哈长城市群生态系统服务时空特征及其权衡/协同关系研究

哈长城市群位列国家二级城市群之首,研究哈长城市群地区的生态系统服务变化及权衡协同关系对促进该区域可持续发展具有深远意义。基于多源遥感数据结合InVEST模型及权衡协同度模型(ESTD),分析了哈长城市群2000年、2010年、2015年土地覆被变化;评估了土壤保持、生态系统碳储量及产水量3种生态系统服务的时空分布及其权衡协同关系。结果表明:(1)2000-2015年,哈长城市群内建设用地共增加1462 km²,其中,2000-2010年增长量(958 km²)高于2010-2015年(504 km²),15年间林地共增加1527 km²,草地、耕地及裸地分别减少661 km²,1611 km²,780 km²;(2)15年间土壤保持量持续降低,生态系统碳储量先减后增,产水量先增后减;(3)6种土地覆被类型中,单位面积下林地提供的土壤保持力最高,湿地提供的生态系统碳储量和产水量最高;(4)协同作用在哈长城市群3种生态系统服务间占主导地位;南部的土壤保持-生态系统碳储量及土壤保持-产水量多为协同关系,北部相反,从全区来看生态系统碳储量-产水量间的相关关系相对较弱。研究结果可为哈长城市群地区制定更为全面具体的生态保护策略提供参考依据。     

大豆籽粒大小遗传调控研究现状

籽粒大小是大豆产量和外观品质的重要构成要素,具有巨大的经济价值,一直以来都是育种的主要目标之一.大豆籽粒大小由胚、胚乳和种皮发育共同协调决定.目前已报道的与大豆籽粒重相关的QTL位点309个,但大多位点尚未进行功能验证.已发现的与大豆籽粒大小相关的基因有17个,多数与母本种皮发育调控相关,其它与合子组织和植物激素调控途...     

土壤动物与土壤健康

土壤动物与土壤健康息息相关,土壤动物多样性和功能能够灵敏反映人类活动和气候变化引起的土壤扰动。同时,土壤动物还通过与生物和非生物组分间的相互作用对地上生态系统产生反馈作用。当前土壤动物在土壤健康评价体系中的应用相对较少,主要集中在土壤线虫、节肢动物和蚯蚓等类群,仍缺乏基于土壤动物的系统性评价指标。因此,本文围绕土壤动物在指示土壤健康方面的潜力,系统总结了现有基于土壤动物的土壤健康评价指标,强调未来应建立和完善土壤动物基因组信息数据库,挖掘土壤动物的功能性状,加强土壤食物网结构和生态功能的研究,建立集成土壤动物物种多样性、功能性状和土壤食物网的指标体系,从而促进土壤健康和生态系统的可持续发展。     

Identification of quantitative trait loci controlling nodulation and shoot mass in progenies from two Brazilian soybean cultivars

Nitrogen (N) demand of soybean [Glycine max (L.) Merrill] can be supplied via biological nitrogen fixation (BNF), however, higher yielding cultivars increase plant demand for N. Phenotypes differing for traits associated with biological nitrogen fixation result from the expression of the multiple genes of both the host plant and the microsymbiont, but limited studies have been done on the genetics of the soybean BNF. Integrated maps of soybean with simple sequence repeat (SSR) markers [Cregan, P.B., Jarvik, T., Bush, A.L., Shoemaker, R.C., Lark, K.G., Kahler, A.L., Kaya, N., Van Toai, T.T., Lohnes, D.G., Chung, J., Specht, J.E., 1999. An integrated genetic linkage map of the soybean genome. Crop Sci. 39, 1464–1491.] offer an excellent opportunity for the identification of traits related to BNF. This study aimed at the identification of quantitative trait loci (QTLs) controlling BNF and nodulation in an F₂ population of 160 plants derived from an intraspecific cross between two Brazilian cultivars, Embrapa 20 × BRS 133, previously identified as having good potential for mapping of QTLs [Nicolás, M.F., Arias, C.A.A., Hungria, M., 2002. Genetics of nodulation and nitrogen fixation in Brazilian soybean cultivars. Biol. Fertil. Soils 36, 109–117.]. From 252 SSR markers tested in the parental genotypes 45 were polymorphic with high heterozygotes resolution. Mapping was performed with those 45 SSR markers for nodulation [nodule number (NN) and nodule dry weight (NDW)] and plant growth [shoot dry weight (SDW)] phenotypes in F_2:3 lines. A total of 21 SSR loci were mapped with a likehood of odds (LOD) value of 3.0 and a maximum Haldane distance of 50 cM, and were distributed in nine linkage groups with coverage of 251.2 cM. The interval mapping analysis with Mapmaker/QTL revealed two genomic regions associated with NN and NDW, with a contribution of putative QTLs of 7.1 and 10%, respectively. The regression analysis identified 13 significant associations between the marker loci and QTLs due to additive effects, with some of them being significantly associated with more than one phenotypic trait. Effects were observed in all variables studied, ranging from 2 to 9%. A one-way analysis of variance (ANOVA) also detected 13 significant associations, related to dominance effects. A two-way-ANOVA showed six epistatic interactions among non-linked QTLs for SDW, NN and NDW, explaining up to 15% of the trait variation and increasing the phenotypic expression from 8 to 28%. The data obtained in this work establish the initial stage for additional studies of the QTLs controlling BNF and indicate that effective marker-assisted selection using SSR markers may be feasible for enhancing BFN traits in soybean breeding programs.     

