In flowering plants, anthers produce pollen containing male reproductive cells. Pollination transfers pollen to a compatible stigma. A pollen tube can grow towards an ovule, carrying male gametes. Fertilisation occurs when a male gamete fuses with the egg inside an ovule. Pollination is a transfer step; it does not guarantee fertilisation. Wind and animal pollinators can transfer pollen between flowers.
After fertilisation, an ovule develops into a seed containing an embryo; the ovary commonly develops into a fruit. Seeds protect embryos and may contain food reserves. Dispersal carries seeds away from the parent, reducing local competition and helping colonise suitable sites. Germination begins when conditions such as water, oxygen and temperature are suitable. Flowers differ in their structures, but the distinction between pollen transfer and gamete fusion remains useful.
Example 1
A bee carries pollen from an anther to another flower’s stigma. Has fertilisation necessarily happened?
No. This is pollination. A compatible pollen grain must germinate and male gametes must reach and fuse with an egg for fertilisation.
Example 2
Which structures become a seed and, commonly, a fruit?
The fertilised ovule develops into a seed. The flower’s ovary commonly develops into the fruit around it.
Watch out: Pollination transfers pollen to a stigma. Fertilisation is the later fusion of gametes.