Roots have several primary functions including anchoring the plant, absorbing water and minerals, transporting nutrients, storing food, and reproducing. Most dicots have a taproot system with one main root and smaller branch roots, optimized for support and storage. Monocots have a fibrous root system of many similarly sized roots that maximizes absorption. Adventitious roots develop in unusual locations to aid reproduction or support. Specialized roots include storage, gas exchange, photosynthesis, and parasitic roots. Mycorrhizal and nodular roots form mutualistic relationships with fungi and bacteria respectively.

1. ROOTS
Professor Joan S. Awingan

2. Functions:
1. Anchorage – to locate water and
minerals, roots permeate the soil. In doing so,
they anchor the plant in one place for its entire
life.
2. Absorption – roots absorb large
amounts of water and dissolved minerals
(nitrates, phosphates, and sulfates) from the soil.

3. Functions:
3. Conduction - water and minerals upward into the stem
and food from leaves to storage regions of roots
4. Storage – roots store large amounts of energy reserves,
initially produced in the leaves of plants via photosynthesis, and
transported in the phloem, as sugar, to the roots for
storage, usually as sugar or starch, until they are needed.
5.Reproduction
6.Photosynthesis

4. What are the primary functions of
roots?

5. Embryonic root or radicle
The first root that comes from
a plant is called the radicle

6. Root System - the entire mass of
underground roots produced by a
plant

7. MAJOR KINDS OF ROOT SYSTEM
1. Taproot system – a strongly developed main root which grows
downwards bearing lateral roots much smaller than itself.
– In most dicots, the radicle enlarges to form a prominent taproot
that persists throughout the life of the plant.
– Many progressively smaller branch roots grow from the taproot.
– This system is called a taproot system; common in dicots and
conifers.
– In plants such as carrots and sugar beets, fleshy taproots store
large reserves of food, usu. as carbohydrates.
– Taproots are modified for reaching deep water in the ground:
e.g. the long taproots of poison ivy (Rhus toxicodendron),
dandelion (Taraxacum sp.) and mesquite (Prosopis sp.).

8. 2.Fibrous (diffuse) root system – has several to many roots of
the same size that develop from the end of the stem, with
smaller lateral roots branching off of them.
a. Most monocots (including grasses and onions) have a
fibrous root system.
b. In these plants, the radicle is short-lived and is replaced by
a mass of adventitious roots (from the Latin, adventicius,
meaning “not belonging to”), which are roots that form on
organs other than roots. Because these roots arise not from
preexisting roots, but from the stem, they are said to be
adventitious.
c. The adventitious roots of monocots are very extensive and
cling tenaciously to soil particles. These plants are excellent for
preventing erosion.
d. The fibrous root of a few plants are edible – sweet
potatoes (Ipomoea batatas) are the fleshy part of a fibrous root
system.

10. Tap root and Fibrous (Diffuse) Root
Systems – Both arise from radicle

11. Adventitious roots – roots that develop in an unusual place.
There are several types of adventitious roots besides those
of monocots.
a. Adventitious roots are common along rhizomes
(underground stems) of ferns, club mosses (Lycopodium),
and horsetail (Equisetum).
b. In some plants, adventitious roots are a primary means
of vegetative reproduction: forests of quaking aspen
(Populus tremuloides) are often a single clone spread by
adventitious roots. Prop roots of mangrove (Rhizophora sp.)
are like stilt roots, an adventitious root that grows out from
the lower part of a stem into the soil to support the stem, or
grows down from a lower branch in to the soil to support
that branch (strangler figs).
c. You might see adventitious roots of ivy (Hedera helix)
growing along the stem as it climbs along a fence or into a
tree.
Ex: strawberry

12. TAKE HOME POINT :
MOST DICOTS HAVE A TAPROOT SYSTEM CONSISTING OF A
LARGE TAPROOT AND SMALLER BRANCH ROOTS. TAPROOT
SYSTEMS MAXIMIZE SUPPORT AND STORAGE.
MONOCOTS HAVE A FIBROUS ROOT SYSTEM CONSISTING OF
SIMILARLY SIZED ROOTS THAT MAXIMIZE ABSORPTION.
ADVENTITIOUS ROOTS ARE ROOTS THAT FORM ON ORGANS
OTHER THAN ROOTS.

13. Adventitious Roots: roots that arise
from anything other than the radicle

14. Adventitious Roots: roots that arise
from anything other than the radicle

15. SPECIALIZED ROOTS
1. Storage – thickened roots which contain large
amount of stored food (starch or carbohydrates)
or sometimes water to survive cold or dry seasons
Fusiform roots : These root are thicker in the middle and
tapered on both ends. In this type of roots both
hypocotyl and root help in storage of food.
ex: Radish.
Conical roots : These roots are thicker at their upper side
and tapering at basal end.
ex: Carrot.

16. Napiform : These roots become swollen and spherical at
upper end and tapered like a thread at their lower end.
ex: Turnip

17. 2. Reproduction/Propagation – formation of adventitious
roots, that is, roots that develop in an unusual place
ex: sweet potato, pandan

18. 3. Gas Exchange/Aeration – presence of pneumatophores
(erect root that rises up above the soil or water and
promotes gas exchange). Internally, they are filled with
a specialized parenchyma called aerenchyma. Externally,
they have numerous pores or lenticels over their surface.
Common in plants that grow in water-logged soils
ex: mangrove, cypress

19. Cypress Knees

20. 4. Photosynthesis – can perform photosynthesis, usually
with green aerial roots (with chloroplasts)
ex: epiphytic orchids

21. 5. Support –
a. Buttress roots – big roots that look like they arise from
the base of the tree trunk provide additional tensile
forces to resist uprooting of large tropical trees. Ex: fig

22. Buttress Roots

23. b. Prop / stilt roots – Large pillars like roots develop
from horizontally spread branches of tree. They grow
vertically downward into the soil and support the
spreading branches. The main function is mechanical
support or pillars
Ex: corn, pandan, banyan

24. c. Climbing / clinging roots – these roots arising from
nodes attach hemselves to some support and
climb over it;
ex: ivy

25. d. Brace roots - arise from the main stem. These
penetrate obliquely down in to the soil and give
support to the plant
ex: corn, sugarcane, pandan

26. 6. Parasitic roots
Haustorial roots are adventitious parasitic roots usually
common in flowering plants called haustoria . They
penetrate the tissues of the host and connect to the
vascular system, thus becoming part of the host pipelines.
Parasitic roots lack most of the tissues of ordinary roots.
Ex: dodder and mistletoe

27. Parasitic roots - Dodder

28. 7. Mutualistic roots
Mycorrhizal roots are known from 90 percent of plant
species and are a mutualistic association of a fungus
with plant root tissue.
Most plants require specific mycorrhizal fungi without
which they are unable to absorb sufficient quantities
of P, Zn, and Mn.
The fungus takes the place of root hairs and may
penetrate the cortex completely ( endomycorrhizae)
or remain on the surface of the root
(ectomycorrhizae).

30. • Mycorrhizae or "fungus roots"
where a symbiotic relationship
forms between a plant and a
fungus.
• In this partnership the fungus
provides protection against
some types of pathogens and
increase the surface area for
the absorption of essential
nutrients (e.g. phosphorous)
from the soil. The plant in
return provides food for the
fungus in the form of sugar
and amino acids

31. There are also associations between bacteria and roots
of certain plants.
Nodules – spherical structures at the roots of
leguminous plants (e.g. peas), where nitrogen-fixing
bacteria live. These bacteria convert the atmospheric
nitrogen into a form that can be used by plants