Study On Changes Of Endogenous Hormones Contents In 'Hongdeng' Sweet Cherry (Prunus Avium L.) And The Effection Of Exogenous Hormones

The present experiment, with the sweet cherry (Prunus avium L.) "Hongdeng" as its cultivar, investigated the dynamic changes of the fruit growth and development,the endogenous hormones contents of the pulp as well as the effects of different exogenous hormones on the fruit set rate and fruit quality. The main intention were to study the relationship between the endogenous hormones and fruit growth and development as well as the most effective exogenous hormones and its concentrations to improve the fruit quality. The main results were as follows:1.The results showed that the growth and development period of 'Hongdeng' sweet cherry could be divided into three phases:â… . The first fast-developed period (5^th -15^th days after full bloom), during which the fruit weight, vertical and horizontal diameters developed fast, with the vertical diameter developed faster than the horizontal one;â…¡. The core-harden period (15^th-25^th days after full bloom), during which the fruit developed slowly;â…¢. The second fast-developed period (25^th -40^th days after full bloom), during which the fruit weight, vertical and horizontal diameters resumed to develop fast, but the horizontal diameter developed faster than the vertical one this time. The contents of dissolved sugars and titrated acid in fruit increased with its development until maturity.The contents of dissolved sugars increased faster than the contents of titrated acid in fruit at the end period of the fruit development. As a result,the ratio sugar/acid was increased corresponding with the fruit growth and development until maturity.All that make it a good advantage to improve the fruit quality.2.The relationship between the contents of endogenous hormones and the fruit growth and development was consanguineous.The content of ZR_s in the pulp had the highest values in the beginning of the first fast-developed period, and then had a tendency of decrease with the fruit' grew and developed until maturated. The contents of IAA and GA_s in the pulp of young fruit were high in the fast-developed-period, then decreased with its development until the end of the core-harden period, and they all had a tendency of increase in the second fast-developed period until maturity, corresponding with the fruit growth. The content of ABA had the peak values in the physiological dropping period of the flower and fruit respectively, similar to the fruit (flower) dropping periods.3. Different exogenous hormones with different concentrations were used to study the effects of them on the fruit set rate and fruit qulity. The results showed that:The treatments of GA₃(10-50mg.kg^-1) enhanced the fruit set rate and it had the peak value at the 40mg.kg^-1 concentration,which is 67.9093%,but the fruit guality was decreased.The fruit set rate was 65.0534% on treatment of 30 mg.kg^-1GA₃,which was only about 3.0% lower than the 40mg.kg^-1 GA₃ treatment,but the fruit quality was significantly improved.The fruit set rate and the fruit quality were both more significantly improved under the treatment of GA₃(30 mg.kg^-1)+6-BA/6-KT(10-30 mg.kg^-1) in full bloom than the treatment of GA₃(30 mg.kg^-1.The results showed that:The effection of GA₃(30 mg.kg^-1)+6-KT on the fruit set rate and the fruit quality were both more significantly improved than the treatment of GA₃(30 mg.kg^-1)+6-BA.The fruit set rate had the highest value (71.8532%) on the treatment of GA₃(30 mg.kg^-1)+6-KT(20 mg.kg^-1),and the fruit quality was also had the most level.