Callus competence—What is the term for the ability of callus cells to regenerate a whole plant? Choose the precise biological term used in plant tissue culture for the capacity of component cells in a callus to form an entire plant under appropriate conditions.

Introduction / Context:
Plant tissue culture exploits the remarkable capacity of somatic cells to regenerate whole plants. The correct term for this inherent ability is “totipotency,” a foundational idea that underlies micropropagation, somatic embryogenesis, and organogenesis.

Given Data / Assumptions:

• Callus cells can be induced to form shoots, roots, or somatic embryos.
• Appropriate hormonal regimes (auxin/cytokinin balance) and media are provided.
• Regenerated plantlets are genetically similar to the donor (barring somaclonal variation).

Concept / Approach:
Define and distinguish related terms. Totipotency is the potential to regenerate an entire organism. Dedifferentiation refers to the reversion of specialized cells to a meristematic state (often forming callus). Redifferentiation is the subsequent specialization into organs or embryos. Somaclonal variation denotes genetic/epigenetic changes arising during culture.

Step-by-Step Solution:

Verification / Alternative check:
Classic examples include regeneration from tobacco and carrot callus; single cells or small aggregates can yield complete, fertile plants.

Why Other Options Are Wrong:

• Redifferentiation/dedifferentiation describe steps within regeneration, not the overarching capacity.
• Somaclonal variation is a by-product, not a capacity.
• Transdifferentiation is not the standard term in this context.

Common Pitfalls:
Using “redifferentiation” as a synonym for totipotency; they are not interchangeable.

Final Answer:
Totipotency