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Question #46802
The Question
The stele in a primary dicot root is anatomically defined as all tissues inner to the endodermis. However, in a mature dicot root that has undergone extensive secondary growth, this classical stelar boundary is completely obliterated. Which of the following statements correctly explains the developmental basis for this obliteration?
Options
- A.
The vascular cambium originates partially from the endodermis, consuming the boundary layer during the formation of the secondary vascular cylinder.
- B.
The expansive outward pressure of the secondary xylem crushes the primary xylem, pith, and endodermis simultaneously.
- C.
The pericycle dedifferentiates to form the cork cambium, resulting in the isolation and eventual sloughing off of the endodermis along with the cortex.
- D.
The primary phloem dedifferentiates into the phelloderm, pushing the endodermis outward until it ruptures and merges with the epidermis.
Check Your Answer
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
Stele|Vascular_Cambium|Pericycle
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: The transition from static primary anatomy to dynamic secondary growth.
Students often memorize that the stele is bounded by the endodermis, but fail to synthesize this with the NCERT fact that in dicot roots, the cork cambium originates from the pericycle.
This pericyclic origin means all tissues external to it (including the endodermis) are sloughed off, destroying the classical stelar boundary.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Anatomy of Flowering Plants - Class 11 |
| Concept | Stele Definition |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |