世界罗非鱼捕捞和养殖的动态特征研究

罗非鱼类原产于非洲和东南亚，具有生长迅速、耐粗食、肉质好等优点，目前已成为世界渔业的重要鱼品。世界罗非鱼生产以捕捞和养殖两种方式进行。九十年代，世界罗非鱼养殖业迅速崛起，养殖产量开始逐渐超过捕捞产量。世界罗非鱼养殖主要品种是尼罗罗非鱼。与此同时，世界罗非鱼的加工与贸易，亦有比较快速的发展。根据1981—2002年FAO关于罗非鱼捕捞和养殖的统计资料，分析了世界罗非鱼产业的动态特征，目前中国罗非鱼养殖年产量世界第一，有必要继续关注和提升中国罗非鱼养殖业发展的世界地位。     

Response of hot pepper (Capsicum annuum L.) to mulching practices under planted greenhouse condition

Mulch is considered a desirable management technology for conserving soil moisture, improving soil temperature and soil quality. This study aimed to investigate soil conditions and hot pepper (Capsicum annuum L.) performance in terms of leaf photosynthetic capacity, fruit yield and quality, and irrigation water use efficiency (IWUE) under such practices in greenhouse condition. A field experiment across 3 years was carried out with four types of mulch (without mulch [CK], wheat straw mulch [SM], plastic film mulch [FM], and combined mulch with plastic film and wheat straw [CM]). Mulch could improve soil physical properties regardless of mulch materials. FM and CM treatments improved soil moistures status and soil temperature in comparison to CK control, while SM increased soil water content and decreased soil temperature. Mulch increased leaf net photosynthesis rate (P_N), stomatal conductance to water vapor (gs), intercellular CO₂ concentration (Ci), and transpiration rate (E), but declined instant water use efficiency (WUEi). No significant effect of mulch application on chlorophyll fluorescence was existent for the entire growth season. Fruit yield and irrigation water use efficiency (IWUE) showed some increment under all the mulch conditions. Compared to CK, the yield was enhanced by 82.3%, 65.0%, and 111.5% in 2008; 38.1%, 17.4%, and 46.5% in 2009; and 14.3%, 6.5%, and 19.6% in 2010 under SM, FM, and CM conditions, respectively. Although FM produced better fruit quality than other treatments, CM is the recommended practice for hot pepper cultivation in greenhouse condition due to working well to facilitate soil condition (moisture and temperature), plant growth, and marketable yield.     

橘园土壤中嘧菌酯的残留消解动态分析

为了了解嘧菌酯在柑橘园土壤中的消解动态规律,采用气相色谱-电子捕获检测法,对贵州、湖南、浙江3地的橘园土壤中嘧菌酯残留进行了检测,并建立了嘧菌酯在土壤样品中的残留检测体系.结果表明,在试验检测条件下,嘧菌酯的最小检出量为1×10-11 g,相对保留时间为4.86 min;添加回收率为98.3％～105.4％,变异系数为5.0％～7.2％,标准偏差为5.15％～7.15％,均能达到我国农药残留检测的要求;湖南、浙江、贵州柑橘园土壤中嘧菌酯的消解半衰期分别为14.0、13.2、11.6d.这表明在自然条件下,嘧菌酯在土壤中消解较快,不会造成土壤中累积性残留污染.     

广东省海洋捕捞产量灰色预测

为摸清今后海洋捕捞业的发展动态,以广东省海洋与渔业局提供的1996～2003年广东省海洋捕捞业统计数据为基础,分别建立灰色预测模型,通过模型对广东省海洋捕捞业发展趋势做出了近5年预测。预测结果,2010年海洋捕捞产量在167×104t,南海的捕捞产量为156.78×104t,远洋渔业产量为19.82×104t。通过对预测结果的可信度进行分析,进一步确定这种分析结果的合理性,从而为确定今后广东省海洋捕捞业发展方向,渔业生产部门制订投资决策和合理安排生产提供科学依据。     

TC/IC-RT-PCR检测黄瓜绿斑驳花叶病毒

根据GenBank上登录的黄瓜绿斑驳花叶病毒(CGMMV)外壳蛋白基因保守序列,设计特异性引物,利用试管捕捉RT-PCR(TC-RT-PCR)和免疫捕捉RT-PCR(IC-RT-PCR)技术对黄瓜绿斑驳花叶病毒进行检测.结果表明,TC-RT-PCR和IC-RT-PCR均具有良好的特异性,检测灵敏度分别比DAS-ELISA高10和100倍;通过对一批进境黄瓜样品的检测,验证了2种检测技术的实际应用效果.因此,本研究建立的TC-RT-PCR和IC-RT-PCR检测技术,可有效应用于CGMMV的快速检测.     

不同水分胁迫下的小麦/玉米间作群体响应机理研究

为探明不同水分胁迫下小麦/玉米间作群体响应机理,试验设置了1个充分灌水、3个不同水分胁迫程度间作处理及2个充分灌水单作对照处理。结果表明:共生期内,各间作处理间普遍存在小麦条带水分捕获当量比高于玉米条带的现象,随水分胁迫的加剧,此趋势愈加明显;随着生育期的推进,此趋势渐弱甚至出现反转,而带间的水分相对竞争能力则呈现逐渐下降的规律。在根系分布特征方面,充分灌溉下间作群体平均根系分布深度为17. 15～17. 24 cm,其根质量密度的90. 42%～90. 77%分布于耕层内,其中小麦为87. 49%～88. 70%,玉米为92. 63%～92. 81%,而水分胁迫会显著影响间作群体根系的空间分布。在间作优势方面,要保持间作优势,每次灌水最少需满足80%左右的田间持水率,随水分胁迫程度的增加,间作群体土地当量比呈现先微升、后下降的规律,且间作玉米的偏土地当量比下降速率快于间作小麦。在种间相对竞争能力方面,表现出随水分胁迫的加剧,小麦相对于玉米先微升、后快速下降,并逐渐近于消失的趋势。间作群体的特殊性造成了两作物条带存在时间与空间上的土壤水分差异,进而导致灌溉水入渗速度及入渗总量的不同,而水分胁迫增大了这种趋势,这在一定程度上满足了灌溉水的最佳去处,从而提高了间作群体的水分利用效率,进而揭示了间作群体的节水增产机理。     

迪北地区致密砂岩气藏测井评价新技术

迪北地区侏罗系阿合组属于致密裂缝性砂岩储层,沉积相类型以辫状三角洲平原为主,岩性复杂,粒度变化大,岩石骨架受多种矿物影响。利用元素俘获测井(ECS),结合常规测井资料分析岩性对储层有效性的影响,为评价储层孔隙度提供准确的骨架参数。同时,裂缝是改善该区储层渗透性的重要因素,裂缝的发育程度决定了储层的渗流能力,引入EARTH IMAGER新型油基钻井液成像测井仪,并利用岩心标定成像,有效解决了裂缝的识别问题。     

Pseudorabies virus infection in mink: a host-specific pathogenesis

Pseudorabies virus (PRV) is an alphaherpesvirus that causes a neurological disease in many wild and domestic animals. The neuropathology elicited by PRV is quite consistent regardless of the host with the only exception of mink, in which it is characterized by a vasculopathy rather than by an encephalitis. In this study, we aimed to investigate the underlying pathogenic mechanism(s) of PRV infection in mink by using immunohistochemistry and laser capture microdissection (LCM) on material from naturally and experimentally infected animals. The inflammatory reaction induced by PRV was minimal or absent not only in the nervous system, where we identified a low number of macrophages and a few T lymphocytes, but also in the primary replication site, the oropharyngeal mucosa; however, the number of PRV-infected cells detected by immunohistochemistry was extremely high both in the peripheral mucosa and in the nervous tissue. On the other hand, the vascular pathology included parenchymal hemorrhages of various degrees and, in specific cortical areas of the brain, fibrinoid degeneration of the capillary walls. Detection of viral antigens by immunohistochemistry revealed infection of endothelial cells of capillaries situated both in the oropharyngeal mucosa and in the brain stem; the presence of PRV DNA in vessels was further demonstrated by PCR performed on LCM samples of brain capillaries. These results can be interpreted as supporting the idea that the different pathology of the disease in mink may be the consequence of an increased endotheliotropism of PRV in this species. Infection of the vessel wall may then lead to vascular pathology and impairment in endothelial cell function, resulting in a weak immune response to infection.