Morphology and Leaflet Anatomy of the Ceratozamia norstogii (Zamiaceae, Cycadales) Species Complex in Mexico with Comments on Relationships and Speciation
Morphology and Leaflet Anatomy of the Ceratozamia norstogii (Zamiaceae, Cycadales) Species Complex in Mexico with Comments on Relationships and Speciation
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墨西哥 Ceratozamianorstogii（Zamiaceae、Cycadales）物种复合体的形态学和传单解剖，并对关系和物种形成进行评论
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Sergio Avendaño
中科院分区：
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作者：
M. A. Pérez‐Farrera;A. Vovides;Sergio Avendaño
许多种之间亲缘关系密切，并在组成分类群之间形成具有很大相似性的种复合体，特别是在幼虫阶段。这一点，加上标本馆标本中特征的丧失，导致了关于该种的识别和验证的争论。本研究从形态和小叶解剖学的角度，对组成北欧藜种复合体的四个种进行了研究，以阐明该复合体中四个分类群之间的关系。方法：对于形态变异， 从四个物种的每个种群中的29个个体中抽取了9个营养变量和6个生殖变量。对于小叶解剖变异，取自每个物种的5个成年植株，在均匀的条件下培养5年。用标准植物组织学技术获得小叶和角质层的横切面，并在明视场光学显微镜下进行检查。描述了小叶的横断面解剖和角质层特征。在考虑生境信息，特别是海拔的情况下，用多元统计方法对形态和解剖变量进行了分析。关键结果：在物种间的解剖和形态数据之间发现了 一致性。四个物种的多变量间距没有重叠。结论： 这四个分类群由不同的种组成。生态梯度的影响，特别是种群之间海拔高度的明显差异，而不是地理距离，似乎解释了物种之间发现的形态和小叶解剖差异，这支持了一种在北冰草复合体中生态物种形成过程的情景。
Premise of research. Many Ceratozamia species are closely related and form species complexes with great similarity among the component taxa, especially in juvenile stages. This, coupled with character loss in herbarium specimens, has resulted in debate regarding recognition and validation of the species. This study, focused on the four species comprising the Ceratozamia norstogii species complex from a morphological and leaflet anatomy viewpoint, was undertaken to clarify relationships among the four taxa in the complex. Methodology. For morphological variation, 29 individuals from one population of each of the four species was sampled for nine vegetative and six reproductive variables. For leaflet anatomical variation, leaflets were taken from five adult plants of each species held under cultivation for >5 yr under uniform conditions. Cross sections of leaflets and cuticular peels were obtained using standard plant histological techniques and examined under bright-field light microscopy. Cross sections of leaflet anatomy and cuticular features are described. Both morphological and anatomical variables were analyzed by multivariate statistical methods taking habitat information into account, especially elevation. Pivotal results. Consistency between anatomical and morphological data among the species was found. The multivariate spacing for the four species showed no overlap. Conclusions. The four taxa comprise distinct species. Effects of ecological gradients, especially distinct differences in elevation between the populations rather than geographical distances, appear to explain the morphological and leaflet anatomical differences found between the species, which supports a scenario for an ecological speciation process in the C. norstogii complex.