The accurate equation for presenting water potential is

Options

A. `Psi _W =Psi_S+ Psi _p`
B. ` Psi _ S =Psi _W +Psi _P`
C. ` Psi _W =Psi _S -Psi_P`
D. `Psi_W=Psi_S-Psi_P`

Answer

### Step-by-Step Solution:

1. **Understanding Water Potential**: Water potential is a measure of the potential energy in water, which influences the movement of water in plants. It is crucial for understanding how water moves from one area to another within plant tissues.

2. **Components of Water Potential**: Water potential (Ψ) is made up of two main components:
- **Solute Potential (Ψs)**: This component is influenced by the concentration of solutes in the water. More solutes mean lower water potential.
- **Pressure Potential (Ψp)**: This component is influenced by the pressure exerted on the water. In plant cells, this is often related to turgor pressure.

3. **The Correct Equation**: The relationship between these components can be expressed in an equation. The correct equation for water potential is:
\[ Ψ = Ψs + Ψp \]
This means that the water potential is equal to the solute potential plus the pressure potential.

4. **Analyzing Other Options**: The other options provided in the question can be analyzed:
- **Ψs = Ψ + Ψp**: This is incorrect because it rearranges the components incorrectly.
- **Ψ = Ψs - Ψp**: This is also incorrect as it subtracts pressure potential instead of adding it.
- **Ψ = Ψs - Ψp**: This is a repetition of the previous incorrect option.

5. **Conclusion**: The only accurate equation that correctly represents water potential is:
\[ Ψ = Ψs + Ψp \]