Chapter 10 Solutions — Biotechnology and Its Applications

The meristem (apical and axillary meristems) is best suited for making virus-free plants.

Even if a plant is infected with a virus, the meristematic tissue remains free of the virus. This is because viruses spread through the vascular system and plasmodesmata, but the meristem cells divide so rapidly and are so newly formed that the virus has not yet colonised them.

By removing the meristem and growing it in vitro under sterile conditions (tissue culture / micropropagation), one can obtain virus-free plants. Scientists have successfully cultured meristems of banana, sugarcane, potato and other important crop plants using this technique.

Micropropagation is a method of producing thousands of plants through tissue culture from a single explant in a very short duration.

The major advantage of micropropagation is that it allows the rapid, large-scale propagation of genetically identical plants (somaclones) from a single parent plant. This means:

1. Thousands of plants can be produced in a short time from a small amount of parent material.

2. All produced plants are genetically identical to the original plant, preserving desirable traits.

3. Plants can be produced throughout the year, independent of season.

4. Virus-free plants can be raised by using meristematic tissue as the explant.

5. It enables commercial-scale production of important food plants like tomato, banana, apple, etc.

The ability to generate a whole plant from any cell or explant is based on the property called totipotency.