Hydrophytes are plants that live in water.They may be found on the edge of lakes and ponds, on the surface or submerged in water.The leaves of surface water plants float on the surface of water so the plant receives light and carbon dioxide for photosynthesis.The air spaces must be full of air and not water-logged so that the carbon dioxide can diffuse to the mesophyll cells.Adaptations include: very thin cuticles or no cuticles, Many stomata on the upper surface of the leaf, stomata always open wide, flat leaves reduced structure of the plant underwater, air sacs and aerenchyma.Aerenchyma are specialised parenchyma cells with many large air spaces formed by the programmed cell death(apoptosis) of parenchyma cells.