Angiosperms, or flowering plants, owe much of their diversity and success to flowers and the reproductive processes they support. This lesson examines flower structure, the development of male and female gametophytes, and the distinctive double fertilization of angiosperms.
A flower is made of modified leaves called sporophylls, arranged around a central receptacle. The peduncle usually attaches the flower to the plant. Although flowers vary greatly, their common structures include sepals, petals, stamens, and carpels.
All flashcards
What are the main parts of a typical flower?
Sepals, petals, stamens, and carpels. Sepals and petals form the perianth; stamens and carpels are the reproductive structures.
What is a pollen grain?
The male gametophyte, which develops from a microspore and contains a generative cell and a pollen-tube-forming cell.
What is the embryo sac?
The female gametophyte inside an ovule, containing an egg, two synergids, three antipodal cells, and a central cell with two polar nuclei.
What happens during double fertilization in angiosperms?
One sperm fuses with the egg to form a diploid zygote; the other fuses with two polar nuclei to form a triploid cell that develops into endosperm.
How do monoecious and dioecious plants differ?
Monoecious plants bear separate male and female flowers on the same plant; dioecious species bear them on separate plants.
Quiz questions
What is the collective name for a flower's sepals and petals?Answer: The perianth.
What is pollination in flowering plants?Answer: The transfer of pollen to a stigma.
What defines a perfect flower?Answer: It contains both stamens and carpels.
Which flower structure consists of one or more carpels?Answer: The gynoecium.
What is the primary role of endosperm in an angiosperm seed?Answer: It serves as a food reserve for the embryo.
Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.