基于转录组测序的半滑舌鳎长链非编码RNA的初步鉴定与分析

以抗病家系与易感家系半滑舌鳎为材料,进行哈维弧菌感染实验,并对易感家系感染前(CsSU)、易感家系感染后(CsSC)、抗病家系感染前(CsRU)、抗病家系感染后(CsRC)4组进行转录组测序,根据RNA-seq数据挖掘半滑舌鳎长链非编码RNA信息;通过生物信息学分析,筛选出与抗哈维弧菌病相关的差异长链非编码RNA(long non-coding RNA, lncRNA)。结果显示,共识别出4 584个lncRNA座位,包含5 714个转录本;其基本特征与编码基因的比较分析,lncRNA的GC含量低于编码基因,单外显子基因数多于编码基因,转录本的平均长度长于编码基因,基因表达量低于编码基因。对4组样品进行两两比较(CsRU vs CsSU、CsRC vs CsSC、CsRC vs CsRU、CsSC vs CsSU)分别筛选出818、813、261、140个差异表达lncRNA,其中CsRU与CsSU之间、CsRC与CsSC之间lncRNA数目差异最多,通过聚类分析确定了各实验组的表达模式之间的联系,CsRU与CsSU之间的表达模式最为相近。通过共表达分析,预测出lncRNA和274个编码基因可能存在14 539种相互关系,并进行了功能注释,进而筛选出7个关键lncRNA。qRT-PCR结果显示,差异表达lncRNAs的表达模式和转录组数据得到的基本一致。研究结果为揭示lncRNA在半滑舌鳎抗哈维弧菌免疫调控反应中的作用提供重要的参考数据。     

不同运输条件对合浦珠母贝稚贝存活比较

比较运输方式及环境温度对合浦珠母贝稚贝运输中的存活影响,从而为稚贝运输过程中的运输方式、环境温度及运输时间的把握提供借鉴和参考。以3月龄稚贝为实验材料,运用无水干露、加水淹没及包装充氧等3种方式,分别在环境温度为5、13、21和29℃下模拟运输。每隔3 h从每组运输条件下取出1组实验贝,转移到正常养殖环境下暂养恢复,经48 h后统计其存活率。对运输时间与存活率之间进行非线性参数曲线拟合,计算每组运输条件下的致死时间(T_0)、半致死时间(T_(0.5))及全致死时间(T_1);运用双因素方差分析,Duncan氏方法比较3种运输方式及4种环境温度间的均值。结果显示:包装充氧优于其他两种运输方式,而加水淹没又优于无水干露;温度为13℃和21℃时优于其他2个环境温度,环境温度为17.60～20.05℃是稚贝运输的最佳温度。     

烟草粉螟不同烟叶存放区域消长规律

为探明烟草粉螟在烟叶仓储时的发生规律,以便实施精准防控。在施秉县不同烤房群、烟农 库房及收购点仓库,利用性诱剂对烟草粉螟进行监测。结果表明烟草粉螟在不同烟叶存放区域的始 发期、高峰期和终结期都不尽相同,同一种存区域的烟草粉螟消长规律也不相同。     

叶面阻隔联合土壤钝化对水稻镉吸收转运的影响

为了探讨叶面阻隔联合钝化对水稻镉吸收转运的影响,实现重金属污染农田稻米安全生产,采用大田试验的方式,选用氨基酸螯合硒营养液肥和活性硅肥作为叶面阻隔剂,硅钙肥和贝壳粉作为土壤钝化剂,在田间共设置7个处理：水稻常规种植（CK）,叶面喷施氨基酸螯合硒营养液肥（Se400）,叶面喷施活性硅肥（Si1000）,叶面喷施氨基酸螯合硒营养液肥的同时分别基施硅钙肥（Se400GG）和贝壳粉（Se400BK）,叶面喷施活性硅肥的同时分别基施硅钙肥（Si1000GG）和贝壳粉（Si1000BK）。水稻成熟后对水稻籽粒、颖壳、秸秆、根四部分的镉含量进行检测。结果表明：与对照处理相比,各处理水稻籽粒中镉含量均不同程度降低,且叶面阻隔联合土壤钝化处理的效果更好。Se400GG处理水稻籽粒镉含量下降最明显,降幅为88.13%,水稻籽粒镉含量为（0.18±0.01）mg·kg^-1,低于大米镉限量值0.2 mg·kg^-1（GB 2762—2017）;其次是Si1000GG处理,水稻籽粒镉含量下降了56.77%;单独叶面阻隔的两个处理Si1000和Se400效果较差,水稻籽粒镉含量仅下降了18.28%和9.03%。水稻籽粒镉含量降低的主要原因是水稻各部位的富集系数和转运系数减小,Se400GG和Si1000GG处理水稻根到秸秆的转运系数下降了84.93%和72.60%,水稻籽粒的富集系数下降了87.88%和56.06%,而Se400和Si1000处理水稻根到秸秆的转运系数仅下降46.58%和38.36%,水稻籽粒的富集系数仅下降12.12%和15.91%。可见,叶面阻隔联合钝化技术,尤其是叶面喷施氨基酸螯合硒营养液肥的同时基施硅钙肥能更有效地阻隔水稻对镉的吸收和转运,降低水稻籽粒镉的含量,是值得在镉低污染稻田推广应用的技术。     

