Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Megapascals (MPa) are a unit of pressure or stress, commonly used to measure water potential in plants. One MPa is equal to one million pascals or approximately 10 atmospheres of pressure.
5 Must Know Facts For Your Next Test
Water potential in plants is often measured in megapascals (MPa).
A negative water potential value (in MPa) indicates that the plant has a tendency to draw water in from its surroundings.
Typical water potential values for plant cells range from 0 MPa (pure water) to -2 MPa or lower, depending on the environment and plant type.
The concept of megapascals is crucial for understanding how water moves through the xylem and into cells via osmosis.
Soil water potentials are also measured in MPa and affect how easily plants can absorb water from the soil.
Review Questions
Related terms
Water Potential: A measure of the potential energy in water, influencing its movement within plants.
The vascular tissue responsible for transporting water and nutrients from roots to shoots and leaves.
Osmosis: The process by which molecules of a solvent pass through a semipermeable membrane from a less concentrated solution into a more concentrated one.