Osmoregulation in plants | mesophytes | xerophytes | hydrophytes | f.sc part 2 biology

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Osmoregulation in Plants
Plants are distributed in diferent habitats of aquatic, moderate and severely dry terrestrial nature, thus termed as hydrophytes, mesophytes and xerophytes, respectively.
1=Hydrophytes have the adaptations to remove the looding of its cells in fresh water. In this type the surface area of leaves is very large to transpire water excessively. Extensive stomata are present on the upper surface facing the atmosphere to promote loss of water.

2=Mesophytes have moderate water availability. In suicient supply of water stomata are kept open
to promote loss of excess water, however, in restricted supply stomata close to prevent the loss e.g. Brassica, rose, mango etc.

3=Xerophytes have the adaptations for reduced rate of transpiration. Many xerophytes possess small, thick leaves to limit water loss by reducing surface area proportional to the volume. Their
cuticle is thick, waxy and leathery. Stomata are on lower surface of leaves and located in depression. Some as cacti, during the driest season, shed their leaves to restrict transpiration completely, thus stems are the photosynthetic organs. In rainy season, stem stores water for use in dry conditions