湖北省杉木人工林立地类型划分及评价

以湖北省杉木人工林为研究对象,选择166块具有代表性的杉木人工林标准地,并测定样地的常规立地因子。利用数量化理论Ⅰ的方法建立了杉木优势高与立地因子之间的关系模型,对研究区杉木人工林进行立地类型划分及立地质量评价。结果表明,所选择的5个立地因子与优势高数量化拟合的复相关系数为0.639;海拔、腐殖层厚度和坡位这3个立地因子对优势高的贡献率达84.99%,且影响均达到极显著水平;采用海拔、腐殖层厚度和坡位3个因子构建研究区杉木人工林立地类型,共划分为22类;按照优、良、中、差4个评价等级对166块样地所属的立地类型进行立地质量评价,得出湖北省杉木人工林在中海拔、土壤湿润、土壤养分含量较高的立地条件下生产力较高,研究区立地质量整体处于中等偏上水平的结论。     

色彩对城市山地型公园春冬季植物景观视觉质量的影响

文章采用SBE法、色彩量化分析等研究方法,结合实地调查,应用景观美学、色彩构成理论、色彩量化分析等理论对福州市金鸡山公园植物景观质量提升进行研究,研究结果表明:1)金鸡山公园春冬植物景观整体以绿、黄绿色为主,色相种类相对较少,色彩丰富度较低;明度主要集中在N4,N5等级,位于中等水平;纯度主要分布于1~3等级内,植物色彩饱和度较低。2)根据美景度评价法及景观质量等级划分,将金鸡山植物景观分为5个等级,SBE最高最低差值为146.24,差异较大;景观质量较高的景观主色调色系较多且差别较大,绿色色调的斑块与景观色彩面积比较小(最低值仅63.52%),景观质量较差的景观主色调色系较少且差别不大,绿色色调的斑块与景观色彩面积比较大(高于80%),且美景度较高的照片其明度及纯度也较高。3)从色彩频率分析可知,Ⅰ,Ⅱ组主要为绿色系、蓝色系、黄色系及红色系;Ⅲ,Ⅳ,Ⅴ组多以冷色调的绿色系、灰色系为主。4)应适当增加植物景观主色调色系、控制绿色系色调的比例,多采用邻近色和互补色配置,并注意明度和饱和度变化以提高金鸡山公园植物景观质量。     

基于多反应监测质谱技术的水稻叶片蛋白绝对定量方法

【目的】建立水稻叶片蛋白的多反应监测(MRM)质谱绝对定量方法。【方法】水稻叶片蛋白经含1.0%十二烷基硫酸钠(SDS)的磷酸盐(PBS)缓冲液提取,丙酮沉淀除杂纯化、胰蛋白酶消化,酶解液经液相色谱分离,MRM质谱监测,外标法定量。【结果】向提取缓冲液中加入1.0%SDS可增强水稻叶片中16种靶蛋白和总蛋白质的提取效果;不同有机试剂处理,总蛋白质沉淀量存在显著差异(P<0.05),沉淀能力从强到弱依次为乙腈>丙酮>异丙醇>甲醇>乙醇;对于16种目标蛋白,总体以丙酮沉淀效果最好,其次是异丙醇和乙腈,甲醇和乙醇效果较差。该方法线性范围均达到3个数量级,定量限为0.1~2.5 nmol/L,灌浆期16种水稻叶片蛋白质含量为6.0~2818.1μg/g,相对标准偏差均小于14%。【结论】SDS可显著提高水稻叶片蛋白提取效果,采用丙酮或乙腈可获得较好的蛋白沉淀效果,但不同蛋白质略有差异。结合MRM质谱监测技术可实现水稻叶片蛋白的绝对定量,方法线性范围宽、敏度高、重复性好。     

1978—2018年中国农村环境管理政策演进特征——基于206份政策文本的量化分析

基于手工搜集的1978—2018年中国政府颁布的206份农村环境管理政策文本，从政策发布年度、政策发布主体、政策发布形式、政策作用对象、政策工具及政策效力6个维度构建分析框架，运用政策文献计量和内容分析方法分析了中国农村环境管理政策的演进特征。结果表明:1978年改革开放以来，中国农村环境管理政策在数量上呈整体持续上升态势；农村环境管理政策经历了探索起步(1978—1989年)、初步形成(1990—2004年)、快速发展(2005—2013年)和全面推进(2014年以后)4个阶段的演进；政策发布主体的行政级别较高且呈现多元化特征，政策联合决策程度高，但政策之间统筹性和协调性较低；政策绝大多数以通知、意见等形式发出，缺乏权威性和规范性；政策的着力点主要在原生态保护层面，对农村人居环境整治的重视程度不够；命令控制型政策是政府最为偏好的农村环境管理政策工具，经济激励型、信息公开型和自愿参与型政策工具使用不足；政策整体效力的提升主要由政策发布数量驱动，政策反馈不足、政策措施较少和政策目标量化程度低是导致政策平均效力较低的主要原因。     

