In this lesson we are going to learn about how do pollination and fertilization take place in flowers.
The transfer (move) of pollen grains from the anther (of the stamen) to the stigma (of the pistil) is called pollination.
1) Between pollen grains and stigma of the same flower.
2) Between pollen grains and stigma of different flowers of same species.
Pollen grains are very light in weight, so they can easily float in the air and move to other plants.
1. All flowers don’t have brightly coloured petals.
2. Some grasses have small, dull, off-white flowers.
3. This is because they are not pollinated by insects or other animals.
4. They use the wind to blow their pollen grains to other plants.
When it is raining, pollen grains can be washed away and brought to the stigma.
Animals like insects, birds and squirrels can transfer pollen grain to other flowers.
When insects like bees go one flower to other flower, pollen grains in one flower can be stuck in their body parts and brought to the stigma of another flower.
After a flower is pollinated, each pollen grain which is on the stigma grows a tiny tube towards the ovules in the ovary. Then the male sex cells in pollen grains can reach the ovules and join female sex cells or eggs produced in ovules. Then the female sex cells or eggs can be fertilized. This joining or the combination of male sex cells and female sex cells in a flower is called fertilization. Fertilization cannot take place without pollination.
After fertilization the petals, the stamen and the stigma fall off. The ovules become the seeds. The carpels and the ovary become the fruit.May 4, 2013