几何形态学方法区分短吻鲾地方种群的研究

运用传统形态测量方法和地标点方法对广东阳江和湛江两个短吻鲾的形态特征进行了分析。传统测量方法的主成分分析的前两个主成分(76.29%)能明显地区分出两个种群。相对扭曲主成分分析前3个主成分(64.03%)也能明显地区分出两个种群,但效果差于传统方法的主成分分析。网格变形图显示,两地短吻鲾的形态差异主要表现在头部。地标点法避免了传统的多变量形态测量方法的信息冗余、包含的形状信息不够完整等问题,并能够重建图形,突出局部的形变,能够直观地比较出研究对象之间的细微差别。研究亮点:地标点法是国外最新发展出并被广泛使用的形态测量方法,该方法以地标点的坐标来表示生物的形状信息,再通过旋转与重叠,用网格图形和相对扭曲分析样本间的形状差异。本文在国内首次使用该方法有效地区分了短吻鲾的不同地方种群。     

基于多元统计分析的水污染评价

提出了水质污染的多元统计分析方法,并以湟水流域年平均水质污染指标为例,对其进行多元回归分析,实证分析结果满意。     

Correlations between camptothecin and related metabolites in Camptotheca acuminata reveal similar biosynthetic principles and in planta synergistic effects

Camptothecin (CPT), 9-methoxycamptothecin (9-MeO-CPT), and 10-hydroxycamptothecin (10-OH-CPT) are potent antineoplastic metabolites. We analyzed these metabolites in Camptotheca acuminata sampled from Germany and China, using LC-MS/MS and LC-ESI-HRMS/MS, coupled with chemometrics. Multivariate analysis revealed that fresh stems of C. acuminata from China had the highest comprehensive metabolite load. Significant positive correlations of CPT with 9-MeO-CPT and 10-OH-CPT were observed by Kruskal's multidimensional scaling and principal component analysis. Linear discriminant analysis and hierarchical agglomerative cluster analysis revealed that C. acuminata from China was separated from others. These positive correlations indicate that these metabolites are biosynthesized similarly and operate synergistically in planta.     

Beech leaf disease symptoms caused by newly recognized nematode subspecies Litylenchus crenatae mccannii (Anguinata) described from Fagus grandifolia in North America

Symptoms of beech leaf disease (BLD), first reported in Ohio in 2012, include interveinal greening, thickening and often chlorosis in leaves, canopy thinning and mortality. Nematodes from diseased leaves of American beech (Fagus grandifolia) sent by the Ohio Department of Agriculture to the USDA, Beltsville, MD in autumn 2017 were identified as the first recorded North American population of Litylenchus crenatae (Nematology, 21, 2019, 5), originally described from Japan. This and other populations from Ohio, Pennsylvania and the neighbouring province of Ontario, Canada showed some differences in morphometric averages among females compared to the Japanese population. Ribosomal DNA marker sequences were nearly identical to the population from Japan. A sequence for the COI marker was also generated, although it was not available from the Japanese population. The nematode was not encountered in Fagus crenata (its host in Japan) living among nematode‐infested Fagus grandifolia in the Holden Arboretum, nor has L. crenatae been reported in American beech in Japan. The morphological and host range differences in North American populations are nomenclaturally distinguished as L. crenatae mccannii ssp. n. from the population in Japan. Low‐temperature scanning electron microscopy (LT‐SEM) demonstrated five lip annules and a highly flexible cuticle. Females, juveniles and eggs were imaged within buds with a Hirox Digital microscope and an LT‐SEM. Nematodes swarmed to the tips of freshly cut beech buds, but explants could not be maintained. Inoculation of fresh nematodes from infested leaves or buds to buds or leaves of F. grandifolia seedlings resulted in BLD leaf symptoms. Injuring dormant buds prior to nematode application, in fall or spring, promoted the most reliable symptom expression. The biogeography and physiology of anguinid nematode leaf galling, and potential co‐factors and transmission are discussed.     

四川盆地西缘柳杉人工林结构及生长预测的初步研究

运用多元统计分析的方法,研究了四川盆地西缘山地柳杉人工林的密度和直径—株数分布的规律,筛选出了影响林分密度的主导因子(林今年龄、地位指数和林分平均直径),并建立了林分密度预测模型。还根据西泽正久(1978)所提供的求解Weibull分布参数e的gamma和Cud数值表,对48块林令标准地的林木株数调查结果用Weibull分布函数进行了拟合。结果表明:有33块标准地的拟合结果经卡方检验达到极显著水牛(α=0.01),有10块标准地达显著水平(α=0.05),另有5块标准地的拟合结果则不符合weibull分布。在此基础上,对影响柳杉人上林Weibull分布函数的 b、c参数的林分结构因子进行了回归分析,并用易测林分结构因子建立了两个参数的预测模型。 通过建立上述预测模型,作者对柳杉人工林的结构和生长量进行了综合预测。经检验结果表明:本次研究所建立的预测模型达到精度要求,为森林资源预测、森林经营管理、抚育间伐提供科学依据。     

The effects of changing regional Agricultural Knowledge and Innovation System on Italian farmers’ strategies

The aim of this paper is to identify and assess the role played by innovative extension services in affecting farmers’ strategy. More specifically we implement a multivariate probit model to evaluate the effects of different types of extension services introduced by a reform in the domain of Agricultural Knowledge and Innovation System (AKIS) in Italy. The results show that both generalist and specialized services could play a major role in farmers’ value creation strategies. They also confirm that different strategies for creating value are jointly implemented. Finally, they show that a further improvement in the quality of public provision of extension services within regional AKIS and a greater (systemic) interaction between farmers, rural actors and local networks should be supported.     

环境行政合同制度在我国环境管理中应用研究——以合肥高新区环境管理为例

从内容、结构、技术层面,对美国的“市场与行政结合”模式、欧盟的“多元概率模型”、“环境行政合同救济制度”等理论技术方法进行归纳总结,以构建综合决策型的环境行政合同制度运用于合肥市高新区管理环境事务的具体实践中,并运用污染因子指数分析法对应用效果进行了综合评价。结果表明,构建的综合决策型环境行政合同制度在环境管理的实践应用中具有可行性与可操作性。     

Predicting soil N mineralization: Relevance of organic matter fractions and soil properties

Distinct extractable organic matter (EOM) fractions have been used to assess the capacity of soils to supply nitrogen (N). However, substantial uncertainty exists on their role in the N cycle and their functional dependency on soil properties. We therefore examined the variation in mineralizable N and its relationship with EOM fractions, soil physical and chemical properties across 98 agricultural soils with contrasting inherent properties and management histories. Mineralizable N was determined by aerobic incubation at 20 °C and optimum moisture content for 20 weeks. We used multivariate statistical modelling to account for multi-collinearity, an issue generally overlooked in studies evaluating the predictive value of EOM fractions. Mineralization of N was primarily related to the size of OM pools and fractions present; they explained 78% of the variation in mineralizable N whereas other soil variables could explain maximally 8%. Both total and extractable OM expressed the same soil characteristic from a mineralization perspective; they were positively related to mineralizable N and explained a similar percentage of the variation in mineralizable N. Inclusion of mineralizable N in fertilizer recommendation systems should be based on at least one OM variable. The most appropriate EOM fraction can only be identified when the underlying mechanisms are known; regression techniques are not suitable for this purpose. Combination of single EOM fractions is not likely to improve the prediction of mineralizable N due to high multi-collinearity. Inclusion of texture-related soil variables or variables reflecting soil organic matter quality may be neglected due to their limited power to improve the prediction of mineralizable N.     

Evaluation of genetic identity and variation of local apple cultivars (<Emphasis Type="Italic">Malus</Emphasis> × <Emphasis Type="Italic">domestica</Emphasis> Borkh.) from Spain using microsatellite markers

A collection of 114 local cultivars of Malus × domestica Borkh. from the Northwest of Spain and a group of 26 non-native commercial cultivars, were studied in order to determine the level of genetic differentiation between them, to know the population genetic structure of the three main production regions in North Spain, and to detect possible duplications, misidentifications, and intrusions of foreign cultivars into the present day Spanish apple gene pools. Ten primer pairs of microsatellite loci were selected from previous studies on apple. Allelic frequencies were used to estimate the average expected heterozygosity (Hexp) and F-statistics. A Principal Component Analysis and a Cluster Analysis were conducted in order to determine the relationships among cultivars. Considering all populations (Spanish and commercial cultivars) we found 119 alleles with the 10 microsatellites; 10 out of 119 were rare (with frequencies lower than 0.01). Spanish cultivars can be used as references for those alleles for further studies since they are available in Germplasm banks. Triploid cultivars were quite frequent, 39 out of 140, with the highest number occurring in Galicia (29 cultivars). North Spain presented a high variability for apple according to heterozygosity levels. Microsatellites have provided useful information about the singularity of Spanish apple cultivars, revealed six groups of synonymies and five introgressions of commercial cultivars.     

基于多元回归的牡丹花期预测

利用菏泽牡丹多年的气象要素的测定资料,采用多元回归以及逐步回归法,建立了气温、地温与牡丹花期关系的线性回归模型。该模型的预测结果与牡丹的实际盛花期基本吻合。该模型为确定菏泽牡丹花会的召开提供了依据。