Plant cells are elaborate three-dimensional polymer nano-constructs with complex chemistry. The bulk response of plants to light, in the far-field, is ultimately encoded by optical scattering from these nano-constructs. Their chemical and physical properties may be acquired through their interaction with a modulated nano-tip using scattering scanning near-field optical microscopy. Here, using this technique, we present 20 nm spatial resolution mechanical, spectral and optical mappings of plant cell walls. We first address the problem of plant polymers tracking through pretreatment and processing. Specifically, cellulose and lignin footprints are traced within a set of delignified specimen, establishing the factors hindering complete removal of lignin, an important industrial polymer. Furthermore, we determine the frequency dependent dielectric function \({\epsilon }(\omega)={(n+ik)}^{2}\) of plant material in the range 28 ≤ ω ≤ 58 THz, and show how the environmental chemical variation is imprinted in the nanoscale variability of n and k. This nanometrology is a promise for further progress in the development of plant-based (meta-)materials.

植物细胞是具有复杂化学性质的精细三维聚合物纳米结构。在远场中，植物对光的整体响应最终是由这些纳米结构的光散射编码的。它们的化学和物理特性可以通过使用散射扫描近场光学显微镜与调制纳米尖端的相互作用来获得。在这里，我们使用这种技术，展示了植物细胞壁的 20 nm 空间分辨率机械、光谱和光学映射。我们首先通过预处理和加工解决植物聚合物跟踪问题。具体来说，纤维素和木质素足​​迹在一组脱木质素样本中被追踪，确定了阻碍完全去除木质素（一种重要的工业聚合物）的因素。此外，\({\epsilon }(\omega)={(n+ik)}^{2}\)在 28 ≤ ω  ≤ 58 THz范围内的植物材料 ，并显示环境化学变化如何影响纳米级变异的ñ和ķ。这种纳米计量学有望在植物基（超）材料的开发方面取得进一步进展。