Study On Ziziphus Jujuba Cv. Dongzao And Ziziphus Jujuba Cv. Linyilizao Fruit Development And Quality Formation

The mechanisms of fruit development and quality formation of Ziziphus jujuba cv. Dongzao and Ziziphus jujuba cv. Linyilizao were studied. The variation of titratable acid, soluble sugar, vitamin C, soluble protein, free amino acid, mineral element and indogenous hormone of fresh jujube fruits during fruit development were observed. The differences of biochemical characters among fruits of different sizes, and maturity and different fruit position were also studied. The results were as follows:1 The growrh curves of fresh weight, volume, diameter and length showed double "S"shape.The content of chlorophyll decreased and the content of anthocyanidin increased during fruit development of both "Dongzao" and "Linyilizao". In the early stage of fruit development, the content of chlorophyll in "Linyilizao" was higher than that in Dongzao.During the whole period of fruit development, the anthocyanidin content in Dongzao was always higher than that in "Linyilizao". The anthocyanidin in "Dongzao" was detected 20 days ealier than "linyilizao".2 The variety of soluble sugar content in "Linyilizao" and "Dongzao" had the same trend, i.e., in the early stage of fruit development, the changes of the content of soluble sugar were not obvious; from September 15 to October 5 soluble sugar accumulated rapidly . The content order of different kind of sugar was : fructose) glucose) sucrose before maturation and sucrose ) fructose) glucose at maturation.3 The variation of titratable acid contents in "Linyilizao" and "Dongzao" had the same trend. In the early stage of fruit development, the content of titratable acid were high. With the development of fruit titratable acid content decreased. During fruit maturation, the content of titratable acid increased lightly.4 The content of vitamin C showed low-high-low in the course of fruit developmentand keeped a high level from July 15 to August 15.6 The variation of soluble protein content of "Linyilizao" and "Dongzao" showed similar curves with three peaks. In the stage of fruit setting , the content of free amino acid changed dramatically compared with that in fruit developing period.The content of free amino acid decreased during fruit maturation.7 With the development of fruit, the content of Ca, Fe, Zn, K had a decreasing trend.Variations of the content of Na and Cu were complex and Cu content took a dcreasing trend in the whole period.8 The content of GA3 kept high in the early stage of fruit development and declined gradually from July 15 to October 5. From fruit setting to young fruit stage, the content of IAA increased rapidly and then kept a high level, and decreased gently from August 5 to October 5. Z was detected in the early stage of fruit development and showed a trend of low-high-low. ABA was detected in the late stage of fruit development and increased dramatically.9 Compared with other fruits, the contents of fructose, glucose and vitamin C were the lowest and the contents of soluble sugar , sucrose and titratable acid were the highest in the first grade. With the increasement of fruit coloration the content of sucrose, fructose, the soluble total sugar and titratable acid increased and that of glucose and vitamin C decreased. The fructose, vitamin C content of shady part of fruit surpassed that of sunny partAs a while, the glucose ,sucrose and the soluble total sugar contents of sunny part of fruit surpassed that of shady part.10 Precooling(10 ) could keep the content of titratable acid and vitamin C of fruit in a higher level. The treatment of ice water kept a higher content of soluble sugar and a better storage effect. The treatment of 0.5% citric acid presented a better result in keeping high level of the content of soluble sugar and titratable acid and the treatment of 1.5% citric acid presented a better result in keeping high level of vitamin C content.