Abstract: Mycorrhizal fungi play key roles in vegetation restoration and vegetation reconstruction of degraded ecosystems in arid and semiarid lands. In the present study, a mycorrhizal afforestation experiment in Horqin sandy land was carried out to understand the influence of two mycorrhizal fungi inoculums (arbuscular mycorrhiza inoculum and ectomycorrhizal inoculum) on growth of four kinds of afforestation seedlings. We analyzed mycorrhizal colonization rate and morphological indicators, accumulation and allocation of biomass, and rhizosphere soil nutrients of seedlings of two native species Acer mono and Ulmus pumila, and two introduced species Fraxinus chinensis and Pinus sylvestris var. mongolica in Horqin sandy land, China across one growth season. The results showed that: (1) Both mycorrhiza inoculums could well colonize the roots of the four kinds of seedlings. Inoculation of the mycorrhiza inoculums significantly increased the plant height, basal radium, crown stem length and biomass of all tree species. (2) Inoculation with the mycorrhiza inoculums on roots of seedlings significantly affected the allocation of biomass (P<0.05); the rootshoot ratio significantly decreased in Fraxinus chinensis seedlings, and significantly increased in Pinus sylvestris var. mongolica seedlings. (3) The mycorrhizal colonization rate was significantly positively correlated with the plant height and crown stem length of Fraxinus chinensis seedlings, and significantly positively correlated with the coarse root dry mass, shoot biomass and total biomass of Pinus sylvestris var. mongolica seedlings. (4) Inoculation of the mycorrhiza inoculums also increased the contents of organic matter and total nitrogen of rhizosphere soil, which can improve the soil matrix of seedling growth, but the difference was insignificant (P>0.05). Mycorrhizal effect of the four kinds of afforestation seedlings was significant, which indicated that it was very valuable to apply mycorrhizal fungi inoculum to afforestation in arid and barren regions.

Key words: land use pattern, microbial community diversity, principal component analysis, Biolog microplate