玉米褪绿斑驳病毒及传播介体研究进展

玉米褪绿斑驳病毒(Maize chlorotic mottle virus,MCMV)是中国重要检疫性病毒之一,该病毒与马铃薯Y病毒属成员复合侵染会造成玉米致死性坏死（CLN）,造成严重的经济损失。由于玉米上马铃薯Y病毒属病毒有广泛适生范围,一旦扩散开来,将对玉米生产构成严重威胁。因此,了解MCMV研究的现状和传播介体具有重要意义。综述了近几年MCMV研究进展和传播介体概况,并结合自身研究,评述了西花蓟马作为MCMV传播介体在CLN中的作用,以期为西花蓟马传播MCMV的基础研究和防控提供理论依据。     

Organics Wastewater Degradation by a Mesoporous Chromium-Functionalized γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> with H<Subscript>2</Subscript>O<Subscript>2</Subscript> Assistance

In this study, a mesoporous chromium-functionalized γ-Al₂O₃ (Cr/γ-Al₂O₃) catalyst was prepared by an impregnation method, and the catalytic activity was evaluated by the degradation of organics wastewater. The prepared catalyst was characterized by X-ray photoelectron spectroscopy, X-ray diffraction, nitrogen adsorption-desorption experiments, and scanning electron microscopy. The characterization results confirmed that the pores in the Cr/γ-Al₂O₃ catalyst distributed broadly in the mesoporous region, and the active chromium species were highly dispersed on the catalyst surface. The catalytic activity tests showed that the Cr/γ-Al₂O₃ catalyst exhibited a superior performance for the degradation of organics wastewater with H₂O₂ assistance. And the methylene blue (MB) disappeared within 20 min and the COD removal reached 76.5% within 40 min for the MB-simulated wastewater; for the phenol-simulated wastewater, the phenol removal was above 95% and the corresponding COD removal reached 71% within 40 min. Such an excellent catalytic performance demonstrates that the Cr/γ-Al₂O₃ catalyst has a potential application in the degradation of complex organics wastewater simultaneously.     

The importance of proleptic branch traits in biomass production of poplar in high?density plantations

Branch phenotypic traits determine tree crown architecture, which in turn governs leaf display, light inter-ception, and biomass production. Sylleptic and prole...     

农民专业合作社的联合路径研究——基于联合社的多案例分析

随着农民专业合作社联合社在农业现代化进程中的地位逐渐凸显,识别其联合路径对联合社的良性发展具有重要意义。基于系统理论框架,以"苏合"销售合作联社、"邓村绿茶"专业合作社联合社、黑龙江"龙联"联合社为案例,分析基于合作社服务功能系统的合作社联合路径,并探讨各联合路径的差异性和共性。结果表明,合作社之间的"二次合作"有助于激活组织间的互补和协同作用,打破原有合作社服务能力提升的禀赋约束,增加农民合作经济的效用;合作社的联合有同服务区位联合,服务系统内联合和跨服务系统联合3条联合路径;各路径之间没有优劣之分,但联合效用的充分发挥需要联合社对自身有清晰的定位,还需与成员能力相匹配,并且以完善的运营模式为保障。研究表明,不同的联合路径适用于不同规模的合作社。因此,对已具规模的合作社鼓励其结成战略联盟,对初具规模的合作社鼓励其进行同类产品的联合,对规模较小的合作社鼓励其进行专业性联合。     

湖北省武汉市某门诊犬细小病毒病病例统计分析

[目的]了解武汉市犬细小病毒病(CPD)的流行情况和特点。[方法]以华中农业大学动物医院门诊为依托,应用胶体金试纸条和PCR检测技术,对2015年9月至2016年9月的犬门诊病例进行调查分析。[结果]共检测门诊犬病例2 728例,检出CPD阳性121例,阳性检出率为4.4%。从时间分布看,该期间大部分月份的阳性检出率在3%~5%之间,2015年10月的最高,2016年6—9月的最低。从群间分布看,阿拉斯加、边牧、哈士奇、比熊、萨摩耶、博美、巴哥等犬种的CPD阳性数量均占该品种就诊犬总数量的10%以上,而拉布拉多、雪纳瑞、德牧、贵宾、金毛犬则在5%以上;雄性犬的CPD阳性检出率明显高于雌性;在阳性病例中,2~4月龄幼犬的占比最高,在40%~60%之间;未免疫或未按规定免疫犬的CPD阳性数量与总阳性数量的占比高达86.7%,而按规定免疫犬仅为13.3%。[结论]CPD的发生与犬的品种、年龄、性别、免疫状况和气候等因素存在一定的关系,尤其是其年龄和免疫状况。本研究有助于了解该病的流行特点,并可为该病的防治提供参考。     

