Question

In vitro direct organogenesis using leaf explants involves which of the following processes?
A. Dedifferentiation
B. Embryo formation
C. Callus formation
D. Redifferentiation
Choose the correct answer from the options given below:

• A. A and C only
• B. C and B only
• C. D and A only
• D. B and A only

Hint:

In Direct regeneration, you go straight from Explant to Organ. You always need De-differentiation (to reset) and Re-differentiation (to build).

Answer 1

The Correct Option is C

Concept: Direct organogenesis is the formation of organs (shoots or roots) directly from the explant tissue without an intervening callus phase.

Step 1: Dedifferentiation (A).
Even in direct organogenesis, the specialized cells of the leaf (like parenchyma) must first undergo Dedifferentiation. This process allows the cells to revert to a meristematic (undifferentiated) state so they can divide and form new structures.

Step 2: Redifferentiation (D).
Once the cells have become meristematic, they must then Redifferentiate into the specific tissues required to form a new shoot or root.

Step 3: Excluding Callus and Embryos.
Since the question specifies "direct" organogenesis, Callus formation (C) is excluded by definition. Similarly, organogenesis involves the formation of unipolar organs, whereas Embryo formation (B) refers to somatic embryogenesis, which is a different developmental pathway.