[Seasonal Variation and Influencing Factor Analysis of Antibiotic Resistance Genes in Water Supply Reservoirs of Central China].

This study quantified an integron gene intI1 and 19 antibiotic resistance genes(ARGs) to identify the ARGs pollution characteristics in 11 drinking water reservoirs of central China. The results indicated that the ARGs abundance did not change significantly over time in the studied reservoir waterbodies. Tetracycline, sulfonamide, and ß-lactam ARGs were dominant. The high abundance and detection rate of two sulfonamide ARGs(sul1 and sul2) suggested that they were the predominant ARGs. No polymyxin resistance genes(mcr-1) were detected, which indicated that the antibiotic restriction policy of China has achieved positive outcomes. Compared with that in other environmental media, the ARGs abundance in the reservoir environment was low. The correlation analysis showed relevance between the water quality indicators and the ARGs, which suggested that the water quality indexes can be used as ARGs pollution indicators in the reservoir environment. The abundance and detection rate of carbapenem ARGs were low owing to their dosage restriction and high degradability. Tetracycline ARGs were closely related to the other resistance gene types, which might have been due to horizontal gene transfer. Although the overall correlation between intI1 and ARGs was modest, it might be the main reason for the spread of several individual ARGs in the reservoir environment.

[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.