Subtree analysis and three area satements (TASS) procedure are used to deal with the area relationship in historical biogeography. On the basis of the taxon cladogram, the procedure could identify and eliminate the ...Subtree analysis and three area satements (TASS) procedure are used to deal with the area relationship in historical biogeography. On the basis of the taxon cladogram, the procedure could identify and eliminate the paralogy node and determine the informative subtree. The area relationships are generally illustrated in several subtrees and the consensus tree. The distribution pattern of the genus Caragana comprising about 72 species and occurring in 13 areas, was analyzed by using subtree method and TASS procedure in this study. The results showed seven subtrees representing the area relationships of section and series of the genus, and the consensus tree provided the 13 area relationships. These results are congruent with our former result using component analysis for Caragana.展开更多
Lead concentrations in roots, stems and leaves of accumulating and non accumulating ecotypes of Sedum alfredii (Hance) were studied through a hydroponic experiment with different Pb concentrations supplied as Pb(...Lead concentrations in roots, stems and leaves of accumulating and non accumulating ecotypes of Sedum alfredii (Hance) were studied through a hydroponic experiment with different Pb concentrations supplied as Pb(NO 3) 2. Lead concentrations in leaves and stems of the accumulating ecotype were 4-9 times and 3-5 times those of the non accumulating ecotype, and Pb accumulated amounts in stems and leaves of the accumulating ecotype were 4-9 times and 8-11 times higher than those of the non accumulating ecotype, respectively. The results indicated that the accumulating ecotype had better ability to transport Pb from roots to shoots. The subcellular distributions of Pb in the root, stem and leaf tissues were studied using sucrose differential centrifugation. Approximately 50% of Pb contents was found to be associated with the cell wall fraction in stems of the accumulating ecotype and the percentage increased to 80% both in roots and leaves, no matter when plants were grown with different levels of Pb. The results indicated that the distribution of Pb on cell walls of the accumulating ecotype could mainly account for the high tolerance to Pb.展开更多
文摘Subtree analysis and three area satements (TASS) procedure are used to deal with the area relationship in historical biogeography. On the basis of the taxon cladogram, the procedure could identify and eliminate the paralogy node and determine the informative subtree. The area relationships are generally illustrated in several subtrees and the consensus tree. The distribution pattern of the genus Caragana comprising about 72 species and occurring in 13 areas, was analyzed by using subtree method and TASS procedure in this study. The results showed seven subtrees representing the area relationships of section and series of the genus, and the consensus tree provided the 13 area relationships. These results are congruent with our former result using component analysis for Caragana.
文摘Lead concentrations in roots, stems and leaves of accumulating and non accumulating ecotypes of Sedum alfredii (Hance) were studied through a hydroponic experiment with different Pb concentrations supplied as Pb(NO 3) 2. Lead concentrations in leaves and stems of the accumulating ecotype were 4-9 times and 3-5 times those of the non accumulating ecotype, and Pb accumulated amounts in stems and leaves of the accumulating ecotype were 4-9 times and 8-11 times higher than those of the non accumulating ecotype, respectively. The results indicated that the accumulating ecotype had better ability to transport Pb from roots to shoots. The subcellular distributions of Pb in the root, stem and leaf tissues were studied using sucrose differential centrifugation. Approximately 50% of Pb contents was found to be associated with the cell wall fraction in stems of the accumulating ecotype and the percentage increased to 80% both in roots and leaves, no matter when plants were grown with different levels of Pb. The results indicated that the distribution of Pb on cell walls of the accumulating ecotype could mainly account for the high tolerance to Pb.
