Modification of Root, Stem and Leaf: Examples & Functions

Botany Sir Himansu

Modification of Root, Stem and Leaf

A. Modification of Root

1. For Storage of Food

  1. Fusiform — Radish
  2. Napiform — Beetroot, Turnip
  3. Conical — Carrot
  4. Tuberous — Mirabilis

2. Modification of Root for Respiration

  • Pneumatophores — found in mangrove plants.
  • Examples: Rhizophora, Avicennia, Sonneratia.

3. For Reproductive / Vegetative Propagation

  • Root suckers — Populus, Dalbergia
  • Root tubers — Sweet potato
  • Root buds — Dahlia and others

B. Modification of Stem

1. Underground Modification of Stem

Rhizome

  • Ginger
  • Turmeric

Root Stock

  • Ferns

Suckers

  • Pineapple
  • Chrysanthemum
  • Banana

Bulb

a. Scaly bulb

  • Lily

b. Tunicated bulb

  • Simple: Onion
  • Compound: Garlic

Corm

  • Colocasia
  • Amorphophallus
  • Zaminkand

Tuber

  • Potato

Other examples:

  • Asparagus
  • Ipomoea

2. Sub-aerial Modification of Stem

1. Runner

  • Cynodon
  • Oxalis

2. Sucker

  • Chrysanthemum
  • Banana
  • Pineapple

3. Offset

  • Pistia
  • Eichhornia

3. Aerial Modification of Stem

1. Stem Tendril

  • Vitis
  • Passiflora
  • Gourd
  • Cucumber
  • Watermelon

2. Stem Thorn

  • Citrus
  • Bougainvillea
  • Aegle

3. Phylloclade

  • Opuntia
  • Cactus
  • Euphorbia

4. Cladode

  • Ruscus
  • Asparagus

5. Bulbil

  • Agave
  • Dioscorea

Modification of Leaf

1. Leaf Tendril

Tendril is a thread-like, coiled structure which acts as a climbing organ.

If the complete leaf or any part of leaf — leaf, petiole, stipule, apex, margin or surface — is modified into a tendril, it is called a leaf tendril.

Examples

  1. Lathyrus aphaca — Wild pea
    • Complete leaf modified into tendril.
  2. Pisum sativum — Garden pea
    • Upper leaflets modified into tendril.
  3. Clematis & Nepenthes
    • Petiole modified into tendril.
  4. Gloriosa
    • Leaf apex modified into tendril.

2. Leaf Spine

Spine is a sharp, pointed but soft structure formed by modification of the complete leaf or any part of the leaf.

Function

To check transpiration; hence found in xerophytes and protection of plant.

Examples

  1. Opuntia & Cactus
    • Complete leaf modified into spine.
    • The stem is phylloclade.
  2. Phoenix
    • Leaf apex modified into spine.
  3. Argemone
    • Apex, margin and surface modified into spine.
  4. Acacia & Ziziphus
    • Stipule modified into spine.

3. Phyllode

Either petiole or rachis of leaf becomes modified into a flattened, green, leaf-like structure called a phyllode.

Function

Synthesis of organic food by photosynthesis.

Examples

  1. Australian Acacia
    (Acacia auriculiformis)
    • Petiole modified into phyllode.
  2. Parkinsonia
    • Rachis of compound leaf modified into phyllode.

4. Pitcher

Lamina of leaf becomes modified into pitcher.

Insectivorous pitcher plants

  1. Nepenthes
  2. Sarracenia — pitcher

Function: To fulfil the requirement of nitrogen.

Epiphytic pitcher plant

Dischidia — storage of water.

5. Bladder

Utricularia — Bladderwort

The lamina becomes dissected and appears root-like. A part of the lamina becomes modified into a bladder to trap insects.

The bladder contains sensitive hairs and a valve.