Abstract: The study on the responses of spring wheat (Triticum aestivum) potted in open-top chamber to elevated CO₂ (542.1±24.8 and 738.8±25.7 μl·L^-1 vs.382.4±24.8 μl·L^-1) and their effects on Sitobion avenae aphid growth,development and reproduction showed that elevated CO₂ was advantageous for spring wheat growth.In treatments 550 and 750 μl CO₂·L^-1,the plant height during May 5～June 14 increased by 2.80%～14.92% and 6.30%～17.56%,and leaf area per plant during April 30～June 19 increased by 5.68%～50.52% and 6.14%～83.45%,respectively,compared with CK.The DC₅₀ and DC₇₅ were brought forward about 0.39 and 0.53 d for treatment 550 μl CO₂·L^-1,and 0.90 and 1.02 d for treatment 750 μl CO₂·L ^-1, respectively.Moreover,the stem,leaf,ear and above-ground biomass also had some increase under elevated CO₂.Compared with CK,a significant increase of ear length (0.56% and 3.20%) and grain number per ear (12.5% and 18%),but a significant decrease of 1000-grain dry weight (2.23% and 6.34%) were observed for treatments 550 and 750 μl CO₂·L^-1,respectively.With increasing CO₂,the chemical constituents in ear,such as glucose, disaccharide, amylose and TSCs/nitrogen ratio increased significantly,while fructose,trisaccharide and total nitrogen decreased significantly.CO₂ elevation shortened the preoviposition duration and longevity of S.avenae,and increased the number of offspring per female aphid and mean relative growth rate (MRGR).Compared with CK,the MRGR increased 33.26% in treatment 550 μl CO²·L^-1,and 74.34% in treatment 750 μl CO₂·L^-1. Furthermore,there was a significant correlation between the MAGR of S.avenae and the TSCs/nitrogen ratio of spring wheat ear.

Key words: Mycorrhizae, Desertification, Application of mycorrhizae