Morphological Characteristics And CpDNA Sequence Analysis Of Oil Plant Symplocos’ Complex In Hunan Areas

Symplocos paniculata, Symplocos chinensis and Symplocos hunanensis, which widely distribute in Hunan province and enrich with fat, have great potential of application as oil feedstocks and ornamental plants. For the three species are of similarity morphologically, and of co-existence, they were often referred to as Symplocos species or Symplocos complex. Also there was some dissent about their classfication. In this paper, nine populations of the three species concerning their distribution in Hunan province, plant morphological and anatomical structure, anther and pollen traits were invistigated and measured. The analysis of chloroplast DNA sequences of plant among the complex was conducted. Of those would be reference for their identification. The main results showed as follo wings:(1) Population distribution of the three species’s was different and sympatric. Symplocos chinensis scattered at area under 500 m altitude, its community characterized with both temperate and tropical broadleaf forest; Symplocos paniculata distributed between 400 to 1200m altitude area in scattered、cluster and gregaroid, and its community provided with subtropical evergreen Broad-leaved Forest traits; Symplocos.hunanensis cluster distribution above1200m altitude,then scattered below 1200m altitude. Its community in Daweishan area is provided with temperate forest nature,the temperate trees were superiority, while community of Hengshan area had the nature of tropical and northern temperate component.(2) The results of Principal component analysis and cluster analysis on 8 quantitative traits and 5 qualitative traits from the plants of 9 different populations of the three species showed:the difference of plant morphological traits among species were greater than that of among differental populations. The differences mainly resulted from leaf shape, ((included leaf length, leaf width, leaf color, leaf margin), branch lenticels,height and crown diameter of plant. Compared with the mophological difference of plant between Hengshan and Daweishan of Symplocos hunanensis., the difference among populations of Symplocos chinensis’and population Symplocos paniculata’,was a little. According to the findings, the 9 populations of Symplocos’complex was classified into 4 categories, namely:Symplocos chinensis、Symplocos paniculata, and Hengshan and Daweishan of Symplocos hunanensis, respectively, for the following study.(3) The anatomical structure traits, including stem cross section, wood construction, pith and bark thickness of plants from Symplocos chinensis、Symplocos paniculata, and Hengshan and Daweishan of Symplocos hunanensis were different. Proportion of lumber of Symplocos hunanensis was the largest, while pith of Symplocos chinensis was the smallest. There were also different to some extent in vascular shape and size, however fiber shape and cellwall thickness had little of different. The transverse section of leaf, except for Symplocos paniculatao, we would find trichome at lower epidermis position, from the other 3 populations’leaves, and the epidermal hairs of Hengshan’Symplocos hunanensis was the longest and most dense one,and its vascular bundle is the most developed.(4) There were morphological differences of anther and pollen among plants from Symplocos chinensis、Symplocos paniculata, and Hengshan and Daweishan of Symplocos hunanensis.The anther of Symplocos chinensis and Symplocos paniculata was etradymous,while anther of Symplocos hunanensis were both etradymous and bilocular. Pollen grain were also different morphologically, pollen grains of Symplocos chinensis and Symplocos paniculata were similar to triangular in the polar view. Pollens grains of Hengshan’ Symplocos hunanensis is flat oval, Daweishan’ Symplocos hunanensis had two forms of pollen grain, one was flat triangular prism with 3-colporate, the other was nearly flat Ellipsoidal with 4-colporate.(5) GC content of cpDNA from Symplocos chinensis, Symplocos paniculata, and Hengshan and Daweishan of Symplocos hunanensis, mainly between 20-60%, GC base pair hasn’t deviation.The length of matK and rbcL gene of the four categories were 1283 and 1414 bp. There was high sequence homology and less mutation sites among the 4 categories, meanwhile mutation sites was found in Symplocos hunanensis.The results from different phylogenetic trees are highly similar and obtain the support with high Bootstrap score, which proves that the analysis of genetic diversity and genetic relationship between four Symplocos populations are correct. Geographical isolation has bring gene difference.(6) Symplocos hunanensis were different from Symplocos chinensis and Symplocos paniculata in plant morphology, anatomy structure of leaf and stem, anther pollen grain shape, even in cpDNA to some extent. Also of those difference existed between Hengshan’Symplocos hunanensis and Daweishan’ Symp/ocos hunanensis.The long-term evolutionary has changed external form of different populations, and differences in gene sequences between them showed truly existence.