Improved tree-ring visualization using autofluorescence
Improved tree-ring visualization using autofluorescence
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DOI：
10.1016/j.dendro.2019.03.003
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发表时间：
2019-06-01
影响因子：
3
通讯作者：
Locosselli, Giuliano Maselli
中科院分区：
文献类型：
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作者：
Godoy-Veiga, Milena;Slotta, Franziska;Locosselli, Giuliano Maselli
在世界各地的树木中发现的木材解剖特征的巨大多样性导致了各种各样的生长边界类型，这些类型并不总是很容易识别，特别是在热带树林中。然而，年轮之间存在清晰可见的界限对于任何年轮研究都是必不可少的。在这里，我们建议使用木材的自体荧光来增强树木年轮的可视化。荧光立体显微镜发出的多光谱光可以在特定的波长下过滤，以提高木材解剖特征的可视化。为了评估这项技术的有效性，我们比较了自然光下的可视化，绿色荧光蛋白(GFP)滤光片，红色荧光蛋白(RFP)滤光片和紫外线滤光片。我们用一组38种不同生长年轮边界的树种测试了这项技术。尽管结果是特定物种的，但荧光已被证明通过增强细胞类型之间的对比度来改善生长环边界的可视化。它可以突出纤维带(例如，空肠草属、多细胞无精子体)、不同的孔洞模式(例如，Myracrodraon urundeuva)、分泌道(例如，Copaifera langsdorffu)和实质组织带(例如Tipuana Tipu)。荧光使以前被描述为在自然光下具有模糊生长轮的物种的生长轮边界可视化。对于树木年轮边界清晰的物种，如雪松和小膜草，这种方法有助于识别假年轮。除了生长轮边界的可视化之外，自体荧光还可以用于木材解剖的其他定性和定量分析，例如木材识别和解剖特征的自动测量。由于年轮可视化的困难，科学家们正在努力解决年轮计数和交叉测年的问题，他们可能会发现荧光很有用。这也可能有助于确定适合树轮研究的新物种。
The great diversity of wood anatomical features found in trees worldwide results in a broad variety of growthring boundary types that are not always easy to recognize, especially in tropical woods. However, the presence of clearly visible limits between tree rings is essential for any tree-ring studies. Here, we propose the use of autofluorescence of wood in order to enhance tree-ring visualization. The multispectral light emitted from the fluorescence stereomicroscope can be filtered in specific wavelengths to improve the visualization of wood anatomical features. To evaluate the effectiveness of this technique, we compared visualization under natural light, GFP (green fluorescent protein) filter, RFP (red fluorescent protein) filter and UV filter. We tested this technique with a set of 38 tree species with different types of growth-ring boundaries. Although results are species-specific, fluorescence has been shown to improve the visualization of growth-ring boundaries by enhancing the contrast among cell types. It may highlight fibrous zones (e.g. Cavanillesia arborea, Aspidosperma polyneuron), different porosity patterns (e.g. Myracrodruon urundeuva), secretory canals (e.g. Copaifera langsdorffu), and parenchyma bands (e.g. Tipuana tipu). Fluorescence allows the visualization of growth-ring boundaries in species that were previously described as having indistinct growth rings under natural light. For species with clear tree-ring boundaries such as Cedrela fissilis and Hymenaea courbaril, this approach aids the identification of false rings. In addition to the visualization of growth-ring boundaries, autofluorescence may be useful for other qualitative and quantitative analyses of wood anatomy, such as wood identification and automated measurements of anatomical features. Scientists struggling with tree-ring counting and cross-dating due to difficult tree-ring visualization may find fluorescence useful. It may also aid to identify new species suitable for tree-ring studies.