Abstract: In order to investigate the inhibitory effects of host plants secondary metabolites on the growth of endophytic and exogenous fungi, the volatile oil
from medicinal plant Atractylodes lancea was extracted with organic solvent extraction method, and its antimicrobial activity against three species of endophytic and seven species of exogenous fungi was determined by paper disc assay and spreadplate. The volatile oil had inhibitory effects on the growth of test endophytic fungi. It had strong antimicrobial activity against Rhodotorula glutinis and Saprolegnia, but weak activity against Rhizopus and Absidia. It suppressed the sporulation of Trichoderma viride and Aspergillus niger, but no effects on the growth of Phytophthora. Under the stress of high concentration volatile oil, the hyphal branches of test endophytic fungi increased, the distance between the branches became shorter, and the growth of aerial hyphae was inhibited. The test endophytic fungi had remarkable ability to metabolize and transform the volatile oil, and decreased the contents of its main ingredients. All the results showed that the volatile oil extracted from A. lancea had inhibitory effects on the growth of endophytic fungi, but the fungi could adapt to the volatile oil via metabolizing and decomposing it.

Key words: Atractylodes lancea, volatile oil, endophytic fungi, antimicrobial activity, inhibitory effect, evapotranspiration, distributed hydrological model, Penman-Monteith formula, BP neural network.