1. What is Water Potential?

Water potential (Ψ) is a measure of the potential energy of water per unit volume relative to pure water in reference conditions. It is the sum of four components: solute potential (Ψ_s), pressure potential (Ψ_p), gravity potential (Ψ_g), and matric potential (Ψ_m).

2. How Does the Calculator Work?

The calculator uses the water potential equation:

Where:

• \( Ψ \) — Total water potential (MPa)
• \( Ψ_s \) — Solute potential (osmotic potential, MPa)
• \( Ψ_p \) — Pressure potential (MPa)
• \( Ψ_g \) — Gravity potential (MPa)
• \( Ψ_m \) — Matric potential (MPa)

Explanation: The equation sums all potential components that affect water movement in plants and soils.

3. Importance of Water Potential Calculation

Details: Water potential determines the direction and rate of water movement in biological systems, crucial for understanding plant water relations, soil-plant-atmosphere continuum, and cellular water balance.

4. Using the Calculator

Tips: Enter all potential components in MPa (megapascals). The calculator sums them to give total water potential. Negative values indicate water potential lower than pure water.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for water potential components?
A: Ψ_s is typically negative (-0.5 to -3 MPa), Ψ_p positive (0.3-2 MPa in turgid cells), Ψ_g depends on height (0.01 MPa/m), Ψ_m negative in dry soils.

Q2: How does water potential affect plant cells?
A: Water moves from high to low potential. When Ψ outside < Ψ inside, water enters (turgor); when Ψ outside > Ψ inside, water leaves (plasmolysis).

Q3: What's the relationship to water potential gradient?
A: The difference in Ψ between two points determines the driving force for water movement.

Q4: How is water potential measured experimentally?
A: Using pressure chambers, psychrometers, or osmometers for different components.

Q5: Why is water potential more useful than water content?
A: It directly indicates water's energy state and movement potential, regardless of system.