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1 期 朱永等: 紫纹兜兰的花形态和双雄蕊花药发育及分类学意义 1 0 3
Abstract: The taxonomy of Paphiopedilum Pfitz. has been disputed and needs more data for clarification. Floral
morphology and anther development in P. purpuratum were observed using microscope and paraffin section. The results
were as follows: (1) It was supported that P. purpuratum should be placed in Paphiopedilum subgenus Paphiopedilum
sect. Barbata by some floral featuresꎬ including a single flowerꎬ sepal white with veinsꎬ petal spotted with blackish ̄
maroonꎬ pouch of a lip auriculate on both sidesꎬ and a staminode lunate. (2) At the early stageꎬ anther primordium
developed into a pair of laterally juxtaposed thecae. An incomplete sterile septa was differentiated in the center of each
thecaꎬ giving rise to two arc ̄shaped microsporangia. When anther splitꎬ the sterile septum was discomposed and
degenerated resulting in a mass of sticky pollens from two pollen sacs were fused into a unit. (3) The developed anther
wall consisted of an epidermisꎬ an endotheciumꎬ a middle layerꎬ and a tapetumꎬ conforming to the monocotyledonous
type. Both tapetum and the inner tapetum cells contained 2 nuclei. At the stage of 2 ̄celled grainsꎬ degeneration occurred
in the epidermis and tapetum layersꎬ while the endothecium became thickened fibrously. (4) Microspore mother cells
underwent a simultaneous cytokinesis resulting in microspore tetrads with varied arrangements of tetrahedralꎬ
isobilateralꎬ and decussate typesꎬ and the meiotic activity of microspore mother cells in the same theca was obviously
asynchronous and different meiosis phases could be observed. (5) Microspores produced 2 ̄celled pollens via a mitosisꎬ
which could be retained in pollen tetrads or released as monad. Based on the data availableꎬ some key features are
selected for taxonomy and conservation biology of Paphiopedilum in Cypripedioideaeꎬ including the differentiation of
incomplete sterile septumꎬ the monocotyledonous type of anther wallꎬ the binucleated tapetumꎬ differentiation of the
inner tapetumꎬ simultaneous cytokinesisꎬ the sticky pollensꎬ and so on. This study provides new information for taxonomy
and conservation biology of Paphiopedilumꎬ as well as of Cypripedioideae.
Key words: Paphiopedilumꎬ Cypripedioideaeꎬ anther wall developmentꎬ microsporogenesisꎬ male gametogenesisꎬ pollen
dispersal unitꎬ taxonomy
杓兰亚科( Cypripedioideae Lindl.) 的花形态特 1987)和细胞学(Karasawaꎬ 1980ꎬ 1982) 将兜兰属
征在兰科里较为独特ꎬ主要因其具有两枚可育雄 分为 2 个亚属或 6 个亚属ꎮ 后来的研究认为该属
蕊和花药开裂时散粉单元为黏性花粉ꎬ明显区别 应该划 分 为 3 个 亚 属 ( Cribbꎬ 1998ꎻ Pridgeon et
于 其 余 4 个 亚 科 ( Dresslerꎬ 1986ꎻ Kocyan & al.ꎬ 1999)ꎬ得到了分子系统学证据的支持( Cox et
Endressꎬ 2001ꎻ Singer et al.ꎬ 2008)ꎮ 作为兰科的 al.ꎬ 1997ꎻ Chochai et al.ꎬ 2012ꎻ Tsai et al.ꎬ
基部类群ꎬ具有两枚可育雄蕊的杓兰亚科与具有 2020)ꎬ但现有中国兜兰属的分类系统仍旧采纳两
三枚可育雄蕊的拟兰亚科( Apostasioideae Rchb.) 个亚属的概念(郎楷永ꎬ1999ꎻ 刘仲健等ꎬ2009) 亟
的亲缘关系较近ꎬ包括 5 个属约 180 种ꎬ每个属都 待澄清ꎮ 在重建兜兰属分类系统的资料中ꎬ叶面
有独立而特定的地理分布( Dresslerꎬ 1986ꎻ Cox et 斑块的有无和唇瓣形态常被用作该属的物种鉴定
al.ꎬ 1997ꎻ Pridgeon et al.ꎬ 1999)ꎮ 除了南美洲特 依据(Cribbꎬ 1998ꎻ Pridgeon et al.ꎬ 1999ꎻ 郎楷永ꎬ
有的 3 个小属以外ꎬ其余 2 个属在我国均有分布ꎬ 1999ꎻ刘仲健等ꎬ2009)ꎬ其余花结构的分类学价值
即 杓 兰 属 ( Cypripedium L.) 和 兜 兰 属 极 少 受 到 关 注ꎮ Cribb ( 1998 ) 认 为 兜 兰 亚 属
( Paphiopedilum Pfitz.) ( Cribbꎬ 1998ꎻ 郎 楷 永ꎬ (Paphiopedilum subgenus Paphiopedilum) 的单花斑
1999ꎻ 刘仲健等ꎬ2009)ꎮ 杓兰亚科具较高观赏价 叶组(sect. Barbata)因普遍具有单花、唇瓣基部直
值(Cribbꎬ 1998ꎻ 郎楷永ꎬ1999)ꎬ其野生资源备受 立的耳状结构、叶片具明暗镶嵌的斑块等可用于
关注ꎬ国产兜兰属和杓兰属均被列入国家重点保 该组的 分 类 依 据ꎮ 它 明 显 区 别 于 多 花 无 耳 组
护植 物 名 录 ( 国 家 林 业 和 草 原 局 农 业 农 村 部ꎬ (sect. Coryopedilum)ꎬ后者普遍具数朵花组成的花
2021)ꎮ 序ꎬ唇瓣基部无耳状结构ꎬ叶片光滑净色无斑块ꎮ
长期以来ꎬ兜兰属的分类系统争议较大ꎬ问题 紫纹兜兰 [P. purpuratum (Lindl.) Stein]是中国兜
主要集中在属下的亚属及其分组的处理ꎮ 早期的 兰属最早被引种栽培和命名发表的物种ꎬ模式标
分类系 统 根 据 唇 瓣 形 态 ( Atwoodꎬ 1984ꎻ Cribbꎬ 本产于我国的香港ꎬ在福建、广东、广西和云南以