accumulation and phenolic content.After hormone treatment,the contents of soluble solids,soluble sugar,VC and other nutrients in grape fruits in different cultivation areas increased significantly;The kernel weight of Centennial Seedless grape in Turpan（high temperature area）increased by 3.78 g;The content of titratable acid decreased significantly.Hormone treatment reduced the contents of tannin,flavonoids and proanthocyanidins by 0.27 mg/g,0.09 mg/g and 0.79 mg/g respectively;The contents of polyphenols and flavanols in fruits increased by 1.20 mg/g and 9.71 mg/g respectively;The contents of tannin,flavonoids,polyphenols and proanthocyanidins in Urumqi（suitable temperature area）increased by 0.65 mg/g,0.89 mg/g,3.87 mg/g and 8.84 mg/g respectively,and the content of flavanol decreased by 5.24 mg/g.5.Turpan（high temperature area）has higher content of aroma substances than Urumqi（moderate temperature area）.After treatment with hormone 70 mg/L GA₃+1 mg/L CPPU,laurene,terpineol,geraniol,linaloolα-The Aroma Contents of pinene,beta.-Myrcene,.alpha.-Terpineol,Geraniol,Linalool,.alpha.-Pinene,2-Buten-1-one,1-（2,6,6-trimethyl-1,3-cyclohexadien-1-yl）-,（E）-,Octanal,Heptanal,Hexanal,2-Isopropyl-5-methylhex-2-enal,Benz Aldehyde,Geranic acid;Benzeneacetic acid,4-Hexen-1-ol,acetate,1-Decanol,2,3-Butanediol;Benzyl Alcohol increased significantly.The 70 mg/L GA₃+1 mg/L CPPU treatment had significant differences in the increase of aroma substances,including terpenoids and aldehydes.