1年生银杏苗嫁接育苗对比试验初报

培育银杏嫁接苗，通常都采用2—3年生实生苗作砧木。我们通过秋、春两季试验，采用1年生实生苗作砧木，同时进行4种嫁接方法比较，其中顶芽劈接嫁接成活率达100%，平均高可达60．70cm，枝径1．04cm，而且苗木质量好。     

新型香蕉种植开坑机器的工作原理及结构分析

针对大规模香蕉种植开坑机器的研发比较缺乏,设计了一种新型香蕉种植开坑机器,其具有开坑质量高、成本低及能适应不同挖坑要求的特点。同时,分析了新型香蕉种植开坑机器的工作原理,对螺旋式刀盘及重要零件利用Inventor自带应力分析模块建立了有限元模型。有限元分析的结果表明:新型香蕉种植开坑机器能够满足工作要求,且各零件满足刚度和强度的要求可为其他类似农作物开坑器的研制提供参考。     

Heart splitting at crosscutting of eucalypt logs

The occurrence of heart splitting during the crosscutting of logs was discussed in relation to the released strain on Eucalyptus spp. logs. The strains released in the longitudinal and tangential directions were measured by the strain-gauge method and were correlated with the length of the heart split measured on the same logs. There were differences in the longitudinal strain; however, no significant correlation was found with the diameter that could be converted to a mean annual increment (i.e., a relation with the growth rate). The initial splits expand with the time after felling. The longer the initial split, the longer is the length 1 week after felling. The split length was significantly smaller at the butt end of the first log of every tree than at the other end, but there were no significant differences between the split length at the top of the first logs and at either end of the second logs, although there were differences among individual trees. The length of the heart split correlated with the released strain near the pith, which was estimated using Kublers equation. The longitudinal released strain measured on the surface of logs is a good indicator of the heart splitting when crosscutting logs.Part of this paper was presented at the 52nd Annual Meeting of the Japan Wood Research Society     

云冷杉林风倒区林隙和掘根微立地微气候变化

2013年7月,在小兴安岭凉水国家级自然保护区云冷杉林风倒区1.5 hm2的样地内,选取由掘根倒木形成且包含坑和丘微立地的大、中、小3个代表性林隙。在每个林隙中心安装HOBO自动气象站,测定了7—9月林隙中心以及林隙内丘顶和坑底的总辐射、光合有效辐射(PAR)、空气温度和相对湿度,并在郁闭林分和空旷地设置对照。分析了不同大小林隙之间以及林隙内丘顶和坑底之间小气候在生长季的动态变化及其差异。结果表明:林隙总辐射、PAR以及空气温度依照大林隙、中林隙和小林隙的次序依次降低;同一林隙内,丘顶的总辐射、PAR和空气温度大于坑底,丘顶空气相对湿度小于坑底;月均气温和月均PAR均为7月>8月>9月,绝大多数按照空旷地、大林隙、中林隙、小林隙和郁闭林分的次序递减,仅9月份小林隙的气温大于中林隙。同一林隙的平均气温日较差均为7月>9月>8月,相同微立地(林隙中心、丘顶、坑底)气温日较差均为大林隙>中林隙>小林隙。相同月份丘顶的气温日较差均大于坑底。各林隙空气相对湿度均为8月>9月>7月,并按照空旷地、大林隙、中林隙、小林隙和郁闭林分的次序依次递增。7月份大林隙的总辐射、PAR与8、9月份相比均差异显著。9月不同大小林隙之间的总辐射、PAR差异均不显著。7—9月,大林隙和小林隙中心的空气湿度均差异显著。同一林隙相同月份丘顶和坑底的PAR、空气相对湿度差异均显著,空气温度差异不显著;无论是在林隙内还是林隙内的丘顶和坑底,同一林隙不同月份的温度差异均显著。     

不同入渗水头条件下的Green-Ampt模型

在蓄水坑灌灌水时,蓄水坑内入渗水头的增加会改变入渗界面土壤结构性状,从而导致土壤水分入渗特性发生变化。为了能够模拟不同入渗水头作用下的入渗过程,该文在分析入渗水头对水分入渗影响的机制基础上,将入渗水头对入渗的影响归结为对概化饱和区导水率的影响,建立了能够模拟不同入渗水头对入渗影响的改进Green-Ampt模型。在室内进行了不同入渗水头入渗试验对改进后的Green-Ampt模型进行验证,结果表明不同入渗水头条件下不同时刻对应入渗率的Green-Ampt模型计算值和试验实测值吻合较好,改进的Green-Ampt模型可以有效地模拟不同入渗水头条件下的入渗过程。     

浅析三相异步电动机如何“走单相”

三相异步电动机和单相异步电动机一样可单相运行,但会引起电动机发热甚至烧毁等现象,探讨在缺少三相电源的情况下,不改变电机任何结构和绕组参数,通过简单的外部接线和增加分相元件来实现三相异步电动机单相运行.具有一定的实用价值.     

