leaf

stemand
4. Study of modifications of root, Date :

undergone certain modifications to

Modifications of roots: have
plants
All the different types of roots in some
perform modified or unusual functions.
Modified Tap Root for Storage
1. Fusiform root -
like radish (Raphanus sativus). are spindleshaped.
They are present in plants ends. They
have aswollen median part and tapering
They

AERIAL
STEM

S,PINDLE SHAPE
swOLLEN
MED| AN

TAPER)N&
END

root -Radish
Fig.Fusiform
storage
Fleshy Adventitiousroots for food shaped structures. They found in
2. Modified spindle
are swollen into
Fasciculated roots - The roots and Asparagus.
seen in Dahlia
cluster. Such roots are

AERIAL STEM
BUDS
STEM

ROOTS
TAPERING
ENDS
Fig. Fasciculated roots- Asparagus.
84
Activity:
Collect the
surrounding area, information of different fusiform root and fleshy adventitious root's your
...
..

Observe and label the all diagram given bellow

properly.
Epiphytic roots (Clinging and aerial roots) :

LEAVES. -CINGING ROOTS

SUBSTRATUM
AERIAL
EPPHc
RoOTS
Fig. Epiphytic roots-Vanda
Plants that grow on other plants (trees) are called epiphytes.
Agroup ofplants çalled orchids and aroids have many epiphytes.
These"derial'roðts produced from nodes have a special tissue called velamen. The velamen is
adapted to absorb atomosphericwater vapour which is used by the epiphyte. e.g Vanda.
Haustorial or sucking roots :
Plants which are holoparasites or total parasistes produce such haustorial roots from the stem.
The stem of the parasite coils around the stem of the host plant and the haustorial roots penetrates
the xylem and phloem tissue of the host plant to obtain water and food respectively.
Such roots are produced by parastitic plants like Cuscuta.

HOST 'HAUSTOR)UM
STEM PARAS ITE

Fig. Haustorial root Cuscuta.

85
Silt rog0s -These are seen in screw pine (Pandaus) and maize( a iin a obliquc dircction and
angle
They develop fromthe lower nodes ofthe stem and grow down at
supports the main stem. VODE
JNTERoDE
NODE
STILT
RoOTS

-Maize
Fig. Stilt root
mangroves.
Respiratory roots : of plants called
a group
Penumatophores-These roots are common in soil is covered with water. pneumatophores or
where the lateral roots
plants grow in the sea coasts he underground
I hese
resuit there is less soil acration. From surface
As a
breathin roots develop. mínute apertures present on the
and through
aebove the water level
Thesc roots come root system.
atomospheric air enters the entire
Rhizophora and Avicennia.
inplants like LENTICEs
Such roots are found
PNEUMHTO
PHØRES

ADVENTOUS
RoonS
Fig. Penumatophores - Rhizophora
of Stem
Study of Different Modifications
Lnderground stems:
sterns that are subterrancan or underground. These stems help in the survival
Many Plants have
conditions (= perennation), in vegetative
of the plants during unfavourable cnviromental storage. In fact, food storage
propogation (reproduction) and such stems also help in food
is a requirement for perennation.
At the nodes
Rhizome :Itisa horizontally growing underground stem with nodes and internodes.
non-functional (Photosynthetically non-functional) leaves are present. The leaves are scaly.
Adventitious roots are produced from nodes. The axillary buds present in the leafaxils produce
new rhizomes which help in vegetative multiplication of the rhizomes. During favourable
environmental conditions the terminal bud produces aerial shoot system and flowers.
86
Arhizome that grows vertically in the soil is called aroot stock. are seen in
plants Iike
ginger (Zingiber oficinale), Canna, Rhizomes
Tumeric (Curcuma longa)
LEr F

AERIAL
SHO0T
SCALE LEAF BUD
JNTERYV0DE
ADVENTToOs
RoOTS Fig. rhizome- ginger
Sub-aerial stems: These stems are found at the air soil interface and they bring about vegetative
reproduction (-propogation) very rapidly.
Runner : They are slender stems developing from the axillary buds of parent plant. They grow
out in all directions. They develop adyentitious roots at the nodes and also new plants at the
nodes. The runner creeps horizontally on the soil surcface. It is sen in Oxalis, Centella. and
cynadon.

LEAF
NaDE
RUNNER
ADVENTTOUs
ROOTS
Fig. Runner - cynadon
Aerial stems : The aerial stems are variously modified to perform special fuctions like
photosynthesis, protection, vegetative reproduction ad mechanical suppor.
Phylloclades : These modified stenms are found in a group of plants called xerophytes (plants that
grow in regions with a shortage of water). In most of these plants the leaves are reduced
to scales to prevent water loss by foliar transpiration. In the absence of leaves of the stems
becomes flat and green to harness maximum light for photosynthesis such a flat, green stem
with many internodes is called a phylloclade. In prickly pear (opuntia) the phylloclade are
fleshy.
FLOWER PHYLLOCLADE
7SPNES
NODE
Fig. Phylloclade-opuntiu
87
 the caldode is a flat
Cladodes - They are found in xerophytic plants like Ruscus and Asparasgus
which as many
internodes a
green stem similar to a phyllocade. But unlike the phyllocalde
cladode had just one or two internode.

