PLANT FERTILISATION

          growth of pollen tube
pollen grains on the sigma germinate and a tube begins to grow downwards towards the ovule.
this tube is called the pollen tube.
the male nucleas from the pollen grain uses this tube to travel down and into the ovule.

          fertilisation
when the male nucleas travels down and into the ovule it fertilises the ovule.
this leads to the formation of the zygote which grows into the embryonic plant.

          seed formation
the outside of the ovule turns into the seed coat or testa
the testa not only holds the zygote which is the embryonic plant but it also contains the cotyledons which are food stores which will support the plant until it grows leaves and is able to make their own food.

          fruit formation 
the thickening of the walls of the ovary (carpel) combined with sugar and protein that the plant gives up forms the fruit.