毕节市油茶产业发展现状及对策

油茶作为世界四大木本食用油料植物之一,在林业产业和山区经济发展中占有十分重要的 地位。近年来,毕节将油茶产业作为助推脱贫攻坚的重要支柱产业之一,大力发展。文章介绍了毕节 市近年推进油茶产业的一些主要做法,并指出了当前发展油茶产业存在的一些问题,针对问题,提供 了现阶段的一些对策,以期为促进全市油茶产业发展,助推脱贫攻坚提供一定的理论依据。     

潍坊市蓝莓主要虫害及无公害防治方法

随着蓝莓面积增长,虫害对我市蓝莓的影响逐渐明显。从生态安全和食品安全出发,无公害 防治方法有利于环境保护,也能保证给消费者提供优质安全的蓝莓产品。本文总结了潍坊市蓝莓主 要虫害的发生种类、发生特点,并提出了各虫害的无公害防治方法。     

Forage legumes in grass pastures in tropical Brazil and likely impacts on greenhouse gas emissions: A review

Beef cattle producers seldom use fertilizers for their pastures in tropical regions of Brazil. Slowly, this is changing but because of the need for repeated applications, N fertilizer is rarely applied. The introduction of a forage legume is an appropriate solution for this problem, but until recently adoption has been very low as the legumes generally have not persisted in the sward. We report research on how grazing management can affect the persistence of stoloniferous legumes in pastures of Brachiaria spp. and the problems of establishing and maintaining crown-forming legumes such as Stylosanthes spp. With suitable management, milk or bovine carcass yields can be equal or greater from mixed than from grass-alone pastures fertilized with 120 or 150 kg Nha^-1 year⁻¹. In addition to savings in CO₂ emissions from fossil fuels for the production and distribution of N fertilizers, nitrous oxide emissions from cattle excreta and legume residues are lower than those from N-fertilized brachiaria grass monocultures. Other studies indicate that enteric methane emissions from cattle may be mitigated when forage legumes are included in their diet. The use of forage legumes in mixed pastures for tropical regions is emerging as a feasible strategy to keep meat and milk production at acceptable levels with reduced greenhouse gas emission rates.     

China's alfalfa market and imports: Development,trends, and potential impacts of the U.S.–China trade dispute and retaliations

This study examines the development and trends of China's alfalfa market and imports, identifies key factors for the rapid increase in China's alfalfa imports, and discusses potential impacts of the U.S.–China trade dispute and retaliations on the alfalfa markets and trade in both nations. China's rapid transition toward larger-scale commercial dairy production, with enhanced feed and cost management as well as quality and safety control, and its limited resources for high-quality alfalfa production are key factors for the dramatic increase in its alfalfa imports, from 19 601 metric tons in 2008 to 1.38 million metric tons (mmt) in 2018. While the United States dominated China's alfalfa imports with an average share of 97.01% from 2007 to 2017, the share dropped to 83.76% in 2018 and 63.28% in January 2019 due to the trade dispute and retaliations started in 2018. China will likely remain a large importer of alfalfa because of both its growing demand and the comparative advantages of imported alfalfa in quality and price, but the imports from the United States will be highly affected by the ongoing trade dispute and negotiations. China is also expected to make more efforts to reduce its dependence on U.S. alfalfa through increased investment in domestic alfalfa production and identification of alternative sources of alfalfa and other hay imports.     

覆膜方式对雨养饲用玉米生长、产量及水分利用效率的影响

为促进冀西北坝上高寒半干旱区旱地饲用玉米稳产、高产和提高水分利用效率,于2016—2017年在农业部张北农业资源与生态环境重点野外观测试验站,进行了露地平作(ck),双垄沟覆膜、微垄覆膜、土下覆膜处理对饲用玉米叶面积指数、干物质积累、土壤水分、产量和水分利用效率影响的试验研究。结果表明,在丰水年,双垄沟覆膜处理效果最好,与露地相比叶面积指数、干物质积累量、土壤蓄水量分别提高36.45%、70.24%、13.25%,产量和水分利用效率提高了67.24%和87.66%;在欠水年,土下覆膜处理效果最佳,较露地增产71.31%,水分利用效率提高81.69%。双垄沟覆膜是寒旱区提高饲用玉米产量和高效利用降水的有效技术,土下覆膜则更适用于土壤贮水丰富农田的高水效生产。     

猕猴桃细菌性溃疡病研究进展

笔者总结了近年来国内外学者对猕猴桃细菌性溃疡病的研究和发现,详细介绍了猕猴桃细菌性溃疡病的症状、危害和传播途径以及致病菌Pseudomonas syringae pv. actinidiae的特征、分类和起源,分析了其可能的致病机理并总结了猕猴桃的抗病性研究。基于目前对猕猴桃细菌性溃疡病的防治方法和相关研究发现,展望了猕猴桃细菌性溃疡病的研究方向和防治措施,提出采取预防致病菌传入、增强树势和药剂防治相结合的防治措施,为以后的研究和生产实践提供了理论依据。