西部欠发达地区农村图书馆建设对策研究

面对建设社会主义新农村的重大历史任务，本文通过对西部欠发达地区农村图书馆建设现状及发展滞后的原因分析．提出了适合西部农村图书馆发展的对策和建议。     

高速公路沙害防治技术研究-以丹东-拉萨高速公路新地-麻黄沟段为例

本文以新地—麻黄沟高速公路防沙体系效益为依据,探讨分析了高速公路沙害的特点以及防沙体系建设的基本要求。研究表明,高速公路沙害防治需要采取适当抬高路基,建立稳固的防沙体系并要适当加大防护带宽度的综合措施。该地区公路防沙体系的结构配置对干旱、半干旱沙漠地区高速公路沙害防治具有一定的借鉴作用。     

Phylogenetic Analysis of Sugarcane Rusts Based on Sequences of ITS, 5.8 S rDNA and D1/D2 Regions of LSU rDNA

Phylogenetic analysis of sugarcane rusts based on sequences of ITS and the 5.8 S rDNA revealed two highly divergent ITS groups among isolates of Puccinia sp. sensu Muta, 1987 and P. kuehnii specimens. Although there is sufficient divergence (exceeding normal intraspecific variation) between the ITS regions of the two groups to support separation into different species, unusually high homology of the ITS group I sequences with those of members of Cronartium and identical sequences of the D1/D2 regions of the LSU rDNA for all the isolates of “Puccinia sp.” and P. kuehnii that otherwise exhibited different ITS sequences, suggest that the two highly divergent sequences may have resulted from abnormal genetic events leading to non-orthologous, intraspeciflc polymorphisms. The other sugarcane rust, P. melanocephala and the grass rusts, P. miscanthi and P. rufipes, were separated from “Puccinia sp.” and P. kuehnii and from each other in D1/D2 region analyses, indicating that D1/D2 region sequences may more correctly reflect phylogenetic relationships in these rusts than do the ITS regions. Further studies to examine differences in patho-genicity or finer morphological features within P. kuehnii that may be correlated with the high divergence in ITS sequences and experiments to determine if these two sequence types represent intraspeciflc polymorphism are necessary. Received 11 October 2000/ Accepted in revised form 24 November 2000     

高寒牧区青稞南北向条播增产试验

在高寒牧区巴音布鲁克种种青稞，南北向条播比东西向条播能充分利用太阳光能，可提高种子产量１４．６％，南北向条播的适宜密度为３３０万株／ｈｍ＾２，种子产量最高。     

山西省临汾地区草坪草与牧草引种评价

1998—1999年,在临汾地区引入7个草坪草品种和6个牧草品种进行栽培、评价。草坪草品种中。草地早熟禾适宜在该地区种植,尤其是BarVB5649。牧草品种中。多花黑麦草生长快。产量高,但不耐旱、不抗寒,大田推广有困难。苜蓿抗寒耐旱。3个供试品种Baraffa54,Sanditi和Sitel均适宜大面积种植。     

贵州喀斯特地区牧草引种试验评价

对国内外引进的6个禾本科牧草品种,9个豆科牧草品种以及喀斯特地区的4个对照品种,在贵州独山地区进行引种试验。结果表明：各参试品种生长良好,能安全越冬、越夏,一年可刈割5～6次,鲜草产量达36558．2～66450．0kg／hm2,干草产量10771．0～19869．0kg／hm2。综合性状表现较好的依次为鸭茅Totter,Wana,Tuoa;多年生黑麦草Nui,Bronsys;白三叶Alice,C6151,Prop,Pitua,Sustain;百脉根Mareb,Lel。     

高寒地区一年生人工草地地上生物量动态及光能转化效率

对燕麦单播草地、燕麦+箭舌豌豆混播草地牧草组成及地上生物量动态,光能转化效率进行了观测和分析。试验结果表明,混播草地的两组分在生长发育节律和牧草产量积累过程方面均存在着较大的差异,箭舌豌豆与燕麦干物质之比随牧草生长发育的进展而逐渐增大。2种草地的干草产量在牧草生长期间差异不显著。8月中旬,单、混播草地干物质分别可达10.19、11.74t/hm2,地上净初级生产力分别为18874.69、21204.79kJ/(m2·a),光能转化率分别达0.3502%、0.3922%。     

