Light wavelength absorbed by `P_r ` and `P_(fr)` state of phytochrome absorbed are respectively

Options

A. 660nm and 730 nm
B. 730 nm and 660 nm
C. 640nm and 700nm
D. 700 nm and 640 nm

Answer

To solve the question regarding the light wavelengths absorbed by phytochrome R (P_r) and phytochrome FR (P_fr), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Types of Phytochrome**:
- Phytochrome exists in two interconvertible forms: Pr (phytochrome red) and Pfr (phytochrome far-red).

2. **Determine the Wavelengths**:
- Phytochrome R (P_r) absorbs red light at a wavelength of approximately **660 nm**.
- Phytochrome FR (P_fr) absorbs far-red light at a wavelength of approximately **730 nm**.

3. **Match the Wavelengths to the Options**:
- Based on the information above, we can summarize:
- P_r: 660 nm
- P_fr: 730 nm
- Therefore, the correct answer corresponds to the option that states these wavelengths.

4. **Evaluate the Given Options**:
- Option 1: 660 nm (P_r) and 730 nm (P_fr) - **Correct**
- Option 2: 730 nm and 660 nm - **Incorrect**
- Option 3: 640 nm and 700 nm - **Incorrect**
- Option 4: 700 nm and 640 nm - **Incorrect**

5. **Conclusion**:
- The correct answer is **Option 1**: The light wavelengths absorbed by P_r and P_fr are 660 nm and 730 nm, respectively.