* Water Potential: Water potential is the tendency of water to move from one area to another. It is affected by factors like pressure, solute concentration, and gravity.
* High Water Potential: Water has a higher potential in areas with low solute concentration and high pressure.
* Low Water Potential: Water has a lower potential in areas with high solute concentration and low pressure.
Here's the scenario in a plant cell:
1. Hypotonic Environment: The external fluid has a higher water potential (lower solute concentration) compared to the cell's internal environment (cytoplasm). This means the water outside the cell has a stronger tendency to move inwards.
2. Water Movement: Water molecules move across the semi-permeable cell membrane from the area of higher water potential (external fluid) to the area of lower water potential (inside the cell).
3. Cell Turgor: As water enters the cell, the central vacuole swells, pushing the cytoplasm against the cell wall. This creates turgor pressure, which is the pressure exerted by the cell's contents against the cell wall.
Factors influencing water flow:
* Solute Concentration: Higher solute concentration inside the cell compared to the external environment will cause water to flow inward.
* Pressure Potential: If the external pressure is higher than the internal pressure, water will move inwards.
* Cell Wall: The rigid cell wall limits the expansion of the cell, preventing it from bursting due to excessive water intake.
In summary:
External fluid flows into a plant cell due to a difference in water potential between the cell's internal environment and the external fluid, primarily driven by the higher solute concentration inside the cell compared to the external environment. This process, known as osmosis, is crucial for maintaining cell turgor and overall plant health.
