Development Of The Fruit And Seed

Question 1

What does the zygote become?

Answer 1

Divides by mitosis to become an embryo which consists of a pumule (developing shoot) and radicle (developing root) and 1/2 cotyledons (seed leaves).

Question 2

What does the triploid nucleus become?

Answer 2

The triploid endosperm nucleus develops into the endosperm which is a food store for the developing embryo.

Question 3

What does the outer integument become?

Answer 3

Dries out,becomes hard, water proof and has deposits of lignin, becoming the seed coat or testa. The micropyle remains as a pore.

Question 4

What does the ovule become?

Answer 4

Comprising the embryo, endosperm and testa, it becomes the seed.

Question 5

What does the funicle of the ovule become?

Answer 5

The funicle of the seed, attaching to the seed at the hileum.

Question 6

What does the ovary become?

Answer 6

The fruit. In some species it is sweet, juicy and pigmented like the cherry, and in some it is dry and hard like the almond.

Question 7

What are dicotyledons and monocotyledons?

Answer 7

Monocotyledons = one cotyledon
Dicotyledon = 2 cotyledons
Cotyledons are seed leaves.

Question 8

Give an example of a dicotyledon.

Answer 8

The broad bean. The ovary elongates in the pod, which is the fruit, and the ovules mature into seeds which are the broad beans. The embryo lies between the cotyledons.

Question 9

Why is the broad bean a non-endospermic seed?

Answer 9

Because the endosperm is absorbed into the cotyledons.

Question 10

Give an example of a monocotyledon.

Answer 10

Maize. The endosperm remains so this is an endospermic seed. The cotyledon remains small and doesn’t develop further. The testa of the seed fuses with the ovary wall so maize is a one seeded fruit.

Question 11

What happens to seeds after they’re produced?

Answer 11

They remain dormant. Their water content falls below 10% reducing metabolic rate. They can survive for long periods of time in this state and won’t germinate until conditions are correct.

Question 12

Compare monocots and dicots.

Answer 12

1 cotyledon / 2 cotyledons
Leaf veins parallel / leaf veins in a network
Sepals, petals and stamen in multiples of 3 // multiples of 5
Vascular bundles scattered in stems / in rings in the stems
Vascular bundles scattered in roots / in centre of roots.