Topic 7 - Fertilisation and Germination in Plants

Question 1

how are plant gametes fertilised?

Answer 1

a pollen grain lands on the stigma of a flower. a pollen tube grows out of the pollen grain and down through the style to the ovary and into the ovule. a nucleus from the male gamete moves down the tube to join with a female gamete in the ovule. the two nuclei fuse to make a zygote, which divides to form an embryo, which forms a seed. the ovary develops into a fruit around the seed.

Question 2

what conditions do seeds need for germination?

Answer 2

1. water - to activate the enzymes that break down the food reserves in the seed
2. oxygen - for respiration
3. temperature - for enzymes to work

Question 3

what happens when a seed germinates?

Answer 3

1. the seed takes in water and starts to grow using its store of energy
2. the first root starts to grow down into the soil
3. the shoot grows up
4. extra roots grow and the first green leaves appear

Question 4

what does a developed seed contain?

Answer 4

an embryo and a store of food reserves contained in a hard seed coat