Variation in fruit sugar composition of Lycium barbarum L. and Lycium chinense Mill. of different regions and varieties

In this study, the contents of fructose, glucose, sucrose, Lycium barbarum polysaccharide (LBP) and total sugar were determined in the fruits of different cultivated varieties of L. barbarum and of the congeneric species Lycium chinense from different regions. The results showed that the sugar accumulated mainly in the form of hexoses (glucose & fructose). Significant correlations among metabolism-related sugars, LBP and total sugar in the fruit of Ningqi No.1 implied the important role of sugar metabolism in the syntheses of LBP and total sugar. The LBP content of Ningqi No.1 in Ningxia region was the highest among all the cultivated varieties and species. The sugar accumulation was significantly affected by ecological factors such as HCO3−, Na+, Ca2+, Mg2+ and Cl− in soil total salt, pH, soil organic matter and available nitrogen. These findings have profound implications for proper fertilization management and any attempt to grow L. barbarum in new sites.