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Hierarchical structures of cactus spines that aid in the directional movement of dew droplets / David, Gethin; Marc, Clement; David, Beynon

Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Volume: 374, Issue: 2073, Start page: 20160110

Swansesa University Authors: David, Gethin, Marc, Clement, David, Beynon

DOI (Published version): 10.1098/rsta.2016.0110

Abstract

Three species of cactus whose spines act as dew harvesters were chosen for this study: Copiapoa cinerea var. haseltoniana, Mammillaria columbiana subsp. yucatanensis and Parodia mammulosa and compared with Ferocactus wislizenii whose spines do not perform as dew harvesters. Time-lapse snapshots of C...

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Published in: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Published: 2016
URI: https://cronfa.swan.ac.uk/Record/cronfa29601
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Abstract: Three species of cactus whose spines act as dew harvesters were chosen for this study: Copiapoa cinerea var. haseltoniana, Mammillaria columbiana subsp. yucatanensis and Parodia mammulosa and compared with Ferocactus wislizenii whose spines do not perform as dew harvesters. Time-lapse snapshots of C. cinerea showed movement of dew droplets from spine tips to their base, even against gravity. Spines emanating from one of the areoles of C. cinerea were submerged in water laced with fluorescent nanoparticles and this particular areole with its spines and a small area of stem was removed and imaged. These images clearly showed that fluorescent water had moved into the stem of the plant. Lines of vascular bundles radiating inwards from the surface areoles (from where the spines emanate) to the core of the stem were detected using magnetic resonance imaging, with the exception of F. wislizenii that does not harvest dew on its spines. Spine microstructures were examined using SEM images and surface roughness measurements (Ra and Rz) taken of the spines of C. cinerea. It was found that a roughness gradient created by tapered microgrooves existed that could potentially direct surface water from a spine tip to its base.
College: College of Engineering
Issue: 2073
Start Page: 20160110