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Question #46294

Difficulty: 8/10 | 🟢 Free

The Question

During water stress, Abscisic Acid (ABA) initiates a signal transduction cascade in guard cells. If a mutation causes a sustained, ABA-independent surge of cytosolic $Ca^{2+}$ in both the guard cells and the glandular trichomes of a plant, which of the following physiological outcomes is most likely to occur?

Options

A.
Stomata will remain closed due to continuous efflux of $K^+$ and malate, while glandular trichomes will exhibit enhanced exocytosis of secretory products.
B.
Stomata will remain open due to $Ca^{2+}$ -induced influx of $K^+$ , while glandular trichomes will inhibit the fusion of secretory vesicles with the plasma membrane.
C.
Stomata will close due to the active pumping of protons ( $H^+$ ) into the guard cells, while glandular trichomes will undergo rapid plasmolysis.
D.
Both stomatal opening and glandular secretion will be completely inhibited due to the loss of differential permeability in the tonoplast.

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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

Stomatal Apparatus Anatomy|Structural Organisation in Animals|ABA

Why This Question Is Tricky

Common Mistakes

Conceptual Pivot: Students often memorize 'ABA closes stomata' without understanding the underlying secondary messenger ( $Ca^{2+}$ ) mechanism.

The trap lies in failing to connect the universal role of $Ca^{2+}$ across different cell types.

Students might assume a single ion ( $Ca^{2+}$ ) would have a universally 'inhibitory' effect on all cellular activities, missing that it triggers solute efflux in guard cells (causing closure) but triggers vesicle fusion in glandular cells (causing active secretion).

Quick Facts About This Question

Question Information

Subject	Biology
Chapter	Anatomy of Flowering Plants - Class 11
Concept	Stomatal Apparatus Anatomy
Difficulty	8
Cognitive Load	5
Target Solve Time	120 sec
Access	Free