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Question #46214
The Question
A mutant leguminous plant fails to establish a symbiotic relationship with a compatible Rhizobium strain, leading to severe nitrogen deficiency in unfertilized soil. Microscopic analysis reveals bacterial accumulation near the root surface, but absolutely no root hair curling is observed. Which of the following statements correctly identifies the most likely physiological or structural failure in this plant?
Options
- A.
The epidermal cells in the region of elongation fail to secrete specific flavonoids to attract the bacteria.
- B.
The root hairs in the region of maturation lack functional receptor proteins for bacterial Nod-factors.
- C.
The cortical cells fail to initiate dedifferentiation to form the infection thread.
- D.
The plant is unable to express the nif genes required for the synthesis of the nitrogenase enzyme complex.
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
Infection Thread|Root Hair|Leg-hemoglobin
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the specific root zones (Elongation vs.
Maturation) and the origin of specific genetic components (Plant Nod-receptors vs.
Bacterial nif genes).
The trap in Option A tests location specificity, while Option D tests the functional boundary between host and symbiont.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Morphology of Flowering Plants - Class 11 |
| Concept | Root Region Differentiation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |