Reproduction in plants Flashcards
State the functions of the following parts of a flower:
Sepals, Petals, Stamens, Filaments, Anthers, Carpels, Style, Stigma, Ovary and the ovule
Sepals - Protect the flower while it is a bud
Petal - To attract insects
Stamens - The male parts of a flower
Filament - The stalk part of a stamen
Anther - To secrete pollen
Carpel - The female parts of a flower
Style - Connects the stigma to the ovary
Stigma - Recives pollen
Ovary - Holds the ovules
Ovules - Contain the female gametes
Describe the anther and stigma of a wind-pollinated flower
Stigma - Large and feathery, hanging outside of the flower
Anther - Dangling outside the flower
Distinguish between the pollen grains of insect-pollinated and wind-pollinated flowers
Pollen grains are spiky in insect-pollinated flowers and are smooth in wind-pollinated flowers
Define pollination
The transfer of pollen grains from an anther to a stigma
Define self pollination
The transfer of pollen grains from the anther of a flower to the stigma of the same flower or a different flower on the same plant
Define cross-pollination
The transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant but of the same species
Give the effects of self pollination and cross-pollination
there is less variation in self-pollinated plants than in wind-pollinated plants
Define fertilisation
When a pollen nucleus fuses with a nucles in the ovule
Describe the structural adaptations of an insect-pollinated flower
Large feathery stigma/ increases surface area/higher chances of catching pollen grains
Anthers dangling outside the flower/ increases chances of wind pollination
How does water affect germination of a plant
It is absorbed through the micropyle unitl the radicle has forces its way out of the testa
How does temperature affect the germination of a seed?
To allow enzymes to work at their best, speeding up the rate of germination
How does oxygen affect germination of a plant
It is needed for respiration to release energy for growth
How is a pollen tube formed?
Once the pollen grain reaches the stigma, it grows a tube by secreting enzymes that digest a pathway to the ovary. The pollen tube continues growing through the micropyle allowing for the male nucleus to reach the female nucleus
