Studies On Physiological Mechanism Of Sugar Accumulation In Jujube Fruit

’Hupingzao’,’Popozao’ and ’Pozao’ were used as materials to study the characteristics of soluble sugar accumulation, the activity changes of sucrose-metabolizing enzymes and the role in sugar accumulation during the development of Jujube. In addition, the sugar content and the activity of sucrose-metabolizing enzymes were compared in’Hupingzao’on different culture way and Jujube hanging. The aim was to lay the foundation for further studying sugar accumulation mechanism and the correlation of sugar content and disease in Jujube, and also provide the scientific basis and technical means for good quality and high efficiency culture and breeding high-sugar cultivars of other fruits through regulation and reform sugar accumulation process. The result showed as follows:(1) The soluble sugar in Jujube mainly be consisted of sucrose, glucose and fructose, and the content and the ratio of sugar were different in3Jujube varieties. In the first developmental stage, the main ingredient of soluble sugar were fluctose and glucose, the content of sucrose was lower and it began to accumulate in the slow growth stage and then got to the highest at harvest, and the lowest was ’Pozao’,’Popozao’ was close to’Hupingzao’. The changes of contents of the fructose and glucose remained same tendency in3Jujube varieties. The fluctose and glucose began to accumulate rapidly in ’Popozao’ and ’Pozao’ from September8, but there was no obvious changes in’Hupingzao’. At the harvest, the main sugars in ’Pozao’ was glucose and fructose, and was sucrose in ’Hupingzao’, then in’Popozao’suerose and hexose was equal. Total sugar increased gradually during the fiuit development of3varieties. At last, the content of total sugar in’Popozao’ was highest, and ’Hupingzao’ was close to’Pozao’(2) In the first development stage, the activity of AI in3Jujube varieties were high, but the activity of SC, SS, NI and SPS were very low. The content of sugar was controlled by AI. With the development of fruit, the activity of AI decreased, but activity of SS and SPS were increased gradually, the activity of SPS was significant positive correlated with sucrose. Intheslow growth stage, the activity of AI and NI decreased gradually and were not correlated with hexose accumulation in ’Hupingzao’, but was converse in’Popozao’ and ’Pozao’. SS and SC were almost the same in the first development stage, but was higher than SC along with the fruit ripen and showed the activity of synthetic direction. The content of sucrose was significantly correlated with SS and fluctose and glucose was no significant correlation with the activity of SC. Sucrose was not correlated with SS activity of’Pozao’and’Popozao’, but the correlation of the SC and reducing sugar reach to the level of significance or highly significance. The net activity of enzyme was significant positive correlated with accumulation of sugar in’Hupingzao’. In conclusion, the enzyme closely related to sucrose metabolism were AI, NI, SC, SS, SPS in’Hupingzao’, while is SPS, SC, NI, AI in’Popozao’and ’Pozao’.(3) The content of fructose, sucrose and glucose of older Jujube were more than those of young tree. And for the sucrose-metabolizing enzymes, there was no significant difference in the activity of AI, NI,SS and SC, but significant difference in the activity of SPS. So the difference of SPS activity may be one of the reasons that the difference of sugar content between Jujube fruit of older and young tree. The content of fructose, sucrose and glucose of fruit had a slight differencein in Lignification and unlignified jujube hanging. The same to the sucrose-metabolizing enzymes (AI, NI, SS, SC, SPS).