Laboratory of Plant Systematics, Institute of Botany & Microbiology, K.U. Leuven, B-3001 Heverlee (Leuven), Belgium.
Ann Bot. 2010 Apr;105(4):555-71. doi: 10.1093/aob/mcq010. Epub 2010 Mar 2.
In Cyperoideae, one of the two subfamilies in Cyperaceae, unresolved homology questions about spikelets remained. This was particularly the case in taxa with distichously organized spikelets and in Cariceae, a tribe with complex compound inflorescences comprising male (co)florescences and deciduous female single-flowered lateral spikelets. Using ontogenetic techniques, a wide range of taxa were investigated, including some controversial ones, in order to find morphological arguments to understand the nature of the spikelet in Cyperoideae. This paper presents a review of both new ontogenetic data and current knowledge, discussing a cyperoid, general, monopodial spikelet model.
Scanning electron microscopy and light microscopy were used to examine spikelets of 106 species from 33 cyperoid genera.
Ontogenetic data presented allow a consistent cyperoid spikelet model to be defined. Scanning and light microscopic images in controversial taxa such as Schoenus nigricans, Cariceae and Cypereae are interpreted accordingly.
Spikelets in all species studied consist of an indeterminate rachilla, and one to many spirally to distichously arranged glumes, each subtending a flower or empty. Lateral spikelets are subtended by a bract and have a spikelet prophyll. In distichously organized spikelets, combined concaulescence of the flowers and epicaulescence (a newly defined metatopic displacement) of the glumes has caused interpretational controversy in the past. In Cariceae, the male (co)florescences are terminal spikelets. Female single-flowered spikelets are positioned proximally on the rachis. To explain both this and the secondary spikelets in some Cypereae, the existence of an ontogenetic switch determining the development of a primordium into flower, or lateral axis is postulated.
在莎草科的两个亚科之一 Cyperoideae 中，有关小穗的同源性问题仍未解决。在小穗呈二列状排列的类群中尤其如此，在 Cariceae 中也是如此，Cariceae 是一个具有复杂复合花序的族，包括雄性（合生）花序和脱落的雌性单花侧小穗。使用个体发生技术，研究了包括一些有争议的类群在内的广泛的类群，以找到理解 Cyperoideae 中小穗性质的形态学论据。本文综述了新的个体发生数据和当前的知识，讨论了一个莎草状、一般的、单轴小穗模型。
使用扫描电子显微镜和光学显微镜检查了来自 33 个莎草属的 106 种植物的小穗。
提出的个体发生数据允许定义一个一致的莎草状小穗模型。对有争议的类群，如 Schoenus nigricans、Cariceae 和 Cypereae 的扫描和光学显微镜图像进行了相应的解释。
在所研究的所有物种中，小穗由一个不定的穗轴和一个或多个螺旋状或二列状排列的颖片组成，每个颖片下面都有一朵花或空的。侧小穗由一个苞片支撑，并有一个小穗原基。在二列状排列的小穗中，花的联合合生和颖片的背侧合生（新定义的体侧位移）过去曾引起解释上的争议。在 Cariceae 中，雄性（合生）花序是顶生小穗。雌性单花小穗位于穗轴的近端。为了解释这一点以及某些 Cypereae 中的次生小穗，假设存在一个决定原基发育成花或侧轴的个体发生开关。
