耕作方式和秸杆还田对纤维素降解细菌多样性的影响

免耕和秸秆还田是培肥地力的重要措施,明确其对土壤纤维素降解细菌群落的影响对于土壤质量提升具有重要意义。选择中国科学院封丘农业生态国家试验站耕作秸秆还田(WtS)、免耕秸秆还田(WntS)、耕作秸秆不还田(Wt)和免耕秸秆不还田(Wnt)4种处理小区并采集土壤样品,用CMC-Na刚果红培养基对纤维素降解细菌计数,采用PCR-RFLP技术研究保护性耕作和秸秆还田对纤维素降解细菌群落的影响。结果表明,秸秆还田与免耕处理均不同程度提高了纤维素降解细菌数量。WtS、WntS、Wt和Wnt4个纤维素降解细菌基因文库中,OTUs数量分别为23、26、20和19个,秸秆还田加免耕处理多样性指数最高。本文获得的纤维素降解细菌共属于11个属,秸秆还田土壤中Streptomycetaceae、Flavobacterium、Sphingobium相对丰度明显多于秸秆不还田处理土壤;免耕处理土壤中Pseudomonas、Phyllobacterium、Paenibacillus、Promicromonosporaceae、Sphingobacterium相对丰度明显高于耕作处理土壤。典范对应分析显示四种处理纤维素降解细菌群落结构发生了较大变化,p H、全磷、有机碳和全钾与免耕处理呈显著正相关性,全氮、碱解氮、速效钾、速效磷和有机碳与秸秆还田处理呈显著正相关性。免耕和秸秆还田能提高土壤中纤维素降解细菌数量及多样性,改变纤维素降解细菌群落结构。     

茅苍术间作对连作花生土壤线虫群落的影响

以连作10年花生的红壤为基质,分别设置花生单作和花生/茅苍术间作处理,于花生成熟期采集单作花生根际土壤、间作处理花生和茅苍术根际土壤,分析土壤线虫的数量、多样性和群落结构,以揭示茅苍术间作对土壤线虫群落的影响及对花生连作障碍的缓解机制。结果表明,与花生单作相比,间作处理花生的株高、主根长、秸秆干重和荚果干重显著增加(p0.05)。茅苍术间作减少了连作花生土壤线虫的总数,显著提高了花生根际土壤食细菌线虫、食真菌线虫和捕食/杂食线虫的相对丰度,降低了植物寄生线虫的相对丰度(p0.05)。与花生单作相比,间作提高了花生根际土壤线虫的Shannon-Wiener多样性指数(H′)和均匀度指数(J),而土壤线虫群落的优势度指数(λ)显著降低。间作处理花生根际土壤线虫的瓦斯乐斯卡指数(WI)和自由生活线虫成熟度指数(MI)显著升高,植物寄生线虫成熟度指数(PPI)显著降低,而线虫通道比(NCR)无显著变化。综合分析得出,茅苍术间作可以提高花生连作土壤线虫多样性、优化土壤线虫群落结构,进而增强有益线虫的生态功能、改善花生连作障碍。     

不同植物类型昆虫群落结构的研究

研究了４种不同园林植物类型内昆虫群落的组成、结构及多样必的变化。研究结果表明，构成复杂的植物类型内昆虫群落种类丰富、结构复杂、多样性指数高；反之则相反。而且复杂植物类型内昆虫群落数量变化规律明显，排序结果显著其变化可在时间过程中明显区分为几个阶段；简单植物类型内昆早群落变化无明显规律性。     

从多重理论视角重新认识草原生态经济系统价值

过去对草原价值的认识仅仅局限在家畜的饲草饲料功能上,近几年人们逐步认识到其生态功能,但都未从多重理论的高度全面、深刻的挖掘其内在价值,这是导致滥垦、过牧、草原生态经济系统退化的重要原因之一。为此,从多重理论视角如从自然资源稀缺、外部性、生物多样性、土地伦理、草原文化等方面对草原生态经济系统价值进行了初步探讨。     

Hemocyte diversity of the American bollwormHelicoverpa armigera

The hemocytes of the American bollwormHelicoverpa armigera (Hübner) were studied in the last instar larvae by phase contrast microscopy to investigate the differences among 14 populations, collected from ten locations, spread over a distance of approximately 3000 km in six different states of India. The cluster analysis of differential hemocytes showed as many as 11 clusters of populations at 5% and six clusters at 10% homogeneity level. The cluster analysis of hemocytes of seven populations from cotton crops showed five and three clusters at 5% and 10% homogeneity levels, respectively. Diversity of hemocytes of four populations from chickpea was wider than that from cotton. The differences in hemocytes of various populations may be due to space, time, host plant, insecticide use, other agroecological conditions, and insect genetic variabilityper se. The field populations ofH. armigera heavily treated with insecticides appeared to contain more spherulocytes at the expense of plasmatocytes and granulocytes. The treatment of 6-day-old larvae ofH. armigera with cypermethrin decreased plasmatocytes and granulocytes, and increased prohemocytes and spherulocytes in the hemolymph of last instar larvae. Thus, differential hemocyte counts may serve as an indicator of insecticide exposure and the diversity of insect populations. http://www.phytoparasitica.org posting Dec. 20, 2004.     

