Differences between terrestrial and aquatic habitats lead to big differences in the characteristics of aquatic and terrestrial vascular plants. The high density of water makes aquatic organisms more buoyant, so aquatic plants invest less resources in support tissues than terrestrial plants. Because aquatic plants are surrounded by water, water loss is not a problem. Thus, submerged plants lack the structural and protective structures produced by terrestrial plants. For example, submerged aquatic plants lack a well develop waxy cuticle layer to prevent desiccation. Because submerged plants are capable absorbing water, nutrients, and dissolved gases directly through their leaves, xylem (the part of the plant responsible for carrying water and nutrients from the roots to the leaves) is reduced or absent. Leaves of submerged aquatic vegetation lack stomata, the pores in the leaves through which terrestrial plants exchange gases such as carbon dioxide and water vapor with the environment. In terrestrial plants roots play an important role in the absorption of water and nutrients. Roots are often reduced (or lacking) in submerged aquatic vegetation and their only function is to anchor the plant to the ground.
HOPE IT HELPS YOU IF YOU SATISFY WITH MY ANSWER A THUMB UP PLEAE