In isotope 137 Cs tracing studies, it is a premise to determine suitable 137 Cs reference inventory（CRI） plots and the CRI values. Owing to the heterogeneous spatial distribution of 137 Cs deposition in the ground a...In isotope 137 Cs tracing studies, it is a premise to determine suitable 137 Cs reference inventory（CRI） plots and the CRI values. Owing to the heterogeneous spatial distribution of 137 Cs deposition in the ground and diverse, or even irregular, operations in sampling and testing procedures, CRI determination is usually faced with many difficulties and uncertainties. In addition, more difficulties occur in an investigation of a large-scale region because of time constraints and measurement cost limitations. In this study, traditional CRI acquiring methods were summarized first, and then a new complex scheme was established, involving seven core steps and coupling the model estimate and sample measurement. The above CRI determination methodology was implemented in the central-eastern Inner Mongolia Plateau. The case study results showed that the CRI in the dark chestnut soil sub-region, located in the east and south of Xing＇an City, exhibited 2447 Bq·m–2; the CRI in the aeolian sandy soil sub-region, positioned in the south central Tongliao City and central Chifeng City, showed 2430 Bq·m–2; the CRI in the sandy chernozem soil sub-region, situated in the northwestern Chifeng City, presented 2384 Bq·m–2; and the CRI in the chestnut soil sub-region, in the southern Xilin Gol City, was 2368 Bq·m–2. The newly proposed CRI determination scheme was proved effective, and the determined CRI plots and CRI values were convincing. The methodology offered a framework for 137 Cs tracing studies in large-scale regions or long-distance transects.展开更多
Soil seed banks play an important role in the distribution and composition of plant communities in semiarid grassland ecosystems. However, information on how spatial scale influences the spatial heterogeneity of soil ...Soil seed banks play an important role in the distribution and composition of plant communities in semiarid grassland ecosystems. However, information on how spatial scale influences the spatial heterogeneity of soil seed banks in a grassland under grazing disturbance is still lacking. Based on field sampling and greenhouse germination, we measured the species composition and seed density of soil seed banks at different spatial scales （30 mx30 m, 30 mx60 m and 30 mx90 m） along a topographical gradient in a sandy grassland in Horqin Sand Land, Northern China. By applying geostatistical methods, we examined how spatial scale and topography affected the spatial distribution of soil seed banks in the study area. Our results showed that the total number of species in soil seed banks, as well as the number of dominant annuals, increased with the increase of spatial scales. Seed density in soil seed banks decreased with the increase of spatial scales due to an increase in the slopes and relative heights of the sampling points. Geostatistical analysis showed that the relative structural variance （C/（C0＋C）） of seed density and species richness were over 65% for all spatial scales, indicating that these variables had an ob- vious spatial autocorrelation and the spatial structured variance accounted for the largest proportion of the total sample variance. Spatial autocorrelation of seed density in soil seed banks increased with the increase of measured scales, while that of species richness showed a reverse trend. These results suggest that the total number of spe- cies in soil seed banks is spatial scale dependent and lower topography may accommodate more seeds. Spatial distribution of seed density in soil seed banks is also scale dependent due to topographic variation. Grassland management, therefore, needs to consider local grazing disturbance regime, spatial scale and topography.展开更多
为探究一步法基因组最佳线性无偏预测(SSGBLUP)法应用于内蒙古绒山羊育种的选择效果,本研究基于课题组前期积累的健康状况良好的内蒙古绒山羊(阿尔巴斯型)2256只个体的70 K SNP芯片测序数据,收集整理1至8岁个体的绒毛性状(绒长、绒细和...为探究一步法基因组最佳线性无偏预测(SSGBLUP)法应用于内蒙古绒山羊育种的选择效果,本研究基于课题组前期积累的健康状况良好的内蒙古绒山羊(阿尔巴斯型)2256只个体的70 K SNP芯片测序数据,收集整理1至8岁个体的绒毛性状(绒长、绒细和产绒量)生产性能数据和系谱记录,通过设定SSGBLUP法中H逆矩阵的不同矩阵参数(ω,τ)进行基因组育种值估计,并利用五倍交叉验证法评价基因组育种值估计的准确性。结果表明:随着ω的不断增加,SSGBLUP法用于内蒙古绒山羊绒毛性状的基因组育种值估计准确性越高。结合ABLUP和GBLUP的遗传参数估计结果可知,当τ为0.3、ω为0.9时,内蒙古绒山羊绒毛性状的基因组选择准确性较好。其中,绒长的准确性为0.7028,绒细准确性为0.6682,产绒量准确性为0.7131。对SSGBLUP方法的H矩阵选择合适的尺度参数可提高内蒙古绒山羊绒毛性状基因组育种值估计的准确性,加快种群的遗传改良,缩短世代间隔。展开更多
