Which of the following statement is true?

Options

A. The positive hydrostatic pressure is called turgor pressure.
B. Diffusion pressure deficit equals osmotic pressure of a solution plus wall pressure.
C. Diffusion is more rapid in liquids than in gases.
D. Diffusion of water through a semipermeable membrane is called imbibition.

Answer

To determine which statement is true, let's analyze each option step by step:

1. **Statement 1: Positive hydrostatic pressure is called Turgor pressure.**
- Turgor pressure is indeed the pressure exerted by the protoplast (the living part of the cell) against the cell wall. This pressure is a result of water entering the cell and pushing the plasma membrane against the cell wall. Therefore, this statement is **true**.

2. **Statement 2: Diffusion pressure deficit equals osmotic pressure of a solution plus wall pressure.**
- The diffusion pressure deficit (DPD) is defined as the difference between the osmotic pressure of a solution and the turgor pressure. It can be expressed as:
\[ \text{DPD} = \text{Osmotic Pressure} - \text{Turgor Pressure} \]
- Therefore, this statement is **false**.

3. **Statement 3: Diffusion is more rapid in liquid than in gases.**
- This statement is incorrect. The rate of diffusion is generally highest in gases due to the greater intermolecular space and lower density compared to liquids. Therefore, this statement is **false**.

4. **Statement 4: The diffusion of water through a semi-permeable membrane is called imbibition.**
- The correct term for the diffusion of water through a semi-permeable membrane is **osmosis**, not imbibition. Imbibition refers to the absorption of water by solids (like seeds) causing them to swell. Therefore, this statement is also **false**.

Based on the analysis, the only true statement is:
**The first statement: Positive hydrostatic pressure is called Turgor pressure.**