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Question #47526
The Question
In gymnosperms like Pinus, wind-borne pollen grains are captured by a 'pollination drop' exuded at the micropyle of the ovule. The volume and retraction dynamics of this fluid are strictly regulated by its solute concentration (sugars and amino acids), analogous to how plasma proteins maintain colloid osmotic pressure in human capillaries. If a specific mutation causes a severe deficiency of these solutes in the micropylar exudate, which of the following is the most likely immediate consequence?
Options
- A.
The droplet will fail to maintain its osmotic volume and surface tension, preventing the successful capture and retraction of pollen into the pollen chamber.
- B.
The pollen tube will fail to penetrate the archegonium due to the loss of chemotropic gradients within the nucellus.
- C.
The winged pollen grains will undergo rapid endosmosis and burst upon contact due to the extreme hypotonicity of the micropylar fluid.
- D.
The megasporangium will rapidly desiccate, preventing the functional megaspore from undergoing free-nuclear divisions.
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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
Gymnosperm Pollination Geometry|Pachytene Crossing Over|Polyembryony
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: This question bridges Plant Reproduction with Plant/Human Physiology (Osmotic Pressure).
Students often memorize that gymnosperms are wind-pollinated but overlook the micro-fluidics of the pollination drop.
The trap lies in confusing the mechanics of the initial 'pollination' (pollen capture via the drop) with 'fertilization' (pollen tube chemotropism), testing the student's ability to sequence reproductive events and apply universal principles of solute potential to novel anatomical structures.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Kingdom - Class 11 |
| Concept | Gymnosperm Pollination Geometry |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |