Question

A virus-free plant could be regenerated from a virus-infected plant mainly through:

• A. Root culture
• B. Callus culture
• C. Ovule culture
• D. Apical meristem culture

Hint:

Meristem Culture = Virus-Free. The virus can't catch up to the fastest-growing cells at the very tip!

Answer 1

The Correct Option is D

Concept: Viruses spread through the vascular system (phloem) of a plant. However, the rapidly dividing cells at the very tip of the plant—the apical meristem—are typically free of viral particles.

Step 1: Why Meristems are Virus-Free.
The apical meristem lacks a mature vascular system (xylem and phloem), which prevents the systemic movement of viruses into this region. Additionally, the high metabolic activity and rapid cell division in the meristem often outpace viral replication.

Step 2: The Regeneration Process.
By carefully excising the meristematic dome (often with one or two leaf primordia) and culturing it in a sterile medium, a complete, healthy plant can be grown. This technique is the standard method used globally for "cleaning" infected cultivars of economic importance.

Step 3: Conclusion.
Root, callus, and ovule cultures are more likely to contain viral particles if the parent plant is infected, whereas apical meristem culture specifically targets the one region that remains "sanitized."