The Phylogeny Of Subgenus Clavicarpa(Impatiens)

In this paper,the gross morphology of plants in subgenus Clavicarpa were researched,based on herbarium study and field observations,combined with pollen micromorphology,molecular characters.It disscussed the phylogeny of subgenus Clavicarpa(Impatiens).The results were summarized as follows:1.MorphologyWith herbarium study on specimen and field observations,we researched the variation pattern of morphological characters of the subgenus Clavicarpa species.The results confirmed the good characters for taxonomy included in flowers.Inflorescence types,the lateral sepal number,the dorsal sepal and capsule shape,are the most constant and most reliable diagnostic taxonomic characters in the subgenus.subgenus Clavicarpa are characterized by perennial herb,more than 5-flowered racemose inflorescence,4 lateral sepals,hammer-shaped capsule,4-carpellated ovary with one seed per loculus.2.Pollen micromorphologyIn order to clarify taxonomic significance of pollen from subgenus Clavicarpa,14 species plus one contrast species were selected and investigated under scanning electron microscope in this study.Theresult of this study showed: pollen presented as single grain,and appeared the characteristic of 3-colpate,actinomorphic and triangular or subcircular in polar view.The exine of pollen was of reticulate ornamentation and muri of reticulate ornamentation were smooth or sinuolate towards margin.There were granules in the lumina with different density.The pollen morphology of subgenus Clavicarpa was similar to that of Hydrocera,showing the subgenus was original in Impatiens.However,variation in the aspects of pollen shapes in polar and equatorial view and reticulate ornamentations were consensus within species,which expressed the taxonomical value in circumscription among species within Clavicarpa.3.Phylogeny of subgenus ClavicarpaBased on DNA sequence data from nuclear ribosomal ITS and chloroplast atpB-rbcL space and trn L-F for 13 taxa of subgenus Clavicarpa,the phylogeny of the subgenus was investigated using Baysian Inference.The results strongly support the monophyly of Balsaminaceae.Impatiens and Hydrocera are confirmed as sister group relationship.subgenus Clavicarpa were recognized through very high posterior probability value,thus subgenus Clavicarpa is sister to all other studied Impatiens species.Subgenus Clavicarpa with high supporting located in basal,showing the subgenus was original in Impatiens.Each branch's approval rating is low,which speculated that subgenus Clavicarpa plants are split radiation rapidly in a short time.