三江源区高寒草原土壤湿度变化特征及与气候因子的关系   总被引：1，自引：0，他引：1  

郭连云 《草业科学》2018,35(1):46-53

利用青海省三江源区兴海县牧业气象站1999-2016年高寒草原土壤湿度、牧草生育期资料,分析了高寒草原土壤湿度的年、季变化特征以及牧草生长季不同生育期土壤湿度的变化特征及与气候因子的关系。结果表明:高寒草原0-10、10-20、20-30、30-40和40-50 cm土壤湿度均随年际延长呈增加趋势,春季除40-50 cm土层外,其他各层土壤湿度均随年际延长呈显著增加趋势(P<0.05)。高寒草原牧草生长季的土壤相对湿度随年际延长呈显著上升趋势(P<0.05),且与生长季降水量之间呈极显著正相关关系(P<0.01)。随着气候变化,牧草抽穗、开花、成熟和枯黄期的土壤相对湿度随年际延长呈显著增加趋势(P<0.05)。牧草抽穗期、枯黄和全生育期的土壤湿度与气温呈显著负相关关系(P<0.05)。高寒草原牧草生长季土壤湿度的增加有利于草地植被生长。  相似文献   

Genetic bases of source-,sink-,and yield-related traits revealed by genome-wide association study in Xian rice     

Yun Wang  Yunlong Pang  Kai Chen  Laiyuan Zhai  Congcong Shen  Shu Wang  Jianlong Xu 《作物学报(英文版)》2020,(1):119-131

The source-sink relationship determines the ultimate grain yield.We investigated the genetic basis of the relationship between source and sink and yield potential in rice.In two environments,we identified quantitative trait loci(QTL)associated with sink capacity(total spikelet number per panicle and thousand-grain weight),source leaf(flag leaf length,flag leaf width and flag leaf area),source-sink relationship(total spikelet number to flag leaf area ratio)and yield-related traits(filled grain number per panicle,panicle number per plant,grain yield per plant,biomass per plant,and harvest index)by genome-wide association analysis using 272 Xian(indica)accessions.The panel showed substantial variation for all traits in the two environments and revealed complex phenotypic correlations.A total of 70 QTL influencing the 11 traits were identified using 469,377 high-quality SNP markers.Five QTL were detected consistently in four chromosomal regions in both environments.Five QTL clusters simultaneously affected source,sink,source–sink relationship,and grain yield traits,probably explaining the genetic basis of significant correlations of grain yield with source and sink traits.We selected 24 candidate genes in the four consistent QTL regions by identifying linkage disequilibrium(LD)blocks associated with significant SNPs and performing haplotype analysis.The genes included one cloned gene(NOG1)and three newly identified QTL(qHI6,qTGW7,and qFLA8).These results provide a theoretical basis for high-yield rice breeding by increasing and balancing source–sink relationships using marker-assisted selection.  相似文献   

小麦白粉病菌越夏,越冬和春季菌源毒性结构比较     

王锡锋  张忠山 《植物病理学报》1995,25(4):301-305

 分析了1992年和1993年不同时期采集的小麦白粉病菌越夏、越冬和春季菌源共238个菌株的生理小种、毒性基因结构和对9个推广品种的毒力频率。结果表明三种菌源在生理小种和毒性基因组成及出现频率是相似的,对9个推广品种的毒力频率均较高。这样在白粉病菌毒性和品种抗病性研究中,可以采集应用越夏和越冬菌株标样,避免了夏季高温季节保存菌株的工作;而且从毒性结构方面进一步证实白粉病菌主要以分生孢子在夏季侵染高海拔地区的自生麦苗而越夏,再逐渐扩展至秋播麦苗越冬后导致春季大田发病,病菌的子囊孢子在平原地区侵染循环上作用不大。  相似文献   

青藏高原江河源区退化草地人工改良措施对高原鼠兔种群动态影响   总被引：1，自引：0，他引：1  

张清香  严作良周立 《四川草原》2006,(5):33-36

通过对江河源区退化草地采取建植人工和半人工草地的措施进行改良,以影响害鼠(高原鼠兔)种群,达到防治鼠害的目的。  相似文献   

Gene Expression of Enzymes for Starch and Sucrose Metabolism and Transport in Leaf Sheaths of Rice (Oryza sativa L.) during the Heading Period in Relation to the Sink to Source Transition     

