Reproduction in flowering plants may occur both sexually or asexually.
Pollination can take place with the help of agents: wind or insects.
Pollination: transfer of pollen grains from the male part of the plant (anther) to the female part (stigma).
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Pollen
grains.
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Structural
adaptations
Common misconceptions
Students often get confused between pollination and
seed dispersal. When animals such as insects carry pollen, they aid
pollination. When animal carry seeds, they aid seed dispersal.
Growth
of pollen tube and the process of fertilization
Figure below shows a section through a single carpel.
If pollen grains are of the same species as the flower they land on, they may germinate.
Germination is triggered by a sugary solution on the stigma, an involves the
growth of a pollen tube from the pollen grain.
The pollen tube contains the male
nucleus, which is needed to fertilise the ovule inside the ovary. The pollen
tube grows down the style, through the ovary wall, and through the micropyle of
the ovule.
Fertilisation is the fusion of the male nucleus with the female
nucleus. If the ovary contains a lot of ovules, each will need to be fertilised
by a different pollen nucleus.
Video: Flower Reproduction
Video: Sexual Reproduction in Flowering Plants
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