南方地区高水分玉米安全度夏技术探讨

根据水分的高低,对新收购的高水分玉米分别储存在露天囤和高大平房仓中,将露天囤里的玉米通风降水后转入高大平房仓储存,再对玉米通风降温,并采取仓房密封、悬挂防晒网、空调控温等配套措施控制粮温,期间采取磷化铝多次补药熏蒸杀灭粮堆内害虫及霉菌,使玉米安全度夏。     

不同补水方式下砂壤土渗滤系统对硝态氮去除效果

在水资源短缺的北京地区利用再生水回补城市河湖,一方面对于水资源的可持续利用有着十分重要的作用,另一方面也可能带来地下水环境的潜在污染风险.该文采用100 cm砂壤土柱模拟(河湖岸底)土地渗滤系统,设置定水头淹水、交替淹水落干、定流速补水和侧向补水4种不同再生水回补方式,研究再生水中硝态氮(NO3-N)在土地渗滤系统中的去除效果和迁移转化规律.结果表明,当水力负荷在0.25~2.65 cm/d范围内时,渗滤系统对NO3-N的去除率随着水力负荷的增大而减小;侧向补水方式下渗滤系统对NO3-N的去除效果最优,平均去除率高达96.1%.在定水头淹水和侧向补水方式下,系统对NO3-N的去除主要发生在土柱的上部,而交替淹水落干和定流速补水条件下,土柱中下部对NO3-N也有一定的去除作用.渗滤系统对NO3-N的去除主要取决于系统内部微生物的分布情况,土层中的反硝化细菌数量越大,该土层对NO3-N的去除率就越高.当水温在15~32℃范围内变化时,定水头淹水和交替淹水落干补水方式下,系统对NO3-N的去除率与温度分别呈指数和幂函数关系.该研究表明土地渗滤系统可实现再生水的进一步净化处理,可为再生水安全回补河湖提供参考.     

粮食烘干塔换热器智能折边设备研发

结合螺旋板式换热器的应用领域及其板材折边生产现状,分析了其生产弊端。针对板材折边工艺要求,研发了粮食烘干塔换热器智能折边设备,并剖析其工作机理。根据典型产品结构参数,设计智能折边装备总体装配图并计算主要零件参数,为智能折边装备制作提供理论依据,从而实现换热器板材折边智能加工,提高换热器卷板折边质量及精度。     

后备公猪的科学选育与利用

后备公猪的科学选育及利用直接影响猪场制种效果和经济效益,同时也能体现规模化猪场的制种技术与水平。文章针对后备公猪选育的基本环节和操作要点,从如何选种选育、科学饲养管理、合理配种利用等方面进行系统阐述,为规模化猪场后备公猪生产提供技术指导和参考依据。     

棉花SSR-PCR过程中聚丙烯酰胺凝胶电泳操作常见问题的解决与优化

在大批量聚丙烯酰胺凝胶电泳过程中,难免会出现条带空白、弯曲或者拖尾等各种异常现象。本文以棉花DNA为例,综述了多年实验操作中遇到的突发情况及解决方法,为广大科研工作者提供参考。     

烤烟套种甘薯对烟叶质量、烟薯产量及土壤温湿度的影响

为筛选出适宜与烤烟套种的甘薯品种,解决部分烟区烤烟种植调茬难度大与综合效益低等问题,通过田间大区试验,研究烤烟套种不同甘薯品种对烟叶质量、烟薯产量及土壤温湿度的影响。结果表明,烟薯套种能够明显提升土壤相对含水率和烟叶产量,其相对含水率提高幅度介于12.03%~91.88%,烤烟产量增幅为12.29%~31.26%。烤烟套种甘薯以紫薯产量最高,块根产量达29400 kg/hm ²,且单薯质量大于100 g占总薯重的比例在紫薯中最高。烤烟套种甘薯提升了烤烟中上部烟叶的总糖和还原糖含量,降低了烟碱和总氮含量,有利于改善烟叶内在品质。烤烟套种甘薯降低了上部烟叶含梗率,但增大了上部烟叶叶面密度,以烤烟套种紫薯表现突出。烤烟与紫薯套种,可作为一种烟田增产、烟叶增值和烟农增收的种植模式。     

