1. What Is an Explant?

An explant is the starting tissue used to grow a plant in vitro. It may be:

• A section of leaf, stem, or root

• A meristem or bud tip

• Even a single cell or protoplast

These cells must retain totipotency (the ability to regenerate into an entire plant) to be usable.

📌 More on explants and regeneration

2. How to Choose Explants

Young, actively growing plants are the best explant source due to:

• Lower contamination risk

• Higher regenerative potential

3. Harvesting Guidelines

• Harvest in the morning to minimize contaminants.

• Select tissue from healthy, well-watered plants.

• Avoid tissue with:

  • Insect damage

  • Yellowing

  • Wilting or disease

📌 Explants in Propagation and Micropropagation

4. Surface Sterilization Protocol

Purpose: Remove bacteria, fungi, and other microbes from the surface of the explant.

Typical Steps:

1. Rinse explants in tap water to remove debris

2. Dip in 70% ethanol (kills bacteria & fungi on contact)

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

4. Rinse thoroughly with sterile water 3–5 times

Note:

• Over-sterilizing can damage plant tissue.

• Under-sterilizing can allow contaminants into your culture.

5. Handling and Transferring Explants

• Use sterilized forceps, scalpels, scissors

• Perform all work under a laminar flow hood

• Minimize exposure time to the open air

• Be careful not to touch culture media or vessel edges

📌 Sterile Transfer Protocols