The upside-down water collection system of Syntrichia caninervis

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Desert plants possess highly evolved water conservation and transport systems, from the root structures that maximize absorption of scarce ground water1,​2,​3,​4,​5, to the minimization of leaf surface area6 to enhance water retention. Recent attention has focused on leaf structures that are adapted to collect water and promote nucleation from humid air7,​8,​9. Syntrichia caninervis Mitt. (Pottiaceae) is one of the most abundant desert mosses in the world and thrives in an extreme environment with multiple but limited water resources (such as dew, fog, snow and rain), yet the mechanisms for water collection and transport have never been completely revealed. S. caninervis has a unique adaptation: it uses a tiny hair (awn) on the end of each leaf to collect water, in addition to that collected by the leaves themselves. Here we show that the unique multiscale structures of the hair are equipped to collect and transport water in four modes: nucleation of water droplets and films on the leaf hair from humid atmospheres; collection of fog droplets on leaf hairs; collection of splash water from raindrops; and transportation of the acquired water to the leaf itself. Fluid nucleation is accomplished in nanostructures, whereas fog droplets are gathered in areas where a high density of small barbs are present and then quickly transported to the leaf at the base of the hair. Our observations reveal nature's optimization of water collection by coupling relevant multiscale physical plant structures with multiscale sources of water.

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  1. 1.

    & Fog-basking behaviour and water collection efficiency in Namib desert darkling beetles. Front. Zool. 7, 23 (2010).

  2. 2.

    , & Animal or plant: which is the better fog water collector? PloS ONE 7, e34603 (2012).

  3. 3.

    Environmental factors and survival strategies of annual plant species in the Negev Desert, Israel. Plant Species Biol. 15, 113–125 (2000).

  4. 4.

    & Root systems of some Chihuahuan Desert plants. J. Arid Environ. 49, 221–263 (2001).

  5. 5.

    Root systems of certain desert plants. Bot. Gaz. 177–205 (1917).

  6. 6.

    Soil phosphate and its role in molding segments of the Australian flora and vegetation, with special reference to xeromorphy and sclerophylly. Ecology 47, 992–1007 (1966).

  7. 7.

    et al. A multi-structural and multi-functional integrated fog collection system in cactus. Nature Commun. 3, 1247 (2012).

  8. 8.

    et al. Leaf surface structures enable the endemic Namib Desert grass Stipagrostis sabulicola to irrigate itself with fog water. J. R. Soc. Interface 9, 1965–1974 (2012).

  9. 9.

    , , & Three-dimensional hierarchical structures for fog harvesting. Langmuir 27, 3798–3802 (2011).

  10. 10.

    et al. Morphological adaptations to drought and reproductive strategy of the moss Syntrichia caninervis in the Gurbantunggut Desert, China. Arid Land Res. Manage. 25, 116–127 (2011).

  11. 11.

    , , & Sex expression, skewed sex ratios, and microhabitat distribution in the dioecious desert moss Syntrichia caninervis (Pottiaceae). Am. J. Bot. 87, 517–526 (2000).

  12. 12.

    & Effects of leaf hair points of a desert moss on water retention and dew formation: implications for desiccation tolerance. J. Plant Res. 125, 351–360 (2012).

  13. 13.

    & Poikilohydry and homoihydry: antithesis or spectrum of possibilities? New Phytol. 156, 327–349 (2002).

  14. 14.

    in Bryophyte Systematics 479–509 (Academic, 1979).

  15. 15.

    The relationship between leaf hydrophobicity, water droplet retention, and leaf angle of common species in a semi-arid region of the western United States. Agric. Forest Meteorol. 152, 11–16 (2012).

  16. 16.

    Bryophyte Ecology, Vol. 1: Physiological Ecology (Michigan Technological University and the International Association of Bryologists, 2007).

  17. 17.

    et al. Directional water collection on wetted spider silk. Nature 463, 640–643 (2010).

  18. 18.

    & The narrow-leaf syndrome: a functional and evolutionary approach to the form of fog-harvesting rosette plants. Oecologia 151, 561–573 (2007).

  19. 19.

    , , , & Optimal design of permeable fiber network structures for fog harvesting. Langmuir 29, 13269–13277 (2013).

  20. 20.

    Some fog droplet size distributions obtained by an impaction method. Q. J. R. Meteorol. Soc. 97, 483–494 (1971).

  21. 21.

    & Drops on a conical wire. J. Fluid Mech. 510, 29–45 (2004).

  22. 22.

    & The fastest drop climbing on a wet conical fibre. Phys. Fluids 25, 052105 (2013).

  23. 23.

    , , & Comparison of raindrop size distribution measurements by collocated disdrometers. J. Atmos. Ocean. Technol. 30, 1672–1690 (2013).

  24. 24.

    , & Simulations of vapor water clusters at vapor–liquid equilibrium. J. Chem. Phys. 123, 024504 (2005).

  25. 25.

    et al. Desiccation-tolerance in bryophytes a review. Bryologist 110, 595–621 (2007).

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Author information


  1. Department of Mechanical Engineering, Brigham Young University, 435 CTB, Provo, Utah 84602, USA

    • Zhao Pan
  2. Department of Chemical Engineering, Brigham Young University, Clyde Building, Room 350, Provo, Utah 84602, USA

    • William G. Pitt
  3. Key Laboratory of Biogeography and Bioresources, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi, 830011, Xinjiang, People's Republic of China

    • Yuanming Zhang
    • , Nan Wu
    •  & Ye Tao
  4. Department of Mechanical and Aerospace Engineering, Utah State University, 419J 4130 Old Main Road, Logan, Utah 84322, USA

    • Tadd T. Truscott


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N.W. and Y.Z. originated the research on S. caninervis and provided anatomical studies, both macro and microscopic. Z.P., T.T.T. and W.G.P. designed the experiments, and Z.P. and T.T.T. performed the experiments and analysed the data. Z.P and W.G.P. proposed the mechanisms of nucleation on the moss awn. W.G.P., Z.P. and T.T.T. wrote the text.

Competing interests

The authors declare that they have no competing financial interests.

Corresponding author

Correspondence to Tadd T. Truscott.

Supplementary information

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    Supplementary Information

    Supplementary Section ‘Dew nucleation and fog droplet collection in a groove’, Supplementary References, Supplementary Figs 1–3 and captions for Supplementary Videos 1–5.


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