Abstract: Cyclobalanopsis glauca is a common afforestation species in the karst rocky desertified region of Southwest China. We used two arbuscular mycorrhizal fungi Glomus mosseae (Gm) and Glomus intraradices (Gi), an ectomycorrhizal fungus Pisolithus tinctorius (Pt), and mixed mycorrhizal fungi to inoculate C. glauca seedlings. The seedlings were maintained under three soilwater conditions: well watered, moderate drought, and serious drought. Then, the root scanner Epson Perfection V700 and root analysis software WinRhizo were used to measure root morphological indexes, in order to study the effects of mycorrhizae and drought stress on the C. glauca seedlings. The results showed that under the two conditions of drought stress, root biomass, total root length, root surface area, and root volume of the inoculated seedlings were significantly improved, while average root diameter decreased significantly. Under moderate drought stress, root surface area of the seedlings treated with Pt was significantly higher than that of the seedlings treated with Gm or Gi, while the average root diameter of the seedlings treated with Pt was smaller than that of the seedlings treated with Gm or Gi. However, under severe drought stress, root biomass and root volume of the seedlings treated with Pt were significantly lower than those of the seedlings treated with Gm or Gi, while average root diameter of the seedlings treated with Pt was significantly larger than that of the seedlings treated with Gm or Gi. The correlation of mycorrhizal infection rate with root biomass and total root length was positive. This experiment suggests that the root morphology of C. glauca seedlings was changed by the mycorrhizal fungi, which promoted the accumulation and allocation of carbohydrates to the roots of C. glauca under conditions of drought stress.

Key words: CH₄, global warming potential, rice-wheat rotation system, greenhouse gas intensity, N₂O, aged-biochar