As the ecologically important recipient channels for riverine ecosystems, tributaries provide unique microhabitats for microorganisms, among which zooplankton constitutes the most important heterotrophic organisms. In...As the ecologically important recipient channels for riverine ecosystems, tributaries provide unique microhabitats for microorganisms, among which zooplankton constitutes the most important heterotrophic organisms. In particular, the reduced water velocity caused by dams is more favorable for zooplankton development;therefore, dammed rivers are expected to support extremely diverse and abundant zooplankton communities and notably different spatiotemporal distribution patterns. So far,however, only very few molecular studies support these assumptions. Using high-throughput sequencing, a high number of 350 operational taxonomic units(OTUs;97% cutoff) were retrieved from 30 samples collected in the Xiangxi River, the nearest large tributary upstream of the Three Gorges Dam. Zooplankton did not show significant spatial distribution in the channel. Instead,the community structures varied significantly over sampling dates, corroborating the seasonal patterns found in lakes and ponds in the subtropical zone. As expected, the community compositions were deterministically governed by environmental filtering processes(phylogenetic clustering), in which water velocity appeared to be much less important than other investigated environmental factors. Moreover, most of the detected phylotypes(OTUs) had a relatively high(>90%) sequence similarity to previously deposited sequences, suggesting a mediocre degree of genetic novelty within the zooplankton communities in the Xiangxi River.展开更多
为探究大豆基于株高抗旱系数(drought resistance coefficient based on plant height,DCPH)和主茎节数抗旱系数(drought resistance coefficient based on number of main stem nodes,DCNS)的抗性遗传基础,本研究选取由113份大豆品种(...为探究大豆基于株高抗旱系数(drought resistance coefficient based on plant height,DCPH)和主茎节数抗旱系数(drought resistance coefficient based on number of main stem nodes,DCNS)的抗性遗传基础,本研究选取由113份大豆品种(系)组成的自然群体作为研究材料,在全生育期干旱胁迫和正常供水条件下测定了株高和主茎节数,分别计算两种类型的抗旱系数,并利用全基因组关联分析技术(Genome-Wide Association Study,GWAS),挖掘与大豆株高和主茎节数抗旱性相关的基因和位点。结果显示:利用1882531个SNP标记进行GWAS分析,DCPH显著关联的位点全部位于9号染色体上,而DCNS显著关联的位点全部位于6号染色体上。进一步分析确定了DCPH和DCNS的候选基因区间,分别筛选出41个与DCPH相关的候选基因和15个与DCNS相关的候选基因。这些基因可能参与大豆生长发育的调控、激素信号传导、细胞分裂和生长等过程。本研究不仅为深入解析大豆抗旱性的分子机制提供了重要线索,还为培育抗旱性强的大豆品种提供了宝贵的基因资源。展开更多
选用美棉33B和泗棉3号两个叶色深浅差异明显的品种,设置氮素水平(0、120、240、360和480 kg hm-2纯氮)试验,研究棉花主茎叶SPAD值的叶位分布,对棉花进行氮素营养诊断。结果表明,棉花主茎顶部4张定型叶片的SPAD值对施氮水平反应的敏感程...选用美棉33B和泗棉3号两个叶色深浅差异明显的品种,设置氮素水平(0、120、240、360和480 kg hm-2纯氮)试验,研究棉花主茎叶SPAD值的叶位分布,对棉花进行氮素营养诊断。结果表明,棉花主茎顶部4张定型叶片的SPAD值对施氮水平反应的敏感程度存在显著差异,随施氮量增加,棉花主茎顶1、2、3、4定型叶SPAD值的大小位次发生明显变化,其中以顶1定型叶对施氮量增加的响应最为敏感,顶4定型叶最为迟钝。利用顶1定型叶与顶4定型叶SPAD值的相对差值,可较精确地诊断棉花的氮素营养水平,并能克服品种和生育时期不同的影响,是一种具有普适性的棉花氮素营养诊断指标。展开更多
基金supported by the National Natural Science Foundation of China (31772433, 31801984)Biodiversity survey of aquatic organisms in Three Gorges Reservoir area and the illustrated handbook compilation (2014FY120200)
文摘As the ecologically important recipient channels for riverine ecosystems, tributaries provide unique microhabitats for microorganisms, among which zooplankton constitutes the most important heterotrophic organisms. In particular, the reduced water velocity caused by dams is more favorable for zooplankton development;therefore, dammed rivers are expected to support extremely diverse and abundant zooplankton communities and notably different spatiotemporal distribution patterns. So far,however, only very few molecular studies support these assumptions. Using high-throughput sequencing, a high number of 350 operational taxonomic units(OTUs;97% cutoff) were retrieved from 30 samples collected in the Xiangxi River, the nearest large tributary upstream of the Three Gorges Dam. Zooplankton did not show significant spatial distribution in the channel. Instead,the community structures varied significantly over sampling dates, corroborating the seasonal patterns found in lakes and ponds in the subtropical zone. As expected, the community compositions were deterministically governed by environmental filtering processes(phylogenetic clustering), in which water velocity appeared to be much less important than other investigated environmental factors. Moreover, most of the detected phylotypes(OTUs) had a relatively high(>90%) sequence similarity to previously deposited sequences, suggesting a mediocre degree of genetic novelty within the zooplankton communities in the Xiangxi River.
文摘为探究大豆基于株高抗旱系数(drought resistance coefficient based on plant height,DCPH)和主茎节数抗旱系数(drought resistance coefficient based on number of main stem nodes,DCNS)的抗性遗传基础,本研究选取由113份大豆品种(系)组成的自然群体作为研究材料,在全生育期干旱胁迫和正常供水条件下测定了株高和主茎节数,分别计算两种类型的抗旱系数,并利用全基因组关联分析技术(Genome-Wide Association Study,GWAS),挖掘与大豆株高和主茎节数抗旱性相关的基因和位点。结果显示:利用1882531个SNP标记进行GWAS分析,DCPH显著关联的位点全部位于9号染色体上,而DCNS显著关联的位点全部位于6号染色体上。进一步分析确定了DCPH和DCNS的候选基因区间,分别筛选出41个与DCPH相关的候选基因和15个与DCNS相关的候选基因。这些基因可能参与大豆生长发育的调控、激素信号传导、细胞分裂和生长等过程。本研究不仅为深入解析大豆抗旱性的分子机制提供了重要线索,还为培育抗旱性强的大豆品种提供了宝贵的基因资源。
文摘选用美棉33B和泗棉3号两个叶色深浅差异明显的品种,设置氮素水平(0、120、240、360和480 kg hm-2纯氮)试验,研究棉花主茎叶SPAD值的叶位分布,对棉花进行氮素营养诊断。结果表明,棉花主茎顶部4张定型叶片的SPAD值对施氮水平反应的敏感程度存在显著差异,随施氮量增加,棉花主茎顶1、2、3、4定型叶SPAD值的大小位次发生明显变化,其中以顶1定型叶对施氮量增加的响应最为敏感,顶4定型叶最为迟钝。利用顶1定型叶与顶4定型叶SPAD值的相对差值,可较精确地诊断棉花的氮素营养水平,并能克服品种和生育时期不同的影响,是一种具有普适性的棉花氮素营养诊断指标。
