Phenotypic variations of wheat cultivars from the North China Plain in response to cadmium stress and associated single nucleotide polymorphisms identified by a genome-wide association study

Understanding the genetic mechanisms for cadmium(Cd) uptake and translocation in common wheat(Triticum aestivum) is of significance in food Cd contamination control. In this study, a diverse panel of 132 wheat cultivars was collected from the North China Plain. The cultivars were evaluated in terms of their phenotypic variations in response to Cd stress and subjected to a genome-wide association study(GWAS) to identify single nucleotide polymorphisms(SNPs) associated with the phenotypic variatio...     

高原鼠兔刈割对青海湖流域高寒草甸植物种间关联的影响

高原鼠兔喜欢刈割茂密高寒草甸中高大植物而影响植物群落内的种间关系。采用方差比率法、χ²检验和Spearman秩相关分析相结合的方法,分析了高原鼠兔刈割行为对高山嵩草草甸植物群落种间关联的影响。结果表明:高原鼠兔刈割会促进植物群落的种间总体联结从不显著正关联变为显著负关联,降低植物群落稳定性,减少植物群落内正关联和正相关的种对数量,增加负关联、无关联和负相关的种对数量。而综合χ²检验结果、AC值和OI指数,洞口植物群落大部分种对的种间关联均不显著,种间联结程度不强。这表明χ²检验和Spearman秩相关分析能够评价小型草食动物对植物群落种间关联的影响,为全面解析高原鼠兔整体干扰驱动植物群落结构变化提供了基础信息。     

卷管式喷灌机绞盘速度自动控制系统的研究

在实时控制理论的基础上,针对现有绞盘卷管式喷灌机喷头小车随绞盘速度的变化而变化并最终影响喷灌均匀性的问题,设计了一种由8051芯片构成的智能控制系统,给出了其软硬件系统实现的方案,并对该系统效率进行了分析.研究表明,该系统实现了对绞盘卷管式喷灌机绞盘速度的自动控制,有效地控制了喷头小车的行走速度,可大大地提高绞盘卷管式喷灌机的喷灌均匀性和自动化程度,具有很好的应用及推广价值.     

农业机械化与黑龙江省农业发展实证分析

从各国农业发展经验看,农业机械化对各国农业的发展具有重要的促进作用,而黑龙江省是我国的农业大省,有必要对其农业机械化与农业发展关系进行研究。为此,运用多元线性回归模型,分析了阻碍农业机械化的影响因素:农村剩余劳动力转移缓慢,农户分散经营,投入少。同时,提出了具体措施来提高黑龙江省农业机械化水平:促进农村剩余劳动力的转移,加大政府对农业机械的投入,建立农业机械化服务体系,以此促进农业机械作用的发挥从而推进黑龙江省农业的发展。     

STUDY OF DETERMINING THE DEGREE OF GRAPHITIZING OF COKE WITH X-RAY DIFFRACTION METHOD

In the paper, the process of determining the degree of graphiti-zing of metallurgy coke with X-ray diffraction method was discussed. The extrapolation was used in order to obtain the interplanar distance. of (002) crystaloface of metallurgy coke. The finding showed that the dmax. wasn''t 3.44A, butO4.31A. A rational formula which could be used to characterize the degree of gra-phitizing of metallurgy coke was found.     

基于像元尺度耕地质量局部空间自相关的基本农田划定

划定永久基本农田保护区是我国农业可持续发展的战略要求,耕地质量是保护区位置选择的重要依据。以湖北省嘉鱼县为例,引入植被指数信息,完善耕地质量综合评价指标体系,通过网络层次分析法确定指标权重,结合局部空间自相关分析结果,分别对基于耕地质量与莫兰指数的基本农田逐像元补划结果进行了分析。研究结果表明,嘉鱼县耕地综合质量在空间上表现出较强的相关性,全域和耕地范围的局部自相关系数分别为0. 864 5和0. 991 6;基于耕地质量和莫兰指数的划定结果在空间上保持高度的一致性,两种方法均优先将空间上呈HH型聚集的99. 97%的像元划入了基本农田保护区;两种方法互为补充,可以为最终决策提供参考。     

