Patterns of Morphological and Plastid DNA Variation in the Corallorhiza striata Species Complex (Orchidaceae)
Patterns of Morphological and Plastid DNA Variation in the Corallorhiza striata Species Complex (Orchidaceae)
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DOI：
10.1600/036364409789271245
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发表时间：
2009-07-01
影响因子：
1
通讯作者：
Freudenstein, John V.
中科院分区：
文献类型：
--
作者：
Barrett, Craig F.;Freudenstein, John V.
Corallorhiza striata是一种分布广泛，形态多变，真菌异养的复杂物种，分布在北美。本研究的目的是评估以前划分的纹状草品种的关系和检验有效性，包括最近描述的本特利。对来自北美几个种群的个体的两个质体DNA区域进行了测序，确定了四个主要的进化支。花大的C. striata变种striata（美国北部，加拿大南部）是花小的变种vreelandii（美国西南部，墨西哥）的姐妹，它们是加利福尼亚一个花相对中等大小的分支的姐妹。墨西哥的C. striata变种. involuta和美国东部的濒临灭绝的C. bentleyi有密切的亲缘关系，是现存的C. striata的姐妹种。以质体DNA支系为自变量，对9个定量形态学性状进行主成分分析和非参数多变量方差分析，结果表明分子类群与形态学类群之间存在较强的相关性。形态学分析表明，相对于所有其他种类的纹状麻，渐开线变种和本特利变种都存在分化，表明它们是单独的种；这些发现将对未来的保护产生影响。生物地理情景比以前认为的要复杂得多，两个主要的质体DNA谱系(C. bentley /var.；存在于墨西哥和美国/加拿大的involuta和剩余的C. striata)。这些发现有助于对延伸到墨西哥南部的北美植物分布进行大量研究。
Corallorhiza striata is a wide-ranging, morphologically variable, mycoheterotrophic species complex distributed across North America. Objectives of this study were to assess relationships and test validity of previously delimited varieties of C. striata, including the recently described C. bentleyi. Two plastid DNA regions were sequenced for individuals from several populations across North America, identifying four major clades. The large-flowered C. striata var. striata (northern U.S.A., southern Canada) was sister to the smaller-flowered var. vreelandii (southwestern U.S.A., Mexico), and these were sister to a Californian clade with relatively intermediate-sized flowers. C. striata var. involuta (Mexico) and the endangered C. bentleyi (eastern U.S.A.) shared a close relationship, sister to the remaining C. striata. Principal Components Analysis and Nonparametric Multivariate Analysis of Variance on nine quantitative morphological characters, using plastid DNA clades as independent variables, demonstrated strong correlations between molecular and morphological groupings. Morphological analyses supported differentiation of both C. striata var. involuta and C. bentleyi relative to all other accessions of C. striata, suggesting their recognition as separate species; these findings will have future implications for conservation. The biogeographic scenario was more complex than previously thought, with members of two major plastid DNA lineages (C. bentleyi/var. involuta and the remaining C. striata) existing in Mexico and U.S.A./Canada. These findings contribute to a burgeoning body of data on poorly studied North American plant distributions extending into southern Mexico.