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Difficulty: MediumSpermatophytes: Gymnosperms and Angiosperms

A major reproductive difference between gymnosperms and angiosperms lies in the process of seed development and food storage. Which of the following statements correctly compares the endosperm in these two groups of spermatophytes?

  1. The endosperm in angiosperms is a triploid tissue formed after fertilization, while in gymnosperms it is a haploid tissue formed before fertilization.Answer
  2. B
    The endosperm in angiosperms is a haploid tissue formed before fertilization, while in gymnosperms it is a triploid tissue formed after fertilization.
  3. C
    Both angiosperms and gymnosperms develop a triploid endosperm as a direct product of double fertilization.
  4. D
    The endosperm in gymnosperms is diploid and enclosed within a fruit ovary wall, while angiosperm endosperm is haploid and exposed.

Answer

The endosperm in angiosperms is a triploid tissue formed after fertilization, while in gymnosperms it is a haploid tissue formed before fertilization.
In angiosperms, double fertilization leads to the formation of a triploid (3n) endosperm after fertilization. In contrast, the nutritive endosperm tissue of gymnosperms represents the female gametophyte, which develops prior to fertilization and is haploid (1n).

Step-by-Step Solution

1
Analyze endosperm formation in angiosperms
In flowering plants (angiosperms), double fertilization occurs where one sperm nucleus fertilizes the egg (forming a 2n zygote) and the second sperm nucleus fuses with the two polar nuclei to form the triploid (3n) endosperm nucleus after fertilization.
This unique process ensures nutritive tissue develops only when fertilization is successful.
2
Analyze nutritive tissue formation in gymnosperms
In gymnosperms, the female gametophyte develops into the nutritive tissue before fertilization, making it haploid (1n).
No double fertilization occurs in gymnosperms to form triploid tissue.
3
Compare the ploidy and timing between the two divisions
Angiosperm endosperm is 3n (post-fertilization), whereas gymnosperm endosperm is 1n (pre-fertilization).
This establishes the key reproductive contrast between gymnosperms and angiosperms.

Key Concept

Ploidy level and timing of endosperm development in Spermatophytes
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Topics

Spermatophytes: Gymnosperms and Angiosperms

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