The most common monosaccharides in plants ae glucose, galactose, mannose and rhamnose. They can be separated and identified by GLC-MS (after derivatisation) or high-performance liquid chromatography on a polar column.
mainly glucose sugar in leaves which is soluble sugar. for estimaz\tion u can extract the leaves, purify it , then estimate the sugar by different methods for sugars like molish , barfoed .....etc