2101 - Roots

Question 1

Organs definition

Answer 1

Different type of tissues working together for a unique function.

Root
Stem
Leaf

Question 2

Primary functions of Roots

Answer 2

Anchorage
Absorbs water from the soil
Absorbs minerals from the soil

Question 3

Tap Root system

Answer 3

In most Dicotyledon species, first root to emerge is the radicle. The Radicle develops into dominant and main root with secondary lateral roots branching.

Taraxacum official (Dandelion)

Question 4

Fibrous Root system

Answer 4

In some Dicotyledon species, radicle does not develop into tap root.
Many lateral roots grow and develops a fibrous root system.

Tagetes patula (French Marigold)

Question 5

Adventitious root

Answer 5

A root which develops from a structure other than an existing root (stem or leaf).

Question 6

Root Hairs

Answer 6

Tiny elongated outgrowths from the epidermis. Behind the zone of elongation. Increase the water-absorbing area of the roots.

Question 7

Root Cap

Answer 7

Sacrificial cap of mesophyll cells that protect the apical meristem, as the root pushes though the soil.

Question 8

Apical Meristem

Answer 8

Area of rapid cell division. Primary growth point of the root.

Question 9

Zone of Elongation

Answer 9

(above meristem) Meristematic cells increase in size to push the root tip through the soil.

Question 10

Zone of differentiation

Answer 10

Root cells have matured and become specialised - such as epidermal or vascular.
No cuticle on the root epidermis for wager absorption.
Lots of root hairs.

Question 11

Dicot Cross section

Answer 11

Vascular bundles arranged in star formation. Has Vascular cambium.

Question 12

Monocot Cross section

Answer 12

Vascular bundles arranged in rings. Does not have Vascular cambium (no secondary thickening).

Question 13

Epidermis

Answer 13

Single layer closely packs cells, protective cover.

Question 14

Cortex

Answer 14

gives structure to the root. Mainly loosely packed parenchyma cells.

Question 15

Stele (Vascular Cylinder)

Answer 15

Contains Phloem, Xylem, Vascular Cambium (in dicots) and Pericycle.
The inner portion (like a carrot). Does not include endodermis.

Question 16

Vascular Cambium

Answer 16

Only in Dicotyledons, responsible for secondary thickening.

Question 17

Pericycle

Answer 17

Outer layer of Vascular Cylinder. Lateral roots emerge from meristematic tissue in the Pericycle.

Question 18

Phloem

Answer 18

Transport of Sugars

Question 19

Xylem

Answer 19

Transport Water and Minerals

Question 20

Endodermis

Answer 20

Single layer of cells found only in roots, encircling the vascular tissue.
Regulates water and mineral movement between the Cortex and the Xylem.

Question 21

Casparian Strip

Answer 21

Waterproof band of material inside the Endodermal cells. This protects the root from entering soil solution.

Question 22

Dicot vs Monocot rooting system

Answer 22

Dicots
Produce a radical which becomes a tap root.
Lateral roots from from the pericycle.

Monocots
Produce a radical, but it quickly dies off.
Have fibrous roots derived from the stem.

Question 23

Root Adaption - Food Storage

Answer 23

Store food in enlarged roots or tubers.
Example of perennation.
Dauscus carota (carrot)
Dahlia ‘Bishop of Leicester’

Question 24

Root Adaption - Additional Support

Answer 24

Plants produce prop roots to help support their stems and branches.

Zea mays (Sweetcorn)

Question 25

Root Adaption - Water Storage

Answer 25

Aerial roots of epiphytic plants store water.

Orchid

Question 26

Root Adaption - Reproduction

Answer 26

Suckers - adventitious buds that grow into shoots.

Rubus idaeus (Raspberry)
Rumex acetosella (sheep sorrel)

Question 27

Root Adaption - Climbing

Answer 27

Adventious roots from stems, cling to surfaces for height (light/polination)

Hedera helix (ivy)