Roots obtain oxygen from air in the soil for respiration. In the absence or deficiency of O2, root growth is restricted or completely stopped. How do the plants growing in marshlands or swamps obtain their O2 required for root respiration?
The plants which are growing in marshlands or swamps have vertical growths from their roots. These roots are hollow from within, and thus they make way for air to enter through these roots. These are known as pneumatophores. In consequence, pneumatophores assist the plants in swamps and marshland areas to acquire oxygen for root respiration.