高寒地区多年生禾草混播草地种间竞争效应分析

从高寒地区3组分禾草混播草地群落的种问竞争机制出发,建立了适合高寒地区3组分禾草混播草地群落种间竞争机制的Lotka—Volterra竞争效应模型,并对该模型所描述的竞争进行了计算机模拟试验。模拟结果表明,试验所选的3种高寒地区3组分禾草混播草群的种间相容性分为两种类型,即不稳定的群落：多叶老芒麦 无芒雀麦 垂穗披碱草和垂穗披碱草 多叶老芒麦 扁穗冰草,其竞争结局是：群落内多叶老芒麦和垂穗披碱草二者共同表现为优势种群,无芒雀麦或扁穗冰草与优势植物的竞争结果将导致其从群落中消失,多叶老芒麦和垂穗披碱草种群将能稳定共存;不稳定-稳定过渡群落：无芒雀麦 多叶老芒麦 扁穗冰草,在没有多叶老芒麦种群的时候,无芒雀麦和扁穗冰草种群可以共存,但是如果多叶老芒麦种群加入无芒雀麦和扁穗冰草所占的区域,它将导致无芒雀麦和扁穗冰草种群趋于灭绝。通过对3个混播试验组计算机模拟竞争模型的竞争效应分析,其结果与方法对科学建植同类型的多年生混播人工草地具有一定的指导意义。     

江河源区退化草地鼠害的治理研究

针对江河源区草场退化、高原鼠兔危害严重的状况,采用了翻耕、耙耱、撒播、轻耙、镇压等一系列治理措施.结果表明,这种以生态工程为主的治理措施,不仅使草场植被在短期内得到恢复,而且害鼠种群数量也得到了有效控制;同时,为防止鼠兔数量回升、减少扩散、播种牧草幼苗免遭啃食和挖掘破坏,在不同处理区又采取了以药物防治为辅的控制措施.在现场药效试验和大面积灭鼠中,0.075%敌鼠钠盐、0.1%C型肉毒杀鼠素和0.1%D型肉毒杀鼠素毒饵对鼠兔均具有良好灭效,且不污染环境,无二次中毒,对保护天敌、发挥生物控制危害具有一定意义.因此,在退化草场鼠害治理中,综合分析各组分之间的相互关系,有针对性地进行治理,才能收到良好效果,从而达到综合治理的目的.     

Phylogenetic Analysis of Field Isolates of Feline Calcivirus (FCV) in Japan by Sequencing Part of Its Capsid Gene

The molecular epidemiology of the infectious disease caused by feline calcivirus (FCV) in Japan was investigated by analysing the phylogenetic relationship among 21 Japanese field isolates, including the F4 strain, and 30 global isolates. Parts of the capsid gene (B–F) of the isolates were amplified by RT-PCR, and the amino acid sequences were compared with those from the global isolates. Thirty-seven and 14 out of a total of 51 isolates were clustered into two distinct genogroups, I and II respectively, by UPGMA and NJ analysis. Seven of the 21 Japanese isolates (33%) fell into group I together with 30 global isolates, while the other 14 Japanese isolates (67%) belonged to group II. The bootstrap repetition analysis of groups I and II formed by the NJ method gave a value of 99.0%. The 14 latter Japanese isolates were clearly separated from the isolates in group I, and they were different from any previously known FCV, forming a new genogroup, which implies that this lineage has been confined to Japan. Comparing the amino acid sequences shared by groups I and II, the amino acid at position 377 in B region was asparagine (Asn or Asp (NH₂)) in group I, while it was lysine (Lys) in all the strains in group II. Similarly, the amino acid at position 539 in the F region was alanine (Ala) or proline (Pro) in group I, while it was valine (Val) in group II; glycine (Gly) at position 557 in group I was serine (Ser) in Group II; and phenylalanine (Phe) or leucine (Leu) at position 566 in genogroup I was tyrosine (Tyr) in group II.