Tian-Gang Gao

Raman scattering study of rutile SnO2 nanobelts synthesized by thermal evaporation of Sn powders

The Raman spectrum of single-crystalline rutile tin dioxide (SnO2) nanobelts synthesized by thermal evaporation of tin powders was studied. Three Raman shifts (474, 632, 774 cm−1) showed the typical feature of the rutile phase of the as-synthesized SnO2 nanobelts. It was found that two infrared (IR)-active modes (313 and 690 cm−1) appeared in Raman spectrum and some peaks were broadened.

Alumina nanowire arrays standing on a porous anodic alumina membrane

Alumina nanowire arrays standing on the surface of a porous anodic alumina membrane have been achieved by first forming a porous anodic alumina membrane with parallel Y-branched nanochannels by reducing the applied anodizing voltage by a factor of in the anodization process of high-purity Al foil, and then chemically etching the Y-branched nanochannel alumina membrane in an aqueous phosphoric acid solution. The novel nanostructures may be used for two-dimensional photonic bandgap structural materials.

Tree of life for the genera of Chinese vascular plants

We reconstructed a phylogenetic tree of Chinese vascular plants (Tracheophyta) using sequences of the chloroplast genes atpB, matK, ndhF, and rbcL and mitochondrial matR. We produced a matrix comprising 6098 species and including 13 695 DNA sequences, of which 1803 were newly generated. Our taxonomic sampling spanned 3114 genera representing 323 families of Chinese vascular plants, covering more than 93% of all genera known from China. The comprehensive large phylogeny supports most relationships among and within families recognized by recent molecular phylogenetic studies for lycophytes, ferns (monilophytes), gymnosperms, and angiosperms. For angiosperms, most families in Angiosperm Phylogeny Group IV are supported as monophyletic, except for a paraphyletic Dipterocarpaceae and Santalaceae. The infrafamilial relationships of several large families and monophyly of some large genera are well supported by our dense taxonomic sampling. Our results showed that two species of Eberhardtia are sister to a clade formed by all other taxa of Sapotaceae, except Sarcosperma. We have made our phylogeny of Chinese vascular plants publically available for the creation of subtrees via SoTree (http://www.darwintree.cn/flora/index.shtml), an automated phylogeny assembly tool for ecologists.

Thin Au film with highly ordered arrays of hemispherical dots

Thin Au films with highly ordered arrays of hemispherical dots have been fabricated by evaporating Au on the surface of porous anodic alumina template.The hemispherical Au dot arrays arranged in a hexagonal pattern are highly ordered.The densities of the hemispherical Au dots in the array are approximately 1.2=10 m with dot diameters and heights of 12 y2

Gymnaconitum, a new genus of Ranunculaceae endemic to the Qinghai-Tibetan Plateau

The monophyly of traditional Aconitum remains unresolved, owing to the controversial systematic position and taxonomic treatment of the monotypic, Qinghai-Tibetan Plateau endemic A. subg. Gymnaconitum. In this study, we analyzed two datasets using maximum likelihood and Bayesian inference methods: (1) two markers (ITS, trnL-F) of 285 Delphinieae species, and (2) six markers (ITS, trnL-F, trnH-psbA, trnK-matK, trnS-trnG, rbcL) of 32 Delphinieae species. All our analyses show that traditional Aconitum is not monophyletic and that subgenus Gymnaconitum and a broadly defined Delphinium form a clade. The SOWH tests also reject the inclusion of subgenus Gymnaconitum in traditional Aconitum. Subgenus Gymnaconitum markedly differs from other species of Aconitum and other genera of tribe Delphinieae in many non-molecular characters. By integrating lines of evidence from molecular phylogeny, divergence times, morphology, and karyology, we raise the mono- typic A. subg. Gymnaconitum to gener ic status.

