猫尾草的价值与栽培技术

文章介绍了猫尾草的形态特征及其实用价值,并总结了其栽培管理技术.     

岳阳市城区藤本植物的应用现状

藤本植物的应用是增加城市绿化面积的有效措施,文章对岳阳市城区藤本植物的应用现状进行调查分析,举例介绍了应用中存在的问题并提出建议,以期在城市绿化中更科学地应用藤本植物.     

配种后母猪返情的原因分析及对策

配种分娩率是衡量猪场生产成绩的重要指标,而配种后母猪的返情会降低配种分娩率,影响猪场生产成绩和经济效益.所以,提高母猪的配种分娩率的重要途径就是要减少配种后母猪返情情况的发生.     

猪源表皮葡萄球菌的分离与鉴定

葡萄球菌广泛分布于空气、饲料、饮水、地面及物体表面,在人及畜禽的皮肤、粘膜、肠道、呼吸道及乳腺中也存在,大部分无致病性[1].但使机体抵抗力下降的诸因素,特别是皮肤和粘膜受损时,可导致葡萄球菌病的发生.2006年9月,在河北昌黎地区某养猪场,从外地购买的100头仔猪陆续发生以背部、四肢渗出性皮炎为主要症状,并伴有体温升高、眼结膜潮红等症状的疾病.作者从该养猪场病猪皮肤溃疡浆液中分离出2株表皮葡萄球菌,并对分离菌的主要生物学特性进行了初步研究,旨在为临床上防治本病提供参考.     

Complete Genome Sequencing and Analysis of Rehmannia Mosaic Virus Isolate from Shanxi Province

Using double-stranded RNA(dsRNA) technology and sequence-independent amplification(SIA), the molecular identification on infected Rehmannia glutinosa in the field with mosaic symptoms was performed and the whole-genome of the Rehmannia mosaic virus(ReMV) Shanxi isolate(ReMV-SX) was sequenced. Sequencing analysis showed that the virus that infected Rehmannia glutinosa was Rehmannia mosaic virus(ReMV). The full-length of the obtained ReMV-SX sequence(GenBank accession no. JX575184) was 6 395 nt, containing four open reading frames(ORFs). The sequence homology analysis of the complete nucleotide sequence showed that ReMV-SX was 93.8%-97.0% homologous to ReMV in Tobamovirus subgroup I, while only 49.8%-58.9% homologous to the isolates in subgroups II and III of the same genus. Phylogenetic analysis showed that ReMV-SX and ReMV-Henan formed a separate branch and had the closest genetic relationship. The results laid the foundation for ongoing researches in the taxonomic status and evolution of ReMV and for further investigating the pathogenic mechanism of ReMV infecting Rehmannia glutinosa.     

A Novel Alginate Lyase: Identification,Characterization, and Potential Application in Alginate Trisaccharide Preparation

Alginate oligosaccharides (AOS) have many biological activities and significant applications in prebiotics, nutritional supplements, and plant growth development. Alginate lyases have unique advantages in the preparation of AOS. However, only a limited number of alginate lyases have been so far reported to have potentials in the preparation of AOS with specific degrees of polymerization. Here, an alginate-degrading strain Pseudoalteromonas arctica M9 was isolated from Sargassum, and five alginate lyases were predicted in its genome. These putative alginate lyases were expressed and their degradation products towards sodium alginate were analyzed. Among them, AlyM2 mainly generated trisaccharides, which accounted for 79.9% in the products. AlyM2 is a PL6 lyase with low sequence identity (≤28.3%) to the characterized alginate lyases and may adopt a distinct catalytic mechanism from the other PL6 alginate lyases based on sequence alignment. AlyM2 is a bifunctional endotype lyase, exhibiting the highest activity at 30 °C, pH 8.0, and 0.5 M NaCl. AlyM2 predominantly produces trisaccharides from homopolymeric M block (PM), homopolymeric G block (PG), or sodium alginate, with a trisaccharide production of 588.4 mg/g from sodium alginate, indicating its promising potential in preparing trisaccharides from these polysaccharides.     

几种生长调节剂对四翅滨藜全光喷雾扦插效果的影响

四翅滨藜全光照喷雾嫩枝扦插试验结果表明:采用NAA、ABT 2号生根粉、IBA等3种外源植物生长调节剂处理插条2 h,对插条具有良好的促根作用,其中100 mg/L NAA为最好,生根率可达到93.6%;100 mg/LABT2号生根粉和100 mg/L IBA次之,生根率分别可以达到92.6%,92.3%.     

东北典型农区土地利用变化的生态效应研究——以公主岭市为例

在人为活动占优势的景观内,不同土地利用方式和强度产生的生态效应是不同的,并且可以直观地反映在生态系统的结构和组成上。因此,本文利用Landsat TM和MSS遥感数据,以具有相对完整的自然生态过程的小流域作为评价单元,借助GIS空间分析和地统计分析功能,从景观生态学角度提出了景观生态指数来反映LUCC变化所带来的生态效应。研究发现,公主岭市1975—1986年间由于土地利用/土地覆被变化造成的生态风险不断增加,随后逐渐减小,到2000年局部地区又有所回升,这种变化与该地区土地利用类型的变化,特别是耕地、林地和草地的变化趋势呈高度相关,说明该地区土地利用/土地覆被变化对生物多样性及生态安全具有重要影响。     

土壤秸秆注孔对土壤含水量及作物生长的影响

[目的] 研究土壤秸秆注孔对土壤含水量及作物生长的影响,为旱作农田增加雨水蓄集能力及提高水分利用效率提供理论依据。[方法] 开展玉米-小麦轮作田间试验,设置常规种植(CK)、土壤秸秆注孔2孔/m²(T₁),4孔/m²(T₂),8孔/m²(T₃)4个处理。[结果] 秸秆注孔所有处理均提高了整个试验期表层土壤含水量。T₂,T₃处理提高了收获期深层土壤含水量,试验结束时两者底层土壤(60-80 cm)含水量较CK分别提高了29.19 %和28.18 %。秸秆注孔处理提高了作物株高、经济产量和生物量,以及降水利用效率和水分利用效率,T₂,T₃处理的提高效果最明显,且彼此差异不显著。[结论] 秸秆注孔具有保水性能和增产能力,根据成本和效果综合考虑,推荐秸秆注孔4孔/m²(T₂)作为优选处理。     

放牧干扰下荒漠草原植物功能群数量特征与输沙量的关系

[目的]分析放牧干扰下草地群落及功能群数量特征变化与草地土壤风蚀间的关系,阐明草地不同功能群对草地侵蚀过程的影响,为荒漠草原合理放牧利用及保护提供理论依据。[方法]以内蒙古短花针茅荒漠草原为研究对象,采取完全随机试验设计设置对照、中度和重度3个不同的放牧处理,对不同处理下的草地输沙量和功能群特征进行研究。[结果](1)随放牧强度增加,各功能群内物种高度、盖度和地上生物量基本呈下降态势。适当放牧能显著提高Simpson优势度指数和Shannon-Wiener多样性指数。(2)各放牧处理间的草地输沙量差异显著,不同输沙高度处的草地输沙量变化规律均为HG>MG>CK,同一放牧处理下,随输沙高度上升输沙率显著降低。(3)各功能群高度、盖度与输沙量均存在指数负相关关系,其中多年生禾草和多年生杂类草的高度变化对输沙量的影响更显著。各功能群的地上生物量与输沙量存在负相关指数关系,其中多年生禾草的生物量与输沙量的拟合程度最高。[结论]过度放牧会显著影响功能群特征并降低草地的防风固沙能力,建议放牧强度控制在中度及以下。