1. Introduction

Sterility is the foundation of plant tissue culture. Without it, your nutrient-rich media becomes a microbial buffet. This lesson covers how to clean, sterilize, and monitor every part of your setup—from tools to explants.

📌 Understanding Sterilization in Plant Tissue Culture

2. The Enemies: Common Contaminants

Contaminants usually enter through:

• Unsterilized explants

• Dirty tools or hands

• Air currents or dust

• Contaminated water or media

3. Sterilizing the Lab Space

• Wipe down surfaces with 70% alcohol before and after work.

• Use UV-C light in hoods or grow rooms for 15–30 minutes to kill microbes.

• Operate in a closed, low-dust space.

• Don’t wear outside clothes into sterile zones.

📌 Sterility Maintenance Guide

4. Sterilizing Equipment and Media

• Do not autoclave plant growth regulators—they are heat-sensitive!

5. Explant Surface Sterilization

The most common source of contamination is the plant material itself.

General Explant Sterilization Protocol:

1. Wash in tap water

2. Dip in ethanol (70%)

3. Soak in bleach (5–10%) + drop of Tween-20

4. Rinse in sterile water (3–5x)

Notes:

• Delicate tissues (e.g., meristems) may require milder disinfectants like hydrogen peroxide.

• Use sterile tools and laminar flow hood for explant transfer.

📌 Explant Sterilization Methods

6. Managing Contamination

No system is perfect. You must learn to:

• Recognize early signs (smell, texture, discoloration)

• Isolate contaminated cultures

• Decontaminate the area

• Record and learn from contamination events

Cultures showing systemic contamination (e.g., viral) must be discarded and avoided in future stock collections.