1. A thin cuticle. Cuticles primarily discourage water loss; thus most hydrophytes have no need for cuticles. 2. Stomata that are open most of time because water is abundant and therefore there is no need for it to be retained in the plant. This means that guard cells on the stomata are generally inactive. 3. An increased number of stomata, that can be on either side of leaves. 4. A less rigid structure: water pressure supports them.
5. Flat leaves on surface plants for flotation.
6. Air sacs for flotation.
7. Smaller roots: water can diffuse directly into leaves. 8. Feathery roots: no need to support the plant.
9. Specialized roots able to take in oxygen.
All floating plants
• Have either air spaces trapped in their roots or large air spaces (aerenchyma) to help them float to obtain sunlight • Have hair on their leaves to trap air
• Structural adaptation
Duckweed, water cabbage
• Chloroplast found on the top surface of the leaves
• Upper Surface has a thick, waxy cuticle to repel water and help to keep the stomata open and clear • Structural adaptation
• Small and light
• Structural material to reach higher points and receive more sunlight • Structural adaptation
Floating heart, water lily, lotus, yellow pond lily, water-shield • Leaves tend to be broader without major lobing, remain flat on water surface, maximize surface area and make use of full sunlight; chloroplasts found on the top of leaves • Structural/ behavioral adaptation
Most partially-submerged ("emersed") plants
• Air spaces within the tissues to keep it buoyant so that its leaves can reach the top of the pond, maximizing the amount of sunlight received • Structural adaptation
Dissected: Parrot's Feather, Hornwort
Thread-like: ditch-grass, quillwort
• Highly dissected/ divided leaves or thread-like ones, allows for a bigger surface...