Can you give me some information on Xerophytes?

Xerophytes are plants that can survive in environments where little water or moisture is available to them. Xerophytes have evolved on many different continents, and show a wide range of adaptations.

Some plants avoid drought by surviving as seeds or tubers and then start again when water is available - some (Ocotillo) shed their leaves when water is scarce and then sprout a new set.

Some are adapted to sit out the drought and they have adaptations such as being able to extract water from soil (by having very salty cell sap and therefore a very low water potential in the roots / by having very extensive or deep roots or very shallow roots which pick up the slightest dew and survive on that).

Others have special features about their shape or structure (xeromorphs):-

• Thick leathery cuticle (Aloe)
• Hairy surfaces (Edelweiss)
• Dense packing of leaves, reduced leaf size (Cupressus)
• Reduced density of stomata (Cactus)
• Pitted and grooved position of stomata (Ammophila)
• Water storage in stem and tubers, etc. (Baobab)
• Protection (by spines and chemicals) of this water store.
• C4 / CAM photosynthesis and nocturnal opening of stomata for carbon fixation (a big subject)

Stephen Tomkins and John Hewitson