Effect Of GA₃ Treatment On Respiration,Ethylene Characteristics And Quality Changes Of Huangguan Pear During Its Development And Storage

Huangguan pear is a medium-early-maturing variety in the Pyrus bretschneideri Rehd system.Because of its good quality,taste,and suitable cultivation,it has been widely planted in China.In order to increase the volume of fruit,promote early fruit ripening,and avoid harvest pressure caused by concentrated harvest,gibberellin is widely used in Huangguan pear production.In order to determine whether gibberellin treatment has adverse effects on fruit quality and storage performance,the fruit of Huangguan pear was used as the test material,and the effects of GA₃ on the respiratory and ethylene characteristics,quality formation and storage performance of Huangguan pear during the whole growth period were systematically studied.The results showed that:1.The fruit development period of Huangguan Pear was 141 d.During the whole development period,the hardness of the fruit gradually decreased,and it decreased to 5.85kg·cm^-22 when it matured.The contents of soluble solids,soluble sugars and reducing sugars are all increasing.The titratable acid content showed a“decrease-rise-decrease”dynamic,which was 0.06%when matured.Soluble protein content and Vc content were highest in young fruit,and showed a decreasing trend with fruit maturity.GA₃ treatment can accelerate the development of Huangguan Pear fruit,increase the fruit weight,promote the accumulation of starch content in the early stage of development,and harvest the fruit of Huangguan pear14 d earlier than CK,and the fruit hardness,soluble solids,and titratable acid and Vc content did not cause adverse effects.2.The fruit respiration rate was higher in the young fruit period and gradually decreased with the fruit growth.Ethylene was released slightly in the early fruit development period and then decreased to 0 until the fruit was released when it was ripe.GA₃ treatment reduced the respiratory rate and ethylene release rate in the early fruit development period.When fruit ripening was harvested,the respiratory rate and ethylene release rate of GA₃ treatment were57.79 mg·kg^-1·h^-1and 0.046?L·kg^-1·h^-1,respectively.It was 8.08%and 55.73%lower than the control harvest.3.The fruit of GA₃ treatment had respiratory peaks at room temperature for 7 d and at low temperature for 180 d,and the peaks reached 103.11 mg·kg^-1·h^-1and 57.36 mg·kg^-1·h^-1respectively.GA₃ treatment inhibited the respiration rate of fruits at the early stage of storage at room temperature and at the early stage of low temperature storage,the peak of respiration of fruits stored at low temperature occurred 60 d later than that of CK.The ethylene release of GA₃ treated fruit reached maximum at 14 d and 240 d storage,which were 0.41?L·kg^-1·h^-1and 0.06?L·kg^-1·h^-1,respectively.During storage at room temperature,GA₃ treatment promoted the release of ethylene from fruits,which was 30.74%higher than that of CK at the14th day of storage.GA₃ treatment inhibits the release of ethylene from fruit during low temperature storage,and it was 50.07%lower than the same period of control at 240 d storage.4.During normal and low temperature storage,GA₃ treatment significantly?P<0.05?increased the content of soluble solids,titratable acid and Vc content of postharvest fruits,making the fruit quality of Huangguan pear better than the corresponding CK fruits.However,GA₃ treatment significantly?P<0.01?aggravated the incidence of jizhua disease in Huangguan pear fruit during harvest and storage at normal and low temperature.At 28 d and240 d of storage,the incidence of jizhua disease was 2.13 and 2 times that of the corresponding CK fruits,respectively.