Question

Is water movement due to dpd?

Answer 1

DPD stands for diffusion pressure deficit. Water molecules possess kinetic energy. We all know that movement takes place from high to low concentrated places.

Complete answer:
DPD stands for diffusion pressure deficit which is also known as suction pressure (SP) is the difference in pressure of pure water and solution. DPD is responsible for movement of water in plant cells. As we all know, water moves from a region or cell of low DPD to a cell or region of high DPD.
When a plant cell is placed in a hypotonic solution, water enters inside the cell through osmosis. The cell membrane becomes stretched and osmotic pressure decreases. Cells absorb excess water due to turgor pressure. In a fully turgid cell osmotic pressure is equal to turgor pressure and hence DPD is zero. That means the cells cannot absorb any water. It can be described as DPD= OP- TP.
When DPD becomes zero the entry of water will stop. It means to represent the water absorbing ability, called suction pressure. DPD is directly proportional to the height of the plant or organisms. It is governed by factors like turgor pressure and osmotic pressure. The diffusion pressure value for pure water theoretically is 1245.69 atm at STP.

NOTE -
The term diffusion pressure deficit was given by BS. Meyer in 1938 and it was originally described as suction pressure by Renner in 1915. It is defined as the reduction in diffusion pressure of water in solution over its pure state due to the presence of solute in it and forces that oppose diffusion.