Callus biology — The reversion of mature, specialized plant cells to a meristematic, dividing state that leads to callus formation is called what?

Introduction / Context:
Dedifferentiation and redifferentiation are paired concepts in plant regeneration. Dedifferentiation first produces callus from mature tissues; subsequent redifferentiation gives rise to organs or embryos.

Given Data / Assumptions:

• Explants originate from mature organs.
• Hormone regimes trigger cell cycle re-entry and loss of specialized features.
• Later stages direct formation of shoots/roots or somatic embryos.

Concept / Approach:
Define terms precisely: dedifferentiation = specialized to unspecialized; redifferentiation = unspecialized to specialized. The phenomenon described (mature cells returning to a meristematic state and forming callus) matches dedifferentiation.

Step-by-Step Solution:

Verification / Alternative check:
Histological sections of induced callus show small, isodiametric, actively dividing cells typical of dedifferentiation.

Why Other Options Are Wrong:

Common Pitfalls:
Using “redifferentiation” for early callus; reserve it for organ/embryo formation.

Final Answer:
Dedifferentiation (mature cells reverting to a meristematic state).