Life cycle of an angiosperm.
- Anthers contain microsporangia; microsporocytes divide by meiosis to produce
microspores.
- Microspores form male gametophytes (pollen grains) which produce 2 sperm and a pollen tube.
- Ovaries contain megasporangia;
a megasporocyte divides by meiosis to yield 4 megaspores; one forms a female
gametophyte (embryo sac).
- 2 sperm nuclei reach an ovule and double fertilization
occurs.
- One sperm fertilizes an egg to form a zygote,
the other fuses with 2 nuclei of a central cell to form a
triploid
endosperm.
- The diploid
zygote develops into an embryo within a seed.
- A seed can germinate into a sporophyte.
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