Elements causing deiayed flowering at low concentration are

Options

A. N, S, P
B. N, S, Mg
C. N, S, Mn
D. N, S, Mo

Answer

To solve the question regarding the elements causing delayed flowering at low concentrations, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Elements**: We need to consider the elements provided in the options and their roles in plant physiology, particularly in relation to flowering.

2. **Analyze Each Element**:
- **Nitrogen**: This element is essential for plant growth and development. It is a key component of amino acids and nucleic acids. Low concentrations of nitrogen can lead to delayed flowering because it affects overall plant health and growth.
- **Sulphur**: Similar to nitrogen, sulphur is vital for the synthesis of certain amino acids and proteins. Low levels of sulphur can also result in delayed flowering as it impacts the plant's metabolic processes.
- **Phosphorus**: While phosphorus is crucial for energy transfer (ATP) and photosynthesis, it does not directly cause delayed flowering. Instead, it promotes flowering when present in adequate amounts.
- **Magnesium**: Magnesium is a core component of chlorophyll and is important for photosynthesis. However, it does not directly influence flowering time negatively.
- **Manganese**: This element plays a role in photosystem II during the light reactions of photosynthesis. Like magnesium, it does not contribute to delayed flowering.
- **Molybdenum**: This element is involved in the reduction of nitrates to ammonia, which is essential for nitrogen metabolism. Low levels of molybdenum can lead to delayed flowering due to its impact on nitrogen availability.

3. **Select the Correct Elements**: Based on the analysis:
- Nitrogen
- Sulphur
- Molybdenum

4. **Conclusion**: The elements causing delayed flowering at low concentrations are Nitrogen, Sulphur, and Molybdenum.

### Final Answer:
The elements causing delayed flowering at low concentration are **Nitrogen, Sulphur, and Molybdenum**.

---