Root Morphology4

Question 1

Root Functions (4)

Answer 1

-Anchor plants in soil
-absorb water and minerals from soil
-conduct water and minerals to and from shoots
-Area for storage

Question 2

1.Root cap

Answer 2

-protective layer of cells produced from root tip
-protects apical meristem
-constantly replaced by more cells from meristem
-gravity & amyloplasts result in downward growth

Question 3

2.Region of cell division

Answer 3

-directly behind root cap
-include apical meristem
-cells divide every 12-36 hours

Question 4

3. cell elongation

Answer 4

-above region of cell division
- cells elongate causing roots to lengthen

Question 5

4.cell maturation

Answer 5

above region of cell elongation
-primary tissues mature into secondary
-root hairs are formed

Question 6

the 3 root tissues

Answer 6

epidermis
Cortex
Endodermis

Question 7

Epidermis (5)

Answer 7

-Outer absorbing layer
-single layer
-covers entirety of root except root cap
-usually lacks stomata and cuticle
-absorbing surface increased through root hairs

Question 8

Cortex(

Answer 8

-large thinned cell walls, above epidermis
-occupies greatest area in primary roots
-food storage
-loosely packed to allow water and minerals to flow through

Question 9

Symplastic

Answer 9

travelling through living cells (cytoplasm)

Question 10

apoplastic

Answer 10

through cell walls and intercellular spaces
-50% less resistance

Question 11

hypodermis, and what its lined with

Answer 11

outermost layer of cortex,
protective, lined with suberin(slows loss of water)

Question 12

Endodermis

Answer 12

-inner to cortex
-single layer cells
-boundary between cortex and vascular cylinder
-tightly packed cells

Question 13

casparian strip

Answer 13

the border of the endodermis
creates a barrier for substances within roots

Question 14

DICOT roots

Answer 14

-xylem forms star shape core with phloem bw arms of xylem
-pericycle

Question 15

Pericycle

Answer 15

-one or more layers of cells surrounding vascular tissues in DICOT roots
-from which branch roots and lateral roots arise
-generates vascular cambium b/w xylem and phloem

Question 16

MONOCOT roots

Answer 16

-ring of alternating bundles of xylem and phloem surround pith
-no vascular cambium

Question 17

Pith

Answer 17

ground tissue in center of root
-spongelike

Question 18

Mycorrhizae fungi

Answer 18

-assosiation is mutualistic w plants
-roots, facilitate nutrient acquisition
concentrates phosphorus
-facilitate N and micronutrients such as zonc and copper
-plant gives sugar and amino acids to mfs
-lots of woody species have these

Question 19

Ectomycorrhizae

Answer 19

mycorrhizae grow between cell walls
more common

Question 20

Endomucorrhizae

Answer 20

penetrate cell walls

Question 21

Rhizobium bacteria
what family are associated with these?

Answer 21

produces nitrogenases to convert nitrogen to nitrates and other substacnes
-legume familly associated w these
-plant provides “food and lodging”(root modules)-less oxygen

Question 22

what is produces in root modules?

Answer 22

leghemoglobin-binds to o2, allowing low enough o2 for nitrogenases to function , but high enough for bacteria life