[Comparison on the diversity of antibiotic resistance genes of three rodent species]. / 3ç§å•®é½¿åŠ¨ç‰©æŠ—ç”Ÿç´ æŠ—æ€§åŸºå› å¤šæ ·æ€§æ¯”è¾ƒ.

Antibiotic resistance genes (ARGs) have attracted widespread attention as a new global pollutant, mainly due to the abuse of antibiotics. To investigate the diversity of ARGs in three rodent species, we used metagenomic sequencing analysis to analyze the diversity of antibiotic resistance genes of 17 individuals of Apodemus peninsulae and 17 individuals of Myodes rufocanus collected from Mudanfeng, and nine individuals of Apodemus agrarius collected from Sandaoguan. A total of 19 types and 248 subclasses of ARGs were detected in the three rodent species. Seven ARGs showed significant difference and five ARGs showed extremely significant difference between M. rufocanus and A. agrarius. Seven ARGs showed significant difference and four ARGs showed extremely significant difference between A. peninsulae and A. agrarius. Four ARGs showed significant difference and five ARGs showed extremely significant difference between M. rufocanus and A. peninsulae. ARGs showing high abundance in three rodents were macrolides, lincoamides, tetracyclines, and ß-lactams. ARGs were widely distributed in the three rodent species. The significant differences in ARGs among different species might be due to the different distribution areas and their diet differentiation. The study could provide a basis for further studies of ARGs in mice and improve the understanding of the harm of ARGs transmission.

[Effects of irrigation on the water soluble carbohydrate contents in different wheat cultivars stem and sheath and the grain yield].

Taking two wheat (Triticum aestivum L.) cultivars Jimai 20 and Taishan 22 as test objects, this paper studied the effects of different irrigation treatments on the water soluble carbohydrate contents in penult stem internode and sheath and the grain yield. Four irrigation treatments were installed, i. e. , no irrigation (W0), irrigation at overwintering and jointing stages (W1), irrigation at overwintering, jointing and anthesis stages (W2), and irrigation at overwintering, jointing, anthesis and filling stages (W3). In treatment W0, the contents of total soluble sugar and of fructan with the degree of polymerization (DP) > or = 4 and = 3 in the penult stem internode and sheath of the two cultivars at early filling stage and the fructose content at later filling stage were the highest, indicating that the accumulation and degradation of water soluble carbohydrate in the penult stem internode and sheath were promoted under no irrigation, which in turn increased the 1000-grain weight. In treatment W1, the contents of fructan with DP > or = 4 and DP = 3 in the penult stem internode and sheath of Jimai 20 at early filling stage, the total soluble sugar and fructose contents at middle and later filling stages, and the grain yield were the highest. In treatment W2, Taishan 22 had the highest contents of fructan with DP > or = 4 and DP=3 in the penult stem internode and sheath at early filling stage, lower fructose content at higher filling stage than in treatment W1, and the highest grain yield. Comparing with Jimai 20, Taishan 22 had higher contents of total soluble sugar and of fructan with DP > or = 4 in the penult stem internode and sheath at early filling stage and higher content of fructose at later filling stage, and lower grain yield in treatments W0 and W1 but higher grain yield in treatments W2 and W3. In this study, treatments W1 and W2 promoted the accumulation and degradation of water soluble carbohydrate in the penult stem internode and sheath of Jimai 20 and Taishan 22, and gained the highest grain yields of the two cultivars, respectively, being most appropriate irrigation treatments for Jimai 20 and Taishan 22, respectively.

[Effects of irrigation stage and amount on winter wheat fructan accumulation and translocation after anthesis and water use efficiency].

Field experiments were conducted in Tai' an and Yanzhou of Shandong Province in 2004-2005 and 2005-2006 to study the effects of irrigation stage and amount on the accumulation and translocation of fructan in winter wheat penult stem and sheath after anthesis and the water use efficiency. No irrigation in whole growth period promoted the translocation of fructan from penult stem and sheath to grain at late grain-filling stage. Irrigation with 60 mm water at jointing and anthesis stages increased the flag leaf photosynthetic rate and photo-assimilate accumulation after anthesis, and the contribution of the photo-assimilates to the grain. Irrigation with 60 mm water at jointing, anthesis, and grain-filling stages, and with 90 mm water at jointing and anthesis stages decreased the flag leaf photosynthetic rate at late grain-filling stage, increased the photo-assimilate accumulation before anthesis and the contribution of the photo-assimilates to the grain, and reduced the translocation of the photo-assimilates after anthesis to the grain. Excessive irrigation also increased the contents of fructan with the degree of polymerization (DP) > or = 4 and = 3 in penult stem and sheath at late grain-filling stage, limiting the translocation of fructan from penult stem and sheath to grain. Irrigation with 60 mm water at jointing and anthesis stages led to a higher grain yield and the highest water use efficiency, while irrigation with 60 mm water at jointing, anthesis, and grain-filling stages, and with 90 mm water at jointing and anthesis stages had little effects on the grain yield but decreased the water use efficiency.