The study of plant anatomy, which can be traced back to the seventeenth century, advanced hand in hand with light microscopy technology and relies on traditional histologic techniques, which are based on serial two‐dimensional (2D) sections. However, these valuable techniques lack spatial arrangement of the tissue and hence provide only partial information. A new technique of whole‐mount three‐dimensional (3D) imaging termed high‐resolution episcopic microscopy (HREM) can overcome this obstacle and generate a 3D model of the specimen at a near‐histological resolution. Here, we describe the application of HREM technique in plants by analyzing two plant developmental processes in woody plants: oil secretory cavity development in citrus fruit and adventitious root formation in persimmon rootstock cuttings. HREM 3D models of citrus fruit peel showed that oil cavities were initiated schizogenously during the early stages of fruitlet development. Citrus secretory cavity formation, shape, volume, and distribution were analyzed, and new insights are presented. HREM 3D model comparison of persimmon rootstock clones, which differ in their rooting ability, revealed that difficult‐to‐root clones failed to develop adventitious roots due to their inability to initiate root primordia.

中文翻译：

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高分辨率落射显微镜可以实现植物形态和发育的三维可视化。

植物解剖学的研究可以追溯到十七世纪，与光学显微镜技术齐头并进，并依赖于基于连续二维 (2D) 切片的传统组织学技术。然而，这些有价值的技术缺乏组织的空间排列，因此仅提供部分信息。一种称为高分辨率落射显微镜 (HREM) 的整体三维 (3D) 成像新技术可以克服这一障碍，并以接近组织学分辨率生成标本的 3D 模型。在这里，我们通过分析木本植物的两个植物发育过程：柑橘类水果中的油分泌腔发育和柿子砧木插条中的不定根形成来描述HREM技术在植物中的应用。柑橘类果皮的 HREM 3D 模型表明，油腔在果实发育的早期阶段就开始分裂。对柑橘分泌腔的形成、形状、体积和分布进行了分析，并提出了新的见解。生根能力不同的柿砧木无性系的 HREM 3D 模型比较表明，难生根无性系由于无法启动根原基而未能发育不定根。