With reference to plant cells, the DPD can be described as the actual thrust of a cell for water and can be expressed as DPD=OP-TP.
When a plant cell is placed in a hypotonic solution, water enters into a cell by osmosis and as a result turgor pressure develops.
The cell membrane becomes stretched and the osmotic pressure of the cell decreases. As the cell absorbs more and more water its Turgor Pressure increases and Osmotic Pressure decreases.
When a cell is fully turgid, its OP is equal to TP and DPD is zero. Turgid cells cannot absorb any more water.
Answer : (a)