Question

what re xerophytic and hydrophytic plants

Answer 1

Xerophytes

Plant adapted to live in dry conditions. Common adaptations to reduce the rate of transpiration include:Thick waxy cuticle: The cuticle cuts down water loss in two ways: it acts as a barrier to evaporation and also the shiny surface reflects heat and so lowers temperature.Sunken stomata: Stomata may be sunk in pits in the epidermis; moist air trapped here lengthens the diffusion pathway and reduces evaporation rate.

Hydrophytes
 Plant adapted to live in extremely wet conditions. Common adaptations to increase the rate of gaseous exchange:Leaf Shape: The submerged leaves are often highly dissected or divided to create a very large surface area for absorption and photosynthesis. It also minimises water resistance and hence potential damage to the leaves. In many cases, the submerged leaves are totally different to floating or emergent leaves on the same plant. The emergent leaves are usually much less divided, if not entire and have a more similar internal structure to those of land plants.Lack of protective layer: The epidermal layer shows very little, if any, sign of cuticle formation, as water loss is not a problem. All the surface cells appear to be able to absorb water, nutrients and dissolved gases directly from the surrounding water. As a result, the xylem tubes is often greatly reduced, if not absent. *There are also no stomata on the underside of the leaves.

Answer 2

Plants absorb water from the soil, which then evaporates from their outer surfaces; this process is known as transpiration. In dry environments, a typical (mesophytic)plant would evaporate water faster than the rate at which water was replaced in the soil, leading to wilting.