中国葡萄野生种对葡萄根癌病的抗性   总被引：7，自引：0，他引：7  

柴菊华  贺普超  程廉  崔彦志 《园艺学报》1997,(2)

通过田间接种鉴定，系统研究了中国葡萄属１３个种和变种的２６个株系对葡萄根癌病的抗性，筛选出高抗株系１０个。其中燕山葡萄（♀）因扦插容易生根，可用自根苗作为抗葡萄根癌病砧木进行嫁接试验，其余可用作抗葡萄根癌病的育种资源  相似文献   

Variation in virulence of Greek isolates ofPhytophthora citrophthora as measured by their ability to cause crown rot on three peach rootstocks     

Thomas Thomidis 《Phytoparasitica》2002,30(2):191-193

The virulence ofPhytophthora citrophthora isolated from various host-plants on three peach rootstocks (GF677, PR204, KID I) was examined. There was no significant difference among the rootstocks with respect to their susceptibility to testedP. citrophthora isolates. The most virulent isolate originated from sycamore (Acer pseudoplatanus); isolates from pistachio trees (Pistacia vera) also showed high virulence but were significantly less virulent than the sycamore isolate. Isolates originating from plum (Prunus domestica), almond (Prunus amygdalus) and lemon (Citrus limon) trees were moderately virulent on peach rootstocks; those from cyclamen (Cyclamen persicum) showed the lowest virulence of those tested. There was thus great variation in virulence among the testedP. citrophthora isolates. It is possible that the isolates ofP. citrophthora from sycamore, pistachio, plum, almond and lemon trees are a threat to peach trees, whereas the low virulence of the isolates from cyclamen hosts suggests that these pathogens are not a serious threat to peach trees. http://www.phytoparasitica.org posting Jan. 3, 2002.  相似文献   

Rectangular Cover System of Manifold Method and Its Auto Mesh Algorithm   总被引：2，自引：0，他引：2  

CAI Yong chang  ZHANG Xiang wei 《保鲜与加工》2001,(1):42-46

In contrast to the finite element method, another form of numerical method which is based on the using of rectangular math covers in manifold method is proposed. In this method, the element data is not a necessary in the input data files and it can be incorporated with the CAD technology conveniently. The theory and application of the method are discussed and the auto mesh algorithm of the cover system is also given in this paper. The numerical examples indicate that the method and the algorithm are accurate and effective.  相似文献   

大学生逃课现象的原因及对策分析     

吉颖  倪杰 《湖南农机》2007,(11):136-137

目前,高校大学生逃课现象十分普遍.本文从主、客观两方面对大学生逃课现象的原因进行了剖析,并从教育管理者的角度提出了若干对策建议.  相似文献   

Influence of dietary protein levels on growth performance, carcass composition and liver lipid classes of juvenile Spinibarbus hollandi (Oshima)   总被引：2，自引：0，他引：2  

Shuenn-Der Yang  Tain-Sheng Lin  Chyng-Hwa Liou  & Hung-Kuang Peng 《Aquaculture Research》2003,34(8):661-666

A feeding trial was conducted to investigate the influence of dietary protein levels on growth performance, carcass proximate composition and liver lipid classes of juvenile Spinibarbus hollandi (Oshima), a cyprinid fish. White fish meal was the primary protein source in the study. Eight experimental diets containing 13–55% crude protein were fed to three replicate groups of six fish weighing nearly 8.5 g each for 10 weeks. Both percentage weight gain and feed efficiency ratio increased significantly with increasing dietary protein levels up to 31%, but there was no further increase for protein levels from 31% to 55%. Application of broken‐line regression analysis to the percentage weight gain provided an estimate of 32.7±1.5% dietary protein for maximum growth. The protein efficiency ratio and productive lipid value were inversely correlated with dietary protein level. The hepatosomatic index and the viscerosomatic index were also inversely related to dietary protein level. The carcass protein of fish fed lower protein diets was significantly lower than that of the fish fed higher protein diets. Carcass lipid content decreased with increasing dietary protein levels, whereas moisture was inversely related to lipid content. Both liver glycogen and liver lipid contents decreased with increasing dietary protein levels. Triglyceride was the major component in the liver lipid, and the amount of triglyceride deposited in the liver also decreased with dietary protein levels. The results indicated that both carcass proximate composition and liver lipid class of juvenile Spinibarbus hollandi were affected by dietary treatments.  相似文献   