野生大豆芽期耐盐性状的关联分析

盐渍化是危害大豆生产的主要非生物胁迫因素之一。目前大豆耐盐性研究主要集中在栽培大豆的苗期耐盐性,而芽期耐盐性状的研究相对较少。野生大豆蕴含丰富的耐逆基因,是栽培大豆遗传改良的重要资源。为了研究野生大豆芽期耐盐性状的遗传机制,以113份野生大豆为试验材料,进行芽期耐盐性状的鉴定,结合群体的分子标记对包括2年平均值在内的3个环境下的3个耐盐指数进行全基因组关联分析,共检测到与野生大豆芽期耐盐相关的位点26个,6个SSR标记Satt521、Satt022、Satt239、Satt516、Satt251和Satt285在2个或3个环境下均被检测到,4个SSR标记Satt516、Satt251、Satt285和GMES4990与2个或3个耐盐指数显著相关。对这些SSR标记进行分析,挖掘了最优的等位基因及其载体材料。以上这些结果对于阐明野生大豆芽期耐盐性状的遗传机制,进一步发掘新的耐盐基因具有重要意义。同时也为栽培大豆遗传基础的拓宽、大豆耐盐分子标记辅助选择和分子设计育种等后续研究提供重要依据。     

Selection of soybean elite cultivars based on phenotypic and genomic characters related to lodging tolerance

Soybean lodging can result in serious yield reduction. Detecting the quantitative trait loci (QTL) associated with lodging tolerance for their further application in marker‐assisted selection (MAS) has the potential to enhance soybean breeding efficiency. In this study, a genome‐wide association analysis (GWAS) was performed to identify soybean accessions that could potentially be used to produce lodging‐tolerant varieties, based on the comprehensive evaluation of lodging scores (LS) obtained for the parental cultivar “Tokachi nagaha” and its 137 derived cultivars. Results showed that genotype, environment and genotype × environment interaction significantly influenced LS. Of the 31 significant SNPs identified, 22 were consistently detected in two or more environments and 27 SNPs were located in or close to agronomically important QTL mapped by linkage analysis. Best linear unbiased predictors (BLUPs) of LS tend to decrease with the elite alleles contained by accessions increasing. Some excellent accessions, with lower BLUPs and D_i (stability coefficients) values and more elite alleles, were selected. This study contributed to understand the genetic mechanism of lodging, providing genetic and phenotypic information for MAS.     

Review on the roles and effects of growing media on plant performance in green roofs in world climates

Growing media (substrate) is a fundamental part of a green roof, providing water, nutrients and support to plants. However, little research has reviewed how it affects plant performances in different climatic regions. This study aims to analyse published research on green roof growing medium across world’s climate zones. Findings are structured according to Köppen–Geiger climate classification, aiming to investigate the prevalence of research conducted in different climate zones. Results from full-scale studies and laboratory or greenhouse experiments were reviewed. The later were included as they provide systematic knowledge on the effect of individual factors on system performances although cannot provide climate specific information. Studies discussed effects of major substrate components and depths on plant survival and establishment using standard test procedures. Results showed that most research in the subject were in temperate (group C climate classification), continental (group D) and dry climates (group B), respectively. Considerable number of investigations was conducted in controlled laboratory or greenhouse environments. Based on the results, future green roof research and guidelines should consider climate specifications of the region in designing growing medium, depths and attribute of green roof substrates in order to ensure enhanced plant performance. Especially, for more fragile but less investigated dry climate, considerations should be made to tackle heat fluctuations and drought stress by enhancing water holding capacity and thermal isolation of the substrate. To move forward, sustainable building solutions as a part of future urban forms, climate-adaptive green roof systems should be included into future research, practice and guidelines.