The movement of photosynthate from source (supply end) to sink (consumption end) is known as translocation. The ringing experiment showed that translocation of solute occurs through phloem. Zimmarman and Ziegler 1975 studied the composition of phloem sap of some 500 species by chromatography. The most dominant translocated form of carbohydrate is the non reducing sugar sucrose. In some plants phloem contains raffinose, stachyose, verbascose, mannitol, myoinisitol and sorbitol in low concentration.