Developmental morphology of seedling and shoot and phylogenetic relationship of Diplobryum koyamae (Podostemaceae).
Developmental morphology of seedling and shoot and phylogenetic relationship of Diplobryum koyamae (Podostemaceae).
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DOI：
10.3732/ajb.0900157
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发表时间：
2010-03
影响因子：
3
通讯作者：
S. Koi;Masahiro Kato
中科院分区：
文献类型：
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作者：
S. Koi;Masahiro Kato
我们表明，跳跃进化是经常性的水生被子植物Podostemaceae的幼苗的身体计划，与其他被子植物的幼苗几乎共同的身体计划。本文报道了一种无根的双孢藓属Diplobryum koyamae，该属的植物为水螅属Hydrodiscus。这样的身体平面不同于亚洲Podostemoideae的其他成员，包括根上生长的退化或中等的枝条。分子系统发育分析表明，H. koyamae是亚洲Podostemoideae内的Hanseniella，Hydrobryum和Thawatchaia的甲壳根组的姐妹。萌发的胚没有胚芽和胚根，只有一个子叶和一个短的下胚轴，下胚轴内源产生不定芽。叶是在没有茎顶端分生组织的情况下形成的，伴随着淡染色细胞的分离。通过与亚洲其他种的幼芽和不定根的比较，以及它们之间的系统发育关系，沿着，表明该属植物的苗体平面发生了跳跃式进化。小山阳导致非凡的成年人的身体计划，如在单独的分支Dalzellia，Indodalzellia和Indotristicha的亚科Tristichoideae。
We demonstrated that saltational evolution was recurrent in the body plans of seedlings of the aquatic angiosperm Podostemaceae, in contrast to other angiosperms with seedlings having almost common body plans. Diplobryum koyamae, transferred to the genus Hydrodiscus described in this paper, has long-floating shoots with an anchoring disk-like base and is rootless. Such a body plan is distinct from other members of Asian Podostemoideae comprising reduced or moderate shoots borne on the root. Here, our molecular phylogenetic analysis revealed that H. koyamae is sister to a crustose-rooted group of Hanseniella, Hydrobryum and Thawatchaia within Asian Podostemoideae. The germinating embryo was devoid of plumule and radicle, and comprised a single cotyledon and a short hypocotyl, which produced an adventitious shoot endogenously. The leaves are formed in the absence of the shoot apical meristem, accompanying the separation of lightly stained cells. Comparison with other species of Asian Podostemoideae having the plumule and the adventitious root in the seedling, along with their phylogenetic relationship, suggests that saltational evolution occurred in the seedling body plan of H. koyamae leading to the extraordinary adult body plan, as in the separate clade of Dalzellia, Indodalzellia, and Indotristicha of the subfamily Tristichoideae.