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Question #46004
The Question
A specialized angiosperm relies on an obligate pollinator for reproduction. Under severe biotic stress, the plant exhibits premature synthesis of abscisic acid (ABA) and ethylene in its floral tissues. Evaluate the following statements and identify the INCORRECT one regarding the physiological and ecological outcomes:
Options
- A.
The stress-induced hormonal shift promotes premature floral abscission, leading to reproductive failure and driving the obligate pollinator towards co-extinction.
- B.
If this plant evolves apomixis (agamospermy) as a survival strategy, it must genetically delay ovular senescence to facilitate embryo development without fertilization.
- C.
During apomictic development, the premature activation of the senescence pathway in the nucellus is required to rapidly form diploid embryos directly from maternal tissues.
- D.
In the wild-type sexual plant, the precise timing of metabolic senescence in the ovule acts as a critical evolutionary clock, ensuring maternal tissues remain viable until double fertilization occurs.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Apomixis Genetics|Senescence vs Abscission|Co-extinction Logic
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the 'bypassing' of fertilization in apomixis with the 'degeneration' or 'premature senescence' of floral parts.
While apomixis skips meiosis and syngamy, it strictly requires the prolonged viability (delayed senescence) of maternal ovular tissues to develop into a viable seed.
The question also tests the cross-topic synthesis of Plant Growth Regulators (ABA/Ethylene) with Population Ecology (Co-extinction).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Growth and Development - Class 11 |
| Concept | Senescence vs Abscission |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |