Osmosis is a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one.The trees are having special conduction tissuses for the supply of water and food all over the plant body.Xylem and Phloem are these tissuses.Xylem carries mainly water and minerals, while organic compounds such as sugar and amino acids are transported to the phloem.The flow of liquid in xylem is upward only, whereas the flow of liquid in phloem is bidirectional