Question

Plant shoot differentiation is a multi-step process which involves:
A. Differentiation of shoot meristem
B. Acquisition of competence to respond to the induction conditions
C. Establishment of shoots
D. Determination to form a specific organ
Choose the correct answer from the options given below:

• A. D, B, A, C
• B. C, A, B, D
• C. B, D, A, C
• D. A, D, B, C

Hint:

Remember the order: Competence (Ready) $\rightarrow$ Determination (Decided) $\rightarrow$ Differentiation (Acting) $\rightarrow$ Establishment (Finished).

Answer 1

The Correct Option is C

Concept: In vitro organogenesis is a programmed developmental process where cells in an explant or callus transition from a disorganized state to a highly organized tissue. This follows a logical physiological sequence.

Step 1: Acquisition of Competence.
The first stage is Competence (B). Before a cell can form an organ, it must first gain the ability (competence) to perceive and respond to hormonal signals in the medium. This often involves de-differentiation of the original explant cells.

Step 2: Determination.
Once competent, the cells undergo Determination (D). During this phase, the developmental pathway becomes fixed. Even if the tissue is moved to a different medium, it is now "committed" to forming a specific organ (in this case, a shoot).

Step 3: Differentiation and Establishment.
Following determination, the Differentiation of the shoot meristem (A) occurs, where organized groups of cells (meristemoids) become visible. Finally, this leads to the Establishment of shoots (C), which are the recognizable vegetative structures.