Question

The deficiency symptoms like top sickness of tobacco and hard fruit in citrus is due to the deficiency of which nutrient?

• A. Cu
• B. Mn
• C. Fe
• D. Boron

Hint:

Boron (B) deficiency symptoms:
- Top sickness of tobacco
- Hard fruit Internal gumming of citrus
- Browning Hollow heart of cauliflower
- Hen and Chicken disease of grapes.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Micronutrient deficiency disorders manifest specific anatomical deformities in growing shoot tips and fruit tissues.

Step 2: Detailed Explanation:
Boron ($B$) is an essential plant micronutrient responsible for cell wall synthesis, membrane integrity, sugar translocation, and apical meristem cell division:
1. Top Sickness of Tobacco: Boron deficiency causes cessation of terminal bud growth, death of apical meristems, and distorted, brittle top leaves.
2. Hard Fruit in Citrus: Deficiency causes localized gum pockets in the fruit peel, leading to misshapen, hard, dry, and juice-less fruits with thick rinds.

Step 3: Final Answer:
Therefore, top sickness of tobacco and hard fruit in citrus are caused by Boron deficiency, corresponding to option (D).