雪山草鸡感染传染性法氏囊病病毒新型变异株的鉴定

传染性法氏囊病病毒(infectious bursal disease virus,IBDV)新型变异株正在我国广泛蔓延,给商品肉鸡群和蛋鸡群带来了新的威胁。本研究对一个疑似发生非典型传染性法氏囊病的地方品种雪山草鸡群进行了RT-PCR检测,并对分离的3株毒株进行了基因测序及序列分析。结果显示,引起该鸡群发病的病原是IBDV新型变异株,属于A2dB1基因型;这3个毒株的VP2高变区编码蛋白上含有IBDV变异株的特征性氨基酸,也具有IBDV新型变异株的独特氨基酸。结果提示,我国地方品种鸡群中也有IBDV新型变异株的流行,现有的部分商品化IBDV疫苗已不能有效预防IBDV新型变异株的流行。     

Quantitative trait loci for fruit size and flowering time-related traits under domestication and diversifying selection in cucumber (Cucumis sativus)

In cucumber, the genetic basis of traits under domestication and/or diversifying selection is not well understood. Here, we reported QTL mapping for flowering time and fruit size-related traits with segregating populations derived from a cultivated × wild cross. Phenotypic data of flowering time (FT), fruit size (FS), fruit number (FN) and fruit weight per plant (FW) were collected in multiple environments. QTL analysis identified 19 QTL for these traits. We found that the major-effect QTL FT1.1 played an important role in regulating flowering time in cultivated cucumber, whereas the minor-effect QTL FT6.3 contributed to photoperiod sensitive flowering time during domestication. Two novel consensus FS QTL, FS1.4 and FS2.3, seem to be the targets of selection during breeding for the US processing cucumber. All other FS QTL were co-localized with previously detected QTL using populations derived from cultivated cucumbers, suggesting that they were under selection during both initial domestication and subsequent improvement. Results from this study also suggested that the wild cucumber is a useful resource for capturing positive transgressive segregation and novel alleles that could be explored in cucumber breeding.     

β-carotene attenuates weaning-induced apoptosis via inhibition of PERK-CHOP and IRE1-JNK/p38 MAPK signalling pathways in piglet jejunum

Weaning may cause oxidative injury, immune response impairment, apoptosis and other injuries in piglets. Oxidative and endoplasmic reticulum stress (ERS) can elicit inflammatory responses, and persistent oxidative and ERS also may lead to apoptotic cascades, which is associated with the pathogenesis of multiple diseases. β-carotene, a natural carotenoid, has potential anti-inflammatory and antioxidant functions. However, the effect of β-carotene on apoptosis in weaned piglets and the detailed molecular mechanism remain unclear. In this study, we found that β-carotene decreased malondialdehyde (MDA) levels and increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in piglet serum. β-carotene could inhibit the mRNA levels of caspase-3 significantly, but had no significant inhibitory effect of the mRNA levels of caspase-9 and caspase-12 in the piglet jejunum. In addition, β-carotene decreased the activation of GRP78, CHOP, and JNK/p38 MAPK and the ratio of Bax/Bcl-2. Furthermore, β-carotene had a significant influence on the activation of ERS and apoptosis-related signals in TG-induced IPEC-J2. In the present study, β-carotene pre-treatment attenuated the ratio of Bax/Bcl-2 and prevented TG-induced increases in the level of PERK-CHOP and IRE1-JNK/p38 MAPK pathway activation in a dose-dependent manner. Overall, these findings indicate that β-carotene may protect weaning-induced apoptosis through inhibiting ERS.