how the epidermis of roots , stem and leaves are modified?explain with example.
 
 

Asked by sbidipak | 21st Jun, 2017, 06:33: PM

Expert Answer:

The epidermis is an outer protective covering tissue of plant roots, leaves, and stems of nonwoody plants. It contains closely packed epidermal cells.

Modifications of epidermis of roots, stem and leaves:

  • Walls of epidermal cells are covered with a waxy cuticle to minimise water loss and protect against bacteria.
  • In roots, certain epidermal cells are modified into root hairs that increase surface area of the root for absorption of water and minerals and help to anchor the plant firmly in place.
  • Protective hairs of a different nature are produced by epidermal cells of stems and leaves.
  • Epidermal cells may be modified as glands that secrete protective substances of various types.
  • In leaves, particularly the lower epidermis, specialized epidermal cells (guard cells) form microscopic pores (stomata) and regulate gas exchange between interior and exterior of a leaf.

The roots, stem and leaves of plants are modified for storage of food or protection to the plant.

Root modifications

Adventitious and prop roots

E.g. Maize

Pneumatophores

E.g. Mangroves

Velamen roots

E.g. Orchids

Fleshy roots

E.g. Carrot

Stem modifications

Tendrils

E.g. Grapes

Cladophylls

E.g. Asparagus

Thorns

E.g. Bougainvillea

Storage stems

E.g. Onion bulbs

Runners/Stolons

E.g. Strawberry

Leaf modifications

Spines

E.g. Cacti

Bracts

E.g. Bougainvillea

Carnivorous leaves

E.g. Venus flytrap

Tendrils

E.g. Peas

Plantlets

E.g. Kalanchoe

Answered by Sheetal Kolte | 22nd Jun, 2017, 10:59: AM