长春市建设用地扩张对耕地资源的影响

通过分析长春市区建设用地与耕地的时空变化特征及建设用地扩张对耕地的影响,为黑土区土地合理利用与耕地保护提供参考。本文采用2005年和2019年的Landsat TM/OLI遥感影像,基于面向对象-决策树的分类方法提取研究区土地利用信息,对长春市区建设用地和耕地的时空变化及建设用地对耕地数量、质量和结构的影响进行了研究。结果表明：2005年以来,长春市区建设用地扩张21163.30 hm²,而耕地面积则减少19011.81 hm²。新增加的建设用地占用耕地18170.84 hm²,为建设用地增加面积的85.33%,建设用地的扩张导致耕地破碎化程度增大;建设用地侵占的耕地多为优质耕地,Ⅰ~Ⅲ级的面积比例达72.17%。研究结果对协调黑土区快速城市化过程中耕地资源的保护具有重要的指导意义。     

Development of a new index for automated mapping of ratoon rice areas using time-series normalized difference vegetation index imagery

Over recent decades, the global demand for food has continued to grow, owing to population growth and the loss of arable land. Rice ratooning offers new opportunities for increasing rice production and has received renewed interest because of the minimal additional labor input required for its adoption. Regular, regional-scale monitoring of the spatial patterns of both traditional and ratoon rice cropping systems provides essential information for agricultural resource management and food security studies. However, the similar phenological characteristics of traditional double rice and ratoon rice cropping systems make it challenging to accurately classify these cropping practices based on satellite observations alone. In this study, we first proposed an improved phenology-based rice cropping area detection algorithm using moderate resolution imaging spectroradiometer (MODIS) normalized difference vegetation index (NDVI) imagery. A new index, ratoon rice index, was then developed to automatically delineate ratoon rice cropping areas with the aid of a base map of rice in Hubei Province, China. The accuracy assessment using ground truth data showed that our approach could map both traditional and ratoon rice cropping areas with high user accuracy (91.25% and 91.43%, respectively). The MODIS-retrieved rice cropping areas were validated using annual agricultural census data, and coefficient of determination (R²) values of 0.60 and 0.41 were recorded for traditional and ratoon rice cropping systems, respectively. The total area of ratoon rice was estimated to be 1 283.6 km², 5.0% of the total rice cropping area, in Hubei Province in 2016. These demonstrated the feasibility of extracting the spatial patterns of both traditional and ratoon rice cropping systems solely from time-series NDVI and field survey data and strides made in facilitating the timely and routine monitoring of traditional and ratoon rice distribution at subnational level. Given sufficient historical satellite and phenology records, the proposed algorithm had the potential to enhance rice cropping area mapping efforts across a broad temporal scale (e.g., from the 1980s to the present).     

