青藏高原湖泊沉积物硫酸盐还原菌种群分布

采用聚合酶链式反应(PCR,Polymerase Chain Reaction)、变性梯度凝胶电泳(DGGE,Denaturing Gra-dient Gel Electrophoresis)与实时荧光定量聚合酶链式反应(Q-PCR,Quantitative PCR)相结合的综合分析技术,研究了青藏高原洱海、青海湖、尕海1、尕海2、小柴旦湖沉积物硫酸盐还原菌多样性及丰度。研究结果显示,5个盐湖沉积物中dsrB(编码亚硫酸还原酶β亚基,为硫酸盐还原菌所共有)基因的丰度为每克沉积物1.71×108～1.55×109拷贝,与盐度无明显相关性;所获得的dsrB基因序列分属于3个科:Desulfobacter-aceae,Desulfobulbaceae和Peptococcaceae。其中,Desulfobacteraceae科是主要类群。硫酸盐还原菌多样性(DGGE结果)与盐度呈现出负相关性。故在所研究的盐湖中,盐度可能不是影响硫酸盐还原菌种群分布的唯一因素,可能还受其它未知环境因素的影响,有待于进一步研究。     

兰州百合(Lilium davidii var.willmottiae)遗传多样性和遗传结构北大核心CSCD

采用EST-SSR分子标记,对来自7个主要栽培区的兰州百合(Lilium davidii var.willmottiae)种质资源进行遗传多样性分析。结果显示:(1)兰州百合在物种水平上具有较高的遗传多样性,多态性位点百分率(PPB) 90.91%,Nei’s遗传多样性指数(H) 0.3256,Shannon’s遗传多样性信息指数(I) 0.4875;各栽培居群遗传多样性为西果园>榆中>魏岭>阿干>黄峪>金沟>永靖。(2)兰州百合栽培群体基因分化度Gst为0.2395,基因流(Nm)为1.5876,各栽培居群间遗传分化水平低,遗传差异主要存在于居群内。(3)兰州百合种质材料69个采样点的聚类结果显示,84.05%的材料都聚合到一个类群,这与STRUCTURE遗传结构分析的结果一致,说明兰州百合种质资源的遗传基础相对狭窄。兰州百合种质资源的遗传多样性主要由小部分种质的遗传变异引起,收集研究这些稀有特异种质,将为兰州百合育种改良及优异基因发掘提供重要参考。     

内蒙古河套灌区湿地芦苇根际可培养细菌多样性

以内蒙古河套灌区湿地植物芦苇(Phragmites australis)根际土壤为材料,采用分离培养法对天然湿地和退化湿地的芦苇根际细菌多样性进行了研究。16SrRNA基因系统发育分析的结果显示,分离自天然湿地芦苇根际的45株细菌分属于γ-变形菌纲(44.44%)、厚壁菌门(Firmicutes)(42.22%)和放线菌门(Actinobacteria)(13.33%)3大类群,其中,γ-变形菌纲为最优势类群,芽孢杆菌属(Bacillus)(42.2%)为最优势菌属;分离自退化湿地芦苇根际的44株细菌分属γ-变形菌纲(13.63%)、β-变形菌纲(6.82%)、厚壁菌门(47.73%)及放线菌门(Actino-bacteria)(31.82%)4大类群,其中厚壁菌门为最优势类群,芽孢杆菌属(40.9%)为最优势菌属。研究结果表明,天然湿地和退化湿地芦苇根际细菌都具有较丰富的多样性,但天然湿地与退化湿地芦苇根际细菌群落结构存在一定差异。     

兰州百合(Lilium davidii var.willmottiae)遗传多样性和遗传结构

采用EST-SSR分子标记,对来自7个主要栽培区的兰州百合(Lilium davidii var.willmottiae)种质资源进行遗传多样性分析。结果显示:(1)兰州百合在物种水平上具有较高的遗传多样性,多态性位点百分率(PPB) 90.91%,Nei’s遗传多样性指数(H) 0.3256,Shannon’s遗传多样性信息指数(I) 0.4875;各栽培居群遗传多样性为西果园榆中魏岭阿干黄峪金沟永靖。(2)兰州百合栽培群体基因分化度Gst为0.2395,基因流(Nm)为1.5876,各栽培居群间遗传分化水平低,遗传差异主要存在于居群内。(3)兰州百合种质材料69个采样点的聚类结果显示,84.05%的材料都聚合到一个类群,这与STRUCTURE遗传结构分析的结果一致,说明兰州百合种质资源的遗传基础相对狭窄。兰州百合种质资源的遗传多样性主要由小部分种质的遗传变异引起,收集研究这些稀有特异种质,将为兰州百合育种改良及优异基因发掘提供重要参考。     