落叶松人工林树冠形状的预估   总被引：5，自引：0，他引：5  

刘兆刚  郭承亮 《东北林业大学学报》1996,24(6):14-20

以长白落叶松（Ｌａｒｉｘ ａｌｇｅｒｎｓｉｓ Ｈｅｎｒｙ）人工林为研究对象，利用松江河林业局设置的８块团状枝解析标准地作为基础数据，采用树干一致性削度方程垢研究方法，建立了能预估任意部位的树冠体积（Ｃｖ（ｈ），树冠横断面面积Ｃａ（ｈ）及树冠表面各Ｃｓ（ｈ）的一致性树冠体积／冠形方程系统。由２１７株伐倒木树冠资料采用非线性一回归方法建立了预估全树冠方程，某一指定高度以上的树冠体积，某一指定高度处的累  相似文献   

Concept and feasibility study for the integrated evaluation of environmental monitoring data in forests     

Sabine Augustin  Jan Evers  Hans-Peter Dietrich  Johannes Eichhorn  Thomas Haussmann  Regina Icke  Ansgar Isenberg  Wolfgang Lux  Monica Musio  Hans Pretzsch  Winfried Riek  Thomas Rötzer  Bernd Schultze  Andreas Schulze  Jörg Schröder  Walter Seidling  Nicole Wellbrock  Klaus von Wilpert  Barbara Wolff 《European Journal of Forest Research》2005,124(4):251-260

In the 1970s unexpected forest damages, called “new type of forest damage” or “forest decline”, were observed in Germany and other European countries. The Federal Republic of Germany and the German Federal States implemented a forest monitoring system in the early 1980s, in order to monitor and assess the forest condition. Due to the growing public awareness of possible adverse effects of air pollution on forests, in 1985 the ICP Forests was launched under the convention on long-range transboundary air pollution (CLRTAP) of the United Nations Economic Commission for Europe (UN-ECE). The German experience in forest monitoring was a base for the implementation of the European monitoring system. In 2001 the interdisciplinary case study “concept and feasibility study for the integrated evaluation of environmental monitoring data in forests”, funded by the German Federal Ministry of Education and Research, concentrated on in-depths evaluations of the German data of forest monitoring. The objectives of the study were: (a) a reliable assessment of the vitality and functioning of forest ecosystems, (b) the identification and quantification of factors influencing forest vitality, and (c) the clarification of cause-effect-relationships leading to leaf/needle loss. For these purposes additional data from external sources were acquired: climate and deposition, for selected level I plots tree growth data, as well as data on groundwater quality. The results show that in particular time series analysis (crown condition, tree growth, and tree ring analysis), in combination with climate and deposition are valuable and informative, as well as integrated evaluation of soil, tree nutrition and crown condition data. Methods to combine information from the extensive and the intensive monitoring, and to transfer process information to the large scale should be elaborated in future.

Sabine AugustinEmail:

  相似文献   

Non‐target screening of leaf litter‐derived dissolved organic matter using liquid chromatography coupled to high‐resolution mass spectrometry (LC‐QTOF‐MS)     

Olaf Brock  Rick Helmus  Karsten Kalbitz  Boris Jansen 《European Journal of Soil Science》2020,71(3):420-432

  相似文献   

大比例尺航片正射影像中的树冠提取   总被引：1，自引：0，他引：1  

李超  岳树峰  王胜蕾  王绪鹏  刘银帮  李凤日 《东北林业大学学报》2010,38(9)

为使森林航片的分类精度达到单株林木提取水平,以凉水国家级自然保护区1:8000正射影像、DEM及红松(Pinus koraiensis)生境、立地条件特征为基础,对航片进行了传统的非监督分类、监督分类和专家分类,并对其分类机理进行了分析,提取了红松树冠光谱特征、纹理特征。在构建的红松树冠识别模型基础上,执行分类,并运用混淆矩阵分析法对分类结果进行了精度检验。结果表明:将纹理信息、DEM信息、红松生境及立地条件特征信息作为专家知识,构建红松树冠识别模型进行分类的方法,能有效地降低地物分类中"同物异谱"和"同谱异物"现象,使分类的总体精度达到96%,比监督分类提高了10%,从而使大比例尺森林航片分类精度达到了单株林木提取水平。  相似文献   

Testing variability in pathogenicity ofPhytophthora cactorum, P. citrophthora andP. syringae to apple, pear, peach, cherry and plum rootstocks     

Thomas Thomidis 《Phytoparasitica》2001,29(1):47-49

The relative virulence ofPhytophthora cactorum andP. syringae originating from almond trees, and ofP. citrophthora originating from citrus, to apple, pear, peach, cherry and plum rootstocks, was studiedin vivo andin vitro. Results of the different experiments were in good agreement. All testedPhytophthora isolates showed little virulence to pear rootstocks-causing only minor crown rot symptoms - and no virulence at all to apple rootstocks. In contrast, they were highly virulent to stone fruit rootstocks, causing crown rot disease. The non-pathogenicity of these isolates to pome rootstocks could be interpreted as strict host specificity.  相似文献