3.2: Roots

Question 1

functions of roots

Answer 1

anchorage
absorption
storage
interaction
hormone production

Question 2

• develops from radicle
• branching lateral/branch roots

Answer 2

taproot

Question 3

• arises when radicle dies/ after germination
• root primordia at base grows out

Answer 3

fibrous root

Question 4

extreme tip pushes thorough soil

Answer 4

root tip

Question 5

• protects root apical meristems
• secrete mucigel
• constantly worn (renewed w parenchyma)

Answer 5

root cap

Question 6

inc SA
not lateral roots

Answer 6

root hairs

Question 7

• root epidermis w/o stomata, cuticle
• w/ root hairs
• produces mucigel

Answer 7

rhizodermis (epiblem)

Question 8

rhizodermal cells; gives rise to root hairs

Answer 8

trichoblast

Question 9

rhizodermal cells; don’t produce root hairs

Answer 9

atrichoblast

Question 10

exodermis w heavily sclerified cells

Answer 10

velamen

Question 11

• benefits plants +microbes
• =ecosystem by attracting bacteria
• bacteria helps plants collect nutrients

Answer 11

mucigel

Question 12

• site for gravisensing
• w amyloplasts

Answer 12

columella

Question 13

amyloplasts of columella cells

Answer 13

statoliths

Question 14

statolith-containing cells of columella cells

Answer 14

statocysts

Question 15

• contains new cells of roots
• in apex burried under root cap

Answer 15

Root Apical Meristem (RAM)

Question 16

• reserve for healthy cells (quiescent stage) if damaged
• mitotically inactive region

Answer 16

quiescent center

Question 16

• root hairs, cuticle
• cortex enlarges
• matured vascular tissues

Answer 16

zone of maturation

Question 17

• some meristematic activity
• most permeable = diffusion of water

Answer 17

zone of elongation

Question 18

• support/ground tissues between rhizodermis and vascular tissues
• site of aerenchyma
• storage of starch

Answer 18

root cortex

Question 19

• innermost cortical layer
• lignin + suberin
• = casparian strip

Answer 19

endodermis

Question 20

controls type of minerals that enter vascular tissues
lignin + suberin

Answer 20

casparian strip

Question 21

• parenchyma cells between endodermis and vascular tissues
• formation of lateral roots

Answer 21

pericycle

Question 22

• where lateral roots form
• swells into cortex->tear endodermis->form root cap emerges

Answer 22

root primordium

Question 23

• central vascular cylinder of root
• contains xylem, phloem, protophloem, pericycle

Answer 23

stele

Question 24

“scattered xylem” in ground tissues
monocot stele

Answer 24

atactostele

Question 25

route of movement:
- between cells
- water only cross
- by root hairs

Answer 25

apoplastic route

Question 26

route of movement:
- inside cells
- minerals/water cross
- by root hairs

Answer 26

symplastic roots

Question 27

route of movement:
materials into protoplast of cell -> inward via symplast

Answer 27

transmembrane route

Question 28

route of movement:
flows in cells of endodermis -> vascular bundles

Answer 28

endodermal route

Question 29

support root:
plate-like
tall in tropical trees
against wind blow

Answer 29

buttress roots

Question 30

support root:
for plants subject to powerful water currents

Answer 30

brace roots

Question 31

support root:
adventitious roots extend to soil
for monocots w wider stems

Answer 31

prop roots

Question 32

support root:
for epiphytes
along surface of bark

Answer 32

clinging roots

Question 33

support root:
for figs as epiphytes on host tree

Answer 33

strangling roots