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Question #46835
The Question
A woody dicot stem undergoing active secondary growth is exposed to a severe heat shock, causing localized protein denaturation in its lateral meristems. Subsequently, the inner living tissues of the stem exhibit severe hypoxia and begin accumulating products of anaerobic respiration. Which of the following developmental failures directly accounts for this physiological condition?
Options
- A.
Inability of the vascular cambium to produce secondary xylem, halting the upward transport of dissolved oxygen.
- B.
Failure of the phellogen to differentiate loosely arranged parenchymatous complementary cells on its outer side.
- C.
Excessive suberization of the phelloderm, which completely blocks the radial conduction of respiratory gases.
- D.
Heat-induced permanent closure of the guard cells in the epidermal stomata of the mature woody stem.
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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
Lenticels|Stomata|Heat_Shock_Proteins
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often fail to transition their understanding of gaseous exchange from primary structures (stomata in epidermis) to secondary structures (lenticels in periderm).
The trap relies on knowing the exact cellular origin of lenticels (complementary cells produced by phellogen) and recognizing that without them, the suberized phellem creates an airtight seal, suffocating the stem.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Anatomy of Flowering Plants - Class 11 |
| Concept | Lenticels vs Stomata |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |