Evolution of trichome types and its systematic significance in the genus Phlomoides (Lamioideae-Lamiaceae)
Evolution of trichome types and its systematic significance in the genus Phlomoides (Lamioideae-Lamiaceae)
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DOI：
10.1111/njb.02132
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发表时间：
2019-05-01
影响因子：
0.9
通讯作者：
Salmaki, Yasaman
中科院分区：
文献类型：
--
作者：
Khosroshahi, Elmira Eyvazadeh;Salmaki, Yasaman
尽管一些最近的分子系统发育研究Phlomoides，在毛状体形态的属仍然是最缺乏研究的类群之一，在家庭Lamiaceae。为了检验毛状体特征在划分糙苏属植物的节、亚节和种中的实用性，我们利用体视显微镜和扫描电镜对代表所有已知节和亚节的64种糙苏属植物的毛状体进行了研究。毛状体有两种基本类型：非腺毛型和腺毛型。两种毛状体类型可以是简单的或分枝的。腺毛无柄，短柄或长柄。在大部分的糙苏组中观察到不同类型的分枝毛，即对称星状、星状，中央有长分支、二叉或三叉。丝杆蕨组的种类大多被简单的毛状体所覆盖。此外，毛状体性状的变异似乎具有特殊的价值，不仅在科或亚科等级的分类，而且在每个部分内的物种的划界。例如，所有研究的P. subsect.闪电藻的特征是具有多种星状毛，而闪电藻亚组的星状毛具有多样性。Tetragonae是足够高的物种歧视。为了研究毛状体类型的进化，进行了祖先特征状态重建，揭示了糙苏属毛状体特征的以下进化趋势：1）与简单的毛状体相比，分枝的毛状体在糙苏属中是原始的，2）与短的简单的相比，长的简单的非腺毛状体是衍生的，以及3）柄状腺毛的存在比近无柄或无柄的提前。
Despite a number of recent molecular phylogenetic studies on Phlomoides, in terms of trichome morphology the genus is still among the most poorly studied taxa in the family Lamiaceae. In order to test the utility of trichome characters for delimitation of sections, subsection and species of Phlomoides, we examined trichomes of 64 species representing all recognized sections and subsections using stereomicroscopy and scaning electron microscopy. Two basic types of trichomes could be identified: non-glandular and glandular. Both trichome types can be simple or branched. The glandular trichomes were sessile, short stalked or long stalked. Different kinds of branched trichomes were observed in most species of P. sect. Phlomoides, i.e. symmetrically stellate, stellate with a central long branch, bi- or trifurcate. The species of P. sect. Filipendula were mostly covered by simple trichomes. Moreover, variation in trichome characters appears to have particular value, not only for the classification at sectional or subsectional rank, but also for delimitation of species within each section. For example, all studied species of P. subsect. Fulgentes are characterized by various kinds of stellate trichomes, while the trichome variability in P. subsect. Tetragonae was sufficiently high for species discrimination. An ancestral character state reconstruction was performed in order to investigate the evolution of trichome types and it revealed the following evolutionary trends in trichome characters of Phlomoides: 1) branched trichomes are primitive in Phlomoides as compared to simple ones, 2) long simple non-glandular trichomes are derived as compared to short simple ones and 3) the presence of stalked glandular trichomes is advanced as compared to subsessile or sessile ones.