Which of the following is not a role or function of nitrogen

Options

A. Major constituents of proteins, nucleic acids, vitamins and hormones,
B. Its deficiency causes yellowing of older leaves (chlorosis)
C. Its deficiency causes purple colouration in shoot axis surface
D. Its deficiency causes premature fall of leaf and flowerbuds.

Explanation

**Step-by-Step Solution:**

1. **Understanding Nitrogen's Role in Plants:**
- Nitrogen is a macronutrient essential for plant growth. It is a major component of amino acids, which are the building blocks of proteins, and is also found in nucleic acids (DNA and RNA), vitamins, and hormones.

2. **Identifying the Functions of Nitrogen:**
- Nitrogen plays several key roles in plants:
- It is a major constituent of proteins, which are vital for various physiological functions.
- It is involved in the synthesis of nucleic acids, which are crucial for genetic information and protein synthesis.
- Nitrogen is necessary for the formation of chlorophyll, which is essential for photosynthesis.

3. **Analyzing the Options:**
- The question provides multiple options regarding the functions of nitrogen. We need to identify which one does not relate to nitrogen.
- The options typically include:
a) Major constituent of proteins
b) Major constituent of nucleic acids
c) Deficiency causes yellowing of older leaves
d) Deficiency causes premature fall of leaf and flower buds

4. **Evaluating Each Option:**
- **Option a:** Major constituent of proteins - This is true for nitrogen.
- **Option b:** Major constituent of nucleic acids - This is also true for nitrogen.
- **Option c:** Deficiency causes yellowing of older leaves - This is a known effect of nitrogen deficiency (chlorosis).
- **Option d:** Deficiency causes premature fall of leaf and flower buds - This is incorrect for nitrogen; it is typically associated with phosphorus deficiency.

5. **Conclusion:**
- The option that is not a role or function of nitrogen is **Option d**: "Deficiency causes premature fall of leaf and flower buds."