Question

A scientist wants to produce virus-free plant in tissue culture. Which part of the plant will he use as an explant? a) mature stem b) axillary meristem c) apical meristem d) mesophyll cell Choose the correct option from the following.

• A. b only
• B. c and d
• C. a only
• D. b and c

Hint:

Apical and axillary meristems are preferred for virus elimination in tissue culture due to their active cell division.

Answer 1

The Correct Option is D

• Definition of Virus-Free Plant: Virus-free plants are produced in tissue culture using explants that are typically free of viral infections due to their rapid cell division and lack of vascular connections.
• Option Analysis:
  • (a) mature stem: Mature stems often contain vascular tissues where viruses can reside, making them unsuitable. This is incorrect.
  • (b) axillary meristem: These are regions of active cell division in the axils of leaves, often free from viruses due to their isolation from vascular tissues. This is correct.
  • (c) apical meristem: Located at the shoot and root tips, apical meristems have high mitotic activity and are typically virus-free, making them ideal explants. This is correct.
  • (d) mesophyll cell: These are parenchyma cells in leaves with vascular connections, prone to viral presence. This is incorrect.
• Mechanism Insight: Meristems (apical and axillary) are preferred because viruses do not easily infect rapidly dividing cells, and they lack established vascular systems.
• Conclusion: The correct answer is (4) b and c, as both axillary and apical meristems are used to produce virus-free plants.