-SC9LE
CLADOD ESS EAF

vDE VTEKVODE

Fig. Cladode-Asparagus.
objects vertically. Tendrils are
climb over or
- are structures that help a plant to may be produced from vegetative buds
Tendrils They
weak stems. Tendrils
produced by plants with
from floral buds e.g. Cucurbita.
FLOWER

TENDRILS FROM
LEA
BuDS
Fig. Tendril- Cucubita.
modifications of leaf and Phyllotaxy Also explain
Identify and study the different
Infiorescence Seen in plants
Modifications of Leaves reducing the rate of
modifications that help a plant to conserve water (by
Phyllodes : These are
water loss by transpiration) Bipinnately compound leaf becomne
many Rachillae of the
In species of Acacia, the Rachis and photosynthesis.
highly flattened and green phyllodes for cylindrical
rachis or rachillae (which generraly are
Phyllodes are different parts of leaf like petiole,mentioned above turn flat and green. They perform
and non-green) but which in the plants
water)
the fuction of the leaflets which fall off (to conserve
PHYLLODE
COMPOVND BIPINNATELY
COMPOU N LEn
LEAFLETS THHT
TURN INTO
PHyLLODES

ROOTS
Fig, Phyllodes
88
 into tendrils.
Leaftendrils: leaf as a whole or part of it or its associatcd parts are modified
wCak stemmed plants these tendrils help in climbing.
In Lathyrus aphaca (Wild pea), the whole leaf is changed to tendril.
b) In Pisum sativum (garden pca), some anterior leaflets are modified to tendrils.
LEAFLETa
TeNDRJLS LEAFLET
LEAF TENTRJL
ErDRIS

Pisum sativum Upper leaflets Naravelia. Terminal leaflet

Lathyrus aphaca leaf modified into tendrils.
modified into tendril modified into tendrils.

Fig. Leaf Tendrils

Multiple choice questions
1. Phyllodes are modification of
a. Stems b. Roots
eLeaves d. Bud's
2. Scale leaves are present on underground
aStem b. Root
c. Fasciculated root d. Bulbas root
3. is an example of subaerial modification of stem.
Straw berry b. Colocasia
c. Onion d. Potato

4. In orchid's clinging root's help's in

va. Support b. Absorption of moisture
c. Negetative propagation d. Sexual reproduction
5. Stilt root is the midification for the purpose of
va. Jowar b. Orchid
c. Mangroves d, Cuscuta

6. Fusiform root is the modification for the purpose of

var Storage of food b.Vegetative reproduction
c. Respiration d. Support
7. Pheumatophores is mangroves develop's lenticles for
a. Photosynthesis 6. Respiration
c. Additional support d. Reproduction
8. In Cucurbita tendrils develops from modified
Va. Stem b. Root
c. Leaf d. Stipule
Remark and Signature of Teacher

89
 Inflorescence
5. Study and identification of
Date :

Aim :Study and identification of Inflorescence. the

resproductive axis
clustered together on
Infilorescence : Agroup of flowers are variously
(peduncle) is called inflorescence
There are two main types of infiorescence :
Observe the figure and lable given bellow.
11 Cymose Inflorescence
definate inflorescence.
1. It is determinate or ternminates in a flower.
inflorescene tip ofmain axis
L. Inthis towards
arrangement of fiowers is basipetal. centrifugal that is older
3. The cyme head is Calotropis
4. The arragement of flowers in periphery e.g.
towards the
5. the centre and the younger

MATURE/OLDEST.
FoWER
YoUNGER,
AoWER
BUD
PEDUNCLE
inflorescence- Calotropis
Fig. Cymose
seldom
2]
Racemose in florescence
inflorescence. In this infiorescence growing point
indeterminate
1. It is indefinate or
ends in a flower .
flowers is acropetal.
2. The Arrangement of centripetal that is the younger flower
are
of flowers in a group is
3. The Arrangement outside. eg. Caesalpinia. :
towards the centre and older towards

YoUNG
PLQWER
BUD
MATUREOLDER.
FLOWER
PEDUNCLE
Fig. Racenmose inflorescence- Caesalpinia
90
 Questions
Q.1Whatis
ananeh.Over...whicteuseas
ioccecQpnneti...ideinita..a
..O...
CAL..alaa..,.nat..matme..at.khe.sSaae.time
of inforescence.
o.2What are, thesignifcance,
"hantea.panata.Aalase..anctaAg.
ocence nake
ntoeocence the plant
fruits /n
Enlist edible e
solanaceae.
0.3w
3Fato.Pe.,.BgJatanacecae.o
.eahiat...
protein rich family?,
Q.4 Which family is known as
kodoaccecAl.A..

Mutipal choice Questions Qs. which

Sace) e
characteristic of res8Óse inflorescence. a
1. One of the following What io ito
a. Centrifugal opening of flowers. to
b. Basipetal succession of flowers. has a bhanchecl
e. Acropetal succession of flowers.
d. Simalteineaes opening of flower.
2 Inflorescence axis is bato.t
-whtecin
a. Petiole b. Pedicel
d.Thàlamus
flowerst.
Tnect
Fleanat
Peduncle
inflorescence of different: plants and
Activity : Collect the information about
chart. Teexuayd
Cymose Inflorescence
Racemose Inflorescence by
Name of plants -
Name of plants -asmine ue ewa Caesalpiria,
Üerocendhon XLce
Hibiscus
Calobopis

Remark and Signature of Teacher

91