Lab 2

Question 1

Root

Answer 1

Organ of vascular plants used for anchorage of plant body and uptake of water/nutrients (transported via vascular tissue).

Question 2

Primary root

Answer 2

First root emerging from seed

Question 3

Taproot

Answer 3

In seed plants, the primary root may turn into a taproot growing downward and branching lateral roots
-one main root with smaller roots coming off

Question 4

Adventitious roots

Answer 4

In monocots, primary roots are short lived and the main root system develops from the stem to form adventitious roots.

Question 5

Fibrous root system

Answer 5

In grasses, homogeneous system of adventitious roots

Question 6

Rhizomes

Answer 6

Are horizontal plants stems which are often underground with nodes giving rise to roots or shoots.
-reproduce vegetatively
eg. ginger

Question 7

Rhizoids

Answer 7

Uni or multicellular root like extensions used to anchor a plant.
-no vascular tissue present
-unicellular in liverworts
-multicellular in mosses

Question 8

Rhizophores

Answer 8

Root-bearing organ that grow from stems and form roots in the soil.
0have vascular tissues
-Found in lycophytes

Question 9

Which roots are monocot and dicot?

Answer 9

Fibrous roots are monocot
Tap roots are dicots

Question 10

Root cap

Answer 10

Found at tip of root
-protection
Covered in mucilaginous sheath which lubricates the path for growing roots

Question 11

Root apical meristem

Answer 11

Located behind root cap
Responsible for cell division

Question 12

Root hair zone

Answer 12

Form in the maturation zone after the elongation zone
-outgrowths of epidermal cells
-absorbs water/minerals
Lateral roots emerge further up

Question 13

Pith

Answer 13

Center of the ground tissue
-refers to a region
-not tissue type

Question 14

Cortex

Answer 14

Area between vascular bundles and dermal tissue
-refers to a region
-not tissue type

Question 15

Stele (vascular cylinders)

Answer 15

The pattern of vascular tissue arrangement in the centre of the root or stem

Question 16

Stele types

Answer 16

Protostele
-Haplostele (regular)
-Actinostele (star)
-Plecostele (lines in circle)

Siphonostele
-Solenostele
-Ectophloic siphonostele
-Dictyostele
-Eustele (Dicot)

Atactostele (monocot)

Question 17

Primary xylem

Answer 17

Xylem tissue originating from cell divisions at the apical meristem
2 types:
-Proto and metaxylem

Question 18

Protoxylem vs metaxylem

Answer 18

Protoxylem is thinner walled and differentiated/functioned first as stem was young and undergoing expansion

Metaxylem formed after

Question 19

Exarch

Answer 19

Protoxylem (smaller cells) is outside

Question 20

Endarch

Answer 20

Protoxylem is on the inside

Question 21

Lobed xylem terms

Answer 21

Four lobes of xylem- tetrarch
Three lobes- triarch
Two lobes- diarch
Many lobes- polyarch

Question 22

Endodermis

Answer 22

The innermost layer of the root cortex

Question 23

Casparian strip

Answer 23

-waxy bands on endodermal cells which help control what goes int the primary xylem

Question 24

What movement does the Casparian strip prevent?

Answer 24

Apoplastic movement
The apoplast is the pathway by which water travels from the root cortex’s cell walls and intercellular space.

Question 25

Symplastic movement

Answer 25

The symplastic pathway transports water through the protoplasts of the root cortex.
-more selective than apoplastic movement

Question 26

Pericylce

Answer 26

Layer of cells directly inside the endodermis
-this is the point of origin for secondary roots

Question 27

Four main functions of roots

Answer 27

-Water absorption
-Absorption of mineral salts
-Anchorage
-Food storage

Question 28

Evolution of roots?

Answer 28

This is not fully known.
Early vascular plants did not have roots

Question 29

How can roots gain assistance

Answer 29

By entering in symbiotic relationships with other organisms.
eg. nitrogen fixing nodules in legume roots and mycorrhizae

Question 30

What is the difference between endo and ectomycorrhiza?

Answer 30

Endo- penetrates cell wall
Ecto- doesn’t penetrate cell wall

-Both are a form of symbiotic relationship that occurs between a fungal symbiont and the roots of various plant species

The roots provide carbohydrate for the fungi and the fungi transfer nutrients and water to the plant roots

Question 31

What organism lives together with the plant in mycorrhizal associations?

Answer 31

Fungi

Question 32

Primary growth

Answer 32

Growth derived from divisions of the apical meristem
-all vascular plants have primary growth
-occurs in first few millimeters of each root tip (root apex)

Question 33

Protoderm

Answer 33

-one of three tissue systems differentiating behind the apical meristem
-matures into dermal system

Question 34

Procambium

Answer 34

-one of three tissue systems differentiating behind the apical meristem
-matures into vascular system

Question 35

Ground meristem

Answer 35

-one of three tissue systems differentiating behind the apical meristem
-matures into ground system

Question 36

How do lateral roots arise?

Answer 36

Endogenously (arise from the inside) from the pericycle

Question 37

Stem function

Answer 37

Keeps plant in an upright position towards sunlight
-conducts water/nutrients

Question 37

Stem function

Answer 37

Keeps plant in an upright position towards sunlight
-conducts water/nutrients

Question 38

Bud scales and terminal buds

Answer 38

Surround the shoot apex of annual plants to form terminal buds
-protects apical meristem inside, it can remain dormant in unfavourable conditions

Question 39

Leaf primordium

Answer 39

Lateral outgrowth from the apical meristem that develops into a leaf

Question 40

Lateral buds (axillary buds/bud primordium)

Answer 40

Found in axils of leaves
-may develop into branches