Lecture 9: Seed Germination

Question 1

What is part of the embryo and does not photosynthesize?

Answer 1

Cotyledon

Question 2

What is the embryo?

Answer 2

Grows into a new plant

Question 3

What is the food storage material made of?

Answer 3

Endosperm and 1 or 2 cotyledons

Question 4

What are the two other names for the seed covering?

Answer 4

Seed coat, testa

Question 5

What is the hilum?

Answer 5

Scar where the seed was originally attached to the fruit

Question 6

What is the micropyle?

Answer 6

Small opening on the seed that allows water to enter

Question 7

What is the raphe?

Answer 7

Ridge on the seed

Question 8

What is the radicle?

Answer 8

The embryonic root and primary root

Question 9

What does the embryo of the dicot seed contain?

Answer 9

2 cotyledons, and radicle

Question 10

What is the plumule?

Answer 10

The primary shoot

Question 11

What is the hypocotyl?

Answer 11

Part of the stem below the cotyledons and above the radicle

Question 12

Label the following.

Answer 12

Question 13

What is the general process of Germination?

Answer 13

Imbibition of water by the seed

Activation of hormones and enzymes

Embryo growth and development

Question 14

What happens during the imbibition phase of germination?

Answer 14

Water enters the seed via micropyle.
Seed coat absorbs water and swells
Seed coat softens and ruptures allowing for gas exchange.

Question 15

What happens during the hormone and enzyme activation phase?

Answer 15

Hormones trigger chemical reactions and enzymes speed up chemical reactions

Question 16

What are the steps of dicot seed germination?

Answer 16

The radicle is the first organ to emerge from the germinating seed.

A hook forms in the hypocotyl.

Growth pushes the hook, the attached cotyledons, and epicotyls aboveground. The hypocotyl hook protects the cotyledon and plumule as they emerge from the soil.

Secondary roots grow from the radicle.

Hypocotyl straights out from its hooked position and positions the cotyledons above the soil.

Primary leaves unfold while the stem elongates and the cotyledons eventually wither away.

Question 17

What is the epicotyl?

Answer 17

Epicotyl is the stem above the cotyledons

Question 18

What is the hypocotyl?

Answer 18

Above the radicle, below the epicotyl, and below the cotyledon. Hooked part that eventually straightens out.

Question 19

What is the other name for cotyledons?

Answer 19

Seed leaf

Question 20

What components are in monocot seeds?

Answer 20

1 cotyledon and endosperm which is the second food storage structure

Question 21

What are the steps of monocot seed germination?

Answer 21

Emergence of the radicle and plumule
Coleoptile grows
Either epigeal or hypogeal germination occurs depending on the plant

Question 22

What is the coleoptile?

Answer 22

Membrane covering the plumule which protects it as it comes up from the soil

Question 23

What is epigeal germination?

Answer 23

Cotyledons are pushed aboveground.

Question 24

What is hypogeal germination?

Answer 24

Cotyledons remain underground

Question 25

What is sexual propagation?

Answer 25

Production of new plants through fertilization and the production of seeds. Results in plants with different genetic material from the parent plant

Question 26

What are the advantages of sexual reproduction?

Answer 26

Mass production, variation in plants for more selective traits, easy storage, and greater vigour with controlled hybridization

Question 27

What are the disadvantages of sexual propagation?

Answer 27

Variation in plants can cause issues, waiting period to produce seeds

Question 28

What is asexual propagation?

Answer 28

Production of new plants without fertilization happening.

This results in new plants with the same genetic material as the parent plant

Question 29

What are the advantages of asexual propagation?

Answer 29

Uniformity in offsprings, bypass immature phase where you need to wait for it to produce seeds, germinate and slowly grow, great for species that do not produce seeds (ie. Kwanzan cherry)

Question 30

What are the disadvantages of asexual propagation?

Answer 30

Lack of genetic diversity, more difficult to store vegetative material, special equipment may be required to allow plants to asexually reproduce