沙冬青根瘤菌结瘤基因nodA PCR-RFLP分析

 利用结瘤基因nodA PCR-RFLP和nodA PCR产物序列分析技术,对36株分离自沙冬青根瘤菌菌株的共同结瘤基因nodA进行了遗传类型和系统发育关系分析。试验结果表明,36株根瘤菌nodA PCR-RFLP分析显示在80%的相似水平上聚为两个类群5个亚群;选取不同基因型代表菌株的nodA进行序列测定和系统发育关系分析表明,测试菌株CCNWNX0117、CCNWNX0068、CCNWNX0083、CCNWNX0062、CCNWNX0058与中慢生根瘤菌聚在一起,系统发育地位相近;测试菌株CCNWNX0089、CCNWNX0081、CCNWNX0064与中华根瘤菌聚在一起,有较高的序列相似性。本研究中nodA基因所揭示的沙冬青根瘤菌遗传多样性和系统发育关系说明沙冬青根瘤菌nodA基因遗传多样性较高,宿主结瘤范围较宽。     

长白山地不同次生林土壤动物群落多样性特征及其分布格局

为探讨长白山地不同地貌类型次生林土壤动物群落多样性特征及其分布格局,分别于2015年春季(5月)、夏季(7月)及秋季(9月)对长白山地三种不同地貌类型(玄武岩台地、花岗岩低山和花岗岩丘陵)的次生林土壤动物进行调查研究。研究表明:大型土壤动物类群数季节变化不显著,中小型土壤动物密度季节波动较大。其中,花岗岩低山次生林大型土壤动物密度和类群数均为最低,玄武岩台地次生林中小型土壤动物密度和类群数要显著高于其他两个生境。通过比较三种生境土壤动物多样性指数发现,大型土壤动物多样性指数随着季节变化表现出相同的动态趋势,均无显著性差异,而中小型土壤动物多样性指数季节波动呈显著升高或降低趋势,且同一季节玄武岩台地次生林的中小型土壤动物多样性指数要显著高于其他两个生境。对三种地貌类型次生林的土壤动物群落与环境因子间相关关系进行了RDA分析,结果表明土壤动物对土壤有机质、全效养分(N、P)和速效养分(N、P、K)响应程度较高,其中中小型土壤动物优势类群甲螨亚目分布对土壤温度、湿度呈显著正向响应。研究可为次生林的管理及生态恢复提供土壤动物学依据。     

南海北部陆坡表层沉积物氨氧化古菌多样性初探

基于南海北部陆坡不同深度梯度3个站位表层沉积物古菌氨单加氧酶基因（amoA）文库,对3个站位氨氧化古菌进行多样性和系统发育学分析。多种方法构建的系统发育树表明：3个站位所有的amoA基因序列都隶属于奇古菌门中Group I分枝内的Group I.1a系群,且各站位之间氨氧化古菌多样性没有明显的差异。501站位黑色砂质沉积物中古菌amoA基因与该站位的16S rRNA基因的系统发育比对显示：这2种基因标记的系统发育树整体上具有潜在的对应关系,说明对样品的氨氧化古菌多样性分析比较全面且可靠;并进一步暗示该样品中氨的硝化作用主要由奇古菌门下的Group I.1a系群来执行。由此可以推测：Group I.1a系群可能在南海北部表层沉积物中氮素的生物地球化学循环过程中扮演重要的角色。     

黄河三角洲互花米草的遗传变异和扩散

互花米草(Spartina alternifora)自1990年被引种到黄河三角洲后,快速扩张,已经威胁了该地区潮间带的生态安全。研究黄河三角洲互花米草群体的遗传变异,拟从遗传进化角度了解其扩散机制,以期为防控和管理互花米草扩张提供科学依据。利用了13对微卫星分子标记,对黄河三角洲4个互花米草群体(群体1~群体4的位置分别在一千二、大汶流、五号桩、黄河口)中共160个个体进行了遗传多样性和遗传结构分析。研究结果表明,黄河三角洲互花米草具有较高的遗传多样性,每个位点平均观察等位基因数(Na)为(7.385±2.256),平均有效等位基因数(Ne)为(3.636±1.102),Nei’s基因多样性指数为(0.700±0.094),Shannon信息指数为(1.453±0.343),多态位点百分率为100%。群体1的Na、Ne、Nei’s基因多样性指数和Shannon信息指数都最小,而其它3个群体的遗传多样性水平相似。但是,4个群体间存在中等的遗传分化(群体分化率Fst=0.121),群体间总的基因流也处于中等水平(Nm=1.825)。群体1、群体2和群体3之间的遗传一致度最高,而群体4和其它3个群体间的遗传一致度都比较低。已知群体3是黄河三角洲唯一被引种的互花米草群体,是扩散的源头,根据4个群体的遗传结构,本研究推测互花米草先从群体3扩散到群体4,再从群体3扩散到群体1和群体2,扩散顺序与地理距离不相关,说明互花米草的种子通过海水传播可以实现跳跃式长距离扩散。因此,研制和施用环境友好型药物,使互花米草种子败育,可能是控制互花米草入侵的一种途径。     

新疆贝母(Fritillaria walujewii)的遗传多样性与遗传结构

新疆贝母具较高的药学利用价值,但现存量稀少,被列为新疆Ⅲ级保护植物。为了探明其天然居群的遗传多样性,本研究选取3个叶绿体基因片段对18个居群的235个个体进行测序。结果表明:新疆贝母总的遗传多样性较高;居群间发生了明显的遗传分化;遗传距离与地理距离呈显著的相关性;昭苏县及新源县的居群具有较高的遗传多样性。居群间的地理障碍及自身的有限传播距离可能导致了居群间的遗传分化。较高的遗传灭绝风险提示应该及时对新疆贝母的天然居群进行保护,尤其在遗传多样性较高的昭苏、新源地区。     

塔吉克斯坦哈特隆州土壤可培养细菌多样性分析

采用纯培养、结合核糖体DNA扩增片段限制性酶切分析(16S r DNA PCR-RFLP)、RepPCR及16S r DNA序列测定和系统发育分析方法研究塔吉克斯坦哈特隆州土壤可培养细菌群落结构和种群多样性。从哈特隆州的农田、天然草地、林地及荒漠土壤中分离获得110个菌株,分布在厚壁菌门(Firmicutes)(80.9%)、变形杆菌门(Proteobacteria)(17.2%)和放线菌门(Actinobacteria)(1.85%)三个类群中,归属于芽孢杆菌(Bacillus)、寡养单胞菌(Stenotrophomonas)、短杆菌(Brevibacterium)、节杆菌(Arthrobacter)、棍状杆菌(Clavibacter)、短波单胞菌(Brevundimonas)、贪食菌(Variovorax)、假单胞杆菌(Pseudomonas)、芽孢八叠球菌(Sporosarcina)、赖氨酸芽孢杆菌(Lysinibacillus)、无色杆菌属(Achromobacter)和Rheinheimera共12个属中。其中Bacillus(71.8%)为该地区土壤可培养细菌绝对优势种群,Pseudomonas(10.9%)为次优势种群。对优势种群Bacillus的Rep-PCR基因组指纹图分析表明,63株分离物有17种不同的多态性指纹图谱,具有较为丰富的多样性特征。不同样地土壤中可培养细菌的种群分布、结构组成及多样性存在明显差异,与土壤环境密切相关。Shannon多样性指数、Simpson优势度和Pielou均匀度指数与土壤有机质、全氮、碱解氮及含水量呈显著正相关(p0.05)。土壤速效钾含量也是显著影响细菌Shannon多样性、Simpson优势度的重要因素。研究不仅为后期功能菌株的筛选提供了基础,也为塔国不同土地利用方式下土壤环境评价提供了依据。     

