poikilohydry

P3O1I1K5I1L1O1H4Y4D2R1Y4

noun

The condition of being poikilohydric; the lack of structural or functional mechanisms to actively regulate the equilibrium between the concentration of water in cell tissue and that in the environment.

“Poikilohydry occurs in such organisms as lichens and bryophytes, which lack mechanisms such as waterproofing cuticles or stomata that can help resist desiccation.”

Scrabble 28

Meanings

nounpoikilohydry (uncountable)
  1. uncountablebiologyThe condition of being poikilohydric; the lack of structural or functional mechanisms to actively regulate the equilibrium between the concentration of water in cell tissue and that in the environment.

    Poikilohydry occurs in such organisms as lichens and bryophytes, which lack mechanisms such as waterproofing cuticles or stomata that can help resist desiccation.

    4 more examples

    Frequently, poikilohydry is coupled with the capacity to tolerate dehydration or low water content of cell tissue and to recover from it without physiological damage.

    Nonvascular cryptogams, particularly the lichens and mosses, form a majority of the species and biomass exhibiting poikilohydry within desert regions of the world, including North America.

    1997, S. D. Smith, R. Monson, J. E. Anderson, Physiological Ecology of North American Desert Plants, Springer, page 191

    2011, T. G. Allan Green, Leopoldo G. Sancho, Ana Pintado, Chapter 6: Ecobiology of Desiccation/Rehydration Cycles in Mosses and Lichens, Ulrich Lüttge, Erwin Beck, Dorothea Bartels (editors), Plant Desiccation Tolerance, Springer, Ecological Studies 215, page 113, The strategy of poikilohydry was almost certainly primitive and evolved from the production of desiccation-tolerant spores (Oliver et al. 2000). Organisms employing poikilohydry are confined to a small overall size, in particular because of the limitations to water transport that relies on capillarity (Proctor and Tuba 2002).

    Their small size and ability to adhere to solid substrates allows mosses to occupy habitats where poikilohydry provides a unique advantage, but these characteristics set limits on their distribution to specific types of environments where tracheophytes are unable to dominate.

    2018, Mitchell B. Cruzan, Evolutionary Biology: A Plant Perspective, Oxford University Press, page 33

Origin

From poikilo- + -hydry or a noun-forming modification of poikilohydric (see -y); compare homoiohydry.

Full word history & related roots →
Cite this entry
APA

poikilohydry. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/poikilohydry

MLA

“poikilohydry.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/poikilohydry. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “poikilohydry,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/poikilohydry.

Source: poikilohydry on Wiktionary, CC BY-SA 4.0.