Optimal vein density in artificial and real leaves
Optimal vein density in artificial and real leaves
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DOI：
10.1073/pnas.0709194105
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发表时间：
2008-07-08
影响因子：
11.1
通讯作者：
Zwieniecki, M. A.
中科院分区：
文献类型：
--
作者：
Noblin, X.;Mahadevan, L.;Zwieniecki, M. A.
维管植物的长期进化导致了各种各样的自然网络，这些网络负责蒸发驱动的水分运输。然而，我们对限制血管结构的物理原理知之甚少。受植物叶子的启发，我们使用了由聚合物材料层中的简单平行通道网络组成的微流体装置，可渗透水，以研究蒸发驱动流的机制和限制。我们表明，通过我们的仿生叶片的流速随着通道密度（1/d）线性增加，直到通道之间的距离（d）与聚合物层（5）的厚度相当，高于该厚度，流速饱和。与植物维管网络的比较表明，同样的优化准则可以用来描述叶片中的静脉的位置。这些缩放关系的蒸发驱动流通过简单的网络揭示了基本的设计原则的工程蒸发渗透驱动的设备，并突出了生物设计或叶的物理约束的作用。
The long evolution of vascular plants has resulted in a tremendous variety of natural networks responsible for the evaporatively driven transport of water. Nevertheless, little is known about the physical principles that constrain vascular architecture. Inspired by plant leaves, we used microfluidic devices consisting of simple parallel channel networks in a polymeric material layer, permeable to water, to study the mechanisms of and the limits to evaporation-driven flow. We show that the flow rate through our biomimetic leaves increases linearly with channel density (1/d) until the distance between channels (d) is comparable with the thickness of the polymer layer (5), above which the flow rate saturates. A comparison with the plant vascular networks shows that the same optimization criterion can be used to describe the placement of veins in leaves. These scaling relations for evaporatively driven flow through simple networks reveal basic design principles for the engineering of evaporation-permeation-driven devices, and highlight the role of physical constraints on the biological design or leaves.