A comprehensive generic-level phylogeny of the sunflower family: Implications for the systematics of Chinese Asteraceae

The sunflower family (Asteraceae) is the largest and the most diverse flowering plant family, comprising 24 000–30 000 species and 1600–1700 genera. In China, Asteraceae are also the largest family, with approximately 2336 indigenous species in 248 genera. In the past two decades, molecular phylogenetic analyses has contributed greatly to our understanding of the systematics of Asteraceae. Nevertheless, the large‐scale analyses and knowledge about the relationships of Chinese Asteraceae at the generic level as a whole are far from complete due to difficulties in sampling. In this study, we presented a three‐marker (rbcL, ndhF, and matK) phylogeny of Asteraceae, including 506 genera (i.e., approximately one‐third of Asteraceae genera). The study sampled 200 Chinese genera (i.e., approximately 80% of Chinese Asteraceae genera). The backbones of the new phylogeny were largely congruent with earlier studies, with 13 subfamilies and 45 tribes recognized. Chinese Asteraceae were distributed in 7 subfamilies (Mutisioideae, Wunderlichioideae, Carduoideae, Pertyoideae, Gymnarrhenoideae, Cichorioideae, and Asteroideae) and 22 tribes (Mutiseae, Hyalideae, Cardueae, Pertyeae, Gymnarrheneae, Vernonieae, Cichorieae, Doroniceae, Senecioneae, Astereae, Anthemideae, Gnaphalieae, Calenduleae, Inuleae, Athroismeae, Helenieae, Coreopsideae, Neurolaeneae, Tageteae, Millieae, Eupatorieae, and Heliantheae). Chinese Asteraceae lacked 6 basal subfamilies and 23 tribes. Several previously ambiguous relationships were clarified. Our analyses also resolved some unplaced genera within Chinese Asteraceae. Finally, our phylogenetic tree was used to revise the classification for all genera of Chinese Asteraceae. In total, 255 genera, 22 tribes, and 7 subfamilies in China are recognized.

A SET OF NOVEL MICROSATELLITE MARKERS DEVELOPED FOR THE TRADITIONAL TIBETAN MEDICINAL PLANT HALENIA ELLIPTICA (GENTIANACEAE)

PREMISE OF THE STUDY Microsatellite primers were developed in the traditional Tibetan medicinal plant Halenia elliptica D. Don to investigate its genetic diversity and population genetic structure. METHODS AND RESULTS Using the Fast Isolation by AFLP of Sequences Containing (FIASCO) repeats protocol, 24 primer sets were identified in two wild populations. Of these primers, 12 displayed polymorphisms and 12 were monomorphic. The number of alleles per locus ranged from 2 to 6, with a mean of 3.9. The expected (H(E)) and observed (H(O)) heterozygosities ranged from 0.191 to 0.784 and from 0.417 to 0.917, respectively. All these primers successfully amplified in two close relatives of H. elliptica, Swertia bimaculata (Siebold & Zucc.) Hook. f. & Thomson ex C. B. Clarke and S. tetraptera Maxim. CONCLUSIONS These markers will facilitate further studies on the population genetics of Halenia elliptica and its allied species.

Inaccessible Biodiversity on Limestone Cliffs: Aster tianmenshanensis (Asteraceae), a New Critically Endangered Species from China.

Aster tianmenshanensis G. J. Zhang & T. G. Gao, a new species of Asteraceae from southern China is described and illustrated based on evidence from morphology, micromorphology and molecular phylogeny. The new species is superficially similar to Aster salwinensis Onno in having rosettes of spatulate leaves and a solitary, terminal capitulum, but it differs by its glabrous leaf margins, unequal disc floret lobes and 1-seriate pappus. The molecular phylogenetic analysis, based on nuclear sequences ITS, ETS and chloroplast sequence trnL-F, showed that the new species was nested within the genus Aster and formed a well supported clade with Aster verticillatus (Reinw.) Brouillet et al. The new species differs from the latter in having unbranched stems, much larger capitula, unequal disc floret lobes, beakless achenes and persistent pappus. In particular, A. tianmenshanensis has very short stigmatic lines, only ca. 0.18 mm long and less than 1/3 of the length of sterile style tip appendages, remarkably different from its congeners. This type of stigmatic line, as far as we know, has not been found in any other species of Aster. The very short stigmatic lines plus the unequal disc floret lobes imply that the new species may have a very specialized pollination system, which may be a consequence of habitat specialization. The new species grows only on the limestone cliffs of Mt. Tianmen, Hunan Province, at the elevation of 1400 m. It could only be accessed when a plank walkway was built across the cliffs for tourists. As it is known only from an area estimated at less than 10 km2 and a walkway passes through this location, its habitat could be easily disturbed. This species should best be treated as Critically Endangered based on the International Union for Conservation of Nature Red List Categories and Criteria B2a.