Optimum growth occurs in

Options

A. Blue light
B. Red light
C. White light
D. Green light.

Answer

To determine the conditions under which optimum growth occurs in plants, we need to analyze the effects of different light wavelengths on photosynthesis. Here’s a step-by-step solution:

### Step-by-Step Solution:

1. **Understanding the Role of Light in Photosynthesis**:
- Photosynthesis is the process by which plants convert light energy into chemical energy, producing food (glucose) and oxygen.
- Light is essential for photosynthesis, and different wavelengths of light can have varying effects on plant growth.

**Hint**: Consider how light influences the photosynthesis process in plants.

2. **Identifying the Main Pigment**:
- The primary pigment involved in photosynthesis is chlorophyll, which is predominantly green in color.
- Chlorophyll absorbs light energy from various wavelengths, but it does not absorb green light effectively.

**Hint**: Recall the color of chlorophyll and its absorption characteristics.

3. **Analyzing Light Wavelengths**:
- White light is composed of multiple wavelengths, including red, blue, and green light.
- Chlorophyll absorbs light from the blue and red regions of the spectrum, which are crucial for photosynthesis.

**Hint**: Think about how different colors of light contribute to the energy absorbed by plants.

4. **Comparing Different Light Conditions**:
- When plants are exposed to white light, they receive a full spectrum of light, leading to the highest rate of photosynthesis and, consequently, the fastest growth.
- Blue and red light also promote growth but not as effectively as white light.
- Green light is not absorbed well by chlorophyll, resulting in minimal growth when plants are exposed solely to green light.

**Hint**: Consider which light conditions would maximize photosynthesis and growth.

5. **Conclusion**:
- Based on the analysis, the optimum growth of plants occurs in white light due to its comprehensive spectrum, followed by blue and red light. Green light does not support optimum growth because it is not absorbed effectively by chlorophyll.

**Final Answer**: Optimum growth occurs in **white light**.