Q.Explain the basic techniques of plant tissue culture (Diagrams not needed).

Tissue culture takes a sterilised piece of plant, grows it into an undifferentiated callus on hormone-supplemented medium, then coaxes it into a whole new plantlet.

1. Selection of explant: a small piece of living plant tissue (shoot tip/meristem, leaf, node, anther, embryo, etc.) is chosen based on the objective of the culture.
2. Sterilisation: the explant is surface-sterilised (using agents such as sodium hypochlorite, mercuric chloride, or ethanol), and all glassware, media and instruments are autoclaved; all subsequent handling is carried out aseptically under a laminar air-flow cabinet.
3. Nutrient medium preparation: a suitable medium (most commonly Murashige and Skoog, MS medium) containing macro- and micronutrients, vitamins, amino acids, a carbon source (usually sucrose), and plant growth regulators (auxins such as 2,4-D or NAA; cytokinins such as BAP or kinetin) in a specific ratio is prepared, solidified with agar if needed, pH-adjusted (around 5.6-5.8), and autoclaved.
4. Inoculation: the sterilised explant is aseptically transferred onto/into the prepared nutrient medium inside a culture vessel.
5. Incubation: culture vessels are kept in a controlled growth room with regulated temperature (about 25 degC), light/dark photoperiod, and humidity.
6. Callus induction: under the influence of auxin (often with cytokinin), the explant proliferates into an unorganised mass of dividing, undifferentiated cells called callus. …