Xerophyte

species of plant adapted to survive in environments with little liquid water

Xerophytes are plants which are adapted to dry/desert areas. They are a type of succulent plant. To survive these harsh conditions they have special features.[1] For example, a cactus has white hairs which help to prevent water loss. Another example is manzanita plants, which have a thick waxy coating and keep their leaves vertical to the sun.

A xerophyte species Euphorbia virosa

Adaptions

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Some Xerophytic plants sit out a drought. They can still extract water from soil. They may have very salty cell sap and therefore a very low water potential in the roots; they may have very extensive or deep roots or may pick up the slightest dew and survive on that.

Others have special features about their shape or structure (xeromorphs). Thick waxy cuticle (Aloe); hairy surfaces (Edelweiss); dense packing of leaves, reduced leaf size (species of cypress); reduced density of stomata (many cacti); pitted and grooved position of stomata (Ammophila) Water storage in stem and tubers, etc. (baobab). They may also protect this water store from animals by spines and chemicals.

Mechanism table

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Mechanism Adaptation Example
Limit water loss waxy stomata prickly pear
few stomata
sunken stomata pine
stomata open at night tea plant
CAM photosynthesis provides CO2 during day when stomata are closed cactus
large hairs on surface bromeliads
curled leaves esparto grass
Storage of water succulent leaves Kalanchoe
succulent Plant stem Euphorbia
fleshy tuber Raphionacme
Water uptake deep root system Acacia, Prosopis
below water table Nerium oleander
absorbing surface moisture from leaf hairs or trichomes Tillandsia

References

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  1. Taylor D.J; N.P.O. Green & G.W. Stout 2001. Biological Science 1 & 2, 3rd edition. Cambridge University Press. ISBN 0-521-56178-7.