EXISTENCE OF PERIONDIC SOLUTIONS FOR AUTONOMOUS PLANAR SYSTEMS

In this paper,the existence of periodic solutions for autonomous planar systemsis studied and sufficient conditions for the existence of non-zero periodic solutions of this kind areobtained.Some known results are extended and improved.     

甘蓝型油菜隐性核不育两用系S45AB中与MS2Bnap基因同源片段的克隆及序列分析

以甘蓝型油菜隐性核不育两用系S45AB的可育株和不育株为材料, 提取减数分裂期与单核期的花粉mRNA, 反转录合成cDNA, 并以其为模板扩增花粉特异基因MS2Bnap. 结果减数分裂期能扩出产物, 而单核期无任何产物. 将减数分裂期的扩增产物克隆、测序. 同源性分析表明: 在S45AB上克隆的MS2Bnap基因与Gene Bank公布的拟南芥控     

ON THE EXISTENCE OF LIMIT CYCLES OF A CLASS NONLINEAR EQUATION

This paper uses the Poincare-Bendixson's annular region theorem with existenceof limit cycles of a cfass of nonlinear differential equation.     

刺槐种子硬实破除方法探讨

硬实是豆科植物普遍存在的现象，硬实种子不透水，必须经过适当处理来提高种皮的透性种子才能萌发。研究表明：热水浸种、砂擦处理、浓硫酸浸泡、切除部分子叶对刺槐硬实的破除均有作用，以热水（100℃）浸种24h为最好，硬实种子发芽率达79.33%,若应用逐次增温处理效果更好。本研究为刺槐硬实种子利用提供了依据。     

Introgression of bacterial blight resistance genes Xa7, Xa21, Xa22 and Xa23 into hybrid rice restorer lines by molecular marker-assisted selection

Four bacterial blight (BB) resistance genes, Xa7, Xa21, Xa22 and Xa23, were introgressed into an elite hybrid rice restorer line Huahui 1035, by marker-assisted selection (MAS). Ten promising BB resistant lines identified by MAS approach in Huahui 1035 restorer background and their respective F₁ hybrids with a cytoplasmic male sterile line i.e. Jinke 1A, three BB resistant gene donors and their recurrent parent were evaluated for BB resistance by inoculating them with eleven representative races of Xanthomonas oryzae pv. oryzae (Xoo) in China. Further, the ten marker assisted selection of BB (MAS-BB) resistant restorer lines and their F₁ hybrids were also characterized for agro-morphological traits and grain yield. Results revealed that restorer lines with Xa23 introgression i.e. HBQ809 and HBQ810 were found to be resistant to all eleven Chinese representative Xoo races, showing broad spectrum resistance to BB. However, the lines possessing Xa7 or Xa7+Xa21 were resistant to ten out of eleven Xoo races. While restorer lines with Xa21 were resistant to nine out of eleven Xoo races. Interestingly, the F₁ hybrids with Xa23, Xa7 or Xa7+Xa21 were resistant to two severe epidemic Xoo races of China. Restorer lines i.e. HBQ807 and HBQ808 possessing Xa22 were only resistant to six or five out of inoculated eleven Xoo races. Lesion length comparisons between restorer lines and their F₁ hybrids for the above four BB resistance genes showed them to be dominant in heterozygote genotype. Three promising high yielding F₁ hybrids with BB resistance were identified for immediate exploitation for hybrid rice production in China.     

