[Tolerance and enzyme response of ectomycorrhizal fungi Xerocomus chrysenteron to DDT stress].

The growth effect, tolerance and oxidative enzymes activities of Xerocomus chrysenteron under different concentrations of DDT were studied at the condition of pure culture. The changes of biomass accumulation and laccase activity were also examined along with the liquid medium period under the DDT concentration of 80.0 mg L(-1). The results show that various DDT concentrations don't change the growth mode of the studied ectomycorrhizal fungi, which are all in the mode of classic Logistic growth. Xerocomus chrysenteron has a good tolerant ability to the DDT stress, whose hemi-inhibit concentration reaches 139.75 mg L(-1). Under the liquid medium of 80.0 mg L(-1) of DDT, Xerocomus chrysenteron grows normally and after 36 days and the residue of DDT in the liquid medium is only 3.5% of the original concentration. Under the high concentration of DDT, the laccase and peroxidase activities significantly increase. The laccase is detected since the 16th day. After 36 days' culture, the laccase activity and specific activity in liquid medium reach 107.24 U L(-1) and 61.77 U g(-1) respectively. The ectomycorrhizal fungi Xerocomus chrysenteron responses to the DDT stress in various ways, which suggests large potential of biodegradation or mineralization of DDT.