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Question #45343
The Question
In a Citrus ovule, normal double fertilization occurs, followed by the initiation of nucellar polyembryony. If a localized anomaly causes a complete failure of cytokinesis during the first mitotic division of the specific nucellar cells that are protruding into the embryo sac, what will be the ploidy and genetic nature of the resulting embryos within the mature seed?
Options
- A.
One diploid (2n) embryo showing genetic recombination, and multiple tetraploid (4n) embryos exhibiting only maternal alleles.
- B.
One tetraploid (4n) embryo showing genetic recombination, and multiple diploid (2n) embryos exhibiting only maternal alleles.
- C.
Multiple diploid (2n) embryos, all of which are genetically identical to the maternal plant, with no recombinant embryo present.
- D.
One diploid (2n) recombinant embryo, and multiple triploid (3n) embryos derived from the nucellar tissue.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Nucellar_embryos|Zygotic_embryos|Adventive_embryony
Why This Question Is Tricky
Common Mistakes
The Conceptual Pivot lies in synthesizing 'Nucellar Polyembryony' (Chapter 2) with 'Polyploidy via Cytokinesis Failure' (Chapter 5).
Students often rote-memorize that nucellar embryos are '2n maternal clones'.
By introducing a targeted cytokinesis failure, the student must deduce that the adventive embryos become 4n while retaining their strictly maternal genetic identity, leaving the 2n zygotic embryo unaffected.
This tests the ability to track ploidy and genetic origin simultaneously.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Polyembryony Mechanisms |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |