[Arbuscular mycorrhizal fungal effects on wheat growth in response to elevated tropospheric O3 concentration]

A FACE (Free-air component enrichment) system in a rice/wheat rotation field was used to investigate the effects of arbuscular mycorrhizal fungal (AMF) inoculation on wheat growth and soil microbial biomass under elevated tropospheric O3 concentration. The elevated O3 concentration tended to increase AM colonization of wheat seedling and bate plant growth during the booting period, then significantly (p < 0.05) reduced aerial biomass, individual yield and kernel weight by 22%, 29% and 9%, respectively, and decreased soil microbial biomass N by 37% after wheat harvesting. However, the total N content in wheat grain significantly (p < 0.05) increased from 2.2% to 2.6%. Under elevated O3 concentration, AMF inoculation accelerated AM colonization successfully, and improved colonization rate and aerial biomass significantly (p < 0.05) during the booting period, thus reduced the damage of aerial biomass by 50% when harvesting, and increased soil microbial biomass N significantly (p < 0.05) related to the noninoculated treatment. Although wheat yield didn't increase, the total N content in grain decreased to the same level of that of the control wheat. It suggested that higher AM colonization is the resistance behavior of wheat in response to O3 intimidation, and AMF inoculation can accelerate wheat growth, increase root exudates and soil microbial biomass subsequencely.