Establishment and application of an accurate identification method for fragrant soybeans

In order to screen the aroma characteristics of soybean,a new method was established which can quickly quantify the content of 2-acetyl-1pyrroline (2-AP),an important compound related to soybean aroma,using gas chromatography-mass spectrometry (GC-MS).Based on peak profile,total peak area and retention time as test indexes,an accurate identification method for fragrant soybeans was established.The optimum parameters of the protocol consisted of column temperature70°C,sample injector temperature 180°C,optimum extraction alcohol content 1 m L,Na Cl content 0.1 g,ultrasonication time10 min,and extraction time 1 h,which were established by using the orthogonal test of single factors and three factors with four levels (L_9(3)~4).2-AP content of leaves had significant correlations with seeds,which were easier to measure.The protocol was simple and easy to carry out,consumed only small amounts of reagents,and provided accurate and reliable results with good reproducibility.A total of 101 soybean genotypes from different geographical sources were analyzed using this protocol.The results showed that the average content of 2-AP was 0.29 mg L~(–1),ranging from 0.094 to 1.816 mg L~(–1),and the genetic diversity index was 0.54.Among all genotypes-tested,they were classified into three grades,including seven elite genotypes identified as"grade one fragrant soybeans",which were Zhonglong 608,Heinong 88,Ha13-2958,Hongmiandou,Heinong 82,Huangmaodou,and Jiyu 21.These results provide both an identification technique and several elite aroma genotypes for gene discovery and good quality breeding in soybean.     

Characterization of an intravenous lipopolysaccharide inflammation model in calves with respect to the acute-phase response

Our objective was to develop a lipopolysaccharide (LPS) inflammation model in calves to evaluate the acute-phase response with respect to the release of pro-inflammatory cytokines and acute-phase proteins, fever development and sickness behaviour. Fourteen 4-week-old male Holstein Friesian calves were included and randomly assigned to a negative control group (n = 3) and an LPS-challenged group (n = 11). The latter received an intravenous bolus injection of 0.5 μg of LPS/kg body weight. Blood collection and clinical scoring were performed at 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 8, 12, 18, 24, 28, 32, 48, 54 and 72 h post LPS administration (p.a.). In the LPS group, the following clinical signs were observed successively: tachypnoea (on average 18 min p.a.), decubitus (29 min p.a.), general depression (1.75 h p.a.), fever (5 h p.a.) and tachycardia (5 h p.a.). Subsequent to the recovery from respiratory distress, general depression was prominent, which deteriorated when fever increased. One animal did not survive LPS administration, whereas the other animals recovered on average within 6.1 h p.a. Moreover, the challenge significantly increased plasma concentrations of tumour necrosis factor-α, interleukin 6, serum amyloid A and haptoglobin, with peaking levels at 1, 3.5, 24 and 18 h p.a., respectively. The present LPS model was practical and reproducible, caused obvious clinical signs related to endotoxemia and a marked change in the studied inflammatory mediators, making it a suitable model to study the immunomodulatory properties of drugs in future research.     

Mixed forests and a flexible harvest policy: a problem for conventional risk analysis?