基金National Key Basic Research Program of China（973 Program）,No.2010CB950904 National Natural Science Foundation of China,No.40971223 Knowledge Innovation Project of CAS,No.KZCX2-EW-306
文摘In isotope 137 Cs tracing studies, it is a premise to determine suitable 137 Cs reference inventory（CRI） plots and the CRI values. Owing to the heterogeneous spatial distribution of 137 Cs deposition in the ground and diverse, or even irregular, operations in sampling and testing procedures, CRI determination is usually faced with many difficulties and uncertainties. In addition, more difficulties occur in an investigation of a large-scale region because of time constraints and measurement cost limitations. In this study, traditional CRI acquiring methods were summarized first, and then a new complex scheme was established, involving seven core steps and coupling the model estimate and sample measurement. The above CRI determination methodology was implemented in the central-eastern Inner Mongolia Plateau. The case study results showed that the CRI in the dark chestnut soil sub-region, located in the east and south of Xing＇an City, exhibited 2447 Bq·m–2; the CRI in the aeolian sandy soil sub-region, positioned in the south central Tongliao City and central Chifeng City, showed 2430 Bq·m–2; the CRI in the sandy chernozem soil sub-region, situated in the northwestern Chifeng City, presented 2384 Bq·m–2; and the CRI in the chestnut soil sub-region, in the southern Xilin Gol City, was 2368 Bq·m–2. The newly proposed CRI determination scheme was proved effective, and the determined CRI plots and CRI values were convincing. The methodology offered a framework for 137 Cs tracing studies in large-scale regions or long-distance transects.
基金funded by the National Natural Science Foundation of China(41171414)the Knowledge Innovation Program of Chinese Academy of Sciences(KZCX2-EW-QN313)+2 种基金the National Science and Technology Support Program (2011BAC07B02)the National Basic Research Program of China(2009CB421303)the West Light Foundation of the Chinese Academy of Sciences(0928711001)
文摘Soil seed banks play an important role in the distribution and composition of plant communities in semiarid grassland ecosystems. However, information on how spatial scale influences the spatial heterogeneity of soil seed banks in a grassland under grazing disturbance is still lacking. Based on field sampling and greenhouse germination, we measured the species composition and seed density of soil seed banks at different spatial scales （30 mx30 m, 30 mx60 m and 30 mx90 m） along a topographical gradient in a sandy grassland in Horqin Sand Land, Northern China. By applying geostatistical methods, we examined how spatial scale and topography affected the spatial distribution of soil seed banks in the study area. Our results showed that the total number of species in soil seed banks, as well as the number of dominant annuals, increased with the increase of spatial scales. Seed density in soil seed banks decreased with the increase of spatial scales due to an increase in the slopes and relative heights of the sampling points. Geostatistical analysis showed that the relative structural variance （C/（C0＋C）） of seed density and species richness were over 65% for all spatial scales, indicating that these variables had an ob- vious spatial autocorrelation and the spatial structured variance accounted for the largest proportion of the total sample variance. Spatial autocorrelation of seed density in soil seed banks increased with the increase of measured scales, while that of species richness showed a reverse trend. These results suggest that the total number of spe- cies in soil seed banks is spatial scale dependent and lower topography may accommodate more seeds. Spatial distribution of seed density in soil seed banks is also scale dependent due to topographic variation. Grassland management, therefore, needs to consider local grazing disturbance regime, spatial scale and topography.
文摘为探究一步法基因组最佳线性无偏预测(SSGBLUP)法应用于内蒙古绒山羊育种的选择效果,本研究基于课题组前期积累的健康状况良好的内蒙古绒山羊(阿尔巴斯型)2256只个体的70 K SNP芯片测序数据,收集整理1至8岁个体的绒毛性状(绒长、绒细和产绒量)生产性能数据和系谱记录,通过设定SSGBLUP法中H逆矩阵的不同矩阵参数(ω,τ)进行基因组育种值估计,并利用五倍交叉验证法评价基因组育种值估计的准确性。结果表明:随着ω的不断增加,SSGBLUP法用于内蒙古绒山羊绒毛性状的基因组育种值估计准确性越高。结合ABLUP和GBLUP的遗传参数估计结果可知,当τ为0.3、ω为0.9时,内蒙古绒山羊绒毛性状的基因组选择准确性较好。其中,绒长的准确性为0.7028,绒细准确性为0.6682,产绒量准确性为0.7131。对SSGBLUP方法的H矩阵选择合适的尺度参数可提高内蒙古绒山羊绒毛性状基因组育种值估计的准确性,加快种群的遗传改良,缩短世代间隔。
