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Question #46223
The Question
A researcher induces a targeted mutation in a dicotyledonous plant, altering the procambial differentiation gradient in the shoot apex. Consequently, the primary xylem in the stem exhibits centripetal maturation instead of its normal pattern. Which of the following anatomical and physiological consequences is most likely to occur in this mutant stem during secondary growth under high-transpiration stress?
Options
- A.
The primary phloem will differentiate towards the pith, completely inverting the vascular bundle into a concentric amphivasal type.
- B.
The vascular cambium will be situated between the protoxylem and primary phloem, making the narrow protoxylem highly susceptible to collapse under high transpiration pull.
- C.
The metaxylem will be located peripherally, allowing the stem to maintain centrifugal maturation and normal hydraulic conductivity.
- D.
The mutation will induce the formation of a Casparian strip in the stem endodermis to prevent water loss from the centrally located protoxylem.
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
Stem Morphological Markers|Protoxylem vs Metaxylem Arrangement|Meristematic Polarity
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often rote-memorize 'Stem = Endarch' and 'Root = Exarch' without visualizing the spatial relationship of xylem elements relative to the vascular cambium.
The trap lies in failing to deduce that an exarch shift in a stem places the structurally weaker, narrow protoxylem directly adjacent to the cambium, creating a severe hydraulic bottleneck during secondary growth and high transpiration.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Morphology of Flowering Plants - Class 11 |
| Concept | Stem Morphological Markers |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |