北运蔬菜基地辣椒病毒病病原种类的分子 检测

辣椒病毒病是广东、海南两省北运蔬菜基地的主要病害,十分有必要对其病原 种类进行全面
检测,以便为病毒 病的防治提供依据。本试验运用RT-PCR 方法对这两省北运蔬菜基地的辣椒病毒病或疑
似病毒病的病株样本进行分子检测。结果表明：广东省的病毒检出株率为55.67%,最主要的病毒种类是
黄瓜花叶病毒（CMV）和辣椒轻斑驳病毒（PMMoV）,另有少量的马铃薯Y 病毒（PVY）、马铃薯 X 病毒（PVX）
和番茄黄化曲叶病毒（TYLCV）;海南省的病毒检出株率为44.67%,最主要的病毒种类仍然是CMV 和
PMMoV,另有少量的PVY。在田间,两省均以CMV 和PMMoV 复合侵染辣椒为主。     

Carbon,nitrogen, and gaseous profiles in a humid,temperate region,maize field soil under no‐tillage

Abstract

The effect of four consecutive years of tillage method [conventional tillage (CT) or no‐tillage (NT)] and fertilizer N rate (84, 168, 336 kg N·ha^‐1·yr) on soil carbon, nitrogen and and gaseous profiles was examined in a Wharton‐Cookport (Aquic Hapludults‐Aquic Fragiudults) silt loam soil in West Virginia cropped to continuous maize (Zea mays L.). At midseason (July) of the last cropping year, soil mineral N profile differences were generally discernible only at the high N (336 kg·ha^‐1) rate in the topsoil (0‐ to 30‐cm layer). Ammonium (NH₄ ⁺‐N) levels at this time were significantly (p ≤ 0.05) higher under CT, while NO₃ ^‐‐N levels were the same under both tillage methods. However, after silage harvest in September NH₄ ⁺‐N levels were the same under both tillage systems, while NO₃ ^‐‐N levels were significantly higher under CT. Although no significant (p ≥ 0.05) tillage effects were found for TC, the level was increased by ～16% under NT in the surface soil (0 to 15‐cm) layer at the low N (84 kg·ha^‐1) rate treatment. Total N (TN) was significantly (p ≤ 0.05) increased under NT compared to CT only in the soil surface layer at the high N rate treatment. Soils under both tillage methods after cropping appeared to be equally well aerated to the deepest layer (60 cm) as O₂ levels were near atmospheric concentrations, and no gases commonly associated with more anaerobic environments (CH₄, C₂H₄) were detected. Carbon dioxide (CO₂) levels increased 30‐ to 40‐times atmospheric levels in the deepest layers, and were generally higher under NT. The incidence of detectable N₂O (‐0.36 × 10 ^‐2μg·ml^‐1) was two‐ to seven‐times more numerous at the high N rate, and twice as numerous under NT compared to CT. These results generally corroborate previous results for soil mineral N changes as related to tillage method, but not for organic C, N and microbial activity, as has usually been reported, especially for more arid region soils.     

一种模拟土壤养分提取及及植物吸收的装置研究

In situ evaluating the availability of soil nutrients has been a challenge. In this study, a new type of Device for Simulating Soil Nutrient Extraction and Plant Uptake (DSSNEPU) and its operating procedures were introduced. The device consists of a sampling tube, a fluid supply system, a low pressure system, a tube sheath and an elution cylinder. The sampling tube was firstly soaked in the solution of 0.5 mol L 1 NaHCO 3 and then buried into soils. The fluid supply system was connected to the sampling tube and the deionized water was supplied. During the period, low pressure system started a vacuum for 3 min every 10 min interval. After extraction, the sampling tube was removed and the nutrients on the sampling tube were eluted with 0.5 mol L 1 HCl. The elution solution was used for nutrient measurement. The amounts of P and K extracted by DSSNEPU reached the maximal values after 4 h. No significant increases of P and K were observed for longer extraction duration. The optimal temperature for extracting P and K was 30 C in this experiment. Extracted P and K were increased by 83.3% and 84.6% with the employment of low pressure system in comparison to those without employing low pressure system. Correlation analysis indicated that P and K extracted by DSSNEPU were highly correlated with those by conventional chemical extraction and by plant uptake. The above results suggest that this device is applicable to assess the availability of nutrients in soils.     

Impact of Tillage and Fertilizer Application Method on Gas Emissions in a Corn Cropping System

Tillage and fertilization practices used in row crop production are thought to alter greenhouse gas emissions from soil.This study was conducted to determine the impact of fertilizer sources,land management practices,and fertilizer placement methods on greenhouse gas(CO₂,CH₄,and N₂O)emissions.A new prototype implement developed for applying poultry litter in subsurface bands in the soil was used in this study.The field site was located at the Sand Mountain Research and Extension Center in the Appalachian Plateau region of northeast Alabama,USA,on a Hartsells fine sandy loam(fine-loamy,siliceous,subactive,thermic Typic Hapludults).Measurements of carbon dioxide(CO₂),methane(CH₄),and nitrous oxide(N₂O)emissions followed GRACEnet (greenhouse gas reduction through agricultural carbon enhancement network)protocols to assess the effects of different tillage(conventional vs.no-tillage)and fertilizer placement(subsurface banding vs.surface application)practices in a corn(Zea mays L.)cropping system.Fertilizer sources were urea-ammonium nitrate(UAN),ammonium nitrate(AN)and poultry litter(M)applied at a rate of 170 kg ha^-1 of available N.Banding of fertilizer resulted in the greatest concentration of gaseous loss(CO₂ and N₂O)compared to surface applications of fertilizer.Fertilizer banding increased CO₂ and N₂O loss on various sampling days throughout the season with poultry litter banding emitting more gas than UAN banding.Conventional tillage practices also resulted in a higher concentration of CO₂ and N₂O loss when evaluating tillage by sampling day.Throughout the course of this study,CH4 flux was not affected by tillage,fertilizer source,or fertilizer placement method.These results suggest that poultry litter use and banding practices have the potential to increase greenhouse gas emissions.     

