仓储生态因子和烟叶化学成分的改变直接影响烟叶微生物群落结构和功能。以储存在贵阳库(GY)、坛厂库(TC)及紫云库(ZY)的云南保山C3F烟叶为研究对象,对不同陈化时间(0、6、12、18、24个月)的烟叶样品提取微生物总DNA,利用Illumina Hi Se...仓储生态因子和烟叶化学成分的改变直接影响烟叶微生物群落结构和功能。以储存在贵阳库(GY)、坛厂库(TC)及紫云库(ZY)的云南保山C3F烟叶为研究对象,对不同陈化时间(0、6、12、18、24个月)的烟叶样品提取微生物总DNA,利用Illumina Hi Seq平台对细菌的16S rRNA V4区进行高通量测序,并结合主要化学成分分析,以期揭示烟叶陈化过程中细菌群落演替规律及其与烟叶化学成分间的作用关系。研究结果表明,烟叶细菌群落以假单胞菌属、鞘氨醇单胞菌属、寡养单胞菌属、芽孢杆菌属为优势属;随陈化时间的增加,细菌优势群落呈现出变形菌门和厚壁菌门间消长变化的趋势,陈化后期芽孢杆菌(厚壁菌门)优势度明显增强;烟叶陈化过程中,细菌优势功能群变化与化学成分逐级降解间呈显著的相关关系,主要表现为由降解糖类菌群向降解淀粉类菌群,再向降解纤维素类菌群变化的趋势;其中,影响菌群演替的关键因素是水溶性总糖和纤维素。研究结果揭示了在烟叶陈化过程中存在显著的细菌群落演替特征,加深了对烟叶陈化机制的理解,为微生物调控烟叶陈化过程提供了科学依据。展开更多
Four months after the Wenchuan M_s 8 earthquake in western Sichuan,China,in situ stress measurements were carried out along the Longmenshan fault zone with the purpose of obtaining stress parameters for earthquake haz...Four months after the Wenchuan M_s 8 earthquake in western Sichuan,China,in situ stress measurements were carried out along the Longmenshan fault zone with the purpose of obtaining stress parameters for earthquake hazard assessment.In-situ stresses were measured in three new boreholes by using overcoring with the piezomagnetic stress gauges for shallow depths and hydraulic fracturing for lower depths.The maximum horizontal stress in shallow depths(～20 m) is about 4.3 MPa,oriented N19°E,in the epicenter area at Yingxiu Town,about 9.7 MPa,oriented N51°W,at Baoxing County in the southwestern Longmenshan range,and about 2.6 MPa,oriented N39°E,near Kangding in the southernmost zone of the Longmenshan range.Hydraulic fracturing at borehole depths from 100 to 400 m shows a tendency towards increasing stress with depth.A comparison with the results measured before the Wenchuan earthquake along the Longmenshan zone and in the Tibetan Plateau demonstrates that the stress level remains relatively high in the southwestern segment of the Longmenshan range,and is still moderate in the epicenter zone.These results provide a key appraisal for future assessment of earthquake hazards of the Longmenshan fault zone and the aftershock occurrences of the Wenchuan earthquake.展开更多
文摘仓储生态因子和烟叶化学成分的改变直接影响烟叶微生物群落结构和功能。以储存在贵阳库(GY)、坛厂库(TC)及紫云库(ZY)的云南保山C3F烟叶为研究对象,对不同陈化时间(0、6、12、18、24个月)的烟叶样品提取微生物总DNA,利用Illumina Hi Seq平台对细菌的16S rRNA V4区进行高通量测序,并结合主要化学成分分析,以期揭示烟叶陈化过程中细菌群落演替规律及其与烟叶化学成分间的作用关系。研究结果表明,烟叶细菌群落以假单胞菌属、鞘氨醇单胞菌属、寡养单胞菌属、芽孢杆菌属为优势属;随陈化时间的增加,细菌优势群落呈现出变形菌门和厚壁菌门间消长变化的趋势,陈化后期芽孢杆菌(厚壁菌门)优势度明显增强;烟叶陈化过程中,细菌优势功能群变化与化学成分逐级降解间呈显著的相关关系,主要表现为由降解糖类菌群向降解淀粉类菌群,再向降解纤维素类菌群变化的趋势;其中,影响菌群演替的关键因素是水溶性总糖和纤维素。研究结果揭示了在烟叶陈化过程中存在显著的细菌群落演替特征,加深了对烟叶陈化机制的理解,为微生物调控烟叶陈化过程提供了科学依据。
基金the auspice of National Key Basic Project(973)(granted No.2008CB425702)National Science and Technology Project(granted No.SinoProbe-06)
文摘Four months after the Wenchuan M_s 8 earthquake in western Sichuan,China,in situ stress measurements were carried out along the Longmenshan fault zone with the purpose of obtaining stress parameters for earthquake hazard assessment.In-situ stresses were measured in three new boreholes by using overcoring with the piezomagnetic stress gauges for shallow depths and hydraulic fracturing for lower depths.The maximum horizontal stress in shallow depths(～20 m) is about 4.3 MPa,oriented N19°E,in the epicenter area at Yingxiu Town,about 9.7 MPa,oriented N51°W,at Baoxing County in the southwestern Longmenshan range,and about 2.6 MPa,oriented N39°E,near Kangding in the southernmost zone of the Longmenshan range.Hydraulic fracturing at borehole depths from 100 to 400 m shows a tendency towards increasing stress with depth.A comparison with the results measured before the Wenchuan earthquake along the Longmenshan zone and in the Tibetan Plateau demonstrates that the stress level remains relatively high in the southwestern segment of the Longmenshan range,and is still moderate in the epicenter zone.These results provide a key appraisal for future assessment of earthquake hazards of the Longmenshan fault zone and the aftershock occurrences of the Wenchuan earthquake.
