Question

In plant tissue culture formation of organ primordia-like shoot or root in callus cells is called -

• A. Dedifferentiation
• B. Redifferentiation
• C. Somatic embryogenesis
• D. Regeneration

Hint:

Memorize the sequence in organogenesis via callus culture: {Explant (Differentiated)} \(\rightarrow\) {Dedifferentiation} \(\rightarrow\) {Callus (Undifferentiated)} \(\rightarrow\) {Redifferentiation} \(\rightarrow\) {Organs (Differentiated)}.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The question asks for the specific term that describes the process where undifferentiated callus cells begin to form specialized structures like shoot or root primordia.
Step 2: Detailed Explanation:
Let's define the terms in the context of plant tissue culture:
Dedifferentiation: The process where mature, specialized cells from an explant lose their specialized characteristics and revert to an unorganized, proliferative state, forming a callus.
Redifferentiation: The process where the dedifferentiated cells of a callus differentiate again to form new, specialized cells, tissues, and organized structures like organ primordia (shoots, roots). This perfectly matches the question's description.
Somatic embryogenesis: A process where somatic cells form structures resembling zygotic embryos, which are bipolar (having both a shoot and a root pole). This is different from forming only a shoot or a root primordium.
Regeneration: A general term for the development of a whole plant from a cell or tissue culture. Redifferentiation is the specific cellular process that leads to organ formation during regeneration.
Step 3: Final Answer:
The formation of organ primordia from callus cells is the process of redifferentiation.