不同品种烤烟烘烤前后非挥发性有机酸含量的研究

为探明不同产区主栽烤烟品种烘烤前后主要非挥发性有机酸含量的差异及其对烤烟香气风格的影响,以云南省主栽的3个品种云烟85、K326、红花大金元与福建省主裁的两个品种云烟87、翠碧1号的C3F等级烤烟叶为材料,进行了多元有机酸、高级脂肪酸烘烤前后含量变化的分析比较.结果表明:不同品种间棕榈酸、硬脂酸两种高级脂肪酸含量烘烤前后均无显著性差异,亚油酸、油酸含量烘烤后出现显著性差异,而草酸、苹果酸、柠檬酸3种主要有机酸含量存在极显著差异;云烟87的多元酸含量上升而高级脂肪酸含量降低,红花大金元的多元酸与高级脂肪酸含量均有所降低.对产区因素分析得出,云南产区烟叶烘烤前后非挥发性多元有机酸含量普遍高于福建产区,呈现出极显著差异,而高级脂肪酸略低于福建产区,表现出明显的产区差异.     

基于多元图像分析的包装罐内壁缺陷检

为提高包装罐生产线内壁缺陷检测准确性与可靠性,研究了一种采用单摄像机的内壁缺陷检测系统.利用基于形态学的区域提取算法,从罐内图像中分割出内壁检测区域图像.提出基于多元图像分析(MIA)的内壁缺陷检测算法.利用图像融合构成环形合格样本图像,消除罐内焊缝区域的影响,把多个环形合格样本图像与测试样本内壁检测区域图像堆叠起来,用重合区域的图像构造多元测试图像.用基于主成分分析(PCA)的多元图像处理方法获得多元测试图像的主分量表示,将去掉第一主分量和噪声后的Q统计图像作为内壁缺陷特征的检测空间,利用阈值处理检测缺陷,解决了罐体内壁照明困难、亮度不均造成缺陷误检率高的问题,提高了检测系统的准确性和鲁棒性.实验表明对内壁缺陷检测的误检率降低到2%,验证了检测系统的有效性和可靠性.     

褐牙鲆(♀)×犬齿牙鲆( ♂)杂交子一代胚胎发育及仔稚鱼形态学观察

杂交是目前水产育种中应用最为广泛、最有成效的育种途径,为了选育一个能够促进中国海水鱼类养殖业发展,改善目前养殖褐牙鲆发病严重的现状的牙鲆类养殖新品种,对褐牙鲆(Paralichthys olivaceus)(♀)×犬齿牙鲆(P.dentatus)(♂)的杂交进行了研究。在Nikon MS800解剖镜下对褐牙鲆(♀)×犬齿牙鲆(♂)人工杂交子一代的胚胎及胚后发育进行观察,并使用Nikon数码相机拍摄其发育特征,描述了各发育时期的发育时序和形态特征。杂交子一代胚胎发育可分为卵裂前期、卵裂期、囊胚期、原肠期、神经胚期、器官发生期、尾芽期、肌肉效应期、脱膜孵化期共9个时期,除克氏泡出现时期以及胚体开始扭动时期具有相对特异性外,胚胎发育过程与褐牙鲆相比无显著差异。在水温(16.5±0.5)℃,盐度32~33的条件下,受精卵历时67 h完成孵化。(19±0.5)℃水温下,仔鱼3 d以前营内源性营养(卵黄囊仔鱼),3 d开口摄食营外源性营养(前弯曲期仔鱼),20 d左右进入变态期(弯曲期仔鱼),40 d后基本完成变态进入稚鱼阶段,生活方式由浮游转为底栖生活,50 d左右全身被鳞。同时观察了自胚胎发育时期至幼鱼期体表色素的分布及形态变化过程,描述了仔鱼变态期冠状鳍条、眼位置和尾部的发育、变化过程。早期生活史无鳔器官发生。     

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.     

