J 亚群禽白血病病毒gp85单抗1E3株抗原识别表位的初步分析

J 亚型禽白血病是由 J 亚群禽白血病病毒引起的一种以成髓细胞增生、免疫抑制、生长发育受阻为特点的传染性肿瘤疾病,于1988年首次发现,其病毒囊膜表面蛋白gp85决定了病毒亚群特异性.本试验将原核表达质粒pET-28a-J gp85中的gp85基因分段亚克隆至重组表达质粒pGEX-6p-1上并在大肠杆菌中成功地表达,用ALV-J Sl gp85单克隆抗体1E3株对分段表达的gp85蛋白进行初步的免疫印迹分析.结果表明:ALV-J Sl gp85单抗1E3株所识别的抗原表位位于蛋白N端的第69至112个氨基酸之间.这将为ALV-J gp85抗原决定簇所在位点及其免疫学功能的研究奠定基础.     

Predicting regeneration establishment in Norway spruce plantations using a multivariate multilevel model

This study predicts the regeneration establishment on 3-year-old Norway spruce (Picea abies (L.) Karst.) plantations in southern Finland using regeneration survey data. Regeneration establishment was described by seven response variables: number of planted spruces, natural Scots pines (Pinus sylvestris L.), natural spruces, natural seed-origin birches (Betula pubescens Ehrh. and B. pendula Roth.) and other broadleaves (i.e. sprout-origin birches and other broadleaves than birch), as well as height of crop-tree spruce and dominant height of broadleaves. Due to the multivariate (several responses for each plot) and multilevel (plot, stand, municipality, forest centre) structure, regeneration establishment was modelled by fitting a multivariate multilevel model with explanatory variables such as temperature sum, site fertility, soil quality and method of site preparation. In the model, the numbers of tree seedlings were modelled using over-dispersed Poisson distributed equations, and the tree heights were modelled using normally distributed linear equations. The estimated fixed and random parameters of the equations were logical, and there was no serious bias in predicting the regeneration establishment in the independent test data set. This modelling approach can be used to predict the regeneration establishment stochastically by taking into account the large unexplained variation in regeneration models.     

Economic potential of agroforestry for public recreational parks

The availability of public recreational facilities is being threatened by growing demands, limited supplies, and declining government funding. In response to these pressures, the economic potential of agroforestry for supplementing operating budgets of public recreational parks is examined in a case study park consisting of 324 hectares. Agroforestry enterprises native to the area were selected for development on 70 hectares of the site. Linear programming was used to determine the optimum combinations of 23 agroforestry regimes composed of the following activities: 1) conventional forestry planting, tree density of 1682 trees/hectare, 2) the selected agroforestry planting with hay, tree density of 1495 trees/hectare, 3) the selected agroforestry planting with grazing, 4) hay production, and 5) rental of pasture for grazing. The objective function of the study was to maximize the net present value of the study site subject to land, labor, capital, and minimum annual income constraints. The preferred optimal regime generated $1782 per hectare from an agroforestry planting configuration of 1495 trees/hectare with 75 percent hay, 25 percent grazing, and no annual income requirements. Minimum annual income requirements of $2400 and $4800 were feasible but suboptimal from a net present value criteria. The study found that agroforestry could be used to privatize selective activities of public recreational parks and thus enable public agencies to provide these facilities more effectively.     

泡桐属植物育种值预测方法的研究

分别用最佳线性无偏预测和最佳线性预测方法预测了泡桐属植物的育种值。结果表明，根据亲缘相关距阵对育种值的最佳线性无偏预测结果没有显著影响：数据量较大时，可用小区平均值取代单株值，同时也可用最佳线性预测代替最佳线性无偏预测方法预测育种值；预测育种值与真正育种值之间的相关系数与预测育种值之间的方法或误差方差存在极显著的相关关系，可用前者作预测育种值的精度指标。通过比较毛泡桐种源所预测育种值之间的方差和误差方差可以得出：在对研究材料评选时，最佳线性预测比最小平方估算法具有优越性，但当重复数大于5次，每个小区内的植株多于6时，这两种预测方法的精度非常接近。     

