- Students will be able to:
- name and state the functions of the main parts of a flower
- describe what pollination is
- state differences between animal and wind pollinated flowers and give examples of each.
The main parts of a flower
- Sepals enclose the flower buds.They split open and fold back so the petals can open.
- Petals enclose the reproductive structures. In insect pollinated flowers, these are usually coloured and easily seen so they attract insect and bird visitors. The petals usually have to open before pollination can occur.
- Anthers produce the pollen. Anthers are usually at the end of a filament. An anther and its filament are referred to as a stamen and are the male parts of a flower. The anthers must open or split to release the pollen.
- Pollen grains contain the male genetic material that must be moved to the female reproductive structures for fertilisation to occur.
- Stigmas are at the end of a pistil. They are the female structures that the pollen sticks to.
- The Ovary is normally at the base of a flower and contains from one to many ovules.
- Ovules are the female structures that must be fertilised to produce seeds.
- Nectaries produce nectar to attract animal visitors. These are usually found at the base of the petals.
Pollen, ovules and seeds
Plants usually produce a small number of ovules, but millions of pollen grains.
To produce a seed, pollen must be moved from an anther to the stigma of the same type of flower. This is process is called pollination.
Depending on the plant species, the pollen may have to be moved a few millimetres or many metres, either by animals such as insects, or the wind.
Once on the stigma the pollen grain produces a pollen tube that grows down inside the pistil to reach an ovule and achieve fertilisation. The ovule then grows into a seed.
Differences between insect and wind pollinated flowers
|Flowers||Usually conspicuous* and often large||Inconspicuous*, often dull and small|
|Petals||Often large and brightly coloured||Dull and small|
|Pollen||Heavy and sometimes sticky||Light|
|Stamen||Near entrance to flower||Positioned high on the plants and dangle outside flower|
|Stigma||Sticky and near entrance to flower||Large and feathery|
* Meanings of words in table
Conspicuous: easily seen.
Inconspicuous: not easily seen.
Scented: smells (usually nice).
Unscented: no smell.
Method of pollination
Flowers pollinated by animals
Flowers pollinated by wind
Picture credits: Thumbnail diagram and Parts of Flower diagram (Pixy.org).