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The upside-down water collection system of Syntrichia caninervis

Nature Plants volume 2, Article number: 16076 (2016) | Download Citation


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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We want to thank M. Standing for providing SEM/ESEM support, L. Allphin-Rapier for providing ideas and discussions, Z. Aanderud and his students for providing samples, A. Downing for proof reading and BYU internal support for Z.P. and the SEM/ESEM experiments. The work of Y.Z., N.W. and Y.T. were funded by the National Basic Research Program of China (2014CB954202).

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.

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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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