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Question #45993
The Question
A winter variety of a plant receives adequate vernalization. Post-vernalization, it is exposed to high temperature and high light intensity. Despite the correct photoperiod and successful florigen synthesis, the plant exhibits abortive inflorescence. A genetically modified variant of the same plant flowers normally under identical conditions. Which of the following best explains the developmental failure in the plant?
Options
- A.
High oxygenase activity of RuBisCO depletes the ATP and NADPH pool, creating a metabolic deficit that prevents the energetic investment required for floral development.
- B.
High temperatures cause devernalization in the plant, whereas the bundle sheath cells in the variant protect the shoot apical meristem from heat-induced reversion.
- C.
Stomatal closure at high temperatures increases the internal ratio in the plant, inhibiting the transport of florigen to the apical bud.
- D.
The plant lacks PEP carboxylase, which is directly required to synthesize the amino acids necessary for flowering-time proteins during heat stress.
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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
Vernalization Mechanism|Photorespiration Metabolic Cost|C3 Cycle Stoichiometry
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often study Vernalization (Plant Growth & Development) and Photorespiration (Photosynthesis) in isolation.
The pivot is synthesizing these concepts: recognizing that developmental transitions (flowering) are gated by metabolic stoichiometry (ATP/NADPH availability).
A common misconception is assuming that once the vernalization requirement is met and florigen is synthesized, flowering is guaranteed, ignoring the massive energetic cost of inflorescence development which can be derailed by the photorespiratory ATP drain in plants.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Growth and Development - Class 11 |
| Concept | Vernalization Mechanism |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |