Morphological analysis of the seeds of three pseudocereals by using light microscopy and ESEM-EDS
Morphological analysis of the seeds of three pseudocereals by using light microscopy and ESEM-EDS
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DOI：
10.4081/ejh.2020.3075
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发表时间：
2020-01-01
影响因子：
2
通讯作者：
Gobbi, Pietro
中科院分区：
文献类型：
--
作者：
Ninfali, Paolino;Panato, Anna;Gobbi, Pietro
通过光学显微镜 (LM) 和环境扫描电子显微镜结合能量色散光谱研究了三种假谷物 (PSCg) 的种子形态，即藜麦（Chenopodium quinoa Willd，Chenopodiaceae）、荞麦（Fagopyrum esculenium Moench，Polygonaceae）和苋菜（Amaranthus caudalus L.，Amaranthaceae） （ESEM-EDS）。 LM 用于明场评估未染色切片或用 Azan 混合物染色的切片，以及荧光。该研究的目的是比较三种种子的结构，以便将它们的形态与营养定位联系起来。阿赞染色可以观察到种皮、胚胎（及其芽尖分生组织）和胚根细胞层，而荧光显微镜的使用则可以识别出富含酚类化合物的细胞。最后，ESEM-EDS 分析显示藜麦的种皮比苋菜或荞麦的种皮薄。在所有 PSCg 中，淀粉颗粒似乎位于大的多边形细胞中，周围有薄细胞壁。在胚胎细胞中观察到了几个蛋白质球体。在胚根切片中，原形成层的维管束很明显，而苋菜仅显示出一层一致的钙晶体，位于胚和外胚乳之间。三种 PSCg 的形态差异在其对加工技术的结构抵抗力的背景下进行了讨论，加工技术影响衍生食品的营养价值。
The seed morphology of three pseudocereal grains (PSCg), i.e. quinoa (Chenopodium quinoa Willd, Chenopodiaceae), buckwheat (Fagopyrum esculenium Moench, Polygonaceae) and amaranth (Amaranthus caudalus L., Amaranthaceae) was studied by light microscopy (LM) and Environmental Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (ESEM-EDS). LM was used in bright field to evaluate either unstained sections or sections stained with Azan mixture, and in fluorescence. The aim of the study was to compare the architecture of the three seeds in order to connect their morphology with nutrient localization. The Azan staining allowed for the visualization of the seed coat, the embryo - with its shoot apical meristern - and the radicle cell layers, whereas the use of fluorescence microscopy identified the cells rich in phenolic compounds. Finally, the ESEM-EDS analysis revealed that the seed coat of the quinoa was thinner than that of amaranth or buckwheat. In all PSCg, starch granules appeared to be located in large polygonal cells, surrounded by a thin cell wall. Several globoids of proteins were observed in the embryo cells. In the radicle section, the vascular bundles of the procambium were evident, while Amaranth only showed a consistent layer of calcium crystals, located between the embryo and the perisperm. The morphological differences of the three PSCg were discussed in the context of their structural resistance to processing technologies which impact on nutritional value of derived foods.