Deficiency symptom appears first in young leaves if the soil is deficient in:

Options

A. CI
B. Mg
C. Ca
D. S

Answer

To solve the question regarding which nutrient deficiency symptom appears first in young leaves, we can follow these steps:

### Step 1: Understand Nutrient Mobility
- Nutrients in plants can be classified into two categories based on their mobility: mobile and immobile elements. Mobile elements can move from older leaves to younger leaves, while immobile elements cannot.

**Hint:** Remember that mobile elements are those that can be redistributed within the plant.

### Step 2: Identify Mobile Elements
- Examples of mobile elements include nitrogen, potassium, magnesium, and calcium. If there is a deficiency in these elements, the symptoms will first appear in the older leaves because the plant will move these nutrients to support new growth.

**Hint:** Think about which nutrients can be transported within the plant.

### Step 3: Identify Immobile Elements
- Immobile elements, on the other hand, cannot be moved from older leaves to younger leaves. Therefore, if there is a deficiency in an immobile element, the symptoms will first appear in the younger leaves.

**Hint:** Consider which nutrients are fixed in place and cannot be moved around.

### Step 4: Example of Immobile Element
- An example of an immobile element is sulfur. If sulfur is deficient in the soil, the deficiency symptoms will manifest in the young leaves first.

**Hint:** Recall that immobile elements lead to symptoms in the younger parts of the plant.

### Step 5: Conclusion
- Since the question specifies that the deficiency symptoms appear first in young leaves, the correct answer is sulfur, which is an immobile element.

**Final Answer:** The deficiency symptom appears first in young leaves if the soil is deficient in sulfur (option 4).