3.4 Plant Fertilisation.

Understand that the growth of the pollen tube followed by fertilisation leads to seed and fruit formation.
- pollen grains on stigma germinates and a tube begins to grow.
- the male nucleus travels down the pollen tube in to the ovule.
- pollen nucleus will fertilise the ovule- leads to formation of a zygote -> later grows into and embryonic plant.
- outside of the forms seed coat called testa.
- inside of seed forms cotyledons. food storage for the seedling, this supports the plant until it develops leaves.
- thickening of walls of the ovary occurs- plant uses lots of energy (like sugar and protein) this will form fruit which is developed from the wall of the ovary.