Deficiency of which of the following can cause urea accumulation.

Options

A. Calcium
B. copper
C. Nickel
D. Phosphorus

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which nutrient deficiency can lead to the accumulation of urea in plants. Urea is a nitrogenous waste product that can be toxic at high levels.

2. **Identifying Nutrient Categories**: Nutrients are categorized into macronutrients (needed in large amounts) and micronutrients (needed in smaller amounts). The options provided are:
- Calcium (macronutrient)
- Copper (micronutrient)
- Nickel (micronutrient)
- Phosphorus (macronutrient)

3. **Analyzing the Role of Nickel**: Nickel is a micronutrient that is a crucial component of the enzyme urease. Urease is responsible for breaking down urea into ammonia and carbon dioxide.

4. **Consequences of Nickel Deficiency**: If there is a deficiency of nickel, the activity of urease decreases. This leads to an inability to effectively break down urea, resulting in its accumulation within plant tissues.

5. **Conclusion**: Therefore, the deficiency of nickel is the cause of urea accumulation in plants.

**Final Answer**: Nickel (Option 3)

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