Pollination

• pollination: plant reproduction

• flower: the reproductive structure of an angiosperm; contain gametes (sperm + egg) needed for respiration

• gametophyte: gamete-producing

• male gametophyte: pollen grain (sperm)

• pollen grain forms two cells: generative cell (produces two sperm) + tube cell (makes a path for sperm to ovary)

• female gametophyte: embryo sac (egg)

• anther: produce pollen grains

• ovule: compartment inside ovary that contains embryo sac + egg

• stomata - opens so that oxygen and CO2 can enter/leave the plant; closes if too hot to prevent evaporation rate

• guard cells - open the stomata

• cuticle - protects the leaf (outer layer) from animals etc.

• palisade mesophyll layer - contains the chloroplasts so that the light can be stored

• spongy mesophyll layer - contains CO2 and this area does not need much light

• double pollination - 2 sperm fertilized at the same time

• first: fertilizes the egg (egg → embryo)

• second: fertilizes polar nuclei (PN → endosperm - food for embryo)

• cross pollination: transfer of pollen to a stigma of a different plant

• self pollination: transfer of pollen to the stigma of the same plant

• pigments: absorb all the sunlight

• → red + blue pigments absorbed the most, green the least (reflected)

• after fertilization, a seed forms around the embryo + the ovary ripens into a fruit