《Plant Production Science》2013,16(3):178-183

Abstract

Leaf sheaths of rice plants are known to temporarily accumulate starch prior to heading, which is subsequently remobilized and transported into the panicle after heading. We investigated the time course for both carbohydrate content and steady state mRNA levels of enzymes related to starch and sucrose metabolism in the rice leaf sheath (Oryza sativa L. cv. Nipponbare). Leaf sheaths from the second leaf below the flag leaf accumulated high levels of starch before heading but they rapidly decreased after heading. In contrast, the flag leaf sheath did not accumulate as much starch. In the second leaf sheath, the mRNA levels of enzymes involved in starch synthesis, ADP glucose pyrophosphorylase (EC 2. 7. 7. 27), soluble starch synthase (EC 2. 4. 1.21) and branching enzyme (EC 2. 4. 1. 18) were high before heading, which coincided with rapid accumulation of starch. The mRNA levels of sucrose synthesis enzymes, cytosolic FBPase (EC 3. 1. 3. 11) and sucrose phosphate synthase (EC 2. 4. 1. 14), and the sucrose transporter (OsSUTI) increased at the time of heading, which was largely coincident with a decrease in the mRNA levels of starch synthesis enzymes. In the flag leaf sheaths, changes in mRNA levels of starch synthesis enzymes were not pronounced, however mRNA levels of sucrose synthesis enzymes and the sucrose transporter showed a clear increase throughout the heading period. The different characteristics observed between the two leaf sheaths will be discussed in relation to the sink to source transition.  相似文献   

Particulate phase polycyclic aromatic hydrocarbons in the ambient atmosphere of a protected and ecologically sensitive area in a tropical megacity     

Darpa Saurav Jyethi  P.S. Khillare  Sayantan Sarkar 《Urban Forestry & Urban Greening》2014,13(4):854-860

This study reports, for the first time, the profiles and source analysis of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) associated with PM₁₀ (particulate matter with aerodynamic diameter ≤10 μm) at a protected and ecologically sensitive area – the Yamuna Biodiversity Park – located in the megacity Delhi, India. Weekly PM₁₀ sampling was carried out at this location for 1 year (2009–2010) and the annual mean PM₁₀ level was found to be ～9 times the World Health Organization limit. Seasonal variation of PAHs (range 37.2–74.0 ng m^?3) was significant with winter values being 72% and 68% higher than summer and monsoon respectively. Principal component analysis coupled with multiple linear regression identified diesel, natural gas and lubricating oil combustion (49.5%), wood combustion (25.4%), gasoline (15.5%) and coal combustion (9.6%) sources for the observed PAHs. Heavy traffic on the national highway and arterial roads and domestic emissions from suburban households in the vicinity of the park appeared to have significantly affected its air quality. A substantial portion (～55%) of the aerosol PAH load was comprised of carcinogenic species, which yielded a considerably high lifetime inhalation cancer risk estimate (8.7E?04). If considered as a conservative lower-bound estimate, this risk translates into ～211 excess cancer cases for lifetime inhalation exposure to the observed PAH concentrations in Delhi.  相似文献   

我国PM2.5污染现状及来源解析研究   总被引：1，自引：0，他引：1  

程念亮  李云婷  孟凡  程兵芬 《安徽农业科学》2014,(15):4721-4724

利用2013年我国各城市PM2.5浓度数据及查找大量文献,对我国细颗粒物的污染现状及重点城市细颗粒物来源解析工作进行了初步研究。结果发现,我国PM2.5浓度水平较高且空间差异较大,呈现明显的时空分布特征;PM2.5浓度高值区主要分布在华北平原、四川盆地、长三角地区,华北地区年均浓度在80μg/m3左右,各城市PM2.5浓度季节变化基本为冬季＆gt;春季＆gt;秋季＆gt;夏季;燃煤源、工业源、汽车尾气是对PM2.5有明显贡献的主要排放源类,机动车尾气对PM2.5贡献的大多在10%～30%。  相似文献   

一种土壤重金属污染源位置的分析方法     

李鹏  陈永当  张媛  胡颖  黄国建 《江西农业学报》2014,(2):63-65

对某城市表层土壤中As、Cd、Cr、Cu、Hg、Ni、Pb、Zn等8种重金属元素的含量进行了采样分析,采用域法识别特异值进行数据处理。采用坐标平移法,修正高斯扩散方程,利用MATLAB软件进行拟合,得到了这8种重金属污染源的空间位置坐标。  相似文献   

出口烟叶非烟杂物控制模式探究     

刘佳妮  陈泽斌  彭声静  张瑜瑜  尹利方  张万功  梅文强  赵晟 《农业科学与技术》2017,18(2)

非烟物质来源于大田、编烟、分级、收购等多个环节,对卷烟产品造成极大的质量及安全隐患.通过源头、生产和加工过程中非烟杂物的控制,提高原料利用率,确保原料质量安全.  相似文献   

农村产业结构协调发展的探索——山西省孝义市柱濮镇农村产业状况剖析     

赵月红  孔令节 《山西农业大学学报(自然科学版)》1997,(2)

农业是属于社会效益高、比较经济效益低的特殊产业。在社会主义市场经济条件下，如何深化对农业基础地位的认识，按照经济发展的客观规律，科学地指导农业和农村经济持续、快速、健康地发展，尤其是在工矿业发达的地区，如何扭转工业发展、农业萎缩的局面，使工农业相互促进，协调发展，是农业经济工作者研究的一个重要课题。本文分析了孝义市柱濮镇农村产业现状及其农业发展滞后的原因，提出了农村产业协调发展的对策、建议  相似文献