Seeds and Seed Dispersal

Question 1

What is the role of seeds?

Answer 1

To protect and nourish embryos allowing embryos to survive a wide range of environmental conditions
Allow species to survive and regenerate

Question 2

What is a dormant state?

Answer 2

Enables plant species to disperse into new environments and wait for good conditions to germinate

Question 3

What does it mean to be viable?

Answer 3

They can germinate

Question 4

What is the record for seeds persisting at non-freezing temperatures?

Answer 4

2,000 years

Question 5

How do gymnosperm seeds develop?

Answer 5

From ovules

Lack a surrounding fruit

Question 6

What is a seed wing?

Answer 6

An extension of a seed coat which aid in seed dispersal.

Question 7

What does it mean to not be a fruit?

Answer 7

Not derived from an ovary

Question 8

What is the outermost layer of the seed?

Answer 8

The seed coat

Question 9

Where does the seed coat originate?

Answer 9

From the mother tree (sporophyte) so it is diploid

Question 10

What does resin do?

Answer 10

Plays a role in seed dormancy, protecting the embryo from losing water, and deterring seed herbivore.

Question 11

What is a megagametophyte?

Answer 11

The female gametophyte
Haploid from meiosis
produces eggs
Produces nutritional tissue to protect the embryo

Question 12

What does fertilization do?

Answer 12

Produces embryos of new sporophytes which are diploid

Question 13

What does an embryo consist of?

Answer 13

Cotyledons
Hypocotyl
Radicle

Question 14

What is cotyledons?

Answer 14

embryonic leaves (the number of cotyledons is species dependent)

Question 15

What is the hypocotyl

Answer 15

embryonic stem

Question 16

What is a radical?

Answer 16

embryonic root

Question 17

What is the shoot apical meristem?

Answer 17

a region of cells that has the ability to divide and create all the cells and tissues needed for new stem and leaves

Question 18

What is the root apical meristem?

Answer 18

a region of cells that has the ability to divide and create all the cells and tissues needed for new roots

Question 19

What is a root cap?

Answer 19

a covering that allows the root to grow through soil undamaged

Question 20

Why are embryos oriented in some seeds?

Answer 20

So cotyledons and shoot apical meristems point towards the wider end of the seed so the radicle is near the narrower end of the seed

Question 21

How do you know if a conifer is mature?

Answer 21

1. If the embryo fills most of the cavity

2. The megagametophyte appears firm and waxy

Question 22

What do cone scales do?

Answer 22

Flex and release seeds

Question 23

What conditions promote flexing of cone scales?

Answer 23

Dry conditions

Question 24

Why do conifers have seed cones that hang downwards

Answer 24

Takes advantage of gravity and wind to assist in seed dispersal

Question 25

What does a seedbed do?

Answer 25

Promotes successful germination and early growth

Question 26

Where are angiosperm seeds found?

Answer 26

Inside the fruit

Question 27

What are some common features between gymnosperm seeds and angiosperm seeds?

Answer 27

Surrounded by a seed coat 
Have cotyledons (embryonic leaves)
Shoot and root apical meristems 
Hypocotyl (embryonic shoot)
Radicle (embryonic root)

Question 28

What is the endosperm?

Answer 28

A tissue that holds nutritive reserves for the angiosperm embryo.

Question 29

How is the endosperm produced?

Answer 29

Through the fertilization process in flowering plants

An embryo produces endosperm that is triploid and the endosperm will nourish and protect the developing embryo

Question 30

What are cotyledons like in angiosperm seeds?

Answer 30

They are a lot larger

There can be one or two

Question 31

What are monocot seeds like?

Answer 31

Have endosperm at maturity

Single cotyledon to absorb food

Question 32

How are seeds dispersed?

Answer 32

Via animals

Wind dispersed

Question 33

What is the magagemetophyte and what does it do?

Answer 33

The female gametophyte
Produces eggs when young
Becomes nutritional tissue in mature tree
Embryo is embedded in it

Question 34

What does the suspensor do?

Answer 34

Pushes embryo into megagemtophyte

Question 35

When are Douglas Fir seeds ready?

Answer 35

August and September

Cones are full size in july but mature later

Question 36

What is the sctellum?

Answer 36

Cotyledon modified for food absorption

Question 37

What is the coleoptile?

Answer 37

Protects and guides the plumule

Question 38

What is the coleorhiza

Answer 38

Protects the radical