广东主要茶区春季杂草群落调查与区域差异分析

探明广东茶园春季杂草基本情况,为茶园杂草防控提供基础数据.2020年3-5月,在广东省粤东、粤西、粤北3个茶叶主产区31个茶园共620块样方开展茶园杂草群落调查,采用七级目测法,记录样方杂草种类及生长优势等级.调查共发现杂草313种,出现频度高于10％的杂草有126种,其中菊科杂草23种、禾本科12种、茜草科8种、蔷薇...     

Efficient doubled haploid production in microspore culture of loose-curd cauliflower (Brassica oleracea var. botrytis)

We present an improved protocol for highly efficient production of doubled haploid loose-curd cauliflower plants (Brassica oleracea var. botrytis) via microspore culture. Our experiment explored factors such as donor plant treatment, flower bud pretreatment, embryo germination medium, and ploidy characterization of regenerated plants. Our technique efficiently produced embryos from both tight- and loose-curd donor plants, although the embryo yields were genotype dependent. We achieved a germination rate of around 30 % by employing a hormone combination of zeatin, indole-3-acetic acid, and 6-benzylaminopurine pretreatment culture. We also used 1–4 days of cold pretreatment of the flower buds, which were submerged into NLN-13 medium, to induce microspore embryogenesis. Analysis using an FCM Ploidy Analyzer showed that more than 50 % of regenerated plants were spontaneously doubled haploids, more than 25 % were tetraploids, and fewer than 7 % were haploid. Visual examination of plants in the field revealed that they had distinct phenotypic characteristics relating to their ploidy level. The efficient production of double haploids using our improved microspore culture technique is a promising approach that can be applied in loose-curd cauliflower breeding programmes and genetic research.     

城市水利景观基础设施的研究与设计——以新加坡碧山宏茂桥公园为例

快速、密集的城市化进程削弱了现有城市水利基础设施的正常功能。文中提出以景观与城市水利基础设施相结合作为缓解现有基础设施发展滞后问题的一种手段,对现有城市水利基础设施进行模式改进和功能拓展;以新加坡碧山宏茂桥公园为例,阐述了景观手段在实践中的具体运用,进一步强调景观的引入有益于城市水利基础设施的可持续发展,也为城市的可持续发展奠定了基础。     

基于 Synchro 与 VISSIM 混合仿真的单点交叉口信号配时优化方法研究

交通仿真是设计、分析和评价交通方案的重要技术方法。重点介绍微观交通仿真软件中的Synchro与VISSIM软件。选取上海市某单点交叉口，针对无法利用VISSIM软件对原有交叉口交通信号配时方案进行优化的缺点，先利用Synchro中的信号配时优化功能对交叉口信号配时进行优化，然后再对交叉口进行交通仿真评价。仿真结果表明，利用Synchro对交叉口信号配时进行优化后，交叉口运行效率好于未进行信号配时优化时的运行效率，此方法具有较好的工程实用性与推广意义。     

rbcL Gene Sequencing of Several Species Belonging to Morus and Their Genetic Relationship

[Objective] The paper was to sequence the rbc L gene of several species belonging to Morus, and to explore the genetic relationship of Morus plants. [Method] Through DNA extraction, PCR amplification, sequencing, splicing and correction, a total of 56 rbc L gene sequences were obtained. [Result] Alignment results showed that there were 1 279 permutation sites in rbc L sequence of Morus plants; variable sites accounted for6.8% of the total sequence length, and the ratio of transition pairs to transversion pairs(R= si/sv) was 1.2. The rbc L sequence of Broussonetia papyrifera was selected as the outgroup, which was downloaded from Gen Bank. Genetic analysis results showed that M. alba, M. notabilis, M. rubra and Kuisang(the sample of this study) had distant relationship, and the other Morus plants had relatively close relationship. [Conclusion] The results lay a foundation for selection, identification and classification of Morus plants.     

面向企业需求的《农业机械学》课程教学改革探讨

随着社会经济的发展,企业对农机人才提出了更高的要求.《农业机械学》作为农机专业的主干课程,与农机人才培养质量密切相关.为此,我们以满足企业对农机人才的需求为目标,以提高教学效果为出发点,从提高学生学习兴趣、课程教学内容、教学方法和手段以及考核等方面,对《农业机械学》课程教学进行了一些改革尝试和探索.     

辽宁省规模猪场生物安全状况调查

2018年8月,我国首例非洲猪瘟病例在辽宁省被发现。随后,全国各地区相继发生非洲猪瘟疫情。如何控制、净化非洲猪瘟,已成为国内整个产业亟需解决的问题。为掌握辽宁省规模猪场生物安全状况,分析生物安全在非洲猪瘟防控中的作用,开展了相关流行病学调查工作。对辽宁省部分发生过非洲猪瘟疫情的规模猪场进行流行病学调查发现,没有出猪台、饲料进场不消毒、人员与车辆进出管理不严、防疫管理混乱等,是疫情发生的主要风险因素。对辽宁省56个未发生过非洲猪瘟疫情的规模猪场进行流行病学调查发现,这些猪场的生物安全水平普遍低下,主要表现为:缺乏最基本有效的防护隔离硬件设施,以及相关的规章制度和操作规程;缺少验证消毒灭源等生物安全手段实施效果的经验和方法,没有专业技术人员对饲养场风险点进行评估和分析;饲养场从业人员的"知信行"水平普遍较低。综合分析认为,辽宁省生猪养殖业的生物安全水平与疫病防控需要有很大差距,而规模场生物安全水平低下、从业人员缺乏生物安全意识和知识,是当前疫病防控效果不理想的主要原因。今后需要通过政府扶持、业务部门指导和培训,对饲养场进行科学分析和评估,通过改进硬件、完善制度、加强宣传培训等措施,全面提高养猪场的生物安全水平。     

美洲狼尾草与象草杂交中花期相遇的调节

美洲狼尾草Ｔｉｆｔ２３Ａ（Ｐｅｎｎｉｓｅｔｕｍａｍｅｒｃｕｎｕｍ以下简称２３Ａ）在适宜播期内主茎叶数一般为２５。出叶间隔２～４ｄ。出叶速度总体上依抽出顺序而温慢，其分蘖一期发生在５～７叶龄；拔节则发生在１４叶龄前后，幼穗分化与拔节基本同步，在杂交制种中，当母本２３Ａ拔节前对父本象草Ｎ５１（Ｐ．ｐｕｒｐｕｒｅｕｍ，以下简称Ｎ５１）进行３～４周，每日９ｈ的短日照处理，则父母本花期基本相遇。     

Mark329原料及产品分析法

Mark329系单壬基酚和二壬基酚的混合亚磷酸酯,主要作为聚丙烯等塑料的抗氧化剂和稳定剂。本研究为生产该品种提供了简便的原料(壬基酚和二壬基酚)和产品分析法。     

我省太行山区春季幼兔死亡原因浅析

作者结合生产实际,分析了太行山区幼兔死亡的客观原因和具体原因,针对该区气候特点和幼兔的生理特点,提出了提高幼兔春季成活率的技术措施。