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Question #45763
The Question
A halophyte evolves a structural defense against a soil-borne fungal pathogen by heavily modifying its root hair cell walls, inadvertently losing the ability to actively accumulate soil ions into its cytoplasm. Based on the principles of plant water relations, what will be the most direct consequence of this modification on the plant's survival in a saline habitat?
Options
- A.
The root hair water potential (\Psi_w) will become less negative than the soil solution, halting passive water absorption and collapsing the transpiration stream.
- B.
The active transport of water into the root hairs will cease due to the inability to maintain a proton gradient across the modified cell wall.
- C.
Positive root pressure will drastically increase to compensate for the loss of ion uptake, leading to excessive guttation.
- D.
The cohesive and adhesive forces within the xylem will be directly broken, causing immediate cavitation in the stem.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Halophytes|Salt_Glands|Osmotic_Potential
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Understanding that water movement is strictly passive and driven by a water potential gradient (\Psi_w).
The trap lies in Option B, exploiting the common misconception that water can be actively transported, and Option C, which misapplies the concept of root pressure.
Students must synthesize how active ion uptake in halophytes is the prerequisite for passive water absorption.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | Osmoregulation in Aquatic Adaptations |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |