Poikilohydry

Poikilohydry is the capacity to tolerate dehydration to low cell or tissue water content and to recover from it without physiological damage. This condition occurs in such organisms as the lichens and bryophytes that lack mechanisms, such as a waterproofing cuticle and stomata that can help to prevent desiccation. Poikilohydry is also noted in many forms of algae, which may be able to survive desiccation between successive high tides, or during occasional stranding due to the drying of a lake or pond. Similarly, poikilohydry enables land plants to survive when water supplies are seasonal or intermittent, as in the liverwort genus Targionia, which lives in Mediterranean habitats with hot dry summers.