臺灣莢蒾屬植物葉表皮特徵及其分類之意義

Characteristics of leaf epidermis and its taxonomic implications of Viburnum L. in Taiwan

葉表皮特徵相對穩定，對於解決系統分類問題上有其重要的意義。本研究利用光學顯微鏡對臺灣莢蒾屬15種植物葉表皮、氣孔、毛狀物及花外蜜腺等特徵進行觀察。結果顯示，莢蒾屬植物葉上下表皮細胞形狀為不規則；多數葉上表皮細胞大於下表皮；垂周壁型式多為波狀，部分彎曲或直線；氣孔僅分布於葉下表皮；氣孔器類型以不定型為主，少數為平行型，具平行型的種類常伴有側列型。葉上下表面均有表皮毛，毛狀物可分為腺毛與非腺毛，非腺毛均為單細胞毛。全部種類均被腺毛，多數種類兼具非腺毛，僅三種無之。葉花外蜜腺可區分為葉緣和葉身2種類型。壺花莢蒾上下表皮細胞波狀垂周壁具瘤有其獨特性，其它14種莢蒾屬植物則無，本研究結果均支持其特殊的分類地位。葉表皮細胞及其垂周壁、氣孔器、毛狀物類型、花外蜜腺類型等特徵存在差異，可為莢蒾屬組間、種間的分類學及親緣關係提供一定的佐證。 Leaf epidermal characters were relatively stable and significant for solving systematic problems. The characteristics of leaf epidermal cell, stomata, trichome and extrafl oral nectary of 15 species of Viburnum L. in Taiwan were investigated under light microscope. The shapes of upper and lower epidermal cells were irregular in all examined species. The upper epidermal cells were usually larger than the lower ones. The anticlinal walls of the epidermal cells were undulate, curved or straight. Stomata were present only in the lower epidermis and were mostly anomocytic, rarely paracytic or mixed with paracytic and laterocytic. Trichome were present on the upper and lower epidermis in all examined species. Trichome were divided into glandular trichome and non-glandular trichome. Non-glandular trichome were unicellular or stellate hairs, and absent only 3 species. Leaf extrafl oral nectaries were divided into marginal and laminar leaf extrafl oral nectaries. Knobs were present on the anticlinal wall of the upper and lower epidermal cells of V. urceolatum Sieb. & Zucc. , and absent on other fourteen species.The research results supported the particularly taxonomic status of V. urceolatum Sieb. & Zucc.. Leaf epidermal cell, the anticlinal walls, stomata, trichome types, extrafl oral nectaries were obviously different among different species in Viburnum L. and could provide evidence to identify and study the systematic relationships of its taxa.