Abstract: Symbiosis with orchid mycorrhizal fungi is essential to the orchid seeds germination and seedlings growth in nature. To study the effects of orchid mycorrhizae on the growth of orchid seedlings, especially the direct relationship between inoculation methods and inoculation effects in laboratory, three mycorrhizal fungi (M1, M2 and M3) was isolated from fresh nutritious roots of Dendrobium loddigesii and used to establish the asymbiotic culture system, single and mixed inoculation were adopted, inoculation effects on D.loddigesii seedlings was analyzed. At last, beneficial fungi M1 and M3 were screened out, and mixed inoculating was good for biomass accumulation of D.loddigesii seedlings, such as inoculation modes with two mycorrhizal fungi M1-M2, M2-M3 and with three mycorrhizal fungi M1-M2-M3. Mixed inoculating would play an effective role in orchids production, which has great practical significance.

Key words: Dendrobium loddigesii, orchid mycorrhizal fungi, mixed mycorrhizal fungi, specificity