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#gametophyte

6 public questions tagged with this topic.

plant Development - 1

Dominant generation in angiosperms:

Dominant generation in angiosperms is diploid sporophyte phase comprising conspicuous plant body with true roots, stems, leaves, vascular tissues, and flowers. Massive sporophyte produces via meiosis haploid spores that develop into highly reduced gametophytes: male pollen grain of two-three cells and female embryo sac of seven cells entirely dependent on sporophyte for nutrition, protection, and desiccation resistance. After double fertilization diploid embryo and triploid endosperm develop within seed borne on sporophyte. Sporophyte dominance reflects evolutionary adaptation providing protection, efficient water transport, and advanced reproductive structures compared to gametophyte-dominant bryophytes and ferns.

Ref: Taiz & Zeiger, Plant Physiology: sporophyte is dominant multicellular generation in angiosperm life cycle providing protection.

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Plant Classification

In seed plants, the gametophyte is

Seed plant gametophytes highly reduced matrotrophic depending completely on sporophyte for nutrition and protection throughout life, no independent photosynthesis. Male gametophyte three-celled pollen grain lacks chlorophyll tube cell generative cell plus two sperm, female gametophyte gymnosperms massive haploid within ovule containing archegonia eggs, angiosperm seven-celled eight-nucleate embryo sac within nucellus integuments, both enclosed maternal sporophytic tissues. No free-living photosynthetic phase persists unlike bryophytes where sporophyte dependent on gametophyte or ferns both independent free-living. Dependency ensures sheltered fertilization via pollen tube siphonogamy delivering sperm without external water film, crucial adaptation for terrestrial colonization and dominance.

Ref: NCERT Class 11 Biology, Chapter 3: Gametophyte reduction dependence on sporophyte seed plants

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