Study On The Flora And Phylogeny Of Impatiens L. In Hengduan Mountains

The author studied the flora of Impatiens L. in Hengduan Mountains, including structure and distribution of Impatiens species, floristic features and characteristic, and origin et al. And the phylogenetic relationship and distribution of Impatiens species based on evidences from ITS sequences are also studied. The main results are summarized as follows:1. Species structure and distribution:There are 113 Impatiens species and varieties in the Hengduan Mountains,44.1% of the total species in China,45.2% of the total species in Southeast Asian,12.6% of the total species in the world. Impatiens species unevenly distributes in the Hengduan Mountains, and species in subregion of Yunnan is most abundant accounting for 86 species and for 76.1% of the total species. Vertical distribution of the Impatiens species is evident in Hengduan Mountains, and they distribute between 840 m and 4200 m alt. but mainly distribute between 2600 m and 3500 m (44 species, accounting for 38.9% of the total species). Endemic species are rich in the Hengduan Mountains, there are 95 species (accounting for 84.1% of the total species) endemic to the China,80 species (accounting for 70.1%of the total species) endemic to the Hengduan Mountains, and 40 species endemic to northwest Yunnan (accounting for 35.4% of the total species).2. Floristic characteristic and status:113 Impatiens species can be divided into 6 types of 15 distribution types from Chinese seed plants flora, there are 54 species to be tropic character (accounting for 47.8% of total species) and 59 species to be temperate character (accounting for 52.2% of total species), this shows that Impatiens flora in Hengduan Mountains possesses tropical to temperate transition. Owing to the especial geography location and unique natural environments, rich diversities Impatiens species distributes in Hengduan Mountains region, including evolutional types and primordial types. Morphological traits of Impatiens in Hengduan Mountains including fruit shape, inflorescence type, flowers number, and floral morphology et al., possess more diversity in comparison with Africa and Madagascar et al. So this region should be center of the Impatiens distribution and differentiations, its Impatiens flora is age-old and plays an important station in Impatiens flora of China and even world.3. Phylogenetic relationship of Impatiens:Based the nrDNA ITS of 40 species, which represent most of the Impatiens types, two phylogenetic trees are constructed using Hydrocera triflora, Norantea guianensis and Tetramerista sp. at out groups. The result strongly support Balsaminaceae is a monophyletic, and Impatiens is a sister group of Hydrocera. Four major clades are recognized in high posterior probability value. CladeⅠlocates the root of phylogenetic tree, species of this clade have many primordial character, such as four lateral sepals and 3-colpate pollen et al. This group should be the primordial Impatiens group in Hengduan Mountains, even China and the world. Four lateral sepals, 3-colpate pollen, and mallet-shaped fruit should be ancestral character of Impatiens. CladeⅡis clustered by species with long lineshaped or clavate fruit and inflorescence having numerous flowers (usually more than 4 flowers). CladeⅢis clustered by species with spindle-shaped fruit and inflorescence having less flowers (usually less than 4 flowers). Clade IV is clustered by more evolutional species with long lineshaped or clavate fruit and inflorescence having less flowers(usually less than 4 flowers), and.4. Origin and related flora problem of Impatiens:Impatiens of Hengduan Mountains should not originate from Africa, and not diffuse from Madagascar and India-Pakistan subcontinent. Primordial group of Impatiens widely occurs in Hengduan Mountains before Himalayas uplift, As Himalayas-Hengduan Mountains uplift and climate changed, some of primordial species disappeared or shrinked back, and others differentiated continuously into new taxon. At the same time, Impatiens of Hengduan Mountains continually impacted with other regions. So Southwest China mainly including Hengduan Mountains should be the birthplace of the Impatiens species.5. New discovery of flora:Five new species (Impatiens yaoshanensis K. M. Liu& Y. Y. Cong published in Annales Botanici Fennici,I. fugongensis K. M. Liu & Y. Y. Cong published in Botanical studies,I. quadriloba K. M. Liu et Y. L. Xiang, I. oblonga K. M. Liu & Y. Y. Cong accepted by Novon and I. stipitata K. M. Liu & Y. Y. Cong in review) and 14 new record species of Impatiens are found, so the information of Impatiens flora and germplasm of China are enriched at great extent.