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Question #46233
The Question
An obligate mycorrhizal plant (e.g., Pinus) is grown in a phosphorus-deficient soil where its fungal symbiont is experimentally inhibited. To survive, the plant alters its source-sink dynamics. Which of the following morphological adaptations is most likely to be observed in this plant compared to a healthy symbiotic counterpart?
Options
- A.
Increased root-to-shoot ratio with stunted internodal elongation, altering the spatial distribution of leaves without changing the genetic phyllotactic pattern.
- B.
Decreased root-to-shoot ratio as the plant prioritizes the expansion of leaf lamina to maximize photosynthetic carbon fixation.
- C.
Alteration of the genetic phyllotactic pattern from alternate to whorled to optimize light capture under severe phosphorus deficiency.
- D.
Profuse lateral branching of the shoot system to compensate for the loss of fungal phosphorus solubilization.
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
Leaf Vernation and Phyllotaxy|Mycorrhiza Nutrient Dynamics|Mineral Nutrition
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between genetic architectural constraints (phyllotaxy type) and phenotypic plasticity (internodal elongation and root:shoot ratio) under nutrient stress.
Students often confuse a plant's need to 'compensate for low energy' with growing more leaves (Option B or D), failing to realize that mineral deficiency forces the plant to prioritize root volume over canopy architecture.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Morphology of Flowering Plants - Class 11 |
| Concept | Leaf Vernation and Phyllotaxy |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |