Deficiency symptoms of an element tend to appear first in young leaves. It indicates that the element is relatively immobile. Which one of the following elemental deficiency would show such symptoms?

Options

A. Sulphur
B. Magnesium
C. Nitrogen
D. Potassium

Explanation

To solve the question regarding which elemental deficiency would show symptoms first in young leaves, we can follow these steps:

### Step 1: Understand the Concept of Element Mobility
- Elements in plants can be classified as mobile or immobile. Mobile elements can be transported throughout the plant, while immobile elements are primarily utilized where they are absorbed.

### Step 2: Analyze the Given Options
- The options provided are:
1. Sulphur
2. Magnesium
3. Nitrogen
4. Potassium

### Step 3: Identify the Characteristics of Each Element
- **Sulphur**: Essential for the synthesis of amino acids and proteins; primarily needed in young leaves, stems, and root tips.
- **Magnesium**: A central component of chlorophyll; can be mobile within the plant.
- **Nitrogen**: Important for amino acids and proteins; also mobile and can be redistributed to younger tissues.
- **Potassium**: Plays a role in various physiological processes; mobile but can also show deficiency symptoms in young leaves.

### Step 4: Determine Which Element is Relatively Immobile
- Since the question states that deficiency symptoms appear first in young leaves, we need to identify the element that is relatively immobile.
- Sulphur is known to be relatively immobile in plants, meaning that if it is deficient, the young leaves will show symptoms first.

### Step 5: Conclude the Answer
- Based on the analysis, the element whose deficiency symptoms appear first in young leaves due to its immobility is **Sulphur**.

### Final Answer
- The correct answer is **Sulphur**.

---