Types of roots and its modifications

1. Root
morphology

2. Root
The plant organ that is devoid of
a) Chlorophyll
b) Buds
c) Leaves
d) Nodes and Internodes
• It shows positive
Geotropism and
negative
Phototropism
• Root cap is present at the
tip
• Fine, delicate root hairs
are present for the water
absorption

3. Types of roots
(a)Tap root: The taproot is the differentiated primary root that is thick and grows
straight down deep into the soil. A few lateral roots grow off of this main root.
(b)Fibrous root: The fibrous root consists of several roots of similar size and length
that develop from the stem of the plant; the primary root does not remain.

4. Modification
of roots
Tuberous Root :When the tap
roots are thick and store reserve
food, they are called as
tuberous roots.
Occurs in biennial plants examples:
carrot, radish, turnip and beet,
oak ,dandelion

5. These plants live for two seasons
 In the first season they produce
leaves only and store up the
surplus food in the tap root
 In the nest season, they use
that stored food for flower
production , after they die.
• Conical tap root: it is swollen
form the top and tapering
from the ends e.g. English
radish and English carrot.
• Napiform tap root : this type of
root is very much swollen form
the tap and abruptly tapers
from the lower side. E.g.
turnip and beet

6. Nodulated roots :
In medicago the tap rootbears
small swellings of nodules
( these bacteria fix nitrogen
and forms nitrates)
These bacteria provide nitrates to
plants and
And In return gets protection
and shelter from roots
such as in beans and pea.

8. Adventitious
roots
Roots that grow from any part of
plant other than the radicle or its
branches are
called adventitious roots . They
branch like the tap root. A mass
of adventitious roots along with
their branches constitute
an adventitious root system

9. There are various forms
of adventitious roots
such as :
 Subterranean or
underground
adventitious roots
 Partly subterranean
adventitious roots
 Aerial roots
 Parasitic roots
 Aquatic roots

10. 1: Subterranean or
underground Adventitious
roots
They arose from the part of stem ,
which is in contact with soil . They
may be of fibrous or adventitious type
1: fibrous adventitious root:
They are long and slender commonly
creeping on underground stem. E.g.
grasses , ginger
2: tuberous adventitious root:
They are swollen and fleshy,
containing stored food. They
are present in Dahlia, sweet
potato and many orchids .
In dahlia and sweet potato some roots
remain fibrous, while others enlarge
greatly to form tubers

11. 2: Partly
subterranean
adventitious roots
They are present partly
above or partly below
the ground . They may
be classified into
• Stilt roots
• Prop roots
• Aerating roots

12. a) Stilt
roots
 When the roots arise from
the lower portion of the
stem and grow obliquely
down into the soil where
they develop in the normal
manner
 They are called stilt roots
 They fix the plant firmly in
soil and keep
it erect
 Examples : maize , sugar
cane, bamboo , palms

13. b) Prop
roots
These roots grow vertically
downward in the air from
which they absorb moisture
On reaching the soil they
absorb water and minerals
from it
After this they behave as
stouter and form props and
pillars which support the
branches
Banyan tree ( Ficus
bengalensis) Rubber
tree ( Ficus elastic )

14. c) Pneumatophore
roots/ aerating
roots
Such roots are found in plant
growing in mangroves or
swamps near the sea-shore.
Pneumatophores arise vertically
upwards and come out of soil
and water. They bear small
pores called pneumatophores or
lenticels for exchange of gases,
e.g.Heritiera.

15. 3 : Aerial
roots
They are exposed to air and
carry specific functions .
They are of two types
• Clinging or climbing roots
• Absorbing roots

16. a) Clinging or
climbing roots
They are developed from stem,
They are sensitive to touch and
support
They secrete a fluid and when they are
exposed to air, that dries up , helps
plant to support
Sometimes they form disc like
structure , to ensure the firm
attachment with the host
Ivy ( Hedera helix)
Long pepper ( Pipper longum)

17. b) Absorbing
roots
These are present in
epiphytes , in tropical rain
forest
They have long adventitious
roots which hang freely in air
and absorb moisture from air
These roots are covered by
dead , spongy tissue called
as velamen. That absorbs and
store water

18. 4: parasitic
roots
In parasitic flowering plants,
various roots arise from the
stem of the plant where it is
near to its host .
They are also called as
haustoria
They penetrate into the stem
and become connected with
its conducting tissue
They absorb the manufactured
food from the host and pass it
to the stem of parasitic plant
Cuscutta

19. 5: aquatic
roots
In many water plants , clusters
of fibrous adventitious roots
arise from the stem and dangle
(swing) in water .
They are usually without root
hairs

20. Importance of Roots
FOR PLANTS
•Plant Fixation : Plants are the organisms which do not move in their lifetime. They grow and die in the
same place where they born. This ability to stay at one place is due to their root system.
•Provide Water: The second major uses of roots to plant include water supply .Plants require a continuous
supply to water . This is necessary to move sap in the plant from root to the stem, branches and leaves at
the top. This water is taken up by roots through the capillary action.
•Provide Mineral and Manure: Besides water, roots also supply manures, minerals from the soil to the
plants. Minerals include macro and microelements . Manures include ammonia and nitrogen etc.
•Storage of Food: Some plants have storage roots in which the plants store their food materials. These
include carrot , radish, beet root, turnip, onion etc.
•Water Expulsion: Roots also help to expel the waste from plant body . Accumulation of this waste could
be toxic to the plant.
•Help in Plant Propagation: Roots of some plants help to produce a new plant from the root cutting.
Plants like raspberry , rose , blackberry, phlox ,lilac, trumpet vine etc can be grow by roots.

21. Uses of Roots to Man
•Sources of root medicines and drugs : Roots are some of the important sources of
lifesaving medicines. Plants medicines like Rauwolfia , ipecac, ginseng , ashwagandha etc
are obtained from the roots.
•Sources of the fiber: Like leaves , the fiber from roots is used as brooms , basketsetc.
Examples of these plants include Zacaton.
•Sources life of other organisms: Many microbes and even other plant live on the roots.
They derive nutrition and other essentials from roots. Some of them microbes even help in
return . Example of such bacteria is Rhizobium Bacteria. This is a bacteria which is presentin
the leguminous plants. This bacteria help fix the nitrogen from air as ammonia in soil . Thus
they provide manure to the plant. In return they obtain food and shelter from the plant.
This is called a symbiotic relationship.

22. THANK YOU
MADE BY :
KHUSHAL DUSAD
XI-C