Q82
General ScienceBiology
Pneumatophores are modified root and negatively geotropic. These are —
- a.Respiratory roots
- b.Photosynthetic roots
- c.Food storing roots
- d.Water storing roots
Answer: (A) Respiratory roots
Pneumatophores are 'breathing roots' that grow vertically upward out of the mud (negative geotropism) in mangrove plants such as Avicennia, Sonneratia and Heritiera (sundari). Waterlogged saline mud has almost no oxygen, so these roots take in air through pores called lenticels or pneumathodes. Mangroves of the Sundarbans also show stilt roots (Rhizophora) and vivipary, where seeds germinate while still on the tree. The other options describe different modifications: photosynthetic (assimilatory) roots occur in Tinospora and Trapa; food-storing roots in carrot, radish and sweet potato; and the spongy velamen of epiphytic orchid roots absorbs moisture from the air.