Multi-scale responses of bird species to tree cover and development in an urbanizing landscape

Landscape change is an ongoing process for even the most established landscapes, especially in context to urban intensification and growth. As urbanization increases over the next century, supporting bird species’ populations within urbanizing areas remains an important conservation challenge. Fundamental elements of the biophysical structure of urban environments in which bird species likely respond include tree cover and human infrastructure. We broadly examine how tree cover and urban development structure bird species distributions along the urban-rural gradient across multiple spatial scales. We established a regional sampling design within the Oak Openings Region of northwestern, Ohio, USA, to survey bird species distributions across an extensive urbanization gradient. Through occupancy modeling, we obtained standardized effects of bird species response to local and landscape-scale predictors and found that landscape tree cover influenced the most species, followed by landscape impervious surface, local building density, and local tree cover. We found that responses varied according to habitat affiliation and migratory distance of individual bird species. Distributions of short-distance, edge habitat species located towards the rural end of the gradient were explained primarily by low levels of urbanization and potential vegetative and supplemental resources associated with these areas, while forest species distributions were primarily related to increasing landscape tree cover. Our findings accentuate the importance of scale relative to urbanization and help target where potential actions may arise to benefit bird diversity. Management will likely need to be implemented by municipal governments and agencies to promote tree cover at landscape scale, followed by residential land management education for private landowners. These approaches will be vital in sustaining biodiversity in urbanizing landscapes as urban growth expands over the next century.     

松嫩平原西部盐碱地紫花苜蓿产量和品质对刈割频次与施肥的响应

为探讨刈割频次、施肥以及二者交互作用对轻度盐碱地紫花苜蓿产量和品质的影响,采用以刈割频次（1、2、3、4次）为主处理,施肥（对照;施N肥;施P肥;施NPK复合肥）为副处理的双因素裂区试验进行研究。结果表明：同一生长季内,随着刈割频次的增加紫花苜蓿干草产量显著增加（P<0.05）,3次与4次刈割分别比1次刈割增产123.8%和131.6%;施肥对干草产量无显著影响,而刈割频次与施肥的交互作用对干草产量具有显著影响（P<0.05）,刈割3次并添加NPK复合肥处理的干草产量最高。刈割频次和施肥对紫花苜蓿营养品质具有不同程度的影响,二者交互作用仅对粗蛋白含量具有显著影响（P<0.05）。随着刈割频次的增加,紫花苜蓿茎叶比下降,粗蛋白、粗灰分含量和K⁺/Na⁺显著增加（P<0.05）,粗脂肪和粗纤维含量显著降低（P<0.05）,Ca²⁺含量先增加后降低,Ca²⁺/Na⁺则表现出先升高后稳定的趋势。施NPK复合肥使苜蓿粗蛋白和粗脂肪含量显著增加,粗纤维含量显著降低（P<0.05）。刈割频次对第二年返青率具有显著影响（P<0.05）,4次刈割明显降低了苜蓿的存活率,返青率仅为12.5%,显著低于其他处理。研究表明,在松嫩平原轻度盐碱地种植紫花苜蓿,每年刈割3次并施用NPK复合肥为最佳管理方式。     

农业土壤耕作大气颗粒物排放研究进展

大面积农业活动中释放的颗粒物可能会显著影响其所在地及所在区域的空气质量。我国是农业大国,了解各农业区不同生产环节的颗粒物排放状况是编制国家农业源排放清单和探索减控措施的基础。通过综述近几十年来国内外关于农业土壤耕作造成的大气颗粒物排放的研究进展,对农业耕作产生的颗粒物组成、影响因素、排放清单编制以及模型模拟进行了归纳,重点讨论了清单编制中排放系数的问题,提出了今后我国农业人为源大气颗粒物排放研究需要加强的几方面内容。     

草铵膦对斑马鱼胚胎及仔鱼的毒性研究

草铵膦(glufosinate-ammonium,GLA)是一种广谱触杀型非选择性除草剂,随着在生产中应用的不断增加,其生物安全性也越来越受到人们的重视。试验以斑马鱼Danio rerio胚胎为动物模型,用不同剂量的草铵膦染毒受精后2h的斑马鱼胚胎,观察其死亡率和形态学变化,并应用原位杂交和QRT-PCR技术检测了Vasa基因表达情况,以分析草铵膦的毒性作用。结果表明:1.6μg/L的草铵膦对斑马鱼胚胎有显著致死作用、1.3μg/L的草铵膦有显著致畸作用,其中畸形表现为尾部弯曲和阻碍黑色素沉着。原位杂交结果显示:1.3μg/L的草铵膦可引起Vasa表达的部分缺失,QRT-PCR定量分析发现,草铵膦可引起斑马鱼胚胎Vasa基因表达水平下调3.8倍。表明草铵膦对斑马鱼胚胎有较强的致死毒性、致畸作用和潜在的生殖毒性。