Abstract: In 2006-2009, a Free-Air Controlled Enrichment (FACE) system was applied to study the effects of elevated ozone concentration (［O₃］) on the grain protein components and their dynamics of four winter wheat varieties Yannong 19, Yangmai 16, Yangmai 15, and Yangfumai 2. Two levels of ［O₃］were installed, i.e., ambient level (CK-O₃) and 50% higher than the ambient level (E-O₃). With the increase of ［O₃］, the grain protein content of the varieties increased, with the increment being 7.55%-16.37% (2006-2007), 4.93%-22.63% (2007-2008), and 2.29%-17.65% (2008-2009) in the three years, respectively, and the differences between treatments, varieties, and years being all significant. Adversely, the grain protein yield was decreased significantly by 1.83%-11.64% (2006-2007), -0.41%-24.22% (2007-2008), and -1.90% -15.81% (2008-2009), respectively in the three years. The contents of four grain protein components (albumin, globulin, gliadin, and glutenin) were significantly higher under E-O₃ than under CK-O₃, and the differences between treatments, varieties, and years were significant, except the albumin and glutenin contents between treatments.

Key words: wheat, FACE, elevated O₃ concentration, protein content, protein component, light detection and ranging (LiDAR), gap characteristics, mid-subtropics, evergreen broad-leaved forest.