| The jujube fruit has a high sugar content,which can be used to evaluate the fruit flavor and nutritional quality,thereby determining the commercial value of the jujube fruit.The sugar in the fruit is the photosynthesis of the source leaf tissue,the most enter the fruit in the form of sucrose,through a series of biochemical reactions and then stored away in the form of soluble sugars or starch,lead to changes in fruit sweetness.In order to clarify the mechanism and jujube fruit sugar accumulation of sugar phloem transport law,In this paper,sucrose-accumulated jujube varieties and reducing sugar-accumulated jujube varieties were used as test materials,Starting from sugar components affecting glucose metabolism,enzyme activities related to glucose metabolism and phloem unloading,to compare fruits of different sugar accumulated jujube varieties,Below are key research findings:1.The accumulation of fructose and glucose is mainly concentrated in the early stage of fruit development of five jujube varieties,the Sucrose content of Sucrose accumulation type jujube increased in the late stage of fruit development,reducing sugar content decreased slightly,reducing sugar accumulation type jujube fruit sucrose content decreased,reducing sugar content rises,this difference caused the formation of two types of sugar-accumulated jujube fruits.2.Two kinds of sugar-accumulated jujube varieties mainly decompose enzyme activity in the early stage of fruit development,synthetic enzyme activity is mainly at middle and late development.During the whole fruit growth and development,two kinds of sugar accumulation type jujube varieties fruits glucose,fructose and sucrose significantly are correlated with decomposing enzymes,and no correlation with synthesis.it is indicated that the decomposing enzyme is a common key enzyme regulating the sugar accumulation of the fruit of two sugar-accumulated jujube varieties.3.After the fruit is ripe,The sucrose content and reducing sugar content of the Fengmiguan are respectively26.95%and 27.66%approaching 1:1,the Sucrose content of Jing 39 is 1.84%,less than reducing sugar content 13.91%,the Sucrose content of Dongzao is 36.82%,still more than reducing sugar content 7.90%.It is indicated that different fruit maturity have an impact on the sugar accumulation type of judgment.The sucrose content decreased after fruit ripening,reducing sugar,starch,organic acid content are rise.Explanation:After ripening varieties of jujube sucrose accumulation type sucrose under respiratory metabolism,converted to reducing sugar,starch and organic acids and other primary metabolites,resulting in a shortened storage period of fresh foods,the quality of the fruit is reduced.In this research the mature period of Jing 39 and Fengmiguan are on sept.24th,and the mature period of Dongzao is on Oct.4th.Infering from this,the best harvest time of jing 39 and Fengmiguan are in the late September.and the Dongzao is in the early October.4.Pre-developmental stage,reducing sugar content of blade,petiole,jujube hanging,fruit stalk,fruit in sucrose accumulation type jujube Jun2 separately are:0.77%,0.55%,0.57%,0.45%,5.87%,sucrose content separately are 0%,0.13%,0%,0.15%,0.26%,As can be seen,At the pre-developmental stage of sucrose,accumulation type jujube variety,reducing sugar is high in sucrose accumulation type jujube species,while sucrose is relatively low.Jujube is same as Jinmangguo and Manmanzao.Reducing sugar of blade,petiole,jujube hanging,fruit stalk,fruit in accumulation type jujube Jinlinyuanzao separately are:0.91%,0.87%,0.89%,0.59%,6.86%,sucrose content separately are 0%?0.20%?0.12%?0.16%?2.17%,As can be seen,at first reducing sugar is high in reducing sugar accumulation type jujube,while sucrose is relatively low.Meimizao and Naitouzao are consistent with it.At Mid-development the sucrose content of each organ increased more than the reducing sugar content in two kinds of sugar accumulation type jujube varieties.Late development glucose content of blade,petiole,jujube hanging,fruit stalk,fruit in sucrose accumulation type jujube Jun 2 separately are:0.61%?0.29%?0.76%?1.45%?3.10%.Fructose content separately are:0.83%?0.20%?0.89%?2.22%?3.30%.Sucrose content separately are:1.24%?0.43%?1.29%?7.58%?25.73%.it seems to that sucrose accumulation type jujube varieties has the highest sucrose content at the late stage,and Manmanzao same as Jinmangguo.Glucose content of blade,petiole,jujube hanging,fruit stalk,fruit in reducing sugar accumulation Jinlinyuan separately are:0.22%?0.35%?0.38%?1.94%?4.78%,fructose content are:0.19%?0.21%?0.29%?1.62%?5.65%.Sucrose content separately are:1.92%?0.59%?1.54%?3.14%?15.05%,it seems to that reducing sugar accumulation type jujube variety sucrose content has the highest at the late late stage,and the same as Meimizao and Naitouzao.Infer from this,at the early stage the sugar from photosynthesis synthesis in the blade transport to various organs in the form of reducing sugar.Transported in the form of sucrose in the mid and the late stage.5.Two kinds of sugar-accumulated jujube fruits in the early and late stage of phloem low intercellular filament density at SE/CC and PP interface,separately are 0.48·?m-1,0.55·?m-1,and evenly distributed amorphous filaments in the sieve cavity,high density of intercellular filaments at SE/CC and PP interface at mid stage,separately are 1.65·?m-1,1.01·?m-1,the density of intercellular filaments on the interface of SE/CC and PP is low and the cells are separated by plasmolysis.intracellular osmotic potential is reduced,organic matter is passive transport,the results shows:these jujube sugar unloading path are in the main apoplast at the early stage,The main path in the symplast of the medium term,in the main apoplast at last term. |
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