Leaf surface structures enable the endemic Namib desert grass Stipagrostis sabulicola to irrigate itself with fog water
Leaf surface structures enable the endemic Namib desert grass Stipagrostis sabulicola to irrigate itself with fog water
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DOI：
10.1098/rsif.2011.0847
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发表时间：
2012-08-07
影响因子：
3.9
通讯作者：
Konrad, W.
中科院分区：
文献类型：
--
作者：
Roth-Nebelsick, A.;Ebner, M.;Konrad, W.
纳米草Stiagrostis sumulicola的供水在很大程度上依赖于雾，并能够将收集的水引导到植物基地。这种对植物根部的直接灌溉使浅根能够有效和快速地吸收雾水。在这篇文章中，分析了这种定向水流的机制。萨布氏针茅的表面高度不规则。前进接触角为98度+/-5度，后退角度为56度+/-9度，两者的平均值约为77度。因此，该表面不是疏水性的，表现出相当大的接触角滞后，因此允许形成相当大尺寸的钉扎液滴。水分传导的关键因素是叶表面存在与植物长轴平行的凹槽。这些凹槽可引导超出最大附着尺寸的液滴向下滑动。它还导致工厂周围的低效液滴散布降到最低。这些表面特征和高大挺拔的身材结合在一起，形成了一个高效的自然集雾系统，使该物种能够在极端干旱的环境中茁壮成长。
The Namib grass Stipagrostis sabulicola relies, to a large degree, upon fog for its water supply and is able to guide collected water towards the plant base. This directed irrigation of the plant base allows an efficient and rapid uptake of the fog water by the shallow roots. In this contribution, the mechanisms for this directed water flow are analysed. Stipagrostis sabulicola has a highly irregular surface. Advancing contact angle is 98 degrees +/- 5 degrees and the receding angle is 56 degrees +/- 9 degrees, with a mean of both values of approximately 77 degrees. The surface is thus not hydrophobic, shows a substantial contact angle hysteresis and therefore, allows the development of pinned drops of a substantial size. The key factor for the water conduction is the presence of grooves within the leaf surface that run parallel to the long axis of the plant. These grooves provide a guided downslide of drops that have exceeded the maximum size for attachment. It also leads to a minimum of inefficient drop scattering around the plant. The combination of these surface traits together with the tall and upright stature of S. sabulicola contributes to a highly efficient natural fog-collecting system that enables this species to thrive in a hyperarid environment.