Evolution of Illicium (Illiciaceae): Mapping morphological characters on the molecular tree
Evolution of Illicium (Illiciaceae): Mapping morphological characters on the molecular tree
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DOI：
10.1007/s00606-003-0022-1
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发表时间：
2003-09
影响因子：
1.9
通讯作者：
I. Oh;T. Denk;E. M. Friis
中科院分区：
文献类型：
--
作者：
I. Oh;T. Denk;E. M. Friis
百合属植物属于ANITA级，是开花植物的基本谱系之一。最近发表的分子树的形态特征映射揭示了传统的基于花结构的百合分类与基于分子的系统发育之间的冲突。illillum的花性状，即花被片、雄蕊和心皮的数量、大小和形状是高度可变的。不具萼片的花被片与花瓣状的嵌段。这在其他ANITA分类群中也观察到，从苞片到花被片和雄蕊的渐变发生，但在更多的衍生植物类群中没有，这表明在基生被子植物中花器官的数量可能不是遗传固定的。因此，花性状可能是在不同的illillum类群中平行进化的，单独来看，可能不适合illillum的亚属划分。相比之下，在新世界种中发现的门区和明显的门缘结构等种子结构支持了分子数据表明的新世界和旧大陆种之间的主要划分。表皮特征在属内通常是一致的，但为分子树中识别的分支之一提供了一些支持。一般来说，很少有形态学特征可以用来区分八歧属的天然种群。
Illiciumis a member of the ANITA grade and as such represents one of the basalmost lineages of flowering plants. Mapping morphological characters on a recently published molecular tree sheds some light on the conflict between the traditional classification ofIlliciumbased on floral structures and the molecular based phylogeny. Floral characters ofIllicium, i.e. number, size, and shape of perianth segments, stamens, and carpels, are highly variable. InIlliciumsepaloid perianth segments intergrade with petaloid ones. This is also observed in the other ANITA taxa, where gradations from bracts to perianth segments and stamens occur, but not in more derived plant groups, and indicates that the number of floral organs may not be genetically fixed in basal angiosperms. Therefore, floral characters may have evolved in parallel in different groups ofIlliciumand, taken alone, may be unsuitable for a subgeneric division ofIllicium. In contrast, seed structures such as the hilar area and a conspicuous hilar rim structure found in New World species ofIlliciumsupport a major division between New World and Old World species ofIlliciumas suggested by molecular data. Epidermal features generally are uniform within the genus but provide some support for one of the clades recognized in the molecular tree. In general, few morphological characters can be used to distinguish natural species groups withinIllicium.