Arbuscular mycorrhizal and dark septate fungal associations in riparian plants of the Three Gorges Reservoir Region, Southwest China

Abstract

Arbuscular mycorrhizal fungi (AMF) and dark septate endophyte (DSE) may aid plants surviving in highly stressed environments. Impoundment of the Three Gorges Reservoir (TGR) has dramatically influenced riparian environments and shaped a special riparian vegetation zone, which has been subjected to long-term winter flooding and short periods of summer flooding. Due to the artificial control of the Dam, the riparian environments of the Jialing River and the Yangtze River are completely different, which may influence the AMF and DSE colonized in riparian plants. Thus, a survey for the presence of AMF and DSE associations in the roots of 66 riparian species was done in 5 distinct areas of the Jialing River and the Yangtze River. Obtained results indicated that 52 and 42 species were associated with AMF and DSE, respectively, and 33 species presented both associations. For 30 plant species surveyed, this is the first report on their mycorrhizal status. High colonization levels of AMF and DSE were generally found in those local prevalent species characterized by abundant rhizomes. On average, AMF colonization was higher from Yangtze River than from Jialing River but DSE colonization followed the opposite trend. However, no clear relationship between AMF and DSE fungal colonization was recognized among species which showed dual colonization of DSE and AMF. Pearson’s correlation analysis indicated that available phosphorus was significantly positive correlated to hyphal colonization of AMF. Finally, we assumed the structure of plant communities of TGR might be strongly influenced by the presence of mycorrhiza.