Practical 2

Question 1

The major functions of plant root systems are to:

Answer 1

• Anchor and support
• Absorb water and nutrients
• Store food and nutrients
• Sustain vegetative reproduction through budding and suckering

Question 2

Types of roots.

Answer 2

Aerial root
Haustorial root
Buttress root
Pneumatophore
Modified tap root
Taproot
Ffibrous root 
Adventitious roots

Question 3

Aerial root features and functions.

Answer 3

Roots extend into the air to allow the orchids to grow unconnected to the ground (attached to a tree branch).

Epidemis several cells thick to reduce water loss. May also be green and photosynthetic.

Question 4

Haustorial root features and functions.

Answer 4

Roots that penetrate the host plant that they are entwined around and connects to their xylem and becomes parasitic.

Are photosynthetic.

Open stuma more widely than the hose. Osmotic flow. However, if it ends up with too much nutrients and water will drop leaves.

Question 5

Buttress root features and functions.

Answer 5

Huge roots towards base of trunk that provides stability.

Typical in tropical trees to resist uprooting. Add support to the stem.

Question 6

Pneumatophore features and functions.

Answer 6

Erect roots that extend from the underground root system.

Usually found in species that live in water logged soil, allows exchange of gases.

Use roots to take up air; “breathing roots”.

Question 7

Modified tap root features and functions.

Answer 7

A tap root modified into a storage organ stores water and carbohydrates.

Usually helps plants at some development stage; flame production.

Question 8

What is the function of the root cap?

Answer 8

To protect the apical meristem and to produce mucigen which provides a good environment for nitrogen fixing bacteria.

Question 9

Primary roots of a Monocotyledon contain…

Answer 9

Cortex
Epidermis
Xylem
Pericycle
Phloem
Pith

Question 10

Primary roots of a Eudicotyledon contain…

Answer 10

Epidermis
Xylem
Pericycle
Phloem

Question 11

Major functions of plant stems.

Answer 11

• Provide a structure from which other organs can grow
• Transport water, nutrients, carbohydrates,and hormones through the plant
• Store food, water and nutrients

Question 12

Taproot

Answer 12

Single large root and smaller lateral roots.

Question 13

Fibrous root

Answer 13

Many small roots of similar diameter.

Question 14

Adventitious roots

Answer 14

Roots that arise from the stem of the plant.

Question 15

Stem vs Root

Answer 15

Stem = upward growth.
Root = downward growth.

Question 16

The tip of a growing root contains four distinct regions:

Answer 16

1) the root cap;
2) the zone of cell division;
3) the zone of cell elongation; and
4) the zone of cell maturation.

Question 17

Definie:

Node

Answer 17

Intersection between to branches.

Question 18

Types of stems:

Answer 18

Culm
Excurrent
Decurrent
Rhizome
Thorn
Tendril

Question 19

Major functions of plant leaves,

Answer 19

• Produce food through photosynthesis
• Provide gas exchange for photosynthesis and respiration
• Sustain water transport

Question 20

______ undertake _____ itself, but the key to _______ it lies in ________ in the epidermis of the leaf called _______.

Answer 20

Chloroplasts

photosynthesis

sustaining

tiny openings

epidermis

stoma

Question 21

What are guard cells?

Answer 21

Guard cells are cells surrounding each stoma. They help to regulate the rate of transpiration by opening and closing the stomata

Question 22

Dorsiventral leaf features (eg. Mango).

Answer 22

1. Different structures on their uppers and lower surface.
2. Cuticles are thinnier on the lower surface
3. There’s more stomata on lower surface
4. Mesophyll are differentiated into palisade and spongy parenchyma

Question 23

Isobilateral leaves (eg. Corn).

Answer 23

1. Typically grow vertically (recieve equal amounts of sunlight)
2. Have equal number of stomata on both sides
3. Cuticles the same on both sides

Question 24

Types of leaves.

Answer 24

Dorsiventral and Isobilateral

Question 25

Why do some leaves contain aromatic substances?

Answer 25

For protection against insects and other herbivores.