The famous “Faustmann” equation, which allows for identifying the most profitable tree species on a given unstocked piece of land, assumes constant timber prices. In reality, timber prices may fluctuate dramatically. Several authors have proven for monocultures that waiting for an acceptable timber price (reservation price) before harvesting (flexible harvest policy) increases the net present value of forest management. The first part of this paper investigates how efficient a flexible harvest strategy may be applied in mixed forests and whether the optimal species mixture is changed under such harvest policy. Mixtures of the conifer Norway spruce [Picea abies (L.) Karst] and the broadleaf European beech (Fagus sylvatica L.) were investigated. In order to evaluate mixed forests, the risks and the correlation of risks between tree species as well as the attitude towards risk of the decision-maker (risk-aversion is assumed) were considered according to the classical theory of optimal portfolio selection. In the second part we took up a recent critique on modern financial theory by Mandelbrot. Whether or not the assumption of normally distributed financial flows, which are supposed to occur under risk, would be appropriate to evaluate the risk of forest management was investigated. Market and hazard risks as well as their correlation were integrated in the evaluation of mixed forests by means of Monte-Carlo simulations (MCS). The risk of the timber price fluctuation was combined with the natural hazard risk, caused mainly by insects, snow and wind. Applying the μ-σ-rule, the mean net present value (NPV) from 1,000 simulations and their standard deviation were used for the optimisation. Given a low-return, risk-free interest rate to assess potential species mixtures of the Norway spruce and European beech, optimal proportions of European beech increased according to the theory of optimum portfolio selection with growing risk aversion from 0 (ignorance of risk) to 60% (great risk-aversion). In relation to a fixed harvest policy, the net present value of both, Norway spruce and European beech, could be increased significantly. Since the hazard risks of European beech were substantially lower compared with the Norway spruce (relation of susceptibility 1:4) beech benefited more from the flexible harvest policy. A comparison of simulated frequency distributions of the NPV with the expected density functions under the assumption of a normal distribution revealed significant differences. Only in the case of European beech was the general shape of the simulated frequency distribution similar to a normal distribution (bell-shaped curve). However, the density of NPV close to the mean was much greater than expected under the assumption of a normal distribution. Consequently, the frequency of a negative NPV for a European beech forest was greatly overestimated when applying the normal distribution. Though the shape of the simulated frequency distribution was rather different from a normal distribution for Norway spruce the simulated part of negative NPV was quite well approximated by the normal distribution. Therefore the simulated and expected frequencies of negative NPV were similar in case of Norway spruce; only a slight underestimation was seen in the assumption of a normal distribution. It can be concluded that actually simulated frequencies of negative NPV seem to be better measures for risk than computed probabilities of negative NPV, which assume normal distribution. As the risk for European beech was greatly overestimated by the conventional assumption of a normal distribution, the optimal proportions of European beech were surely rather underestimated according to the theory of portfolio. MCS on optimum mixtures derived by the classical portfolio theory seems necessary to test the robustness of such mixtures.

Direct evidence of surface infestation of seeds and tubers by Plasmodiophora brassicae and quantification of spore loads

Using quantitative PCR, DNA of Plasmodiophora brassicae, the causal agent of clubroot, was detected and quantified on canola, pea and wheat seeds, as well as on potato tubers, all harvested from clubroot‐infested fields in Alberta, Canada. Quantifiable levels of infestation were found on seven of the 46 samples analysed, and ranged from <1·0 × 10³ to 3·4 × 10⁴ resting spores per 10 g seeds; the vast majority (80–100%) of resting spores on these samples were viable, as determined by Evan’s blue vital staining. However, the levels of infestation found were generally lower than that required to cause consistent clubroot symptoms in greenhouse plant bioassays. While the occurrence of P. brassicae resting spores on seeds and tubers harvested from clubroot‐infested fields suggests that seedborne dissemination of this pathogen is possible, practices such as commercial seed cleaning may be sufficient to effectively mitigate this risk.     

Design and validation of a RT‐qPCR procedure for diagnosis and quantification of most types of infectious pancreatic necrosis virus using a single pair of degenerated primers

Infectious pancreatic necrosis virus (IPNV) is an important virus which affects the salmonid aquaculture industry worldwide; therefore, it is important to develop rapid and reliable methods of diagnosis to detect the disease at early stages. Nowadays, RT‐qPCR is replacing other methods because it provides additional information on the viral load, which is important to have a better understanding of the virus replication level and of the stage of the infection and its risk level. The main problem stems from the high diversity of this virus, which can compromise the reliability of the diagnosis. In this study, we have designed an RT‐qPCR procedure for diagnosis and quantification of IPNV based on a single pair of primers targeted to segment B. The procedure has been validated, in vitro and in vivo, testing two different types of standards against seven reference strains and 23 field isolates from different types. The procedure is reliable for the detection of any type, with a detection limit of 31 TCID₅₀ mL^?1, 50 pfu mL^?1 or 66 RNA copies mL^?1, depending on the standard. All the standard curves showed high reliability (R² > 0.95). The results support the high reliability of this new procedure for the diagnosis and quantification of IPNV.     

利用QuantStudioTM 3D数字PCR分析转基因玉米MON863含量

QuantStudioTM 3D数字PCR (QuantStudioTM 3D digital PCR,3D-dPCR)是一种基于超高密度亲疏水微孔芯片实现数字PCR分液原理的新型核酸绝对定量平台,在转基因生物定量领域具有极大的应用前景.本研究基于3D-dPCR平台,以转基因玉米(Zea mays)MON863混合样品为例,建立基于单重和双重数字PCR体系的转基因生物(genetically modified organisms,GMOs)含量分析方法.与传统qRT-PCR比较发现,在缺乏样品纯度、纯合度信息的情况下,数字PCR能够较好地排除这些因素的影响,测定准确的量值.研究结果表明,QuantStudioTM 3D数字PCR是一种适用于转基因生物含量分析的精确定量方法,还可反映转基因玉米种子的基因型.本研究基于3D-dPCR建立的转基因玉米MON863单重和双重定量方法为转基因检测提供了新的方法和参考.