Roots Chapter 5 (Week 2 Lecture 2)

Question 1

What are the four main functions of roots?

Answer 1

Anchor plants into soil
Absorption of water and minerals
Store food or water
Other specialized functions

Question 2

Where does a root arise from?

Answer 2

embryonic root or radicle

Question 3

A ______ root system belongs to monocots while a ______ root system belongs to dicots.

Answer 3

Fibrous, taproot

Question 4

Why does a fibrous root plant not have a single large taproot?

Answer 4

Because the embryonic

root dies back when the plant is still young

Question 5

______ roots are roots that arise from anything other than a radicle.

Answer 5

Adventitious (corn, poison ivy)

Question 6

What are the four regions of the root? Order them from bottom to top.

Answer 6

Root cap
Region of cell division (apical meristem)
Region of cell elongation
Region of maturation

Question 7

______ cells make up the root cap covering each root tip.

Answer 7

Parenchyma

Question 8

Root cap functions in _____ (gravity perception).

Answer 8

gravitropism

Question 9

True or False: The root cap secretes mucilage that acts as lubricant

Answer 9

True

Question 10

The region of cell division is composed of what 3 meristematic areas?

Answer 10

Protoderm, ground meristem, procambium

Question 11

On average, how many times does the apical meristem cells divide per day?

Answer 11

Once or twice per day

Question 12

True or False: The region of elongation does not merge with the apical meristem.

Answer 12

False, the region of elongation does merge with the apical meristem

Question 13

If a cambium is present, how does increase in girth happen?

Answer 13

Through the addition of secondary tissues

Question 14

What happens to tiny vacuoles during the region of elongation?

Answer 14

Tiny small vacuoles merge into 1 or 2 large vacuoles, occupying more than 90% of volume of each cell

Question 15

What happens to cells during the region of maturation?

Answer 15

Cells differentiate into various distinctive cell types

Question 16

The region of maturation consists of what 5 cell structures?

Answer 16

Root hairs
Cortex
Endodermis
Pericycle
Vascular cylinder

Question 17

What is the the function of root hairs?

Answer 17

Absorb water and minerals
Adhere tightly to soil particles
Increase total absorptive surface of root

Question 18

How are root hairs formed?

Answer 18

Formed from epidermal cell extensions with thin cuticle

Question 19

True or False: The cuticle does not exist on root but does on root hairs.

Answer 19

False, cuticle exists on root but not on root hairs

Question 20

What cells is the cortex is made up of?

Answer 20

Parenchyma cells between epidermis and vascular cylinder

Question 21

What is the main function of the cortex?

Answer 21

Mostly stores food

Question 22

What cells is the endodermis is made up of?

Answer 22

Inner boundary of cortex, consisting of a single-layered cylinder of compact cells

Question 23

In the endodermis, cell walls with suberin bands called ______ ______ on radial and tangential walls

Answer 23

Casparian strips

Question 24

In the endodermis, eventually inner cell walls become thickened with suberin, except for ______ ______.

Answer 24

Passage cells

Question 25

What is the function of casparian strips?

Answer 25

Forces water and dissolved substances entering and leaving the central core to pass through endodermis Regulates types of minerals absorbed

Question 26

Where is the pericycle located?

Answer 26

Outer boundary of vascular cylinder

Question 27

True or False: The pericycle stops dividing after it matures.

Answer 27

False, the pericycle continues to divide, even after mature

Question 28

What does the pericycle eventually form?

Answer 28

lateral (branch) roots and part of the vascular cambium

Question 29

Most of cells of ______ ______ are primary xylem or primary phloem

Answer 29

Vascular cylinder

Question 30

Where is the vascular cylinder located?

Answer 30

Lies inside endodermis

Question 31

Vascular cambium develops from parts of the ______ and other ______ cells between the xylem arms and phloem patches in most dicots and conifers.

Answer 31

Pericycle, parenchyma

Question 32

______ ______ forms secondary phloem | to the ______ and secondary xylem to the ______.

Answer 32

Vascular cambium, outside, inside

Question 33

In dicots, the solid core of xylem are in the shape of "______" in cross section.

Answer 33

Arms

Question 34

In monocots, xylem surrounds the ______.

Answer 34

Pith

Question 35

What is determinate growth?

Answer 35

Growth that stops after an organ is fully expanded or after a plant has reached a certain size

Question 36

What is indeterminate growth?

Answer 36

New tissues are added indefinitely, season after season

Question 37

Starch and other carbohydrates like sweet potatoes have ______ ______ roots.

Answer 37

Food storage

Question 38

The pumpkin family, especially in arid regions have ______ ______ roots.

Answer 38

Water storage

Question 39

Fruit trees are an example of ______ ______ roots.

Answer 39

Propagative roots

Question 40

In propagative roots, the adventitious buds on roots develop into ______ (aerial stems)

Answer 40

Suckers

Question 41

What do pneumatophores function as?

Answer 41

Spongy roots that extend above the water’s surface and enhance gas exchange between atmosphere and subsurface roots

Question 42

Where are pneumatophores found?

Answer 42

In plants with roots growing in water (black mangrow)

Question 43

Orchids have aerial ______ roots, with epidermis several layers thick to reduce water loss.

Answer 43

Velamen

Question 44

Corn has aerial ______ roots to support plants in high wind.

Answer 44

Prop

Question 45

Aerial roots in ivies (English ivy, Virginia creeper) aid in what?

Answer 45

Plant climbing

Question 46

______ roots pull plants deeper into soil such as lily bulbs and dandelions.

Answer 46

Contractile

Question 47

______ roots have stability in shallow soil such as tropical tress

Answer 47

Buttress

Question 48

______ roots have no chlorophyll and are dependent on chlorophyll-bearing plants for nutrition such as dodder.

Answer 48

Parasitic

Question 49

What is mycorrhizae?

Answer 49

Fungi that form a mutualistic association with plant roots

Question 50

True or False: Both fungus and root benefit and are dependent upon association for normal development.

Answer 50

True, mutualistic association

Question 51

How does the mutualistic relationship work between fungi and roots?

Answer 51

Fungi facilitate absorption of water and nutrients, especially phosphorus for roots and the plant furnishes sugars and amino acids to fungus.

Question 52

______ ______ contain large number of nitrogen-fixing bacteria.

Answer 52

Root nodules

Question 53

What type of plants contain root nodules?

Answer 53

Legume family (Fabaceae)

Question 54

What are the 7 types of specialized roots?

Answer 54

Water storage, buttress, food storage, parasitic, pneumatophores, propagative, contractile