Ripples at edges of blooming lilies and torn plastic sheets
Ripples at edges of blooming lilies and torn plastic sheets
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DOI：
10.1016/j.bpj.2022.05.018
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发表时间：
2022-06-21
影响因子：
3.4
通讯作者：
Keller，Sarah L.
中科院分区：
文献类型：
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作者：
Portet，Thomas;Cohen，Zachary R.;Keller，Sarah L.
盛开的卡萨布兰卡花瓣的边缘和撕破的塑料布的边缘都起了涟漪。在这两种系统中，波纹都是沿板材边缘沿着的多余长度的结果。通过使用盛开的百合花的延时视频和已发表的撕裂的塑料片的图像，我们发现，在这两个系统中的波纹很好地描述了标度关系，其中振幅，波长，弧长。以前报道的自相似涟漪模式的现象学关系，即，可以恢复通过假设屈曲应力是恒定的。沿花瓣边缘的多余长度沿着也会影响它们的整体高斯曲率，使得花瓣在起霜时从杯形反转成鞍形。先前对这些形状变化的模拟假设花瓣厚度至少以二次方减小。在这里，我们评估了几个品种的百合芽的断层图像，发现这个假设是有效的沿着短轴的芽，但不是长轴。采用传统的断层扫描方法来测量花瓣厚度的一个挑战是样品被破坏;单个花蕾无法在整个开花过程中被跟踪。为了应对这一挑战，我们提供了原则证明，无损，无标记的方法，x射线断层扫描产生高对比度的三维扫描时间尺度短到足以遵循百合开花。
Ripples arise at edges of petals of bloomingLilium casablancaflowers and at edges of torn plastic sheets. In both systems, ripples are a consequence of excess length along the edge of a sheet. Through the use of time-lapse videos of blooming lilies and published images of torn plastic sheets, we find that ripples in both systems are well described by the scaling relationship, whereis amplitude,is wavelength, andis arc length. A phenomenological relationship previously reported for self-similar ripple patterns, namely, can be recovered by assuming that buckling stress is constant. Excess length along petal edges can also influence their overall Gaussian curvature, such that petals invert from a cup shape to a saddle shape upon blooming. Previous simulations of these shape changes have assumed that petal thickness decreases at least quadratically. Here, we evaluate tomograms of several varieties of lily buds and find that this assumption is valid along the short axis of the buds, but not the long axis. A challenge of employing traditional tomography methods to measure petal thickness is that the sample is destroyed; a single bud cannot be followed through the entire blooming process. To address this challenge, we provide proof of principle that the nondestructive, label-free method of x-ray tomography produces high-contrast three-dimensional scans on time scales short enough to follow lily blooming.