Key message

Understanding the mobility and distribution of chemical elements in wood is necessary to apply dendrochemistry. Crystals are likely stable and could be used to analyze changes in nutrient supply.

Abstract

Dendrochemistry uses the variation in wood chemical composition to infer about past environmental conditions and possible effects on tree growth. Elemental or isotopic variation might also help to identify annual growth where tree rings are anatomically not distinct. However, most elements are—to a certain degree—mobile within wood and may be related to anatomical structures. Therefore, understanding what affects elemental distribution is important to make use of and critically assess the potential of dendrochemistry. We studied the variation of wood density and elements at high spatial resolution in wood of six species with anatomically distinct to rather indistinct tree rings from a Thai monsoon forest. Many elements had a higher concentration in parenchyma than in fiber cells, and the co-variation of elements differed strongly between elements and also between species. Strong wood density changes along the ring boundary were found only in Melia azedarach. In all species, the X-ray images showed crystals. EDX spectra showed that these consist of calcium or silicon (in Chukrasia tabularis) as major elemental components. A high concentration of heavy metals (Fe, Cu and Zn) was found in Vitex peduncularis. We conclude that at least for the species studied the radial variation of elemental concentration is unlikely to reveal annual rings that anatomy could not. However, if elements in crystals are more stable than in cell walls or living protoplasts, analyzing the distribution of elements present in crystals may show environmental conditions that, in turn, influence crystal formation and are little known.

中文翻译：

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热带木材的高分辨率密度测定和元素分析。

关键信息

了解木材中化学元素的流动性和分布对于应用树木化学是必要的。晶体可能很稳定，可用于分析养分供应的变化。

抽象的

树木化学利用木材化学成分的变化来推断过去的环境条件和对树木生长的可能影响。元素或同位素变异也可能有助于确定年轮在解剖学上不明显的年生长。然而，在一定程度上，大多数元素在木材中是可移动的，并且可能与解剖结构有关。因此，了解影响元素分布的因素对于利用和批判性评估树木化学的潜力非常重要。我们研究了来自泰国季风森林的六种木材在高空间分辨率下木材密度和元素的变化，这些木材在解剖学上与相当模糊的树木年轮不同。许多元素在实质中的浓度高于纤维细胞中的浓度，元素的共变在元素之间以及物种之间也存在很大差异。沿环边界的强烈木材密度变化仅在苦楝。在所有物种中，X 射线图像均显示晶体。EDX 光谱显示，它们由钙或硅（在Chukrasia tabularis中）作为主要元素成分组成。在Vitex peduncularis中发现了高浓度的重金属（Fe、Cu 和 Zn）。我们得出结论，至少对于所研究的物种，元素浓度的径向变化不太可能揭示解剖学无法揭示的年轮。然而，如果晶体中的元素比细胞壁或活原生质体中的元素更稳定，那么分析晶体中存在的元素的分布可能会显示环境条件，而这些环境条件反过来会影响晶体形成并且鲜为人知。