Practical 2 Flashcards
The major functions of plant root systems are to:
- Anchor and support
- Absorb water and nutrients
- Store food and nutrients
- Sustain vegetative reproduction through budding and suckering
Types of roots.
Aerial root Haustorial root Buttress root Pneumatophore Modified tap root Taproot Ffibrous root Adventitious roots
Aerial root features and functions.
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.
Haustorial root features and functions.
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.
Buttress root features and functions.
Huge roots towards base of trunk that provides stability.
Typical in tropical trees to resist uprooting. Add support to the stem.
Pneumatophore features and functions.
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”.
Modified tap root features and functions.
A tap root modified into a storage organ stores water and carbohydrates.
Usually helps plants at some development stage; flame production.
What is the function of the root cap?
To protect the apical meristem and to produce mucigen which provides a good environment for nitrogen fixing bacteria.
Primary roots of a Monocotyledon contain…
Cortex Epidermis Xylem Pericycle Phloem Pith
Primary roots of a Eudicotyledon contain…
Epidermis
Xylem
Pericycle
Phloem
Major functions of plant stems.
- Provide a structure from which other organs can grow
- Transport water, nutrients, carbohydrates,and hormones through the plant
- Store food, water and nutrients
Taproot
Single large root and smaller lateral roots.
Fibrous root
Many small roots of similar diameter.
Adventitious roots
Roots that arise from the stem of the plant.
Stem vs Root
Stem = upward growth. Root = downward growth.
The tip of a growing root contains four distinct regions:
1) the root cap;
2) the zone of cell division;
3) the zone of cell elongation; and
4) the zone of cell maturation.
Definie:
Node
Intersection between to branches.
Types of stems:
Culm Excurrent Decurrent Rhizome Thorn Tendril
Major functions of plant leaves,
- Produce food through photosynthesis
- Provide gas exchange for photosynthesis and respiration
- Sustain water transport
______ undertake _____ itself, but the key to _______ it lies in ________ in the epidermis of the leaf called _______.
Chloroplasts
photosynthesis
sustaining
tiny openings
epidermis
stoma
What are guard cells?
Guard cells are cells surrounding each stoma. They help to regulate the rate of transpiration by opening and closing the stomata
Dorsiventral leaf features (eg. Mango).
- Different structures on their uppers and lower surface.
- Cuticles are thinnier on the lower surface
- There’s more stomata on lower surface
- Mesophyll are differentiated into palisade and spongy parenchyma
Isobilateral leaves (eg. Corn).
- Typically grow vertically (recieve equal amounts of sunlight)
- Have equal number of stomata on both sides
- Cuticles the same on both sides
Types of leaves.
Dorsiventral and Isobilateral
Why do some leaves contain aromatic substances?
For protection against insects and other herbivores.