开口核桃烘干工艺试验研究

为了开发以核桃为原料的新食品,该文对开口核桃生产中的关键工序——烘干工艺进行了试验研究。试验用热风进行穿流烘干,风速１．７５ｍ／ｓ,风温１００℃和１２５℃。得出了不同烘干条件下的烘干特性曲线。结果表明,开口核桃用风温１２５℃,风速１．７５ｍ／ｓ,穿流烘干２ｈ较适宜。     

Enhancing biological efficacy and rainfastness of foliar applied calcium chloride solutions by addition of rapeseedoil surfactants

The efficacy of a homologous series of biodegradable rapeseedoil derivatives (triglyceride ethoxylates; Agnique RSO® series, Cognis, Düsseldorf, Germany) with an average of 5, 10, 30, and 60 units of ethylene oxide (EO) as adjuvants for foliar‐applied calcium chloride (CaCl₂) was evaluated in Malus domestica L. Borkh. Previous experiments revealed that the surfactants used are not phytotoxic. All the surfactants applied decreased contact angles of spray solutions. The lipophilic surfactants RSO 5 and RSO 10 reduced contact angles more than the hydrophilic ones. Drying time of spray droplets was most prolonged when RSO 5 was added. Our data provide evidence that the most lipophilic surfactant RSO 5 can enhance Ca penetration, which was shown in isolated cuticles of tomato fruits (Lycopersicon esculentum cv. Panovy) as a model system. The surfactant effect was most pronounced during the first 4 h and reached a plateau after 24 h. Rainfastness of Ca on surfaces of Malus domestica leaves was improved when RSO 5 was added to CaCl₂ spray solutions. All surfactants applied improved rainfastness of Ca on ’︁Braeburn’ fruit surfaces compared to the treatment with CaCl₂ alone. Under field conditions, leaf/fruit application of CaCl₂/RSO 5 led to an increased Ca content in ’︁Braeburn’ apple fruits and a reduced bitter pit incidence.     

Environmental determinants of perch (Perca fluviatilis) growth in gravel pit lakes and the relative performance of simple versus complex ecological predictors

Growth of fish is an important contributor to individual fitness as well as fish production. Explaining and predicting growth variation across populations is thus important from fundamental and applied perspectives, which requires knowledge about the ecological factors involved in shaping growth. To that end, we estimated environment-dependent von Bertalanffy growth models for 13 gravel pit lake populations of Eurasian perch (Perca fluviatilis) from north-western Germany. To identify the main drivers of perch growth, we evaluated the performance of 16 different biotic or abiotic lake variables in explaining growth variation among lakes. In addition, we compared growth predictions from the best-performing model incorporating “complex” variables that require intensive sampling effort, with a model using only “simple”, easily measurable lake variables (e.g. shoreline development factor). The derivation of a simple model aimed at future applications in typically data-poor inland fisheries, predicting expected growth potential from easily measurable lake variables. A model combining metabolic biomass of predators, maximum depth and shoreline development factor performed best in predicting perch growth variation across gravel pits. All three parameters in this model were positively related to perch growth. The best-performing simple model consisted only of the shoreline development factor. Length-at-age predictions from both models were largely identical, highlighting the utility of shoreline development factor in approximating growth potential of perch in gravel pits similar to our study lakes. Our results can be used to inform fisheries management and restoration efforts at existing or newly excavated gravel pit lakes.     

基于全转录组分析的苹果苦痘病发生机制初步研究

 苹果苦痘病已困扰多年,但其发生机制仍不明确。本研究通过全转录组分析,比较了苹果健康果实、苹果苦痘病果、病果病斑部位和病果无病斑部位中可能与苹果苦痘病发生相关的差异表达基因(differentially expressed genes, DEGs),研究了苹果苦痘病的可能发生机制。经全转录组测序,GO功能注释和KEGG通路富集分析,筛选出17个可能与苹果苦痘病发生相关的差异表达基因。RT-qPCR 验证结果显示,与苹果健康果实或病果无病斑部位相比,17个DEGs中,3个涉及植物-病原互作通路的DEGs(CDPK26, WRKY26 和ADP/ATP carrier)在苹果苦痘病果和病果病斑部位中均表现上调;2个涉及细胞凋亡通路的 DEGs(TUBA和CTSF)和1个涉及类黄酮生物合成通路的 DEG(RGA4)均表现下调,表明,苹果苦痘病的发生促进了基因CDPK26、WRKY26和ADP/ATP carrier的表达,抑制了基因TUBA、CTSF和RGA4的表达,说明,涉及植物-病原互作、细胞凋亡和类黄酮生物合成相关的基因,在苹果苦痘病发生过程中发挥着重要的作用。