Drought Tolerance - Adaptations To Dry Conditions

Adaptations To Dry Conditions

Drought tolerant plants typically make use of either C4 carbon fixation or crassulacean acid metabolism (CAM) to fix carbon during photosynthesis. Both are improvements over the more common but more basal C3 pathway in that they are more energy efficient. CAM is particularly good for arid conditions because carbon dioxide can be taken up at night, allowing the stomata to stay closed during the heat of day and thus reducing water loss.

Many adaptations for dry conditions are structural, including the following:

• Adaptations of the stomata to reduce water loss, such as reduced numbers or waxy surfaces.
• Water storage in succulent above-ground parts or water-filled tubers.
• Adaptations in the root system to increase water absorption.
• Trichomes (small hairs) on the leaves to absorb atmospheric water.