pollination Flashcards
describe how pollen grains are produced
a young anther had 4 spaces inside it called pollen sacs before the flower bud opens
some cells around the edges of the pollen sacs divide to make pollen grains
when flower bud opens, anthers split and open and pollen grains fly out
what do pollen grains look like?
fine, often yellow powder
under microscope - some are spiky and some smooth
each grain surrounded by hard coat for harsh conditions
coat protects male gametes inside grains as they are carried from one flower to another
describe female gametes in plants
inside ovules in the ovary
each ovule has a nucleus
fertilisation occurs when an ovule nucleus fuses with a pollen grain nucleus (like in humans!)
define pollination
the transfer of pollen grains from the male part of the plant (staMEN) to the female part of the plant (stigma)
define self-pollination
the transfer of pollen grains to the stigma of the same flower (or different flower but same plant)
so pollen grain doesn’t have to travel far
define cross-pollination
transfer of pollen to the stigma of a different plant of the same species
what do the petals do?
they are colourful structures that attract pollinators
what is the stamen?
the entire male part of the flower
what is the anther?
the male part of the flower where pollen grains are made
what does the filament do?
holds up the anther
what is the carpel?
the entire female part of the flower
what does the stigma do?
it is sticky and receives the pollen
what does the style do?
holds up the stigma
what does the ovary do?
holds the ovules
what is the ovule?
it is located inside the ovary and contains the female gametes
describe the process of insect pollination
insects attracted by flower colour and scent
bee follows guidelines to nectaries brushing past anthers so pollen sticks to its body
when bee goes to another flower it transfers some pollen onto its stigma
describe the process of wind pollination
wind pollinated flowers produce more pollen usually since most goes into the air
wind blows pollen from anthers to stigma of flowers
describe adaptations of insect pollinated flowers
- large petals with guidelines often
- strongly scented
- nectaries at base of petals
- anthers inside flower so insect has to brush past them to reach nectar
- stigma inside flower so insect has to brush past to reach nectar
- sticky/spiky pollen grains, sticks to insects
- quite large quantities of pollen, some will be eaten/delivered to wrong type of flower
describe the adaptations of wind pollinated flowers
- small petals or none at all
- no scent
- no nectaries
- anthers dangle outside flower where they can catch wind
- stigmas large and feathery and dangle outside flower, pollen can land on it
- smooth, light pollen, can be blown in wind
- very large quantities of pollen, most will blow away/get be lost
