Observations on Spore Morphology of the Chinese Liverworts

The spore morphology of 9 species of 3 genera of Chinese liverworts was studied by scanning electron microscopic observation. They are Riccia huebeneriana Lindenb., R. hantamensis Perold., R. cavernosa Hoffm., R. warnstorfii Limpr. ex Warnst., R. frostii Aust., R. chinensis Herz., Asterella yoshinagana (Horik.) Horik., A. sanguinia L. et L., and Preissia quadrata (Scop.) Nees. There were evident morphological differences in spores among the above three genera. Difference of species morphology in the same genus was also observed. Therefore in the above genera and species the spore-wall ornamentation can be regarded as a criterion for taxonomic specificity. Meanwhile, slight difference in morphological characters of the same species collected from different sites was observed and reckoned to be an ecological adaptation.

Investigation of Biological Characteristics of Parasitic Fusarium Fungi from Tibetan Cordyceps sinensis

[Objective] This study aimed to investigate the biological characteristics of parasitic Fusarium fungi from tibetan Cordyceps sinensis. [Method] A Fusarium strain was isolated from fresh tibetan Cordyceps sinensis as the experimental material, to observe the morphologies of Fusarium mycelium and spores. [Result] The isolated Fusarium fungus strain grew lushly on rice medium, with white and villiform myceliurn, and the villous stroma appeared in colors from beige to pink. After cultivated at （18 ± 4） ℃ for 14 d, the Fusarium strain produced milky white protrusions containing pale yellow chlamydospores, which can be divided into microconidiums and macroconidiums based on the different sizes. According to Ainsworth＇s classification system, the isolated strain belongs to Fusarium, Tuberculariales, Hyphomycetes, adelomycete subphylum. Further observation identified three types of macroconidium, and two of them showed distinct morphology, which was not described in Ainsworth＇s classification system. [Conclusion] The structure of the strain isolated from tibetan Cordyceps sinensis is significantly different from that of Fusariurn fungi recorded in relevant literatures, which requires further investigation.

Analysis of the Biological Characteristics of a Parasitical Fungus in Chrysosplenium absconditicapsulum J. T. Pan Leaves

[Objective] This study aimed to uncover the biological characteristics of a parasitical fungus in Chrysosp/enium absconditicapsu/um J. T. Pan leaves. [Method] PDA medium was used to isolate the fungus from C. absconditicapsulum leaves; PDA medium, modified KB medium and Czapek medium were adopted to cultivate the isolated strain. [Result] Colonies of the strain were stretched, white, fedora- shaped with smooth and wavy edges, and showed diameter growth on PDA medi- um, modified KB medium and Czapek medium. At the late stage of culture, the colonies turned into cyanish brown on the above media. Spores were black and born on the surface of colonies on PDA medium with blackened medium. While on modified KB medium and Czapek medium, they were born at the edge of colonies with blackened medium. The spores varied in a wide range of shapes, mostly ob- clavate, sometimes spherical or ellipsoidal. The conidia were muriformly septate with transverse or longitudinal or oblique septations. The pseudo-beaks were short and cylindrical. [Conclusion] According to relevant literatures, the isolated strain is a fungus in Alternaria, Dematiaceae, Hylohomycetales, Hyphomycetes, Deuteromycotina.

Colonization Characteristics and Diversity of Arbuscular Mycorrhizal Fungi in the Rhizosphere of Iris lactea in Songnen Saline-alkaline Grassland

To understand arbuscular mycorrhizal(AM)fungi resources and develop AM fungal species in ornamental plants with saline-alkaline tolerances,Iris lactea,which grows in the Songnen saline-alkaline grassland with a high ornamental value,was selected as the experimental material,and the colonization characteristics of its roots and the AM fungal diversity in its rhizosphere were explored.The results of the observations and calculations of mycorrhizae from ten different samples showed that AM fungi colonized the roots of I.lactea and formed Arum-type mycorrhizal structures.There was a significant correlation between soil spore density and pH value,while the colonization rate showed a fluctuating trend with increasing pH values.The observed colonization intensities were of Levels II(1%–10%)or III(11%–50%),and the vesicle abundances were of grades A2 or A3 among different sites.AM fungi produced a large number of mycelia and vesicles in the roots of I.lactea after colonization.Thirty-seven species belonging to 15 genera of AM fungi were isolated from the rhizosphere of I.lactea and identified by morphological identification.Funneliformis and Glomus were the dominant genera,accounting for 21.79%and 20.85%of the total number,respectively.F.mosseae and Rhizophagus intraradices were isolated in all samples with importance values of 58.62 and 51.19,respectively.These results are expected to provide a theoretical basis for the analysis of the salt tolerance mechanism of I.lactea and for the discovery,exploration and further screening of AM fungal resources with salinity tolerances in saline-alkaline soils.

Morphological and molecular diversity of arbuscular mycorrhizal fungi in revegetated iron-mining site has the same magnitude of adjacent pristine ecosystems

Arbuscular mycorrhizal fungi（AMF） are important during revegetation of mining sites, but few studies compared AMF community in revegetated sites with pristine adjacent ecosystems. The aim of this study was to assess AMF species richness in a revegetated iron-mining site and adjacent ecosystems and to relate AMF occurrence to soil chemical parameters. Soil samples were collected in dry and rainy seasons in a revegetated iron-mining site（RA） and compared with pristine ecosystems of forest（FL）, canga（NG）,and Cerrado（CE）. AMF species were identified by spore morphology from field and trap cultures and by LSU r DNA sequencing using Illumina. A total of 62 AMF species were recovered, pertaining to 18 genera and nine families of Glomeromycota. The largest number of species and families were detected in RA, and Acaulospora mellea and Glomus sp1 were the most frequent species. Species belonging to Glomeraceae and Acaulosporaceae accounted for 42%–48% of total species richness. Total number of spores and mycorrhizal inoculum potential tended to be higher in the dry than in the rainy season, except in RA. Sequences of uncultured Glomerales were dominant in all sites and seasons and five species were detected exclusively by DNA-based identification. Redundancy analysis evidenced soil p H,organic matter, aluminum, and iron as main factors influencing AMF presence. In conclusion, revegetation of the iron-mining site seems to be effective in maintaining a diverse AMF community and different approaches are complementary to reveal AMF species, despite the larger number of species being identified by traditional identification of field spores.