Xerophytes and Hydrophtes

• What are xerophytes?

  Organisms adapted to survive in very dry conditions
• What are hydrophytes?


  Organisms adapted to survive in very wet conditions
• What are some generic adaptations of xerophytes?

  Thick waxy cuticle, sunken stomata, large, deep root network or many roots near the surface, less stomata, leaves reduced to spines, less leaves, hairy leaves, curled leaves, specialised water storage parenchyma tissue in succulents, loss of leaves in dry season, dormancy in dry periods
• How is Marram Grass specially adapted to survive in a very dry environment?

  It has a curled, 'C' shaped leaf, which creates a windless, humid environment for stomata to lose water into, as well as hairs near the stomata to collect water, after which it dribbles down to the roots for collection. Also has a very deep root network and an extensive system of shallow roots near the surface
• What are some generic adaptations of hydrophytes?

  Very thin/no waxy cuticle, many permanently open stomata on upper surfaces, reduced plant structure as plenty of water to support, wide, flat leaves to spread across surface of water, small roots, large SA of underwater stems and roots, air sacs to allow leaves and flowers to float, aerenchyma
• What is a pneumatophore?

  A specialised aerial root found in hydrophytes to ensure that they get enough air, which have many lenticels which allow the movement of air into woody tissue
• How does rice contribute to global warming?

  Aerenchyma found in rice may provide a low-resistance pathway for methane produced by the rice plant to move into the atmosphere
• What is aerenchyma?


  Specialised parenchyma tissue formed in the stems, leaves and roots, which have many large air spaces (which seem to be formed by apoptosis in normal parenchyma), which makes stems and leaves more buoyant and forms a low-resistance pathway for the movement of substances such as oxygen to underwater tissues
• Apart from very wet conditions, what does aerenchyma help plants cope with?

  Anoxic (low oxygen) conditions, such as is mud