Physicochemical Properties of Banana Flour as Influenced by Variety and Stage of Ripeness： Multivariate Statistical Analysis

Physicochemical properties of banana flour （BF） were studied in two varieties （Cavendish and Dream） and two stages of ripeness （green and ripe）. BF＇s were analyzed for pH, total soluble solids （TSS）, water holding capacity （WHC） and oil holding capacity （OHC） at 40℃, 60 ℃ and 80 ℃, color values L＊, a＊ and b＊, back extrusion force and viscosity. Physicochemical data were analyzed by Multivariate Analysis of Variance, discriminant analysis and cluster analysis. All statistical analyses showed that physicochemical properties of BF prepared from different variety and stage of ripeness were different from each other. Viscosity, WHC40, WHC60 and TSS were recommended methods for discrimination between banana flour prepared from the two varieties, whilst viscosity, WHC60 and WHC80 were suggested for differentiation of banana flour prepared using green and ripe banana.     

基于VB的积分回归的设计与应用

在一般的多元回归分析中,通过分析因变量和自变量之间的关系,可以预测因变量的值.但是,如果考虑各自变量不同时段对因变量的影响,这时常常采用积分回归分析法.本文介绍了积分回归的基本原理,以及使用Visual Basic(简称VB)编程工具设计积分回归程序的过程.在农业、经济、工业等领域利用积分回归统计程序可以简化积分回归分析过程,所得到的积分回归方程能够真实反映出各自变量不同时段对因变量的影响.该积分回归统计程序界面简单、便于操作.     

利用几何形态测量学方法分析唐鱼群体的形态变异

唐鱼是华南地区小型亚科鱼类的典型代表,国家Ⅱ级保护水生野生动物。本研究利用基于地标点的几何形态测量学方法分析了唐鱼8个野生种群和2个养殖群体的形态变异,旨在从形态学的角度了解唐鱼不同种群间的分化程度,为唐鱼保护策略的制定提供科学依据。新鲜标本冰冻麻醉后随即置于95%酒精中固定,用Nikon D-800单反相机拍照获得固定标本的标准图像。利用tps系列软件提取地标点坐标值,进行相对扭曲主成分分析、网格变形分析和判别分析来解释唐鱼的形态变异。相对扭曲主成分分析结果显示,第1、2、3主成分分别解释了总变异的48.20%、23.12%和14.83%,降维效果较好。其中,Ⅱ型地标点12、13、14和15贡献较大,四者合计贡献率达71.28%,反映出唐鱼群体的形态变异主要表现在眼径大小和头部形态。逐步判别分析和交互验证分析的总体判别正确率分别为97.6%和92.0%,能有效识别唐鱼群体。研究结果还揭示了唐鱼野生种群和养殖群体之间存在显著的形态差异。基于上述结果以及唐鱼呈点状分布的事实,建议将唐鱼的7个野生种群(越南种群除外)各自作为单独的保护单元进行重点保护,同时建议禁止在野外放流养殖群体。     

Stocking density and its influence on shape of Senegalese sole adults

Morphological changes in Senegalese sole adults (Solea senegalensis Kaup, 1858) reared at two stocking density conditions (low stocking density, 60% of bottom occupation and high stocking density, 180% of bottom occupation) were investigated using geometric morphometrics. Canonical variate analysis on weight matrix scores, including the uniform component (W′), at the end of the experiment revealed differences in body shape between experimental groups. The low density group presented a similar change pattern as that of the high density group but was less intense. Differences were discussed in terms of the effect of a high stocking density on the shape of soles which were very close to commercialization. Results did not indicate a significant size-related shape, likely due to fish age. Our results provide the first promising look at environment-related shape changes in reared sole.     

基于多元目标的水利风景区开发规划引导性研究

新时期,在强调水资源可持续利用的总体战略目标下,水利事业已将水土资源的生态保护、娱乐利用、旅游观光作为发展方向和任务之一,把水利风景区的开发建设纳入了重要工作内容.水利风景区的开发目标具有多元特点,其规划具有很强的综合性和多重复合的跨学科特征,是水利风景旅游事业发展面临的重要课题.在阐述水利风景区开发的多元目标基础上,对其科学规划的意义、原则、编制要求及导则等方面进行研究,并明确提出基于水资源保护、自然与景观资源保护、生态环境修复等多元目标的水利风景区规划引导整体框架.     

单轨制与多元化农业科技成果转化运行机制利弊分析

随着经济体制的变革,农业科技成果转化运行机制发生了从单轨制农业科技成果转化运行机制向政府主导的多元化农业成果转化运行机制的转变。文章从不同方面对两种农业科技成果转化运行机制的利弊进行了分析。