The osmotic parameter determining the flow of water from one cell to another is

Explanation -

Diffusion Pressure Deficit (DPD):

• The Diffusion Pressure Deficit (DPD) is the difference in diffusion pressure between two solutions.
• Diffusion pressure deficit is defined as the difference between the diffusion pressure of water or solvent in a solution and that of pure water or solvent.
• The gradient of diffusion pressure allows for rapid water absorption.
• Due to the diffusion pressure gradient, it enables easy water absorption.
• Water flows from a lower to a higher DPD level.
• It's the difference between the osmotic and turgor pressures.
• The osmotic pressure and the wall pressure (turgor pressure) that opposes the endosmotic entry of water influence the DPD of a cell, i.e. DPD = OP - wall pressure.

Thus, the osmotic parameter determining the flow of water from one cell to another is Diffusion Pressure Deficit (DPD).