Changes In Contents Of Sugar, Acid, Vitamin C And Mineral Element During Fruit Development Of Four Plum Cultivars

Four plum cultivars, i.e. Dashi early ripening, Longyuanqiuli, Fraiar, Angeleno, were used to investigate the changes of the dynamitic pattern and contents of main sugar, acid , vitamin C and Ca, Mg, K during fruit development. The results showed as follows:The four cultivars' main sugar contents changed consistently. There were lower sucrose and fructose content in pulp at the early development stage, whereas higher glucose content. Fructose content increased gradually and glucose slowly during fruit development, and the sucrose content accumulated rapidly at the late stage. The contents of acid and Vitamin C decreased along with the development of plum fruits.Ca content decreased in cv. Dashi early ripening at the early development stage and increased in some sort at the core-forming stage , and then decreased rapidly until! the fruit mature. Ca content in cv. Longyuanqiuli, Fraiar and Angeleno increased at the early development stage (7th June) and then decreased steadily , untill the ripening stage. Ca content in cv. Longyuanqiuli descended faster than that in cv. Dashi early ripening, In addition, Ca content in cv. Dashi early ripening was higer than that in cv. Longyuanqiuli.The changes of Ca paralleled with that of Mg in cv. Dashi early ripening. Mg content was higher than Ca content at the early stage, and was close in maturation. Mg content in cv. Longyuanqiuli decreased all the time during plum development. Mg content in cv. Fraiar increased at the early stage, then decreased at the date of hard core, increased when maturated (6.6 mg/100gFW) . Mg content in cv. Angeleno decreased, and then increased in 7th August and reached 14.2 mg/100gFW when matutated.The change of K content in cv. Longyuanqiuli, Fraiar, Angeleno increased at the first development and then decreased and increased again. K content increased slowly before 7th June, and then decreased. It reached minimum at 6th July in cv. Longyuanqiuli (117.5 mg/100gFW) and Fraiar (118.5 mg/100gFW) , at 7th September in cv. Angeleno (110 mg/100gFW) . K content reaced maximum when maturated in cv. Longyuanqiuli (150 mg/100gFW) , Fraiar (162 mg/100gFW) , Angeleno (124 mg/100gFW) .The change of K content in cv. Dashi early ripening was 'W type. K content was relatively high at the early stage (158.5 mg/100gFW) , and then decreased rapidly, reached minimum at 17th May (91 mg/100gFW) , ascended to 124 mg/100gFW when maturated.During the fruit development, the contents of Ca and Mg were negatively correlated with sugar content at different degree, whereas positively correlated with acid and Vc contents. There was less positive correlation between K content and sugar content, but K content was negatively correlated with acid and Vitamin C.At the maturing stage, the above parameters in the fruit of 10 cultivars had large differences. The contents of soluble solid in cv. Dashi early ripening, Longyuanqiuli, Angeleno were significantly higher than others. The contents of total sugar in cv. Longyuanqiuli, Angeleno, Fraiar were significantly higher than others and in cv. Morettini,changli 15 were significantly lower than others.Different sugar contents were observed in various plum cultivars. Sucrose was dominant in cv. Dashi early ripening and Longyuanqiuli. Glucose and sucrose were dominant in cv. Fraiar. Fructose and glucose existed mostly in cv, Angeleno. There were significant difference among the acid content in 10 plum cultivars. The acid content in cv. Morettini markedly higher than others. Furthermore, The difference among Vitamin c contents in 10 plum cultivars were significant. Vc content in cv. Dashi early ripening was exceedingly higher than others. Acid and Vc contents in the late cultivars were lower than those in early cultivars, oppositely was the ratio of sugar to acid in early cultivars.