Certain plants have adapted to be able to survive in very dry environments. These types of plants are known as xerophytes. Xerophytes include cacti and other similar plants, often with thick fleshy leaves to store water.
There are four features that are present in many xerophytes:
The plants are structured in a way that the stems face vertically upwards. This allows them to absorb sunlight in the morning and evening, but not at midday when the sun is most intense.
The stems of the plant are covered with a thick waxy cuticle to prevent the loss of water vapour through transpiration.
Transpiration is also reduced because of spines, rather than leaves, which have a smaller surface area.
Unlike most plants, xerophytes have a CAM physiology. This involves the stomata open during the night, rather than during the day. This is because the nights are cooler, so less water will be lost.
