pollination & Fertilization in Angiosperms

Microspore (male)

• Produced in anthers via meiosis → develops into pollen grain

Megaspore (female)

• Produced in ovules via meiosis → develops into embryo sac

After pollination

• Pollen lands on stigma → pollen tube grows toward ovule → sperm fertilizes egg

Pollination types

• Wind, insects, birds, mammals, water

Pollen tube

Carries sperm to egg

Exine

Protective coat of pollen

Generative nucleus

Divides into 2 sperms

Tube nucleus

Directs pollen tube

Micropyle

Opening in ovule for sperm

Embryo sac

Female gametophyte

Synergids

Help guide pollen

Polar nuclei + sperm

Endosperm (3n)

Egg + sperm

Zygote (2n)

• Gametogenesis occurs from:

• Mitosis in pollen and embryo sac

• Nuclei in pollen grain:

• 1 tube nucleus + 1 generative nucleus → splits into 2 sperm

• Double fertilization in most plants:

False

• Double fertilization in flowering plants

True

• Double fertilization produces:

• Zygote (2n) and endosperm (3n)

Is pollination the same as Fertilization?

NO

Bonus: Invention of Velcro from??

Cockleburt