Endophytes constitute an important component of microbial diversity, and in the present investigation, seven plant species with rich ethnobotanical uses representing six families were analyzed for the presence of endophytic fungi from their natural habitats during monsoon (May/June) and winter (November/December) seasons of 2007. Fungal endophytes were isolated from healthy plant parts such as stem, root, rhizome, and inflorescence employing standard isolation methods. One thousand five hundred and twenty-nine fungal isolates were obtained from 5200 fragments. Stem fragments harbored more endophytes (80.37%) than roots (19.22%). 31 fungal taxa comprised of coelomycetes (65%), hyphomycetes (32%), and ascomycetes (3%). Fusarium, Acremonium, Colletotrichum, Chaetomium, Myrothecium, Phomopsis, and Pestalotiopsis spp. were commonly isolated. Diversity indices differed significantly between the seasons (P<0.001). Species richness was greater for monsoon isolations than winter. Host specificity was observed for few fungal endophytes. UPGMA cluster analysis grouped the endophytes into distinct clusters on the basis of genetic distance. This study is the first report on the diversity and host-specificity of endophytic fungal taxa were from the semi evergreen forest type in Talacauvery subcluster of Western Ghats.
A total of 143 endophytic fungal isolates were recovered from 1350 bark, twig and leaf segments of Vitex negundo L. which has important traditional medicinal value in the Indian system of medicine. The isolates belonged to ascomycetes (24%), coelomycetes (21%), hyphomycetes (51%) and mycelia sterilia (4%) groups. Lasiodiplodia sp. was the dominant endophyte in all the plant parts. The endophytic taxa were identified on the basis of morphology and DNA sequence data. Twig samples harboured higher number of endophytic taxa than the bark and leaf tissues of V. negundo. Phylogenetic relationships of the endophytic fungi were estimated from the sequences of the ITS region. Our studies indicate that diverse endophytic genera are grouped into six clades with respective fungal endophytes grouped in separate clades.
To explore the effect of filler on the electrical conductivity of polymer nanocomposites, polystyrene coacrylonitrile and TiO 2 (PSAN/TiO 2 ) nanocomposites of different TiO 2 wt% have been prepared. The microstructural characterization has been performed by positron annihilation lifetime spectroscopy (PALS). Positron lifetime parameters viz. o-Ps lifetime (s 3 ) and free volume size (V f ) decreases up to 0.6 wt% suggests the filling of the cavities by Ti 31 and O 2 ions as well as complex formation. The increased free volume size (V f ) after 0.6 wt% of TiO 2 was attributed to the o-Ps annihilation at the interface of PSAN and TiO 2 nanoclusters. The variation of electrical conductivity at lower and higher concentration of TiO 2 is attributed to the blocking effect and space charge effect, respectively. The electrical conductivity decreases along with the free volume sizes at lower concentration of TiO 2 due to the hindrance of the ions mobility. The increased conductivity with the increased free volume sizes indicates the formation of more void space at the interface due to the formation of TiO 2 nanoclusters. The surface morphology of the nanocomposites studied by scanning electron microscopy (SEM) shows uniform dispersion at the lower wt% of TiO 2 and increased size of nanocluster formation at the higher concentration of TiO 2 nanoparticles in PSAN matrix. The crystallinity evaluated by X-ray diffraction (XRD) results also indicates the formation of TiO 2 nanoclusters between 0.6 and 1.0 wt% of TiO 2 . Fourier transform infrared spectroscopy (FTIR) suggests the improved chemical and physical interaction between the functional groups of TiO 2 and polymer side chain. POLYM. COMPOS., 00:000-000,
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.