https://youtu.be/Ht3u1nIYEa0?list=PLclc2nJ4SJxDOBaNMyHODEiUpHvr8pvFe
Mechanism of transport
Osmosis.
Normally, the movement of water molecules from a region of their higher concentration to a region of their low concentration through a partially permeable membrane is called osmosis. Endosmosis. If water moves by osmosis into a cell the process is called endosmosis, Exosmosis. .if the water moves out of the cell it is called exosmosis. Permeability of Water. The cell wall of epidermal cells of roots is freely permeable to water and other minerals. The cell membrane, however, is differentially or partially permeable to some substances in the solution.
Transport to xylem.
The water which enters the epidermal cells moves along the concentration gradient and passes through cortex, endodermis, pericycle and ultimately to xylem cells. Transport pathways. Following are the paths taken by water to reach the xylem tissue: Apoplast pathway It is the pathway involving system of adjacent cell walls which is continuous throughout the plant roots. In the roots apoplast pathway becomes discontinuous in the endodermis due to the presence of casparian strips. Symplast pathway It is the system of interconnected protoplasts in the root cells.
The Cytoplasm of neighbouring cells (Protoplasts) is connected with one another by Plasmodesmata Plasmodesmata. These are cytoplasmic strands that extend through pores is adjacent cell walls.