The cause of guttation is mainly

Options

A. root pressure
B. osmosis
C. transpiration pull
D. cohesive force

Answer

### Step-by-Step Solution:

1. **Understanding Guttation**:
- Guttation is the process through which water is expelled from the leaves of plants, typically observed as droplets on the leaf margins in the early morning.

2. **Role of Hydrothodes**:
- The water is secreted through specialized structures called hydrothodes, which are located at the margins of the leaves. These structures facilitate the exudation of water.

3. **Root Pressure**:
- The primary cause of guttation is the root pressure, which is the pressure exerted by the roots of the plant. This pressure is highest in the early morning when transpiration rates are low.

4. **Absorption of Water**:
- During the night, roots continue to absorb water from the soil. Since there is minimal transpiration (loss of water vapor from the leaves), the water accumulates in the plant.

5. **Water Exudation**:
- Due to the high root pressure and the absence of transpiration, the excess water is pushed out through the hydrothodes, resulting in the formation of droplets on the leaf surfaces.

6. **Conclusion**:
- Therefore, the main cause of guttation is the root pressure that builds up in the plant during the early morning hours when transpiration is minimal.