Plant micropropagation — In standard in vitro terminology, what is an “explant”? (Context: leaf or stem piece excised and placed onto culture medium)

Introduction / Context:
An explant is the starting biological material for plant tissue culture. It can be taken from leaves, stems, roots, meristems, embryos, or other organs and placed onto sterile culture media to initiate regeneration.

Given Data / Assumptions:

• Sterile technique is used to surface-sterilize plant material.
• Explants are plated on defined media containing macro-/micronutrients, vitamins, sugar, and plant growth regulators.
• Downstream outcomes can include callus, organogenesis, or somatic embryogenesis.

Concept / Approach:
Terminology precision is vital: “explant” refers to the initial plant piece; “medium” is the substrate; “microshoot” is a regenerated shoot; “scion” is a grafting term mostly outside micropropagation contexts.

Step-by-Step Solution:

Verification / Alternative check:
Standard protocols label culture vessels with “explant type,” reinforcing that the tissue piece itself is the explant.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing explant with callus or microshoot; the stage matters in SOPs and recordkeeping.

Final Answer:
Explant (the excised piece of plant tissue used to initiate culture).