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Question #46222
The Question
A sun-loving herbaceous plant is experimentally transferred from an open field to the understory of a dense forest canopy. Which of the following correctly identifies the change in the microenvironment's light quality, the resulting phytochrome interconversion, and the subsequent morphological adaptation of the stem?
Options
- A.
Decreased Red:Far-Red ratio -> Conversion of Pfr to Pr -> Rapid internodal elongation
- B.
Increased Red:Far-Red ratio -> Conversion of Pr to Pfr -> Suppression of apical dominance
- C.
Decreased Red:Far-Red ratio -> Conversion of Pr to Pfr -> Enhanced lateral branching
- D.
Decreased Red:Far-Red ratio -> Conversion of Pfr to Pr -> Radial thickening of the stem
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
Stem Morphological Markers|Phytochrome Interconversion|Plant Growth and Development
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that 'Red light promotes growth' without understanding the nuance of the R:FR ratio in natural canopies.
The trap lies in failing to connect the physical filtering of light by chlorophyll (which absorbs Red but lets Far-Red pass) to the biochemical shift (Pfr to Pr) and the specific morphological marker (internode elongation vs radial thickening).
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 |