Water flow in plant tissues takes place in two different physical domains separated by semipermeable membranes: cell insides and cell walls. 
Water transport is pressure driven in both, where osmosis plays an essential role in membrane crossing. In this talk I would like to present a microscopic model (on the scale of a single cell) of water flow and transport of an osmotically active solute in a plant tissue. Macroscopic equations  will be derived applying homogenization techniques.  Macroscopic model shall demonstrate how the local concentration difference of osmotically active solute  influences the water flow direction.