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Question #47524
The Question
Gymnosperms rely on anemophily, requiring their ovules to remain exposed to capture pollen directly at the micropyle. If a sudden surge in Abscisic Acid (ABA) occurs in the female strobilus prior to pollination, reproductive failure ensues. What is the primary anatomical and physiological basis for this 'closed-door' failure?
Options
- A.
ABA induces precocious senescence and abscission of ovular tissues, mechanically sealing the micropyle and blocking direct pollen access.
- B.
ABA antagonizes auxin, preventing the formation of the pollen tube within the stylar tissue.
- C.
ABA triggers the premature thickening of the ovary wall, preventing wind-borne pollen from reaching the megasporangium.
- D.
ABA stimulates the rapid division of the nucellus, which consumes the endosperm before double fertilization can occur.
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
Gymnosperm Pollination Geometry|Law of Limiting Factors|Pollen Morphology
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating plant hormone physiology (ABA-induced senescence) with gymnosperm-specific reproductive anatomy.
The trap relies on students projecting angiosperm features (style, ovary wall, double fertilization) onto gymnosperms.
Recognizing the 'naked' nature of the ovule and the direct micropylar entry is crucial to identifying why ABA-induced tissue collapse causes a mechanical barrier.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Kingdom - Class 11 |
| Concept | Gymnosperm Pollination Geometry |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |