Abstract: In this paper, acute bioassay method was used to study the toxic effect of low pHand aluminum on mycorrhizal fungi (Cortinarius russus). At pH 4.3, the aluminum toxicity was the strongest, with a 96 h EC₅₀ of 5.05 mg·L^-1, and the growth of Cortinarius russus was obviously inhibited. The SOD activity of Cortinarius russus was induced by low pH and aluminum, and increased obviously, but decreased when calcium was added, and decreased with increasing calcium concentration. At low pH, there exists an antagonism between calcium and aluminum.

Key words: Superoxide dismutase(SOD), Biomarker, Acid rain, Aluminum, Calcium, Cortinarius russus, SOFM neural network, ecosystem service bundles, Inner Mongolia Autonomous Region, ecological function zoning