Morphology in Flowering Plants 1 Flashcards
explain the parts of seed
there are 2 cotlyedons or food laden tissue. The part above cotyledons is called epicotyl and part below is called hypocotyl. The plumule gives rise to shoot and radicle gives rise to primary root.
Tigellum or embyronal axis passses through the mid of seed dividing into 2 equal halves
what are modifications of root for storage
(a) Fusiform roots/Spindle roots - These roots
are thicker in the middle and tapering on
both ends.
e.g. Radish
(b) Conical roots - These roots are thicker at
their upper side and tapering at lower side.
e.g. Carrot
(c) Napiform roots - These roots become swollen and spherical at upper end and
tapering (like a thread) at their lower end.
e.g. Turnip, sugarbeet (beet root)
(d) Tuberous roots- These roots dont have specific shape and just become swollen and fleshy
-eg: mirabilis
modification of root for n2 fixation
Nodulated roots - Nodules are formed
on branches of roots by nitrogen fixing bacteria (Rhizobium).
e.g. Pea, gram, bean (Fabaceae family)
what are pneumatophores
In marshy / swampy areas,
there is scarcity of oxygen
so, Some branches of tap
root of the plants which
grow in this region, grow
vertically upward and
comes on the surface.
These roots are called
pneumatophores which have minute pores called pneumathodes or lenticels by
which air enters in the plant and plant gets oxygen for respiration.
Pneumatophores are negatively geotropic.
e.g. Rhizophora (Mangrove plant)
what are the modification of adventitious roots for storage
Stilt roots or brace roots - These roots arise from lower node and enter in the
soil. These roots are supporting roots. e.g. Maize, sugarcane
(b) Prop roots or pillar roots - These hanging roots arise from branches of plant
and grow downward towards the soil. These roots support the tree branches.
e.g. Banyan (Ficus benghalensis)
(c) Climbing roots - These roots arise from nodes and help in climbing.
e.g. Money plant (Pothos), Monstera
what are modifiication foa adventititious root for special functions
(a) Foliar roots or Epiphyllous roots :– When roots arise from leaf then they are
called foliar roots. They are used for vegetative reproduction
e.g. Bryophyllum
(b) Sucking roots or Haustorial roots or Parasitic roots :– In parasitic plants, roots
enter in the host plant to absorb nutrition from the host.
e.g. Cuscuta
what are types of stem
(a) Sub aerial- half abv the ground half below
- Runner
-Offset
-Sucker
-Stolon
(b) Undergroud- stem present below ground
-rhizome
-bulb
-corm
-tuber
(c) Aerial- stem present abv the ground
-stem tendril
-phylloclade
-thorn
-bulbil
-cladode
describe sub aerial tems
(i) Runner - In these stems roots develop at lower side and leaves at upper side from
the nodes and these stems spread on the ground e.g. Cynodon dactylon
(doob grass), Oxalis, Strawberry (Fragaria ananassa).
(ii) Stolon - In it branches develop from the lower part of the main stem and grow for
some distance like arch and finally touch the ground to give rise to new shoot.
e.g. Fragaria vesca (Wild strawberry), jasmine, peppermint
(iii) Sucker - The lateral branches originate from the basal and underground portion of
the main stem, grow horizontally beneath the soil and then come out obliquely
upward giving rise to leafy shoots. e.g. Mint, pineapple, Chrysanthemum, banana.
(iv) Offset - Generally these occur in aquatic plants which have fragile stem. Internode
of offset is small & thicker and each node bears a rosette of leaves and a tuft of
roots. It is also known as aquatic runner. e.g. Pistia, Eichhornia
what is organ of perennation
Underground stems of potato, ginger, turmeric, Colocasia, zaminkand
are modified to store food in them. They also act as organ of perennation to tide over
conditions unfavourable for growth.
what are underground modification
Generally for food storage and vegetative
propagation.
(i)
Tuber - The tips of branches become swollen in
the soil. Eyes are found on tuber which are
axillary buds and axillary buds are covered
with scaly leaves. e.g. Potato.
(ii) Rhizome - It is fleshy stem which grows horizontally in the soil. Nodes and small
internodes are found which are covered by scaly leaves.
e.g. Ginger, turmeric, banana.(propogate thru rhizome)
(iii) Corm - It is condensed structure which grows vertically under the soil surface.
e.g. Colocasia, zaminkand (Amorphophallus),
(iv) bulb- Stem is highly reduced and disc like and
surrounded by numerous fleshy leaves. Many roots
arise from its base. e.g. Onion, garlic. The fleshy
leaves of onion and garlic store food.
what are aerial modificatiosn
(i) Stem tendril : In this type of modification axillary bud forms tendril in place of
branches and helps in climbing of those plants which have weak stem.
e.g. Grapes/Grapevines, gourds (cucumber, pumpkins, watermelon)
(ii) Stem thorn : Thorn develops usually from axillary bud of the stem. It may bear
leaves and flowers.
Thorn protects plant from browsing animals. It is a woody pointed structure.
e.g.Citrus
Phylloclade : Stem is modified into a fleshy flat (Opuntia) or fleshy cylindrical
(Euphorbia) and green leaf like structure and carries out photosynthesis like leaf.
The leaves are modified into spines.
(iv) Cladode : In this modification branches of limited growth become green and flat like
a leaf and perform photosynthesis. e.g. Asparagus
(v) Bulbil- modified vegetative stem with stored food/ used for vegetative reproduction
-eg: agave
3 parts of leaf
Hypopodium- leaf base
Petiole= mesopodium
leaf lamina= epipdoium
leaf also c/a phyllopodium
what are two types ofleaves based of presence stipule
Leaves of some plants have two lateral appendages on either side of leaf base, known as
stipules.
Leaf with stipule is known as stipulate leaf, e.g. Fabaceae Leaf without stipule is called
ex-stipulate leaf e.g. Solanaceae, Liliaceae.
modification of leave s
(A) Leaf Tendril :
In some plants whole leaf is modified into a wire like structure which is called leaf tendril.
Tendril helps is climbing. e.g. Lathyrus aphaca (wild pea) Peas.
2.
(B) Leaf Spine :
Leaves are modified into pointed spines. e.g. Opuntia, Cacti.
(C) Leaf Pitcher : Leaves of some plants are modified into pitcher shaped structure.
e.g. Nepenthes (pitcher plant) (Only lamina is modified into pitcher). Water is stored in
the pitcher of Dischidia (complete leaf is modified into pitcher). In Nepenthes
insectivorous pitcher while in Dischidia - non insectivorous pitcher is formed.
Leaf bladder : In some plants, leaves are modified into bladder like structure
e.g. Utricularia (bladder wort)
(E) Phyllode : In some plants petiole becomes flat leaf like green, synthesise food and
function as normal leaf. e.g. : Australian acacia
(F) Leaflet Tendril : In Pisum sativum (garden pea) and Lathyrus odoratus (sweet pea)
leaflets are modified into tendril for climbing.
(G) Fleshy Leaves : In Onion and garlic leaves become fleshy for storage of food
difference between pedicle and peduncle
flower stalk- pedicel
penduncle- stalk or branch bearing pedicels
