, roots in some plants are modified to perform functions other than absorption and conduction, such as respiration . In plants like Rhizophora growing in swampy areas, many roots come out of the ground and grow vertically upwards (negatively geotropic). These roots, called pneumatophores, help to get oxygen for respiration. In contrast, prop roots and stilt roots are modifications for mechanical support, and storage roots (like carrot and turnip) are for storing food.