Evaluation of ibuprofen contamination in local urban rivers and its effects on immune parameters of juvenile grass carp

Ibuprofen as a non-steroidal anti-inflammatory drug can be detected in the aquatic environments all over the world. This study evaluated the effects of ibuprofen on the immune parameters of juvenile grass carp at the concentration in real environments which were determined by detecting its concentrations in the surface water of local rivers. The concentration of ibuprofen ranged from 13.2 to 95.5 ng/L with a mean value of 47.9 ng/L in the surface water of local rivers detected by solid-phase extraction followed by LC-MS/MS analysis. Accordingly, juvenile grass carp were exposed to 4.8, 48.0 and 480.0 ng/L of ibuprofen for 14 days. The serum lysozyme activity of these fish decreased, while the serum creatinine levels were not affected after the exposure. Moreover, the mRNA expression of interleukin 6 in the skin and interleukin 1 beta and tumor necrosis factor alpha in the gills was enhanced by this exposure. These results collectively suggest that ibuprofen at environmentally relevant concentration can affect the immune parameters of juvenile grass carp, providing an insight into the possibility of this contaminant to modify the immunostatus of fish.

     

南阳牛Gli3基因多态性及其与生长性状的相关性

Gli3基因是Gli-Kruppel家族中的一员,其参与的Sonic hedgehog信号通路在动物生长发育,特别是早期生长发育过程中有重要作用.利用PCR-SSCP和DNA测序技术研究了187头纯种南阳牛Gli3基因编码区4个位点(E4、E5、E6和E7)的多态性,发现E4和E5位点存在SSCP多态.对不同SSCP带型的对应片段进行了测序分析,共发现3个新的SNP多态位点(T123600C、T123696C和A128688G),其中第123600和第123696两个位点处于连锁状态.E5位点处于Hardy-Weinberg平衡状态,E4位点处于非平衡状态.不同基因型与生长发育性状的相关性分析显示,E4位点上,CC基因型个体的六月龄体重、胸围、坐骨端宽、日增重指标显著大于TT基因型个体(P<0.05),该位点有可能作为南阳牛早期生长性状标记辅助选择的标记之一.     

A real-time PCR assay for detection and quantification of Verticillium dahliae in spinach seed

Verticillium dahliae is a soilborne fungus that causes Verticillium wilt on multiple crops in central coastal California. Although spinach crops grown in this region for fresh and processing commercial production do not display Verticillium wilt symptoms, spinach seeds produced in the United States or Europe are commonly infected with V. dahliae. Planting of the infected seed increases the soil inoculum density and may introduce exotic strains that contribute to Verticillium wilt epidemics on lettuce and other crops grown in rotation with spinach. A sensitive, rapid, and reliable method for quantification of V. dahliae in spinach seed may help identify highly infected lots, curtail their planting, and minimize the spread of exotic strains via spinach seed. In this study, a quantitative real-time polymerase chain reaction (qPCR) assay was optimized and employed for detection and quantification of V. dahliae in spinach germplasm and 15 commercial spinach seed lots. The assay used a previously reported V. dahliae-specific primer pair (VertBt-F and VertBt-R) and an analytical mill for grinding tough spinach seed for DNA extraction. The assay enabled reliable quantification of V. dahliae in spinach seed, with a sensitivity limit of ≈1 infected seed per 100 (1.3% infection in a seed lot). The quantification was highly reproducible between replicate samples of a seed lot and in different real-time PCR instruments. When tested on commercial seed lots, a pathogen DNA content corresponding to a quantification cycle value of ≥31 corresponded with a percent seed infection of ≤1.3%. The assay is useful in qualitatively assessing seed lots for V. dahliae infection levels, and the results of the assay can be helpful to guide decisions on whether to apply seed treatments.     

基于RS和GIS技术的县域土地流转应用研究

以安徽省肥西县为例,耕地是土地的精华,是农业生产不可替代的重要生产资料,是保持社会和国民经济可持续发展的重要资源。只有确定了比较合理的价格,出让土地才能获得合法收益,农户转让土地才能得到合法补偿,各种形式的土地流转才能顺利进行。建立土地流转制度,核心问题就是要建立科学的土地价格评估系统,因此使用RS和GIS技术进行的地力评价工作为土地流转提供一个科学的依据。     

营养对早期断奶仔猪免疫功能及健康的影响

本文阐述了饲料中主要营养物质(蛋白质、氨基酸、糖类、脂肪、矿物质和维生素)对早期断奶仔猪免疫功能和健康的影响。