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Question #45969
The Question
Mycorrhizal fungi (e.g., Glomus) establish symbiosis by manipulating the host's root system architecture to increase absorptive surface area. A novel soil pathogen hijacks this exact signaling pathway, causing localized, resource-draining root proliferation that stunts the growth of distal non-colonized tissues. Which of the following best explains the physiological mechanism employed by the pathogen?
Options
- A.
It induces a localized increase in the Cytokinin-to-Auxin ratio, stimulating the pericycle to form lateral roots.
- B.
It induces a localized decrease in the Cytokinin-to-Auxin ratio, stimulating the pericycle to form lateral roots.
- C.
It blocks the basipetal transport of Auxin from the shoot, forcing the root apical meristem to synthesize Cytokinin.
- D.
It hyper-secretes Gibberellins to override apical dominance, creating a strong metabolic sink in the roots.
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
Cytokinin|Auxin|Arbuscular_Mycorrhiza|Nutrient_Uptake
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Cross-chapter synthesis between 'Plant Growth and Development' (Hormonal ratios) and 'Anatomy of Flowering Plants' (Origin of lateral roots from the pericycle).
The primary trap is the mathematical inversion of the ratio (Cytokinin-to-Auxin instead of Auxin-to-Cytokinin), testing if students truly understand the relative concentration concept rather than just rote memorizing 'Auxin = roots'.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Growth and Development - Class 11 |
| Concept | Cytokinin-Auxin Ratio |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |