类别辅助变量参与下的土壤无偏采样布局优化方法

为了提高采样点在地理空间和辅助变量特征空间中的代表性,该文提出特征空间偏离指数用以测度采样点在特征空间中的无偏性,采用类别型辅助变量参与下的多维特征空间构建方法,融合地理空间和特征空间均匀分布的多目标优化目标函数,并利用空间模拟退火的方法实现采样点布局优化。以北京顺义区农田土壤重金属采样为例,选取土地利用类型、土壤质地和母质为辅助变量进行样点布局优化,并与特征空间均匀和地理空间均匀采样方法比较,结果表明:用于区域变量总体估计时,地理空间均匀采样估计精度最低,在采样尺度大于0.275时以特征空间均匀采样估计精度最好,而在采样尺度小于0.275时,无偏采样能获得更好的估计结果;在特征空间代表性方面,采样尺度较大时特征空间均匀采样样点代表性最好,采样尺度小于0.302时,无偏采样与特征空间均匀采样的代表性基本一致,地理空间采样点的代表性最差;用于空间制图时,无偏采样总体上比其他2种方法具有更好的制图精度。可见,在辅助变量支持的采样优化中,当采样尺度大且样点数较少时,适合采用特征空间均匀方法,且只能用于总体估计;采样尺度较小,样点数多时,适合采用无偏采样方法。该研究为利用辅助变量设计区域采样布局提供参考。     

獭兔主要繁殖性状遗传力的初步估测

獭兔又名力克斯兔,是著名的皮用兔品种,于1919年由法国普通兔中出现的突变种培育而成。通过对河北兴盛养殖公司饲养的獭兔进行了繁殖性状的测定,根据半同胞组内相关法估测獭兔主要繁殖性状的遗传力。结果表明:繁殖性状的遗传力较低,各个性状的估计值在0.05～0.25范围内,符合繁殖性状遗传力低的规律,具有一定的可靠性。     

Growth and differentiation characteristics of equine mesenchymal stromal cells derived from different sources

Multipotent mesenchymal stromal cells (MSCs) are a promising therapeutic tool for the treatment of equine tendon and other musculoskeletal injuries. While bone marrow is considered the ‘gold standard’ source of these cells, various other tissues contain MSCs with potentially useful features. The aim of this study was to compare clinically relevant characteristics of MSCs derived from bone marrow, umbilical cord blood and tissue and from adipose tissue and tendon. Cell yield, proliferation, migration, tendon marker expression and differentiation into adipocytes, chondrocytes and osteoblasts was assessed, quantified and compared.MSC numbers obtained from adipose, tendon or umbilical cord tissues were 222-fold higher than those obtained from bone marrow or cord blood. Cells derived from tendon and adipose tissues exhibited most rapid proliferation. Osteogenic differentiation was most prominent in MSCs derived from bone marrow, and was weak in MSCs derived from umbilical cord blood and tissue. In contrast, the highest levels of chondrogenic differentiation were observed in MSCs derived from these sources. Collagen 1A2 expression was highest in adipose- and tendon-derived MSCs, while scleraxis expression was highest in cord blood- and in tendon-derived MSCs. The findings indicate that MSCs from different sources display significantly diverse properties that may impact on their therapeutic application.     

冀西北坝上青贮玉米生产中存在问题及对策

冀西北坝上位于河北省西北部,是京津冀地区重要的生态屏障和水源涵养功能区,寻找高产优质的青贮玉米品种,选择合适的技术进行高产优质的青贮玉米生产,成为冀西北坝上地区畜牧业可持续健康发展的最佳选择。但是在实际的生产过程中却存在种植品种不合适、施肥不当、劳动力短缺和人口老龄化等问题。在阐述坝上青贮玉米生产中存在问题的基础上,提出青贮玉米高产优质的发展对策和发展方向,为构建冀西北坝上地区科学合理的青贮玉米生产体系提供理论依据。     

H9N2亚型猪流感病毒对小鼠的致病性及其分子特性研究

本实验从河北地区疑似流感发病猪体内分离到一株病毒,经鉴定为H9N2亚型猪流感(SIV)病毒.将该分离株经滴鼻、点眼途径感染小鼠,观察临床症状和病理变化,同时对血凝素(HA)、神经氨酸酶(NA)、核蛋白(NP)和基质蛋白基因(M)进行克隆和序列测定,与GenBank中登录的相关序列进行比对并绘制系统发育进化树.致病性结果显示:感染小鼠出现精神不振,体重下降,并引起以弥漫性肺泡损伤为主的临床症状和病理变化.序列分析结果显示:该分离株与禽流感病毒(AW) A/chicken/Hebei/4/2008 (H9N2)(简称CK/HB/4/08)参考株的HA、NA、NP和M基因的核苷酸序列和推导的氨基酸序列的同源性最高.HA蛋白的裂解位点序列为PARSSR↓GLF,属于低致病性流感病毒的裂解位点.HA、NP、NA和M基因的遗传进化分析均显示该分离株与AIV的CK/HB/4/08株位于同一分支,具有较近的亲缘关系;由此推测该分离株可能是由CK/HB/4/08演化而来,并在跨物种传播的过程中发生了部分变异.     

草原红牛及其杂种后代A-FABP第4外显子遗传多态性分析

本研究选取没有亲缘关系、月龄相同、并在同一条件下饲养的草原红牛个体78头,草原红牛与利木赞第一代杂交后裔128头进行颈静脉采血提取基因组DNA,并利用PCR-SSCP技术对其肉质性状相关的A-FABP基因第4外显子进行遗传检测分析。研究结果表明,草原红牛A-FABP基因第4外显子区域表现AA、BB和AB共3种基因型,其基因型频率分别为0.59、0.04和0.37;基因频率分别为0.61、0.39;多态信息含量(PIC)为0.37,杂合度(He)为0.48,属于中度变异。草原红牛与利木赞牛杂交后代群体也检测到2个等位基因、3种基因型,基因型频率分别为0.23、0.58和0.19;等位基因频率为0.52、0.48;PIC为0.38,He为0.50。据本研究结果可知草原红牛及杂交后代群体遗传变异较大、具有一定选择潜力,能够较好利用分子遗传标记手段指导育种。     

北方6个不同地区甜菜夜蛾发生为害研究初报

2009年在北方6个地区采用性信息素诱捕法研究了蔬菜田甜菜夜蛾的种群变化动态,同时调查其幼虫为害情况。研究结果表明,不同地区甜菜夜蛾的发生期长短、高峰日及高峰日蛾量等参数均存在明显差异,其中,河南洛阳地区于9月7日达到蛾量高峰,单个诱捕器内蛾量最高达到230.3头,高于天津宝坻（152.3头）、北京昌平（42.7头）和河北张家口（10.67头）,内蒙古呼和浩特和黑龙江哈尔滨地区未诱集到该成虫。田间幼虫的系统监测结果表明,河南洛阳在高峰期百株虫量（414头）远高于天津宝坻、北京昌平和河北张家口（41.2头、21头和2头）3个地区,表明在所调查的地区内,从南到北随着纬度增加,甜菜夜蛾成、幼虫的发生数量和为害程度逐渐降低。最后,初步分析了甜菜夜蛾在不同地区发生为害差异的主要影响因子。     

青海高原春小麦留茬高度对后茬绿肥生物量和水分利用效率的影响

采用裂区试验设计,以华北坝上及其周边寒旱区15个常规栽培品种为供试材料,设置不施氮与施氮两个水平,从块茎产量、氮吸收量、氮生物学效率、肥料氮农学效率、偏生产力、表观利用率等方面进行不同品种氮效率评价;在此基础上,采用隶属函数法对各品种进行综合氮效率鉴评与分类。结果表明：品种、施氮水平、品种×施氮水平等对马铃薯产量具有极显著的影响,在不施氮肥的条件下北方002的产量最高,为5 863 kg·hm^-2,冀张薯12号的氮素生物学效率最高,为92.10 kg·kg^-1;在施氮肥的条件下荷十五的产量最高,为8 284 kg·hm-2,V7的氮素生物学效率最高,为59.05 kg·kg^-1。15个品种在氮效率性状如地力产量、施氮肥后产量、块茎氮吸收量、肥料氮农学效率、肥料氮偏生产力、肥料氮表观利用率等方面存在宽幅变异,变幅范围为21%~58%。在未施氮肥条件下,马铃薯不同品种产量（Y）与块茎含氮量（X）呈极显著负相关,Y=-0.0019X+22.045（R²=0.6269^**）;在施氮条件下,产量与块茎含氮量无显著相关,而肥料氮表观利用率（Y）与肥料氮偏生产力（X）之间呈极显著正相关,Y=1.617X-21.784（R²=0.7465^**）。隶属函数分析表明,荷十五、希森6号与斯凡特（F8）具有较高的综合氮效率,可作为氮高效品种应用于生产或作为氮高效种质材料。     

Microstructural characterisation of commercial kiwifruit cultivars using X-ray micro computed tomography

The skin is the physical barrier between the fruit and the environment in which it develops. Environmental conditions during fruit development have a large influence on fruit quality, both at the time of harvest and during subsequent storage. It is hypothesised that some features of the skin and sub-epidermal tissues could provide information about the past growing conditions to which the fruit was exposed and therefore be of predictive value for storage quality. In this study, five commercial kiwifruit cultivars (‘Hayward’, ‘Hort16A’, ‘G3’, ‘G9’ and ‘G14’) were studied, and ‘Hayward’ fruit were manipulated during growth with different cultural practices. After harvest at horticultural maturity, X-ray micro computed tomography (μCT) was used to investigate features of the skin and the immediate parenchyma tissue. Despite orchard management practices (crop load and girdling) being observed to effect macro fruit quality parameters (mass, firmness, SSC, and DM), differences in microstructure (e.g. porosity) caused by these practices were not observed. However, porosity and pore size were found to be highly variable between cultivars. The thickness of dense sub-epidermal tissue could be readily measured and the 3-D distribution of raphide bundles was visible as high density particles distributed within the parenchyma. Overall, μCT was found to be a powerful technique to explore fruit epidermal and sub-epidermal structures in three dimensions at a micro level. However, the length of time required for data capture and analysis and the large number of samples required to overcome natural variation within horticultural products need to be considered. Future work may define the impact of differences in porosity or sub-epidermal anatomy on kiwifruit physiology (e.g. firmness change or sensitivity to low oxygen storage atmospheres). With this information, μCT could be used as a screening tool during plant breeding, or to determine the response to agronomic treatments, without conducting lengthy storage trials.