Before You Begin
Question #45971
The Question
A researcher treats a batch of dicot seeds with an aqueous solution of Silver Thiosulfate (STS) prior to sowing them deep in the soil. Based on the physiological role of phytohormones, which of the following accurately describes the most likely fate of these seedlings during germination?
Options
- A.
They will exhibit an exaggerated 'triple response' due to the accumulation of endogenous ethylene, leading to a highly thickened hypocotyl.
- B.
They will fail to form an apical hook and exhibit uninhibited longitudinal elongation due to the blockade of ethylene receptors, risking mechanical damage to the shoot apex.
- C.
They will demonstrate rapid horizontal growth of the seedling axis because STS acts as a competitive inhibitor of polar auxin transport.
- D.
They will successfully emerge with enhanced vigor because the inhibition of ethylene perception prevents premature senescence of the cotyledons.
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
Ethylene|Auxin|Apical Hook|Senescence
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the components of the 'triple response' but fail to understand its ecological significance (protecting the shoot apex during soil emergence) and the specific mechanism of inhibitors like Silver Thiosulfate (blocking perception, not synthesis).
The trap lies in assuming that blocking a 'senescence/stress' hormone like ethylene will automatically result in 'enhanced vigor' (Option D), ignoring the crucial protective morphological changes ethylene induces during early subterranean germination.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Growth and Development - Class 11 |
| Concept | Ethylene Triple Response |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |