垃圾渗滤液中好氧反硝化菌的筛选及其反硝化条件优化

从江苏省常州市某垃圾渗滤液处理厂的纯氧曝气池中提取活性污泥,筛选获得1株高效好氧反硝化菌CZ1。根据菌株形态、生理生化特性进行初步鉴定,并结合该菌株的16S rDNA基因序列分析,判定该菌株为蜡样芽胞杆菌(Bacillus cereus)。研究了菌株的好氧反硝化特性,结果表明,以硝酸钾为唯一氮源,CZ1在24h内对硝酸盐氮的去除率达到97.69%。同时考察了碳源种类、C/N、温度、初始pH以及溶解氧对该菌株好氧反硝化能力的影响,通过单因素实验获得其最佳好氧反硝化条件:温度35℃,丁二酸钠为唯一碳源,C/N为6,初始pH值为7.0~7.5,转速为160 r/min。     

一种载样简单的多重可视化PCR微芯片

在核酸检测领域急需一种能够经济、快速、操作简便且同时检测多个靶标的新技术。常规多重PCR能够同时扩增多个靶标,但由于在一个试管中引物间的相互作用和竞争,重数往往受到限制。本研究设计了一种操作简单的多重PCR芯片,可以同时进行54个靶标的扩增。芯片结构简单,一条微通道将正下方平行排列的多个微孔连接在一起,微通道只留加样口和出样口。同时整个微通道呈疏水状态,微孔呈亲水状态。将不同的引物对和低溶点琼脂糖提前固定于不同的微孔中,通过一次加入PCR mix,并加入矿物油推动PCR mix进入到每个微腔室中,同时微孔也被矿物油相互隔离避免交叉反应。加样后将芯片放置于平板PCR仪上进行扩增,在整个反应过程中低溶点琼脂糖呈液态,反应结束后凝固成固体,便可引入核酸染料进行染色,最后利用自制小型的紫外照射仪上进行可视化检测和拍照记录。利用此平台成功实现了对7种非常重要和常用的转基因作物靶标的并行检测,结果显示此平台具有较高的灵活性和特异性。此技术经过进一步优化可应用于包括转基因检测在内的多重核酸检测领域。     

Comparison of genomes of eight species of sections <Emphasis Type="Italic">Linum</Emphasis> and <Emphasis Type="Italic">Adenolinum</Emphasis> from the genus<Emphasis Type="Italic"> Linum</Emphasis> based on chromosome banding,molecular markers and RAPD analysis

Karyotypes of species sects. Linum and Adenolinum have been studied using C/DAPI-banding, Ag-NOR staining, FISH with 5S and 26S rDNA and RAPD analysis. C/DAPI-banding patterns enabled identification of all homologous chromosome pairs in the studied karyotypes. The revealed high similarity between species L. grandiflorum (2n = 16) and L. decumbens by chromosome and molecular markers proved their close genome relationship and identified the chromosome number in L. decumbens as 2n = 16. The similarity found for C/DAPI-banding patterns between species with the same chromosome numbers corresponds with the results obtained by RAPD-analysis, showing clusterization of 16-, 18- and 30-chromosome species into three separate groups. 5S rDNA and 26S rDNA were co-localized in NOR-chromosome 1 in the genomes of all species investigated. In 30-chromosome species, there were three separate 5S rDNA sites in chromosomes 3, 8 and 13. In 16-chromosome species, a separate 5S rDNA site was also located in chromosome 3, whereas in 18-chromosome species it was found in the long arm of NOR-chromosome 1. Thus, the difference in localization of rDNA sites in species with 2n = 16, 2n = 30 and 2n = 18 confirms taxonomists opinion, who attributed these species to different sects. Linum and Adenolinum, respectively. The obtained results suggest that species with 2n = 16, 2n = 18 and 2n = 30 originated from a 16-chromosome ancestor.     

一类具有垂直传播的SEIRS捕食传染病模型的全局分析

通过假设捕食系统中疾病只在食饵种群中传播,被传染的易惑者经过一段潜伏期后才具有传染性,潜伏者与染病者均具有垂直传播能力,染病者恢复后对该病不具有终身免疫力,建立了一类具有垂直传播的SEIRS捕食传染病模型,运用极限系统理论,分两种情形讨论了系统平衡点的存在性及局部稳定性,利用Lyapunov函数和二次复合矩阵等方法,得到了平衡点全局渐近稳定的条件.     

广东省县级建设用地集约利用综合评价——以紫金县为例

基于评价指标的权重和隶属度值构建了广东省紫金县建设用地集约利用水平测度模型,运用最大相容类原则实现了建设用地集约利用水平的模糊识别分类,并通过将城镇及独立工矿区人均建设用地、农村居民点人均建设用地与国家2007年颁布的镇规划用地标准进行比较,测算了2005年广东省紫金县建设用地集约利用潜力.结果表明：2005年紫金县建设用地集约利用水平测度值为0.421,处于低效粗放利用阶段;理论上全县可减少555.69～2197.69 hm²的建设用地,集约利用潜力较大.     

Differential expression and regulation of expansin gene family members during fruit growth and development of ‘Shijia’ longan fruit

In this work, five expansin cDNAs (DlExp1–5) from ‘Shijia’ longan fruit were isolated and characterized. Moreover, the expression profiles of five expansin genes and the effect of naphthalene acetic acid (NAA) and thidiazuron (TDZ) on their expressions were investigated. The results showed that five expansins exhibited different expression patterns during fruit growth and development. DlExp1 was constitutively expressed in the pericarp while the levels of DlExp1 mRNA in the aril were very high at early stage of fruit development, and decreased gradually from 28 to 77 days after anthesis (DAA). DlExp2 and DlExp4 were related to the growth of pericarp, whereas the expression of DlExp2 and DlExp5 in the aril decreased from 28 to 77 DAA. In addition, NAA and TDZ applied at the stage of rapid pericarp (21 DAA) or aril growth (56 DAA) increased the accumulations of DlExp1 and DlExp2 mRNA in the pericarp and aril, while NAA and TDZ had no or little effect on the accumulations of DlExp3, DlExp4 and DlExp5. DlExp1 and DlExp2 also accumulated highly in rapidly growing tissues, such as young stems and leaves. These findings indicated that Exp genes played a different role in longan fruit growth and showed different response to plant growth substances.     

Carbon balance and allocation of assimilated CO2 in Scots pine, Norway spruce, and Silver birch seedlings determined with gas exchange measurements and 14C pulse labelling

Carbon dioxide is released from the soil to the atmosphere in heterotrophic respiration when the dead organic matter is used for substrates for soil micro-organisms and soil animals. Respiration of roots and mycorrhiza is another major source of carbon dioxide in soil CO₂ efflux. The partitioning of these two fluxes is essential for understanding the carbon balance of forest ecosystems and for modelling the carbon cycle within these ecosystems. In this study, we determined the carbon balance of three common tree species in boreal forest zone, Scots pine, Norway spruce, and Silver birch with gas exchange measurements conducted in laboratory in controlled temperature and light conditions. We also studied the allocation pattern of assimilated carbon with ¹⁴C pulse labelling experiment. The photosynthetic light responses of the tree species were substantially different. The maximum photosynthetic capacity (P _max) was 2.21 μg CO₂ s⁻¹ g⁻¹ in Scots pine, 1.22 μg CO₂ s⁻¹ g⁻¹ in Norway spruce and 3.01 μg CO₂ s⁻¹ g⁻¹ in Silver birch seedlings. According to the pulse labelling experiments, 43–75% of the assimilated carbon remained in the aboveground parts of the seedlings. The amount of carbon allocated to root and rhizosphere respiration was about 9–26%, and the amount of carbon allocated to root and ectomycorrhizal biomass about 13–21% of the total assimilated CO₂. The ¹⁴CO₂ pulse reached the root system within few hours after the labelling and most of the pulse had passed the root system after 48 h. The transport rate of carbon from shoot to roots was fastest in Silver birch seedlings.     

Patterns of use and knowledge of wild edible plants in distinct ecological environments: a case study of a Mapuche community from northwestern Patagonia

The multiple use of distinct ecological environments in the search for wild resources has been practiced since ancestral times in aboriginal communities inhabiting northwestern Patagonia. This paper examines the actual use and knowledge of wild edible plants in a Mapuche community presently settled in one of the most arid areas of Patagonia, far from the temperate forests where their ancestors used to live. The difference between knowledge of and use of wild plants is analyzed emphasizing that these differences could contribute to the understanding of eroding processes believed to be occurring in the community. These objectives are studied quantitatively by utilizing ethnobotanical indices, partially derived from ecological theory. Our results indicate that the Paineo dwellers still utilize multiple ecological gathering environments and have thorough plant knowledge of both native and exotic species. The Andean forest, more than 50km away from this community, is the environment from which the Paineo dwellers know the greatest total richness and the highest diversity of wild edible plants, followed by the Monte–Steppe species and lastly, those growing around their homes. The transmission of wild edible plant knowledge in the Paineo community diminishes with age, and the forest plants are the most vulnerable to loss. Our results have shown that the knowledge and consumption of wild edible plants follows a pattern according to ecological conditions of the gathering environments, as well as the cultural heritage of the Paineo people.     

Population dynamics of diploid and hexaploid populations of a perennial herb

BACKGROUND AND AIMS: Despite the recent enormous increase in the number of studies on polyploid species, no studies to date have explored the population dynamics of these taxa. It is thus not known whether the commonly reported differences in single life-history traits between taxa of different ploidy levels result in differences in population dynamics. METHODS: This study explores differences in single life-history traits and in the complete life cycle between populations of different ploidy levels and compares these differences with differences observed between different habitat types and years. Diploid and hexaploid populations of a perennial herb, Aster amellus, are used as the study system. Transition matrix models were used to describe the dynamics of the populations, and population growth rates, elasticity values and life-table response experiments were used to compare the dynamics between populations and years. KEY RESULTS: The results indicate that between-year variation in population dynamics is much larger than variation between different ploidy levels and different habitat conditions. Significant differences exist, however, in the structure of the transition matrices, indicating that the dynamics of the different ploidy levels are different. Strong differences in probability of extinction of local populations were also found, with hexaploid populations having higher probability than diploid populations, indicating strong potential differences in persistence of these populations. CONCLUSIONS: This is the first study on complete population dynamics of plants of different ploidy levels. This knowledge will help to understand the ability of new ploidy levels to spread into new areas and persist there, and the interactions of different ploidy levels in secondary contact zones. This knowledge will also contribute to understanding of interactions of different ploidy levels with other plant species or other interacting organisms such as pollinators or herbivores.     

基于冠层反射光谱的棉花干物质积累量估测

通过分析不同施氮水平下棉花地上部干物质积累量与冠层光谱反射率及其衍生的比值植被指数(RVI)、归一化植被指数(NDVI)及差值植被指数(DVI)之间的关系,确立了棉花地上部干物质积累量的敏感波段及预测模型.结果表明:两个可见光波段(560和710 nm)和5个近红外波段(810、870、950、1 100和1 220 nm)组成的植被指数与棉花地上部干物质积累量的相关性较好,其中RVI(1 100, 560)的相关性最好.通过逐步回归分析确立的棉花地上部干物质积累量的预测模型为:地上部干物质积累量(g·m-2)=66.274×RVI(1 100, 560)-148.84.说明通过遥感手段估测棉花地上部干物质积累量是可行的.