秋海棠属是世界有花植物第六大属，是被子植物分类困难的类群之一，亟需增加形态性状的比较研究，以便于今后对该属开展分类学修订。该研究选取国产秋海棠属中较为常见的侧膜组、秋海棠组、单座组和二室组共21种，应用扫描电镜观察花粉微形态，探讨花粉形态对秋海棠属植物的分类学意义。%Begonia L. is the sixth biggest genus of flowering plants in the world and a major genus in the family Begoniaceae. It is complicated in current section delimitation and more morphological characters are needed for critical revaluation within the genus. In present study,we selected 21 species from sectionsCoelocentrum, Begonia,Platycentrum andReichenheimiaofBegonia mainly distributed in China. Using the method of scanning electron microscopy (SEM),the pollen morphology was carefully examined and its systematic significance was discussed. The results showed that the common palynological characters of studies taxa were exhibited as monads, radially symmetrical,isopolar,3-zono-colporate and perprolate to prolate. For non-metric multidimensional scaling (NMDS) analysis,nine stable pollen characters were selected and coded as unordered and unweighted. The results supported that these sections were not monophyletic groups and the useful palynological features for this study were the pollen sides,outline of the poles,colpus,exine ornamentation,and margo. According to the ornamentation of margo,the studied taxa can be divided into two groups:(A) without margo and psilate margo, (B) regulate,exquisitely regulate and coarsely regulate margo. In relation to Group B,the taxa with regulate and exquisitely regulate grains were gathered while the taxa with coarsely regulate margo were located between Group A and B. It indicated that the feature of margo was exhibited as a transition,from without margo and psilate margo,along coarsely regulate margo to exquisitely regulate. Therefore,it is worthy to pay more attention on the feature of margo and increase more taxa of the genus in further studies.
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