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目的分析石斛及其混淆品茎表皮细胞特征,评价其鉴别价值。方法采用石蜡切片技术制作药用石斛及其混淆品的茎横切片;利用测微尺测量茎表皮细胞的显微特征。结果 39种药用石斛及其混淆品的茎细胞形状特征和细胞壁的增厚程度种间差异较大,而种内差异较小;石斛及其混淆品茎表皮细胞的细胞壁有3种增厚现象,分别为不均匀增厚型、均匀增厚型和无增厚型;金钗石斛属于无增厚型,马鞭石斛和铁皮石斛属于不均匀增厚型,但密花石豆兰和云南石仙桃属于均匀增厚型;《中国药典》收载药用石斛茎表皮细胞的切向和径向直径比值为小于1.65±0.24或大于2.39±0.49,而3种混淆品均为1.98±0.23～2.35±0.77。结论表皮细胞类型和大小以及切向与径向直径比值可以作为鉴别石斛的主要显微特征,尤其对《中国药典》收载的3种药用石斛能够提供更加可靠的鉴别依据。
Objective To analyze the characteristics of stem epidermal cells of Dendrobium and its mixture and to evaluate its differential value. Methods Paraffin sections were used to make stem cross-sections of medicinal Dendrobium and its adulterants. Microscopic features of stem epidermal cells were measured by micrometer scale. Results The morphological characteristics of stem cells and the thickening of cell wall of 39 kinds of medicinal Dendrobium and their adulterated products varied greatly among different species, but there were three kinds of thickening phenomenon in the cell wall of stem epidermal cells of Dendrobium and its mixture , Respectively, non-uniform thickening, uniform thickening and non-thickening; Dendrobium nobile are non-thickened, Dendrobium candidum and Dendrobium candidum are uneven thickening type, Uniform thickened type; the tangential and radial diameter ratios of the Chinese Pharmacopoeia containing stem epidermal cells of Medicinal Herbs were less than 1.65 ± 0.24 or greater than 2.39 ± 0.49, while the three kinds of confused products were 1.98 ± 0.23 ~ 2.35 ± 0.77 . Conclusion The type and size of epidermal cells, as well as the ratio of tangential to radial diameters, can be used as the main microscopic features to identify Dendrobium. In particular, the three Medicinal Dendrobium strains contained in the Chinese Pharmacopoeia can provide a more reliable basis for identification.