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Question #46792
The Question
In a C3 monocot plant experiencing severe and prolonged soil water deficit, the large, colourless adaxial epidermal cells modify their turgor, causing the leaf to roll inwards. While this structural adaptation effectively reduces transpirational water loss, what is the inevitable metabolic consequence within the mesophyll cells if this state persists?
Options
- A.
The internal CO2 concentration falls below the compensation point, causing RuBisCO to bind O2 and initiate the release of CO2 in the mitochondria.
- B.
The plant temporarily shifts to a C4 metabolic pathway, utilizing PEP carboxylase in the mesophyll to bypass the increased boundary layer resistance.
- C.
The accumulation of abscisic acid (ABA) induces turgidity in the bulliform cells, permanently closing the stomata and halting the dark reaction.
- D.
The decreased transpiration pull halts the ascent of sap, causing an immediate cessation of cyclic photophosphorylation due to a lack of water as an electron donor.
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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
Bulliform Cells|Stomatal Apparatus Anatomy|C3 Cycle Stoichiometry
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: This question tests the ability to link an anatomical adaptation (bulliform cell flaccidity causing leaf rolling) to its biochemical trade-off (CO2 starvation triggering photorespiration).
It also utilizes 'Common Half-Truths' as distractors: testing the exact turgor state required for leaf rolling (flaccid vs. turgid) and the specific electron donor requirements of cyclic vs. non-cyclic photophosphorylation.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Anatomy of Flowering Plants - Class 11 |
| Concept | Bulliform Cell Function |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |