The Stages In Seedling Growth

Question 1

Give an example of germination in which the cotyledons remain below the soil

Answer 1

Broad beans

Question 2

What is special about the germination of a broad bean?

Answer 2

The cotyledon remains below the soil

Question 3

What is the first step in the germination of a broad bean

3

Answer 3

The seed absorbs water

Enzymes become active

The radicle begins to grow

Question 4

What is the second step in the germination of a broad bean?

Answer 4

The radicle bursts out through the testa (seed coat) and grows down due to geotropism

Question 5

What causes the radicle to grow downwards?

Answer 5

Geotropism

Question 6

What does the radicle burst out through?

Answer 6

The testa (seed coat)

Question 7

What is the third step in the germination of a broad bean?

Answer 7

The plumule emerges

Question 8

When does the plumule emerge?

Answer 8

After the radicle has grown downwards

Question 9

What is the fourth step in the germination of a broad bean?

Answer 9

The plumule grows up through the soil and its delicate leaves are protected by the plumule being hooked over

Question 10

What direction does the plumule grow?

Answer 10

The plumule grows up though the soil

Question 11

How does the plumule protect its delicate leaves?

Answer 11

By being hooked over

Question 12

Why does the plumule grow upwards while remaining hooked over?

Answer 12

To protect its delicate leaves

Question 13

What is the fifth step in the germination of a broad bean?

2

Answer 13

The cotyledons (and endosperm, if present) shrivel as food is transferred from them

The radicle develops into the primary root (or tap) root, which forms many side roots

Question 14

Why do the cotyledons (and endosperm, if present) shrivel?

Answer 14

As food is transferred from them

Question 15

What does the radicle develop into?

Answer 15

The primary root (tap root)

Question 16

What is the primary root also called?

Answer 16

The tap root

Question 17

What does the primary root do?

Answer 17

It forms many side roots

Question 18

What is the sixth step in the germination of a broad bean?

2

Answer 18

Once above the ground, the plumule straightens up and produces the first true leaves

These soon become green and start to photosynthesise

Question 19

What happens to the plumule once above ground?

Answer 19

It straightens up and produces the first true leaves

Question 20

What will soon happen to the first true leaves?

Answer 20

They will become green and start to photosynthesise

Question 21

List the stages in the growth of a broad bean.

6

Answer 21

1. seed absorbs water - enzymes - active - radicle - grows
2. Radicle bursts through testa - grows down- geotropism
3. plumule emerges
4. plumule grows up - hooked - protect - delicate leaves
5. cotyledons (and endosperm if present) shrivel - food transferred from them - radicle - primary root (tap root) - forms many side roots
6. Once above ground - plumule straightens up - produced first true leaves - become green - photosynthesise

Question 22

Give an example of germination in which cotyledons move above the soil

Answer 22

Sunflower seeds - fruits with the fruit wall (pericarp) and the seed wall (testa) being fused

Question 23

What is different about a sunflower seed compared to other seeds?
(2)

Answer 23

Sunflower seeds are fruits

Their fruit wall (pericarp) and their seed wall (testa) are fused together

Question 24

What is different about the germination of a sunflower seed?

Answer 24

The cotyledons move above the soil

Question 25

List the steps in the germination of a sunflower seed

4

Answer 25

The cotyledons are forced above the soil

Once above the soil the fruit wall (pericarp) falls to the ground

The cotyledons open out, become green and photosynthesise

The plumule emerges from between the cotyledons and forms the first true leaves

Question 26

What is the fruit wall called?

Answer 26

The pericarp

Question 27

What happens to the pericarp when the cotyledons are forced above the soil?

Answer 27

They fall to the ground

Question 28

What first happens when the cotyledons are above the ground?

Answer 28

The pericarp falls to the ground

Question 29

What happens after the pericarp falls to the ground?

Answer 29

They become green and photosynthesise

Question 30

What emerges from between the cotyledons?

Answer 30

The plumule

Question 31

What does the plumule form during the germination of the sunflower seed?

Answer 31

The first true leaves