Secondary Structure And Phylogenetic Relationship On Sevsral Species In Sorbus L.

Sorbus L. with about 100 species of important ornamental, medicinal and edible values, is a genus in Rosaceae, Maloideae. Acetic acid-hydrogen peroxide maceration and collodion embedding were applied to research the interspecific secondary structures differences,and SSR-PCR was used to analysis interspecific phylogenetic relationship in Sorbus L., so as to provide anatomical and molecular biological evidence for the defining of this species. Main conclusions are as follows:1. Secondary structure characteristics of Sorbus L.Secondary structure of 7 taxa: S. alnifolia, S. alnifolia var. lobulata, S. dunnii, S. hemsleyi, S. amabilis, S. hupehensis var. paucijuga and S. pohuashanensis were studied in this paper, the results are shows that:Type of wood as the experimental materials is diffuse porous, which is much primitivity. Parenchyma cells are diffused, occasionally in marginal. The width of rays varies from one to three cells(s). Simple perforation plates occur commonly at both ends of vessel, however, occasionally, there are 1-2 bars on perforation plate(s) or reticulate perforation plate(s) and helical thickening showed on small vessels of late wood. Vessel length varies from 498.6± 122.0?m to 762.5±163.7?m. Fibers are fusiform and sharp, with thin fiber walls and length of 830.1±107.2?m~1184.8±186.3?m; Vessel and wood fiber length of the single leaves group are both longer than compound leaves group, indicating that single leaves group is more primitive compared with compound leaves group.Secondary phloem in all experimental taxa of Sorbus are composed of sieve tube, phloem fiber, phloem parenchyma cell and phloem ray, and with Stone cells distribute occasionally in it. Sieve tube and phloem parenchyma cell are separated by fiber bands in tangential direction, and arrange alternatively. Phloem fiber band of simple leaves Sorbus is in the strip shape, while that of compound leaves Sorbus are parallel to lump; Phloem fiber band width of simple leaves Sorbus is narrower than that of compound leaves Sorbus. Both ends of the phloem fiber are tapered, with thick fiber walls and the length of 583.98±144.7?m~846.6±163.4?m, simple leaves group is longer than compound leaves group.SPSS clustering analysis based on the results of secondary structure shows that: simple leaves Sorbus and compound leaves Sorbus have significant difference.2. Genetic Relationship analysis on Sorbus based on SSR markerThe experiment materials were 12 taxa: S. alnifolia, S. alnifolia var. lobulata, S. alnifolia var. angulata, S. japonicus, S. dunnii, S. folgneri, S. hemsleyi, S. ochracea, S. megalocarpa, S. amab ilis, S. hupehensis var. paucijuga and S. pohuashanensis. 13 pairs of SSR primers were applied to carry out PCR, and amplified 101 polymorphic bands. The variation range of observed alleles(Na) is 4~10, and the average value is 7.7692; The variation range of effective number of alleles(Ne) has a variation range of 2.6782~6.5976, with the average value of 4.9762; The variation range of Shannon information index(I) is 1.0977~2.0400, with the average value of 1.7255; The variation range of observed heterozygosity(Ho) and expected heterozygosity(He) are respectively 0.1273~ 0.4909 and 0.6324~0.8595, and the average values are respectively 0.3385 and 0.7939.The experimental materials were divided into two groups according to UPGMA cluster analysis. Group one contain all compound leaves Sorbus and Group two including all simple leaves Sorbus.According to the analysis result of genetic identity and genetic distance, this study supports to use S. alnifolia var. lobulata in the variant processing of S. alnifolia, but neither support to use S. alnifolia var. angulata in the variant processing of S. alnifolia nor use S. alnifolia var. angulata in the synonym plant processing of S. japonicus.