China Generalized Polygonum Genus (polygonum S.lat.) And Its Closely Related Taxa Of The Phylogenetic And Geographic Distribution

In this paper, the phylogenetic relationships of Polygonum s. lat. and related taxa focusing on Chinese taxa were investigated by phenetic analysis, cladistic analysis and molecular systematics based on field investigation and collected spcimens, and their geographical distribution in China was analyzed. The main results were summarized as follows:1. Phenetic AnalysisThe phenetic analysis included 99 charaters of 70 species and varieties was done with the UPGMA method. The result shows that with the same standards and methods, different OTUs acted different results, the location of some groups and the relationship between groups remain same, others have changed, which are controversial in history. The sections in Polygonum should have been more natural, and the differences between sections are obvious. The results support Koenigia s. lat. is a natural group; sect. Persicria, sect. Echinocaulon, Antenoron, sect. Cephalophilon and Koenigia s. lat. have closer similarity; sect. Bistorta, sect. Aconogonon, Fagopyrum and Fallopia have closer similarity; sect. Polygonum and Pteroxygonum are independent separately. The results support Polygonum s. lat. is a multi-systemy group, which need to be divided into more natural groups.2. Cladistic AnalysisThe cladistic analysis included 49 charaters of 45 species and varieties was done with the maximum parsimony method, Rumex acetosa as outgroup. The result showed that the phenetic tree and cladistic tree based on morphological characters did not showed a good consistency, but still support sect. Persicria, sect. Echinocaulon, Antenoron and sect. Cephalophilon have close relationships, Fallopia and Reynoutria have a close relationships, sect. Polygonum, sect. Bistorta and sect. Echinocaulon are natural groups relatively.3. PhylogenyThe phylogenetic trees based on chloroplast trnL-F sequences of 65 species and varieties, chloroplast rbcL sequences of 64 species and varieties and nuclear ribosomal ITS sequences of 68 species and varieties of Polygonaceae in China were constructed based on individual and joint data matrix with NJ, MP and BI method respectively, Triplaris americana as outgroup. The results showed that:(1) sect. Persicria, sect. Echinocaulon, Antenoron and sect. Cephalophilon have close relationship, sect. Cephalophilon was the sister group of others; (2) sect. Bistorta, sect. Aconogonon and Koenigia s. lat. have close relationship, sect. Bistorta was the sister group of others; (3) Fallopia (except Fallopia denticulata), Reynoutria, sect. Polygonum, Atraphaxis and Polygonum sibiricum have close relationship, Polygonum sibiricum was the sister group of others. The phylogeny of Polygonaceae in China as follows (dotted line means that the relationship between groups could not be resolved in this paper):4. The Geographic DistributionThe geographic distribution of the tribe Polygoneae in China was studied based on our field investigation for many years and statistical analysis. The result shows that their distribution in China has a certain regularity, which the number of species in different regions appears an increasing trend from northeast to southwest in the horizontal distribution. There are six high-density areas, concentrating on the range of Hengduan-Qinba Mountains. The other genera or sections have their concentrated distribution except Fallopia, which widely distributed in the whole country. In the vertical distribution, almost all of the Polygoneae located below the altitude of 5000 meters. the whole Polygoneae widely distributes at an altitude of 1000-3000 meters, Koenigia, Polygonum sect. Bistorta, sect. Aconogonon and annual plants of sect. Cephalophilon mainly distributed above 3000 meters, sect. Polygonum, sect. Persicria, sect. Echinocaulon, Fallopia, Reynoutria, Antenoron and Fagopyrum mainly distributed below 1000 meters.