一起鸡棘沟赖利绦虫病的诊断

从临床症状、组织病理学变化、病原形态学鉴定等方面对一起鸡棘沟赖利绦虫病进行诊断。结果表明,病鸡生长缓慢,消化道增粗、肿大,肠内充满大量黄褐色液体。十二指肠有凸起的白色结节和散在出血斑,HE染色显示肠黏膜层脱落并伴有大量红细胞浸润。病鸡十二指肠、空肠和回肠发现大量绦虫虫体,体长5cm~10cm,头节四周有4个圆形吸盘,中央有1个突起的顶突,顶突上分布有两圈小钩。颈节节片生殖系统未发育成熟,染色不明显。成节节片有一组生殖系统,生殖孔交替开口于节片外缘上1/3处。雄茎囊位于排泄孔外侧,睾丸数目30个~40个。孕节子宫退化,被大量卵囊所取代,散在分布于节片中,每个卵囊内有1个已胚化的六钩蚴。综合以上结果判定病鸡所患寄生虫病为棘沟赖利绦虫病。     

Seed dormancy and soil seedbank of the invasive weed Chenopodium hybridum in north‐western China

Seed dormancy and persistence in the soil seedbank play a key role in timing of germination and seedling emergence of weeds; thus, knowledge of these traits is required for effective weed management. We investigated seed dormancy and seed persistence on/in soil of Chenopodium hybridum, an annual invasive weed in north‐western China. Fresh seeds are physiologically dormant. Sulphuric acid scarification, mechanical scarification and cold stratification significantly increased germination percentages, whereas dry storage and treatments with plant growth regulators or nitrate had no effect. Dormancy was alleviated by piercing the seed coat but not the pericarp. Pre‐treatment of seeds collected in 2012 and 2013 with sulphuric acid for 30 min increased germination from 0% to 66% and 62% respectively. Effect of cold stratification on seed germination varied with soil moisture content (MC) and duration of treatment; seeds stratified in soil with 12% MC for 2 months germinated to 39%. Burial duration, burial depth and their interaction had significant effects on seed dormancy and seed viability. Dormancy in fresh seeds was released from October to February, and seeds re‐entered dormancy in April. Seed viability decreased with time for seeds on the soil surface and for those buried at a depth of 5 cm, and 39% and 10%, respectively, were viable after 22 months. Thus, C. hybridum can form at least a short‐lived persistent soil seedbank.     

关中地区温室越冬茬番茄黄化曲叶病毒病分子鉴定及流行规律

为了明确关中地区越冬茬番茄黄化曲叶病毒病发生和流行规律,通过分析该病发生与番茄品种、定植期及传播介体烟粉虱之间的关系,并采用PCR技术对田间病原进行分子鉴定。结果表明,番茄黄化曲叶病毒病在8月中下旬至11月上中旬开始侵染,翌年3月中下旬发生再侵染,秋季病情减轻;烟粉虱种群数量与病害发生程度呈线性正相关;不同番茄品种对番茄黄化曲叶病毒(Tomato yellow leaf curl virus,TYLCV)的抗性差异显著,其中大番茄品种布鲁尼1288和DRW7728,小番茄品种千禧和美红对该病表现为免疫;分子检测结果表明,4个样品中均扩增出543 bp的特异片段,与NCBI数据库Gen Bank的TYLCV序列(登录号为GU084381、KC138544.1、KC138543.1和JX456642.1)的相似性达99%。研究表明,关中地区番茄病毒病为番茄黄化曲叶病毒病,番茄品种、定植期及烟粉虱发生动态是影响该病发生的主要因素。     

The sequevar distribution of <Emphasis Type="Italic">Ralstonia solanacearum</Emphasis> in tobacco-growing zones of China is structured by elevation

Bacterial wilt, caused by Ralstonia solanacearum, is a devastating disease resulting in tremendous losses of economic crops such as plants in the Solanaceae. Recent studies showed that R. solanacearum is spreading from the lowlands to the highlands in China. We studied 97 Chinese R. solanacearum strains that were isolated from four tobacco-growing zones over a wide range of elevations using phylotype specific multiplex polymerase chain reaction (Pmx-PCR) and phylogenetic relationships (egl and mutS). The results showed that all isolates belonged to phylotype I, which were further clustered into eight egl-sequence type groups (egl-group, sequevar): sequevars 13, 14, 15, 17, 34, 44, 54, and 55. In addition, Sequevar 55, found from the highlands, was a new/unknown one. Southeast China (Z3) had the largest number of egl-groups, containing six sequevars. The basin of the Yangzi River (Z1) and southwestern China (Z2) contained five egl-groups. The basin of the Huai River (Z4), near the north of China, where slight bacterial wilt occurred recently, contained a single group, sequevar 15. The distribution of sequevars was associated with elevation. Sequevar 15 was over-represented in lowland elevations, while sequevar 54 and the new/unknown one were only found in areas of moderate to high elevations. This finding suggested that the phylotype I strains infecting tobacco were diverse in China and regional integrated control strategies should be considered.