Question

Which one of the following is true about pneumatophores of mangroves?

• A. They are negatively aerotropic, positively geotropic and positively hydrotropic.
• B. They are positively aerotropic, geotropic and hydrotropic.
• C. They are negatively aerotropic, negatively geotropic and positively hydrotropic.
• D. They are positively aerotropic, negatively geotropic and negatively hydrotropic.

Answer 1

Answer: (D)

They are positively aerotropic, negatively geotropic and negatively hydrotropic.

Pneumatophores are small negatively geotropic vertical roots. It grows toward the higher saline environment, so it is positively hydrotropic. Pneumatophores have lenticels for gaseous exchange. They are connected with internal aerenchymatous tissues i.e., aerotropic and thus, shows negatively geotropism and hydrotropism. Pneumatophores are common in plants growing in mangroves and marshy areas. In mangroves, a number of halophyte plants possess pneumatophores. Thus, the correct answer is option D.