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Question #45966
The Question
A researcher maintains a dedifferentiated plant callus in a severely nutrient-depleted medium for an extended period, forcing the cells into a prolonged G0 phase. Subsequently, the callus is transferred to an optimal nutrient medium supplemented with a high Cytokinin to Auxin ratio. Which of the following is the most likely outcome and its physiological basis?
Options
- A.
Rapid shoot organogenesis occurs because the high Cytokinin to Auxin ratio directly overrides the G0 arrest and induces redifferentiation.
- B.
Root differentiation occurs because prolonged starvation alters the cellular receptors, reversing the standard hormonal sensitivity.
- C.
The callus fails to undergo organogenesis because prolonged quiescence leads to a loss of morphogenetic competence and an inability to redifferentiate.
- D.
The cells immediately re-enter the S phase and form a larger undifferentiated mass because cytokinins exclusively promote cell division without differentiation.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Cytokinin|Auxin|G0_Phase_Quiescence|Meristematic_Activity
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often reflexively associate 'High Cytokinin to Auxin ratio' with 'Shoot formation' (NCERT Chapter 15: Plant Growth and Development).
The trap lies in ignoring the physiological state of the cell (NCERT Chapter 10: Cell Cycle).
Hormonal signaling is not absolute; it requires a competent, responsive target cell.
Prolonged G0 arrest via starvation destroys this competence, preventing redifferentiation.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Growth and Development - Class 11 |
| Concept | Cytokinin-Auxin Ratio |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |