Studies On Phylogeny Of Sect.Coprosmanthus In Smilax (Smilacaceae)

Smilacaceae is a widely distributed group of monocot plants. This family included three genera: Smilax, Heterosmilax and Ripogonum. Smilax is divided into Sect. China, Sect. Coilanthus, Sect. Macranthus and Sect. Aspera. But some botanists support that the herbaceous Sect. Copromanthus is of independent position in Smilax.We chose the herbaceous species of Sect: Copromanthus as the materials for this study. The phylogeny of Sect. Copromanthus was investigated from leaves morphology and molecular systematics in this paper. One of research method in molecular systematics was RAPD, which was a kind of DNA finger, the other was rpl 16 sequencing of DNA.The aim of this study was to investigate the relationship between the different herbaceous species which was distributed on the Eastern Asia and the Northern America, to investigate the relationship of herbaceous species and woody species and to investigate the relationship of the herbaceous section and the other sections of smilax.1) In the leaves morphology study, we analysed 5 characters of 10 populations. The result showed that S.riparia, S. nipponica and S.herbacea were completely differentiated in two characters.2) The chuster trees of RAPD analysis showed that the 25 populations were divided into two groups. One group including the populations from the Eastern Asia and the other including the ones from the Northern America. It seems that the herbaceous species distributed in the two regions are differentiated completely. Within the group of the Eastern Asia, S. riparia from different populations was clustered into one branch, and the S. nipponica from different populations was clustered into another branch, which showed that S. riparia and 5". nipponica are differentiated completely in the DNA molecular character.3) The phylogeny tree of rpl 16 intron showed that the herbaceous species were located in the same branch and the branch was at the top of the NJ tree. This supported the following spinion: the herbaceous section was of indepent position in Smilax and suggested recovering the Sect. Copromanthus.4) The populations similar to S.riparia, found in the Southern Yunnan, may be a new species, which was supported by the molecualr data. Also, it may be the ancestral group of the herbaceous Smlilax.