Lignans are bioactive compounds that are especially abundant in the Norway spruce (Picea abies L. Karst.) knotwood. By combining a variety of chromatographic, spectroscopic and imaging techniques, we were able to quantify, qualify and localise the easily extractable lignans in the xylem tissue. The knotwood samples contained 15 different lignans according to the gas chromatography-mass spectrometry analysis. They comprised 16% of the knotwood dry weight and 82% of the acetone extract. The main lignans were found to be hydroxymatairesinols HMR1 and HMR2. Cryosectioned and resin-embedded ultrathin sections of the knotwood were analysed with scanning transmission X-ray microscopy (STXM). Cryosectioning was found to retain only lignan residues inside the cell lumina. In the resin-embedded samples, lignan was interpreted to be unevenly distributed inside the cell lumina, and partially confined in deposits which were either readily present in the lumina or formed when OsO4 used in staining reacted with the lignans. Furthermore, the multi-technique characterisation enabled us to obtain information on the chemical composition of the structural components of knotwood. A simple spectral analysis of the STXM data gave consistent results with the gas chromatographic methods about the relative amounts of cell wall components (lignin and polysaccharides). The STXM analysis also indicated that a torus of a bordered pit contained aromatic compounds, possibly lignin.

中文翻译：

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挪威云杉 Knotwood 中的木脂素：使用软 X 射线显微镜定位和使用能量色散 X 射线光谱的扫描透射电子显微镜

木脂素是一种生物活性化合物，在挪威云杉 (Picea abies L. Karst.) 木中含量特别丰富。通过结合各种色谱、光谱和成像技术，我们能够量化、定性和定位木质部组织中易于提取的木脂素。根据气相色谱-质谱分析，木节材样品含有 15 种不同的木脂素。它们包含 16% 的虎杖干重和 82% 的丙酮提取物。发现主要的木脂素是羟基马油脂素HMR1和HMR2。用扫描透射 X 射线显微镜 (STXM) 分析了结木的冷冻切片和树脂包埋的超薄切片。发现冷冻切片仅保留细胞腔内的木脂素残基。在树脂包埋样品中，木酚素被解释为在细胞腔内不均匀分布，并且部分限制在容易存在于腔内或在染色中使用的 OsO4 与木脂素反应时形成的沉积物中。此外，多技术表征使我们能够获得有关虎杖结构成分化学成分的信息。STXM 数据的简单光谱分析给出了与气相色谱方法一致的关于细胞壁成分（木质素和多糖）的相对量的结果。STXM 分析还表明有边界坑的环面含有芳香族化合物，可能是木质素。多技术表征使我们能够获得有关虎杖结构成分化学成分的信息。STXM 数据的简单光谱分析给出了与气相色谱方法一致的关于细胞壁成分（木质素和多糖）的相对量的结果。STXM 分析还表明有边界坑的环面含有芳香族化合物，可能是木质素。多技术表征使我们能够获得有关虎杖结构成分化学成分的信息。STXM 数据的简单光谱分析给出了与气相色谱方法一致的关于细胞壁成分（木质素和多糖）的相对量的结果。STXM 分析还表明有边界坑的环面含有芳香族化合物，可能是木质素。