Due to deficiency of phosphorus

Options

A. the rate of protein synthesis is increased
B. the rate of protein synthesis is decreased
C. there is no effect on the rate of protein synthesis
D. the rate of protein synthesis initially declines but increases later on

Answer

### Step-by-Step Solution:

1. **Identify the Nutrient**: The question specifies a deficiency of phosphorus. Phosphorus is a vital mineral nutrient for plants.

2. **Understand the Role of Phosphorus**: Phosphorus plays a crucial role in various physiological processes in plants, including energy transfer (ATP), photosynthesis, and the synthesis of nucleic acids and proteins.

3. **Effects of Phosphorus Deficiency**: When there is a deficiency of phosphorus, it primarily affects the plant’s ability to synthesize proteins. This is because phosphorus is essential for the formation of nucleotides, which are the building blocks of nucleic acids and are involved in protein synthesis.

4. **Evaluate the Options**:
- **Option A**: "The rate of protein synthesis increases." This is incorrect because phosphorus deficiency leads to a decrease in protein synthesis.
- **Option B**: "The rate of protein synthesis decreases." This is correct as phosphorus deficiency negatively impacts protein synthesis.
- **Option C**: "There is no effect on the rate of protein synthesis." This is incorrect; phosphorus deficiency does have an effect.
- **Option D**: "The rate of protein synthesis initially declined but increased later on." This is also incorrect; phosphorus deficiency consistently leads to decreased protein synthesis.

5. **Conclusion**: The correct answer is that the rate of protein synthesis decreases due to phosphorus deficiency.