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Question #45975
The Question
A dicot seedling is germinating deep within severely waterlogged, compacted soil. Despite the mechanical resistance of the compact soil, the seedling fails to exhibit the characteristic 'triple response' and eventually its apical meristem collapses. Which of the following best explains this physiological outcome?
Options
- A.
The lack of oxygen as a terminal electron acceptor inhibits ACC-oxidase, preventing ethylene synthesis, while anaerobic respiration leads to ethanol toxicity.
- B.
High CO2 concentrations in waterlogged soil competitively inhibit ethylene receptors, preventing the triple response despite continuous ethylene synthesis.
- C.
Anaerobic conditions accelerate ACC-synthase activity, but the lack of a terminal electron acceptor in mitochondria causes fatal lactic acid accumulation.
- D.
Waterlogging induces the rapid synthesis of Abscisic Acid (ABA), which directly degrades ethylene gas and causes the structural collapse of the apical meristem.
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|Terminal Electron Acceptor|Respiration in Plants
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that 'mechanical stress induces ethylene and the triple response' but fail to integrate the biochemical prerequisite: ethylene biosynthesis is strictly an aerobic process.
The trap tests the integration of plant growth regulators (Ethylene synthesis bottleneck) with cellular respiration (Ethanol fermentation in plants vs.
Lactic acid in animals under hypoxia).
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 |