Molecular cloning and expression analysis of the Rf-m candidate genes encoding pentatricopeptide repeat proteins in soybean

Cytoplasmic male sterility (CMS)-restorer system is a useful tool to exploit heterosis in soybean. The major restorer gene for the M-type CMS is known as Rf-m, located in the 162.4-kb region on chromosome 16. Sequence analysis has revealed that the Rf-m locus in Glycine max consists of seven pentatricopeptide repeat (GmPPR) genes. The deduced amino acid sequences contain 8 to 14 PPR motifs, and a phylogenetic analysis grouped these GmPPR proteins into two PPR subfamilies: Glyma.16G161800 belongs to the PLS subfamily, and the P subfamily consists of Glyma.16G161900, Glyma.16G162000, Glyma.16G162100, Glyma.16G162700, Glyma.16G162800, and Glyma.16G163100. The phylogenetic analysis of seven GmPPR proteins and 27 other plant PPR proteins also showed that proteins in the same subfamilies cluster together. Comparative sequence analysis was conducted using the seven Rf-m candidate GmPPR genes from the sterile line W931A, the maintainer line W931B, and the restorer line WR016, the result showed that Glyma.16G161900 had higher polymorphism than the other candidate genes. Based on real-time quantitative RT-PCR data, all seven GmPPR genes were differentially expressed but showed constitutive expression in roots, stems, leaves, and pollen grains. Additionally, the expression level of Glyma.16G161900 in the sterile line W931A was significantly higher in all tissues than in the restorer line WR016. Taken together, these results suggest that Glyma.16G161900 is the most likely candidate for the restorer gene Rf-m. This study is the first report and analysis of candidate fertility restorer (Rf) genes encoding PPR proteins in soybean.     

GnIH在陆川仔公猪泌尿生殖系统及内分泌免疫系统中的分布

【目的】从形态学水平和分子水平探究促性腺激素抑制激素(GnIH)在陆川仔公猪泌尿生殖系统和内分泌免疫系统中的分布情况。【方法】采集30日龄健康陆川仔公猪的睾丸、附睾、附睾管、肾、肾上腺、甲状腺、腭扁桃体、脾、淋巴结、胸腺,采用免疫组织化学和半定量RT-PCR的方法检测GnIH在其泌尿生殖系统和内分泌免疫系统的分布情况。【结果】免疫组织化学分析结果显示,在睾丸、附睾、附睾管、肾、肾上腺、甲状腺、腭扁桃体、脾、淋巴结、胸腺均有不同数量的GnIH免疫阳性细胞分布。半定量RT-PCR的检测显示,GnIH mRNA除了在甲状腺、脾和淋巴结无表达外,在其余组织均有不同程度的表达。【结论】GnIH在泌尿生殖系统和内分泌免疫系统分布广泛,提示GnIH在生殖、免疫和内分泌等生理过程中可能有重要作用。     

惠州市冬种马铃薯卷叶病毒病的发生、鉴定及气象影响因子研究

以惠州冬种马铃薯为研究对象,探索不同气象条件对冬种马铃薯卷叶病毒的影响。以田间调查的形式统计了不同时期冬种马铃薯卷叶病毒的发病情况,并对马铃薯卷叶病毒进行分子鉴定,分析了惠州市冬季气温、相对湿度及降水等气象条件对冬种马铃薯卷叶病毒病的影响。结果表明:3次调查马铃薯卷叶病毒病的平均发病率依次为2.48%、12.6%、70.18%,呈上升趋势;分子鉴定结果显示确为马铃薯卷叶病毒的感染;气象条件对冬种马铃薯卷叶病毒的发生有着重要的影响,其中高温、少雨,相对湿度在70%~80%的气象条件易造成马铃薯卷叶病毒病的发生和传播。     

脂多糖染毒小鼠稳定内参基因的筛选

本研究旨在筛选脂多糖(lipopolysaccharides,LPS)染毒小鼠的理想内参基因。试验以健康小鼠肝脏和LPS染毒后3、6、12、18 h的小鼠肝脏为研究对象,荧光定量RT-PCR评价YWHAZ、HPRT1、PPIA、ACTB和18S rRNA 5个内参基因的表达情况,并用geNorm软件分析其表达的稳定性。结果表明,除18S rRNA在LPS染毒时不能稳定表达外,其余4个内参基因在健康小鼠肝脏和LPS染毒小鼠肝脏中均能稳定表达,其中PPIA和YWHAZ的表达最稳定。本试验结果为荧光定量RT-PCR研究LPS与小鼠相互作用时mRNA表达水平提供了依据。     

猪嵴病毒RT-PCR检测方法的建立及应用

根据GenBank中登录的猪嵴病毒3D基因保守序列,设计合成1对引物,以腹泻哺乳仔猪的小肠为起始材料,建立了猪峭病毒的RT-PCR检测方法,并用该方法对收集的50份哺乳仔猪腹泻样本进行检测。结果显示,该方法对模板的最小检测量是2.3 pg,检测猪其他常见致腹泻病毒均为阴性,同一样品3次试验结果一致;所扩增的序列经测序分析均为猪嵴病毒的3D核苷酸序列;仔猪腹泻样本的猪嵴病毒检出率达58%。结果表明,该方法敏感度高、重复性和特异性良好,可用于猪嵴病毒的分子流行病学调查和临床病例的快速诊断。