Define water potential. How it is measured?

Explanation

### Step-by-Step Text Solution

1. **Definition of Water Potential**:
- Water potential is defined as the potential energy of water in a system compared to pure water. It is the difference between the free energy of water molecules in a solution and that of pure water. In simpler terms, it indicates the tendency of water to move from one area to another, particularly in biological systems.

2. **Components of Water Potential**:
- Water potential (Ψ) is influenced by several factors and can be expressed mathematically as:
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