天然林直径分布的线性表达及其应用

利用非线性函数的线性化方法,使传统的天然林直径分布的反"J"型曲线转化为直线形式,并探讨了直线参数变化的直观表现。通过对长白山天然林123个固定试验地林分直径分布的线性拟合,平均相关系数为0.98,表明天然林的直径分布线性化表达是可行的。可利用参数设计择伐株数和预估采伐前后的直径分布。参数在天然林择伐作业设计中可操作性强,研究结果可以为天然林经营,特别是为择伐作业提供依据。     

北京八达岭人工油松林地表枯死可燃物负荷量研究

地表枯死可燃物负荷量多少是森林火灾发生的基础。调查八达岭林场不同地形条件下油松林地表枯死可燃物和林分因子,取得42块样地资料;用线性相关分析法对各因子与地表枯死可燃物负荷量进行分析,平均树高、坡度和海拔与对应负荷量有显著线性关系;应用多元线性回归中的逐步回归剔除法,建立了估测模型,除平均胸径外,平均树高、密度、郁闭度、海拔、坡度被引入,经检验回归显著,该估测模型可用于其它油松林地表可燃物负荷量估测。     

外界生态因子对油茶品质影响的研究

对21个地区58个油茶物种(或优良品种)进行了含油率、脂肪酸组成、碘值和粗蛋白质等化学品质的分析。通过选取14个不同地区的普通油茶(Camellia oleifera Abel)的品质与19个生态因子进行多元线性逐步回归分析,揭示了不饱和脂肪酸含量与纬度成明显的正相关;种仁蛋白质含量与8、9月份的降雨量呈负相关的趋势。品质之间的相关分析表明:不饱和脂肪酸含量与蛋白质含量存在明显的负相关关系;不同物种之间,其不饱和脂肪酸含量与果实的大小成负相关。     

曲线回归计算器程序编制

利用ＣＡＳＩＯｆｘ－４５００ｐ计算器编程对一套数据同时用农林业常用的８个经验方程进行曲线回归，并进行显著性检验，选出最佳方程。     

北京九龙山油松人工林地位指数表的编制及油松林生长与立地因子的关系

北京地处暖温带半湿润季风气候区，地带性植被是暖温带落叶阔叶林。由于长期受     

Using model scenarios to predict and evaluate forest-management impacts on soil base saturation at landscape level

Silviculture, forest conversion and technical tools of ecosystem management, such as forest liming, display their effects at the landscape level. Therefore their planning and control should take place at the same scale. The primary objective of this work was to assess soil chemical properties and their changes in relationship to ecosystem management, especially forest conversion and forest liming. We calculated scenario models, based on regression analysis, which allow such an examination in the context of understanding landscape processes which can be expected to operate in the sampling region. Stepwise multiple linear regression analysis was used to predict soil chemical attributes (base saturation, pH, C/N content and stock, exchangeable stocks of Ca and Mg) as indicators of site stability or off-site effects of forest ecosystems such as effects on clean drinking water from forested watersheds. Because of space limitations, in this paper only the modelling results of base saturation are presented. Base saturation was used as an integrative example for other soil chemical properties. The transformation of measurements to the regional scale, i.e., the regionalization, was calculated for the forested parts of two test regions in the Black Forest on the basis of measured chemical properties of 90–150 soil profiles per test region. The models have a spatial resolution of 50×50 m, which is a spatial scale relevant for forestry practice and forest management. Topographic variables (e.g., elevation, aspect, slope gradient, and slope length), the stratigraphic classification of the geologic substrate, stand characteristics from forest inventory data, and finally technical information about forest liming were the auxiliary variables (secondary site properties) that provided indirect information about base saturation and were available for the whole forested area of the test regions. Base saturation could be predicted with an accuracy of ~50–70% (in terms of the multiple R²) by using these properties as predictor variables in multiple linear regression analyses. The explained proportion of variance was unexpectedly high considering the high geomorphological heterogeneity of the two test regions. Based upon the regionalization models, it was possible to establish scenarios showing the landscape-related effects on base saturation that may be achieved by forest conversion towards a higher proportion of forests with broad-leaved mixed stands and by forest liming. These scenarios allow the interactions between several influencing factors and management strategies and the impacts on the target variable to be synoptically judged. Thus the presented regionalization models achieve the role of decision support tools for the planning of forest management at the landscape level. They allow an assessment of the environmental effects of forest management strategies in terms of site sustainability or preservation of water resources in forested catchments.