粉色果实花楸母本起源的分子证据

Molecular Evidence for Maternal Origin of Sorbus with Pink Fruits

[目的]探讨河北驼梁山自然风景区内形态介于花楸树和北京花楸之间的粉色果实花楸的起源。[方法]本研究调查了花楸树、北京花楸和粉色果实花楸的海拔分布格局及生长状况,并通过叶绿体DNA序列分析3个类群的系统发育关系。[结果]北京花楸主要分布在海拔1 300 2 000 m,花楸树分布于1 500 2 200 m,粉果花楸出现在两者重叠分布区内;粉果花楸叶绿体单倍型有70%与北京花楸相同,10%与花楸树相同,其余20%为其特有。[结论]表明:粉色果实花楸是花楸树和北京花楸之间的天然杂交种,是多起源的类群,在自然分类系统中应作为独立的种来处理;花楸树和北京花楸均可作为母本。

[Objective]To explore the origin of Sorbus individuals with striking pink fruits,morphologically intermediated between Sorbus pohuashanensis and S. discolor in Mount Tuoliang,Hebei province. [Methods]The altitude distribution and growth state of S. pohuashanensis,S. discolor and Sorbus individuals with pink fruits were investigated and the phylogeny relationships of the these Sorbus species were analyzed by chloroplast DNA sequence. [Results]Most S. discolor are distributed at the elevation from 1 300 2 000 m. The majority of S. pohuashanensis distributes at an altitude from 1 500 to 2 200 m. The individuals with pink fruits appear in their sympathy area.70% haplotype of individuals with pink fruits shared with S. discolor and 10% with S. pohuashanensis,the other is the specific. [Conclusion]The Sorbus individuals with pink fruits originate from interspecific hybridization between S. pohuashanensis and S. discolor,it is also inferred that they have multiple origins and might belong to a new species in natural taxa system. S. pohuashanensis or S. discolor may serve as maternal parent of individuals with striking pink fruits.