Page 61 - 《广西植物》2023年第10期
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10 期 蒋天翼等: 杜鹃花属映山红亚属植物叶表皮显微形态特征及其分类学意义 1 8 1 5
( 1. Co ̄Innovation Center for Sustainable Forestry in Southern Chinaꎬ Nanjing Forestry Universityꎬ Nanjing 210037ꎬ Chinaꎻ 2. College of Biology
and the Environmentꎬ Nanjing Forestry Universityꎬ Nanjing 210037ꎬ Chinaꎻ 3. Guangzhou Baiyunshan Huacheng Pharmaceutical Company
Limitedꎬ Guangzhou 510555ꎬ Chinaꎻ 4. Center of Horticultureꎬ South China Botanical Gardenꎬ Chinese Academy of Sciencesꎬ Guangzhou
510650ꎬ Chinaꎻ 5. Key Laboratory of Plant Resources Conservation and Sustainable Utilizationꎬ South China Botanical Gardenꎬ
Chinese Academy of Sciencesꎬ Guangzhou 510650ꎬ China )
Abstract: In order to clarify the relationships in Rhododendron subg. Tsutsusiꎬ micromorphological characters of leaf
epidermis were examined for 37 species in Rhododendron subg. Tsutsusi using scanning electron microscopy (SEM)ꎬ
among which the relevant features of 29 species are reported for the first time. The results are as follows: (1) The
stomatal apparatus are anomocytic and all on abaxial surface. (2) According to the micromorphological features of
glandsꎬ trichome types and stomatal apparatus of leaf epidermisꎬ subg. Tsutsusi can be divided into five typesꎬ i.e.ꎬ
R. simsii ̄typeꎬ R. mariae ̄typeꎬ R. indicum ̄typeꎬ R. saxatile ̄type and R. farrerae ̄type. (3) The plants in R. simsii ̄type
have the similar morphological featuresꎬ have no or discontinuous ringed striates around stomatal apparatus. (4) The
plants in R. mariae ̄type do not have distinct T ̄pieces at the polar regions of guard cells but have multilayer ringed
striates. (5) It is implied that the plants in R. indicum ̄type have the close affinity with subg. Therorhodion in having
distinct T ̄pieces at the polar regions of guard cells. (6) R. saxatile ̄type differs from other types in its simple trichomes
being virgate but without glands. (7) The leaf epidermis of R. farrerae ̄type has glands only. (8) The relationships
between the closely related species are also discussed on the basis of leaf epidermal micromorphological features. For
exampleꎬ R. hypoblematosum and R. polyraphidoideum tend to be treated as separate species. Support the preservation of
R. naamkwanense var. cryptonerve as a variety of R. naamkwanenseꎬ and do not support the R. adenanthum into R. tenue
as a synonym. The results of this study show that micromorphological features of leaf epidermis are of significant value for
species delimitation in subg. Tsutsusi.
Key words: Rhododendron subg. Tsutsusiꎬ micromorphological featuresꎬ leaf epidermisꎬ taxonomic significanceꎬ SEM
映 山 红 亚 属 ( Subg. Tsutsusi) 是 杜 鹃 花 属 毛(lyriform hair) 和刺毛( setiform hair)ꎻ簇状毛由
(Rhododendron Linn.)中一个中等大小的亚属ꎬ约 表皮细胞向两个相反方向各自生长ꎬ形成簇状ꎻ腺
110 种ꎬ可分为映山红组(Sect. Tsutsusi)、假映山红 体是 表 皮 系 统 的 腺 结 构 之 一ꎬ 呈 毛 状ꎮ Hoff
组 ( Sect. Tsutsiopsis ) 和 轮 叶 杜 鹃 组 ( Sect. (1980)总结了杜鹃花属植物的表皮附属物ꎬ分为
Brachycalyx)ꎮ 中国的南岭山地是映山红组的现代 三大类ꎬ分别是鳞片和束状毛组合、腺体和束状毛
多样化中心ꎬ日本中南部则为轮叶杜鹃组的多样 组合以及腺体和簇状毛组合ꎮ 之后有学者利用光
化中心ꎮ 自 Linnaeus(1753) 发表本属的皋月杜鹃 学显微镜和扫描电子显微镜观察了杜鹃花属植物
(R. indicum) 以来ꎬ共计发表 200 多个新种ꎬ其中 的叶片结构ꎬ如叶片的厚度、气孔大小、气孔形态、
超过半数是在 1978—1987 年间发表的(丁炳扬和 气孔指数以及分布类型、表皮附属物的类型等ꎬ发
金孝锋ꎬ2009)ꎬ这些新种的分类地位仍有待商榷ꎮ 现同属植物具有很多共同形态结构特征ꎬ但各种
Chamberlian 和 Rae(1990)、Yamazaki(1993ꎬ1996) 间也存在结构差异( 石登红和陈训ꎬ2005ꎻWang et
和何明友(1994)对该亚属的修订大大促进了映山 al.ꎬ 2006ꎻ 王玉国等ꎬ2007aꎻ陈翔等ꎬ2015)ꎮ 丁炳
红亚属的分类学研究ꎮ 形态学方面的主要研究成 扬等(1995ꎬ2000) 和王玉国等( 2007b) 先后对杜
果有ꎬHoff(1980) 将杜鹃花属植物叶表皮附属物 鹃花属植物的种子和果实的形态进行了观察研
分为鳞 片 ( scale)、 束 状 毛 ( virgate hair)、 簇 状 毛 究ꎬ发现这两种植物器官的形态特征在杜鹃花属
(flock hair)和腺体( gland)ꎮ 其中ꎬ鳞片是从表皮 系统分类中不容忽视ꎮ 在孢粉学方面ꎬ高连明等
细胞中生长出一定程度后ꎬ顶端细胞沿着表皮细 (2002aꎬ b)、王玉国等(2006) 和周兰英等(2008)
胞的轴向生长ꎬ形成的圆盘状物ꎻ束状毛从表皮细 先后对杜鹃花属植物花粉进行观察和比较ꎬ发现
胞垂直分裂后倾斜生长ꎬ顶端细胞随个体生长逐 孢粉学差异对种的确定具有一定的实际意义ꎮ 随
步延长ꎬ聚集成束ꎬ包含糙伏毛( fringed hair)、琴形 着分子生物学的发展ꎬ也有不少学者从分子角度