Exercise 8: The Root

Question 1

Give the 2 basic functions of root systems.

Answer 1

• absorption of water and minerals
• anchorage

Question 2

Give the 2 classifications of root systems.

Answer 2

• taproot system
• fibrous system

Question 3

Which among the types of roots directly arise from the stem?

Answer 3

adventitious roots

Question 4

TRUE or FALSE:
The fibrous root system is characterized by the loss of tap root in early development, leaving only the adventitious roots.

Answer 4

True

Question 5

Differentiate the root systems of eudicots and monocots.

Answer 5

• eudicots - possess taproot system
• monocots - possess fibrous system

Question 6

Give the 8 types of modified roots and their respective specimens.

Answer 6

• buttress roots - kapok
• climbing roots - philodendron
• pneumatophores - mangroves
• prop roots - corn
• root nodules - makahiya, tamarind
• stilt roots - pandan
• strangling roots - strangler figs
• storage roots - carrot, radish, turnip, sweet potato, or cassava

Question 7

Give the 3 compositions of the primary root tissue.

Answer 7

• epidermis
• ground tissue
• stele

Question 8

It refers to the collection of vascular tissues in an organ.

Answer 8

stele

Question 9

It refers to the outermost layer of parenchyma in the primary root tissue.

Answer 9

epidermis

Question 10

It refers to the layer below the epidermis which comprises of the ground tissue.

Answer 10

cortex

Question 11

It refers to the specialized sub-epidermal layer in the roots of zea mays.

Answer 11

exodermis

Question 12

TRUE or FALSE:
The exodermis arises from the same primary meristem as the cortex.

Answer 12

True

Question 13

It refers to the layer of small, compact cells below the cortex.

Answer 13

endodermis

Question 14

TRUE or FALSE:
The endodermis possesses thicker cell walls in its inner surface.

Answer 14

True

Question 15

It refers to the outermost tissue of the stele below the endodermis.

Answer 15

pericycle

Question 16

In which layer of the primary root tissue do lateral roots arise?

Answer 16

pericycle

Question 17

Describe the arrangement of the primary xylem and phloem in the pericycle.

Answer 17

The primary xylem and phloem are arranged in a radially alternating manner.

Question 18

It refers to the core of the primary root composed of ground tissue.

Answer 18

pith

Question 19

Which type of xylem consists of tracheids and produces secondary cell walls earlier during root development?

Answer 19

protoxylem

Question 20

Which type of xylem consists of either tracheids or vessels and grows larger before depositing the secondary cell wall?

Answer 20

metaxylem

Question 21

Differentiate the 2 patterns of xylem development.

Answer 21

• exarch - the protoxylem is found outer to the metaxylem
• endarch - the protoxylem is found inner to the metaxylem

Question 22

It refers to roots with two, three, four, or many protoxylem poles.

Answer 22

• diarch - 2 protoxylem poles
• triarch - 3 protoxylem poles
• tetrach - 4 protoxylem poles
• polyarch - innumerable protoxylem poles

Question 23

Differentiate the structure of the young Vicia sp. root x.s. to the structure of the Zea mays x.s.

Answer 23

• no exodermis
• less protoxylem poles
• possible absence of pith

Question 24

Give the 2 types of lateral meristems that function in secondary growth.

Answer 24

• vascular cambium
• cork cambium

Question 25

Which lateral meristem arises from undifferentiated remnants of procambium and the pericycle?

Answer 25

vascular cambium

Question 26

Which lateral meristem arises from the epidermis, cortex, endodermis, or pericycle?

Answer 26

cork cambium

Question 27

It refers to the layer that separates the inner secondary xylem and outer secondary phloem of the vascular tissue of the old Vernonia sp. root x.s.

Answer 27

vascular cambium

Question 28

It refers to the collective term which describes the tissue layers outside the cortex.

Answer 28

periderm

Question 29

Give the 3 layers of the periderm from the outermost to the innermost sub-layer.

Answer 29

* phellem (cork) * phellogen (cork cambium) * phelloderm (cork parenchyma)

Question 30

TRUE or FALSE: The cells of the periderm are flattened and radially aligned.

Answer 30

True