Question

Respiratory roots are known as
(a)velamen
(b)pneumatophores
(c)hydathodes
(d)prop roots

Answer 1

Hint: Roots are mainly involved in the absorption of water and minerals from the soils. Roots in some plants undergo modifications in their shapes and structures to perform functions like respiration, storage, and protection.

Complete step-by-step answer:
Pneumatophores are found in plants growing in swampy areas whereas floating roots are found in aquatic plants. Both are the respiratory modification of roots. Various modification of roots is:
Storage roots: Primary tap root modifies to store food and assumes various shapes. For example, sweet potato, carrot, turnip, etc.
Respiratory roots: In swampy areas, the modification of roots that come out of the ground vertically upwards to get oxygen for respiration are called pneumatophores. For example, Rhizophora.
Prop roots: These roots arise from the branches of stems for providing extra mechanical support to heavy branches as pillars. For example, the Banyan tree.
Stilt roots: They arise from lower nodes of stems to support the main axis and enter the soil obliquely. For example, Sugarcane.
Floating roots: In aquatic plants, white spongy roots arise from the branches and help them in floating and respiration. For example, Jussiaea.
Assimilatory roots: The aerial roots of Tinospora and submerged roots of Trapa become green and synthesis food.
Hygroscopic roots: These are found especially in orchids, and help in the absorption of moisture from the atmosphere using special tissues called velamen.
So, the correct answer is ‘pneumatophores.’

Note: Hydathodes are present on the margin of leaves that includes the special type of pores which secretes water. For example, Water hyacinth, Water Lettuce. However, stomata are present on the epidermis of the leaves, young stem, and floral parts.