Phylogenetic And Genetic Relationships Of Cassiinae

Cassiinae are used as traditional Chinese medicine and pasture which have a lot of ecnomic value. Comparing to the world, the amount of Cassiinae in china, is not so much, only around 20. people still have different opinions on the relationship of Cassiinae. In the Species Plantarum (1753), Cassia was primarily proposed by Linnaeus, and was upgraded to subtribe Cassiinae, which was broken into Cassia, Chamaecrista and Senna, by Irwin and Barneby. But studies on them was very insufficient, in the botanic documents there is a lot of confusion about taxonomy(esp. under tribe and genus level and spps. in China) and naming system. take those 20 species for example, same species may have a different latin name. Being used as a traditional chinese medicine and pasture, these plants had a lot of ecnomic value.Systematic relationship of Cassiinae from China were studied by using sequence analysis of the nrDNA internal transcribed spacer (ITS) gene, ribulose-1, 5-bisphosphate carboxylase/oxygenase large subunit (rbcL) gene, germination, isozyme and seedcoat micromorp hological features, combination of traditional morphological classification. The result showed that:(1)Germination of Senna was negatively correlated with protein content, positive correlated with the content of POD.10 POD enzyme bands of Senna were found, characteristic enzyme bands are mainly in b-zone and a-zone.(2)Color, shape and testa ornamentation of Cassiinae seeds were varied. Micromorphology of seed coats were scalariform(1 species), undulate(1 species), stripe(1 species), verrucous(1 species), favulariate(1 species), ruminate(3 species), and smooth type(2 species).(3) Cassiinae could be divided into five clades, Clade I is Chamaecrista, monosymmetric flower, few is asymmetric, EFNs existed, stamens 5 or 10, pod elastically dehiscent CladeⅡ-Ⅴis Senna, polysymmetric flower or monosymmetric, stamens 10 or staminode 3, some has EFNs, indehiscent pod, few dehiscent by slits; Clade VI is Cassia, polysymmetric flower, stamens 10,3 of them long and curved, usually longer than petals, pod indehiscent. (4) Chamaecrista, Cassia and Senna are monophyly and won strong support, Cassia belonged to one branch with Senna, while was far with Chamaecrista. This is same with the results of traditional taxonomy and seed coat morphological.(5) Senna nomame should be placed in Chamaecrista, Senna corymbosa and S. bicapsularis in genetic relationship were near, both belonged to Senna.With phylogenetic tree constructed with the nrDNA internal transcribed spacer (ITS) gene, ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL) gene, germination, isozyme and seedcoat micromorp hological features。The results supported the classification of Irwin and Barneby, Chamaecrista, Cassia and Senna were monophyletic lineages, and proposed the attribution question of Senna nomame and S. corymbosa. this study providing the theory basis for deeply research.