What is the term for the pressure that pushes the plasma membrane against the cell wall?

Turgor pressure refers to the pressure exerted by the fluid (usually water) inside the central vacuole of plant cells against the cell wall. This pressure is vital for maintaining the structural integrity and rigidity of plant cells. When a plant cell is placed in a hypotonic solution, water enters the cell through osmosis, causing the vacuole to swell. As the vacuole expands, it presses against the plasma membrane, which in turn pushes against the cell wall. This creates turgor pressure, which helps keep the plant upright and firm.

In contrast to other terms presented in the options, turgor pressure specifically describes the phenomenon associated with plant cells and their resistance to wilting. It is distinct from hydrostatic pressure, which relates to fluids in motion and is a broader concept that isn't limited to cellular structures. Similarly, cellular pressure and gradient pressure do not accurately capture the unique role of water in maintaining the integrity of plant cells as turgor pressure does. Understanding turgor pressure is essential for appreciating how plants regulate their internal environment and structural stability.