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Question #45977
The Question
In a plant tissue culture experiment, a researcher supplements the nutrient medium with a high Cytokinin-to-Auxin ratio to induce shoot organogenesis from an undifferentiated callus. Concurrently, a significant concentration of Abscisic Acid (ABA) is added to the medium. Which of the following best describes the resulting morphogenetic response and its underlying physiological mechanism?
Options
- A.
The callus will differentiate into roots because ABA chemically degrades cytokinins, effectively lowering the Cytokinin-Auxin ratio.
- B.
The callus will remain in a quiescent, undifferentiated state because ABA acts as a metabolic brake, antagonizing the cytokinin-mediated differentiation program.
- C.
The callus will exhibit accelerated shoot proliferation because ABA acts synergistically with cytokinins to promote rapid cell division.
- D.
The callus will undergo rapid senescence and necrosis because ABA directly inhibits the synthesis of all cellular proteins.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Cytokinin-Auxin Ratio|Meristematic Totipotency|ABA
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often rigidly memorize the 'High Cytokinin = Shoot' rule but fail to integrate the overriding inhibitory role of ABA in a multi-hormone system.
The trap lies in assuming ABA alters the physical ratio by chemically degrading other hormones (Option A) or confusing ABA's role in natural leaf senescence with immediate cellular necrosis in tissue culture (Option D).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Growth and Development - Class 11 |
| Concept | Abscisic Acid (ABA) Antagonism |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |