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Question #45321
The Question
In plants like Citrus and Mangifera, polyembryony frequently occurs when cells of the nucellus divide, protrude into the embryo sac, and develop into embryos alongside the zygotic embryo. Which of the following statements is INCORRECT regarding the genetic and physiological dynamics of such a developing seed?
Options
- A.
The seed contains a single triploid endosperm formed by triple fusion, which must partition its limited nutrients among all developing embryos.
- B.
The nucellar embryos are diploid (2n) clones of the maternal sporophyte, whereas the zygotic embryo is a diploid (2n) recombinant.
- C.
The nucellar embryos derive their nutrition by directly consuming the surrounding diploid nucellus, thereby bypassing stoichiometric competition for the triploid endosperm.
- D.
The primary endosperm nucleus (PEN) contains genetic contributions from both parents, unlike the nucellar embryos which are exclusively maternal in origin.
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
Antipodals|Zygote|Nucellus|Polyembryony_Mechanisms
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume that because nucellar embryos originate from the nucellus, they are nourished directly by it.
The trap relies on failing to understand the spatial and physiological necessity of the nucellar cells protruding into the embryo sac specifically to compete for the endosperm, which acts as the central nutrient sink of the seed.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Double Fertilization Stoichiometry |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |