Endophytic Fungal Diversity And Their Heavy Metal Tolerance Of Six Dominant Plant Species In A Pb-Zn Mine Wasteland In China

The endophytic fungal diversity of6dominant plant species (Arabis hirsuta, Acacia decurrens, Symplocos paniculata, Rabbosia eriocalyx, Arenaria serpyllifolia and Rosa longicuspis) collected from the Huize Pb-Zn mine wasteland of Yunnan Province, southwest China, were investigated.495endophytic fungi were isolated from690stem and leaf segments. The isolation rate of the endophytic fungi in the6plant species ranged from0.42to0.93, and the average isolation rate was0.72. The isolation rate of the endophytic fungi in the stems was significantly higher than that in the leaves (P<0.05, t test). Based on their morphological characteristics, the way of spore production and spore characteristics, the isolates were identified to20taxa including Phomopsis sp., Bipolaris sp. and Alternaria sp. etc, of which Phoma and Peyronellaea were the dominant endophytic fungi.The diversity index of endophytic fungi from the6plant species ranged from0.43to0.72, and it was slightly lower than that of some previous reports in other non-polluted environments, which indicated that the endophytic fungal diversity decreased with the severely Pb-Zn pollution. The similarity index of endophytic fungi from the6plant species ranged from0.455to0.833, which showed that the host specificity was lower in the Pb-Zn mine wasteland in the present study.64isolates from11taxa were selected randomly to test their metal tolerance, and the results showed that Pb2+or Zn2+exhibited the greatest toxicity to some isolates and they did not grow on the metal-amended media. In contrast, some isolates were hormesis in the presence of teseed metals.The isolate of Phoma were more sensitive to Zn2+than the isolates of Alternaria and Peyronellaea. However, the sensitivity of isolates to Pb2+was not significantly different among Phoma, Alternaria, Peyronellaea and other taxa (P>0.05, chi-square test).On separation from different regions (Huize Pb-Zn mine wasteland and Yunnan Yuanjiang Dry-hot Valley) of the same plant endophytic fungi, Peyronellaea strains on Pb2+, Zn2+tolerance studies show that strains L516from Yunnan Huize Pb-Zn mine wasteland and strains J934and J97Yunnan Yuanjiang Dry-hot Valley were well tolerated, where J934showed highest tolerance index. These strains were inoculated corn, to explore their heavy metal absorption, accumulation characteristics on corn at different lead/zinc/cadmium pollution, it was found,1) some strains can promote the lead, zinc, cadmium stress on maize growth, L516growth promoting effect better.2) lead, zinc, cadmium pollution on the growth of corn to produce negative effect, with lead, zinc matrix, increasing concentrations of cadmium, maize biomass declined, inoculation did not change this trend, however, compared with the control, inoculated with endophytic fungi can slow this trend.3) a. under lower Pb concentration, the inoculation strains are beneficial to corn ground, underground part Pb accumulation; under high lead stress, only individual strains (J934) can promote the accumulation of Pb. b. all inoculation strains in favor of the accumulation of Zn of maize aboveground under zinc stress, except J97in high Zn stress. Strains L516and J97in favor of maize root zinc absorption under low zinc stress, all inoculated strains can promote high zinc stress maize root zinc absorption. c. under low Cd stress, strains L516, S363, J934are conducive to Cd accumulation of maize on the ground, underground.