地形因素对水稻生产的影响——以湖南省为例（英文）

Rice(Oryza sativa L.) is the most important staple crop of China, and its production is related to both natural condition and human activities. It is fundamental to comprehensively assess the influence of terrain conditions on rice production to ensure a steady increase in rice production. Although many studies have focused on the impact of one or several specific factors on crop production, few studies have investigated the direct influence of terrain conditions on rice production. Therefore, we selected Hunan Province, one of the major rice-producing areas in China, which exhibits complex terrain conditions, as our study area. Based on remote sensing data and statistical data, we applied spatial statistical analysis to explore the effects of terrain factors on rice production in terms of the following three aspects: the spatial patterns of paddy fields, the rice production process and the final yield. We found that 1) terrain has a significant impact on the spatial distribution of paddy fields at both the regional scale and the county scale; 2) terrain controls the distribution of temperature, sunlight and soil, and these three environmental factors consequently directly impact rice growth; 3) compared with the patterns of paddy fields and the rice production process, the influences of terrain factors on the rice yield are not as evident, with the exception of elevation; and 4) the spatial distribution of paddy fields mismatched that of production resources due to terrain factors. Our results strongly suggest that managers should scientifically guide farmers to choose suitable varieties and planting systems and allocate rice production resources in the northern plain regions to ensure food security.     

A LiDAR-based flood modelling approach for mapping rice cultivation areas in Apalit,Pampanga

Majority of rice cultivation areas in the Philippines are susceptible to excessive flooding owing to intense rainfall events. The study introduces the use of fine scale flood inundation modelling to map cultivation areas in Apalit, a rice-producing municipality located in the province of Pampanga in the Philippines. The study used a LiDAR-based digital elevation model (DEM), river discharge and rainfall data to generate flood inundation maps using LISFLOOD-FP. By applying spatial analysis, rice cultivation zone maps were derived and four cultivation zones are proposed. In areas where both depth and duration exceed threshold values set in this study, varieties tolerant to stagnant flooding and submergence are highly recommended in Zone 1, where flood conditions are least favorable for any existing traditional lowland irrigation varieties. The study emphasizes that a decline in yield is likely as increasing flood extents and longer submergence periods may cause cultivation areas for traditional irrigated lowland varieties to decrease over time. This decrease in yield may be prevented by using varieties most suitable to the flooding conditions as prescribed in the rice zone classification. The method introduced in this study could facilitate appropriate rice cultivation in flood-prone areas.     

Gender and agrobiodiversity: a case study from Bangladesh

Local geography and gender are two major factors determining which crop varieties are cultivated in a case study of two rural villages in Bangladesh. This paper explores the interrelationships between gender, agrobiodiversity, and the use of, and preferences for, improved and local crop varieties. These are examined in relation to rice, minor field crops, and home garden fruits and vegetables. Reasons for both the displacement and the persistence of local varieties (LVs) are analysed in comparison to improved variety (IV) diffusion. The research evaluates agrobiodiversity through the number, types, and varieties of crops grown in fields and home gardens. The desired agroecological, economic, and cultural characteristics of crops grown document how respondents rank their variety preferences. Variety preferences and the perceived importance of LV preservation are compared with what is actually grown. The study indicates that there was little variation between villages in their approach towards the use of IV and LV rice; IVs were cultivated for their high yields and LV rice for taste and culinary uses. However, there were significant differences in relative agricultural dependence between the two villages which led to unique variety preferences. In both villages, women's preferences for IVs or LVs play a major role in crop choices, particularly as they manifest themselves in gendered domains of authority.     

广西晚稻低温冷害空间分析模型构建及其区划

根据晚稻生长状况、受害程度与低温冷害强度关系,确定晚稻冷害等级指标;利用广西90个气象台站46年的气候资料和站点地理信息,采用GIS技术和数理统计回归分析以及气候资源的细网格推算方法,建立晚稻冷害的空间分析模型,推算出1km×1km分辨率的冷害指标因子空间分布;并根据晚稻冷害分级指标,通过GIS的空间分析能力,分析广西晚稻低温冷害的空间分布特征,得出广西无冷害和轻度、中度、严重冷害等四个区域的区划结果,制作广西晚稻低温冷害区划专题图,对分区结果进行评述并指出了冷害的战略防御和应急防御措施,为广西水稻生产的趋利避害和优化布局提供决策依据。     

基于GIS的广东地名景观分析

为对广东地名景观进行定量分析,文章首先依据最新广东省地图集利用数理统计方法进行地名数量统计,在此基础上,利用GIS技术,建立广东地名元数据库(GEODATABASE),通过ARCGIS中的GEOPROCESSING、SPATCIAL STATISTICS TOOLBOX和ANALYSIS TOOLBOX等对数据属性要素进行分析、分区、分异和颜色色差处理,输出所需的直方专题地图和其他所需专题地图。其后得出,广东地名景观表现出岭南特有的地理环境特征和历史发展特征,在空间分布上具有不均衡性,通名和专名具有多样性,齐头地名分布的集中性和具有多族群性及方言性。文章还在统计的基础上,利用GIS技术进行分类和地理区划,将全省地名景观按类型分为四大区,即客家、福佬、壮语和粤语地名区,且各自在空间上表现出核心-边缘分布景观。     

Factors Influencing Indigenous Rice Protection in the Yuanyang Terraced Rice Fields of China

Indigenous rice has maintained the survival of local people for more than a thousand years in the Yuanyang terraced rice fields of southern Yunnan, China. It is the foundation for long-term stable development of local agriculture and food security and its unique and irreplaceable characteristics give the terraces value. The status of indigenous rice resources is threatened by serious loss, so a better understanding of rice diversity and the factors that influence rice variety protection is conducive to policy. Here, we investigate the planting and conservation situation of indigenous rice, analyze factors impacting the protection and loss of traditional rice varieties, and construct an indigenous rice protection influence index system. Controllable factors which have special meaning to the maintenance and management of local rice are identified and corresponding strategies for the protection and maintenance of indigenous rice are discussed.     

元阳梯田水稻地方品种与现代水稻品种的农艺性状比较研究

本文对3个元阳县哈尼族人持续种植了上百年的水稻品种和3个现代品种分别种植在元阳梯田6个不同海拔梯度进行主要农艺性状比较研究。研究结果表明：传统品种在不同海拔的株高、穗长、有效穗等农艺性状差异不显著,而现代品种在不同海拔的农艺性状波动较大,这可能是元阳地方水稻品种长期种植与环境相适应的结果。     

论壮族地区的水稻种植与环境适应的关系

水稻种植过程中,常具有浓厚的环境适应的特征。分布在不同地貌区的壮族是典型的稻作民族,已充分意识到所在地区气候、土壤等自然地理环境对水稻种植的深刻影响。为适应自然地理环境,发挥最大的生产效益,山居壮族多选择种植生长期较长、耐寒、耐肥的粳稻为主;在平原丘陵地区的壮族则以种植生长期短的籼稻居多;为适应岩溶山区干旱少水、不利于灌溉的环境,当地壮族则多种陆稻,但由于陆稻口感不佳以及所在地区人地关系由宽趋紧,导致陆稻在壮族种植结构中的地位不断下降。此外,壮族在生活中对水稻用途的定位,也影响到水稻品种的选择与种植。     

Coupling maximum entropy modeling with geotagged social media data to determine the geographic distribution of tourists

Modeling the geographic distribution of tourists at a tourist destination is crucial when it comes to enhancing the destination’s resilience to disasters and crises, as it enables the efficient allocation of limited resources to precise geographic locations. Seldom have existing studies explored the geographic distribution of tourists through understanding the mechanisms behind it. This article proposes to couple maximum entropy modeling with geotagged social media data to determine the geographic distribution of tourists in order to facilitate disaster and crisis management at tourist destinations. As one of the most popular tourist destinations in the United States, San Diego was chosen as the study area to demonstrate the proposed approach. We modeled the tourist geographic distribution in the study area by quantifying the relationship between the distribution and five environmental factors, including land use, land parcel, elevation, distance to the nearest major road and distance to the nearest transit stop. The geographic distribution’s dependency on and sensitivity to the environmental factors were uncovered. The model was subsequently applied to estimate the potential impacts of one simulated tsunami disaster and one simulated traffic breakdown due to crisis events such as a political protest or a fire hazard. As such, the effectiveness of the approach has been demonstrated with specific disaster and crisis scenarios.