Changes of sugar distribution in different tissues of satsuma mandarine

Abstract

The present study analyzed the changes of total sugar, fructose, glucose, and sucrose contents in leaves, roots, and fruits of Citrus unshiu cv Guoqing No. 1 grafted on Poncirus trifoliata in fruit enlargement period (August) and fruit mature period (October). The results showed an increase of glucose, sucrose, and total sugar from enlargement period to mature period. Total sugar content ranked as the trend of fruit pulp > fruit peel > root > distal leaf > proximal leaf. Significantly higher sucrose content was ranked as the trend of fruit pulp > fruit peel > proximal leaf > distal leaf > root in August and fruit pulp > fruit peel > root> proximal leaf > distal leaf in October. Significantly higher fructose content was rated as the trend of fruit pulp ≈ fruit peel > distal leaf > root ≈ proximal leaf in fruit enlargement period and fruit pulp > fruit peel ≥ distal leaf > proximal leaf > root in fruit mature period. Significantly higher glucose content was ranked as the trend of fruit pulp > root > fruit peel > proximal leaf ≈ distal leaf in fruit enlargement period and fruit pulp ≥ root > fruit peel > proximal leaf > distal leaf in fruit mature period. It concludes that roots recorded relatively lower sugar content than other four tissues, and sugars could transfer from proximal leaf into fruit, which is center of energy requirement, especially fruit pulp.