Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois 60115-2861 USA; and.
Am J Bot. 2001 Nov;88(11):1988-92.
Paniceae demonstrate unique variability of photosynthetic physiology and anatomy, including both non-Kranz and Kranz species and all subtypes of the latter. This variability suggests hypotheses of independent origin or reversals (e.g., from C(4) to C(3)). These hypotheses can be tested by phylogenetic analysis of independent molecular characters. The molecular phylogeny of 57 species of Paniceae was explored using sequences from the grass-specific insert found in the plastid locus rpoC2. Phylogenetic analyses confirmed some long-recognized alliances in Paniceae, some recent molecular phylogenetic results, and suggested new relationships. Broadly, Paniceae were found to be paraphyletic with Andropogoneae, Panicum was found to be polyphyletic, and Oplismenus hirtellus was resolved as the sister group to the remaining ingroup species. A particularly well-supported clade in the rpoC2 tree included four genera with non-Kranz species and three with distinctively keeled paleas. As previously suggested, the PCK (phosphoenol pyruvate carboxykinase) C(4) subtype arose once within Paniceae. All clades with non-Kranz species had Kranz ancestors or sister taxa suggesting repeated loss of the Kranz syndrome.
蒺藜草族表现出独特的光合作用生理学和解剖学变异性，包括非 Kranz 种和 Kranz 种以及后者的所有亚型。这种变异性提出了独立起源或逆转的假说（例如，从 C(4)到 C(3)）。这些假说可以通过对独立分子特征的系统发育分析来检验。使用来自质体基因座 rpoC2 中发现的草特异性插入物的序列，对蒺藜草族的 57 种植物进行了分子系统发育分析。系统发育分析证实了蒺藜草族中的一些长期公认的联盟、一些最近的分子系统发育结果，并提出了新的关系。广义上，蒺藜草族与黍族并系，而短柄草属是多系的，并且糙毛看麦娘被解析为与其余内群种的姐妹群。rpoC2 树中一个特别支持的分支包括四个具有非 Kranz 种的属和三个具有明显龙骨状颖片的属。正如先前所建议的，PCK（磷酸烯醇丙酮酸羧激酶）C(4)亚型在蒺藜草族中仅出现过一次。所有具有非 Kranz 种的分支都有 Kranz 祖先或姐妹分类群，这表明 Kranz 综合征的重复丢失。
