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首页> 外文期刊>Flora >Typical cyperoid reproductive structures in Lipocarpha humboldtiana and Ascolepis brasiliensis (Cypereae - Cyperoideae - Cyperaceae): New evidence from a development perspective
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Typical cyperoid reproductive structures in Lipocarpha humboldtiana and Ascolepis brasiliensis (Cypereae - Cyperoideae - Cyperaceae): New evidence from a development perspective

机译：香脂油菜和巴西天牛（典型的莎柏科（Cypereae-Cyperoideae-Cyperaceae））的典型的环状生殖结构：从发展角度看的新证据

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Ascolepis and Lipocarpha, Cyperaceae, have highly reduced reproductive structures and hypogynous scales that are controversially appreciated. Because of this, flowers and spikelets and, thus, inflorescences have been interpreted in different ways, which, in turn, has led to placing the two genera in different tribes. Some authors interpret spikelets in Ascolepis and Lipocarpha as many-flowered and the so-called hypogynous scales as homologous to the lateral scales of Hypolytrum, or consider these scales comparable to a Scirpus bristle. However, many other authors consider spikelets in Lipocarpha and Ascolepis to be a result of a reductional process from a many-flowered cyperoid spikelet to a single-flowered spikelet, where the adaxial and abaxial hypogynous scales may be seen as the respective prophyll and glume of the reduced spikelets. The latest molecular phylogenies of Cyperaceae show both genera nested in the Cyperus clade, forming, in turn, a clade together with the rest of the Cypereae genera having single-flowered spikelets and hypogynous scales. Alternatively, based on this, the scales of uncertain homology that accompany the Ascolepis and Lipocarpha flower might be seen as special reproductive formations, representing a synapomorphy of such clade, instead of relicts of an ancestor with many-flowered spikelets. In view of this, freshly collected inflorescences of Lipocarpha humboldtiana Nees and Ascolepis brasiliensis (Kunth) Benth. ex C. B. Clarke were studied using light and scanning electron microscopy, with the aim of elucidating the nature of the controversially interpreted reproductive structures of these species from a development perspective. Results show that the "hypogynous scales" simply represent vestigial structures derived from the reduction of typical cyperoid spikelets, rather than a perianth part or specialized formations emerging as evolutionary novelties. Two scales are typically generated in both species, one being abaxial and the other adaxial, homologous to a glume and a prophyll, respectively, which contrasts with the eprophyllate condition so far attributed to Ascolepis. In both cases, the inflorescence is a spike of reduced spikelets, and the floral development in L. humboldtiana and in A. brasiliensis follows the general ontogenetic pattern observed in Cyperoideae. These characteristics support the inclusion of both genera in the Cypereae tribe.
机译：莎草科的Ascolepis和Lipocar​​pha的生殖结构和雌雄同株的鳞片高度减少，备受争议。因此，花和小穗以及因此的花序已经以不同的方式进行了解释，这反过来又导致了两个属处于不同的部落。一些作者认为小花椰菜和脂鳞鱼中的小穗与多头Hy的侧鳞同源，是多花的，所谓的雌性下鳞，或者认为这些鳞片可与短尾ir的鬃毛相提并论。然而，许多其他作者认为脂荚鱼和小叶锦鸡儿的小穗是从多花的小穗小穗减少到单花的小穗的过程的结果，在小花的小穗的近端和近端鳞片可能被看作是各自的预防和颖花。减少的小穗。莎草科的最新分子系统发育表明，两个属都嵌套在莎草属进化枝中，进而与其他莎草属属一起形成了一个进化枝，其具有单花小穗和次生鳞片。或者，基于此，可以将伴随着Ascolepis和Lipocar​​pha花的不确定性同源的鳞片视为特殊的繁殖形式，代表此类进化枝的亚同形，而不是先祖的遗迹带有多花的小穗。鉴于此，新鲜收集的Lipocar​​pha humboldtiana Nees和巴西天蛾Ascolepis brathiliensis（Kunth）Benth的花序。克拉克（C. B. Clarke）的前人用光显微镜和扫描电子显微镜进行了研究，目的是从发展的角度阐明这些物种的有争议的生殖结构的性质。结果表明，“下丘陵鳞片”仅表示源自典型的小穗状小穗减少的残留结构，而不是花被或进化形成的新奇的专门形成的残留结构。通常在两个物种中产生两种鳞片，一种鳞片近轴，另一种鳞片近轴，分别与颖片和叶柄同源，这与迄今为止归因于伞形菌的叶鳞形成条件相反。在这两种情况下，花序都是小穗减少的穗状花序，而汉伯L. humboldtiana和巴西柔毛菜中的花发育遵循在莎草科中观察到的一般个体发育模式。这些特征支持将两个属都包括在Cypereae部落中。

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