云南大面积白三叶种子生产中杂草的多样性调查

通过对农业部白三叶种子生产项目在云南省马龙县马鸣乡大面积生产中杂草的多样性调查,结果表明:(1)在白三叶种子大面积生产中,随着白三叶的生长,田间杂草的种类和数量逐步增加;(2)由于在白三叶播种当年其生长速度不快,因而在其生长前期应适时除杂,以防止杂草的迅速生长。     

Assessment of genetic diversity and species relationships in eggplant (Solanum melongena L.) using STMS markers

Ninety six accessions including 92 of Solanum melongena and four related non-tuberous species (Solanum insanum, S. incanum, S. integrifolium and S. sysimbriifolium) were taken for the assessment of genetic diversity using 23 STMS primers. Eleven of the 23 primers tested showed polymorphism. The number of alleles per primer ranged from three to six with an average of 4.4. S. melongena had maximum average similarity with its closely related species, S. insanum (0.67) and minimum average similarity with the wild species, S. sysimbriifolium (0.50). The two weedy species S. incanum and S. integrifolium showed more average similarity value of 0.62 and 0.61, respectively with the cultivated S. melongena. S. insanum. S. incanum and S. integrifolium were relatively similar to each other with similarity index value of 0.61 (between S. insanum and S. incanum), 0.63 (between S. insanum and S. integrifolium) and 0.62 (between S. incanum and S. integrifolium). In contrast S. sysimbriifolium was most divergent with the similarity value of 0.49, 0.47 and 0.51 with S. insanum, S. incanum and S. integrifolium, respectively. The closely related species S. insanum and S. incanum, which clustered along with S. melongena accessions, being crossable with cultivated species, constitute important sources of genes that can be introgressed by backcross breeding. Molecular markers can be employed to identify the hybrids and also to monitor introgression of the useful genes.     

河南省近年审定小麦品种基于系谱和SNP标记的遗传多样性分析

为了解河南省近年小麦品种的遗传基础,利用Illumina 90k i Select SNP标记技术对豫麦34及该省2000—2013年审定的小麦品种共96个进行全基因组扫描,分析了其遗传多样性和遗传基础。结果表明,在所有SNP位点中,多态性比率为47.39%(38 661/81 587),多态性标记在基因组间分布呈现BAD。96个品种亲缘关系较近,两两遗传相似系数的平均值为0.719,变幅为0.552~0.998,且94.3%的品种间遗传相似系数在0.652~0.812之间;按UPGMA法将96个品种划分为7个类群。综合SNP和系谱分析,近10年河南省审定的96个小麦品种遗传多样性不够丰富,多数品种亲缘关系较近,在育种中迫切需要引入新的种质资源,拓宽遗传背景。     

Multi-agent simulation for the targeting of development policies in less-favored areas

Complex combinations of biophysical and socio-economic constraints characterize the less-favored rural areas in developing countries. More so, these constraints are diverse as they vary considerably between households even in the same community. We propose multi-agent systems as a modeling approach well suited for capturing the complexity of constraints as well as the diversity in which they appear at the farm household level. Given that empirical multi-agent models based on mathematical programming share the characteristics of bio-economic farm models plus some additional features, one may interpret bio-economic farm models as a special case of multi-agent models without spatial dimension and direct interaction. Evidently, spatially explicit, connected multi-agent models have higher requirements in terms of development costs, empirical data and validation. Therefore, we see them as a complement, and not a substitute, to existing bio-economic modeling approaches. They might be the preferred model choice when heterogeneity and interactions of agents and environments are significant and, therefore, policy responses cannot be aggregated linearly. We illustrate the strength of empirical multi-agent models with simulation results from Uganda and Chile and indicate how they may assist policymakers in prioritizing and targeting alternative policy interventions especially in less-favored areas.     

湘北地区草本花卉种类·分布及利用的研究

通过对湘北地区草本花卉种类与分布的研究和利用状况的调查,探讨目前在湘北地区草本植物引种、栽培工作中存在的问题,并提出改进措施。