Gross primary productivity(GPP)of vegetation is an important constituent of the terrestrial carbon sinks and is significantly influenced by drought.Understanding the impact of droughts on different types of vegetation...Gross primary productivity(GPP)of vegetation is an important constituent of the terrestrial carbon sinks and is significantly influenced by drought.Understanding the impact of droughts on different types of vegetation GPP provides insight into the spatiotemporal variation of terrestrial carbon sinks,aiding efforts to mitigate the detrimental effects of climate change.In this study,we utilized the precipitation and temperature data from the Climatic Research Unit,the standardized precipitation evapotranspiration index(SPEI),the standardized precipitation index(SPI),and the simulated vegetation GPP using the eddy covariance-light use efficiency(EC-LUE)model to analyze the spatiotemporal change of GPP and its response to different drought indices in the Mongolian Plateau during 1982-2018.The main findings indicated that vegetation GPP decreased in 50.53% of the plateau,mainly in its northern and northeastern parts,while it increased in the remaining 49.47%area.Specifically,meadow steppe(78.92%)and deciduous forest(79.46%)witnessed a significant decrease in vegetation GPP,while alpine steppe(75.08%),cropland(76.27%),and sandy vegetation(87.88%)recovered well.Warming aridification areas accounted for 71.39% of the affected areas,while 28.53% of the areas underwent severe aridification,mainly located in the south and central regions.Notably,the warming aridification areas of desert steppe(92.68%)and sandy vegetation(90.24%)were significant.Climate warming was found to amplify the sensitivity of coniferous forest,deciduous forest,meadow steppe,and alpine steppe GPP to drought.Additionally,the drought sensitivity of vegetation GPP in the Mongolian Plateau gradually decreased as altitude increased.The cumulative effect of drought on vegetation GPP persisted for 3.00-8.00 months.The findings of this study will improve the understanding of how drought influences vegetation in arid and semi-arid areas.展开更多
目的通过观察推拿对坐骨神经慢性压迫性损伤(chronic constriction injury of the sciatic nerve,CCI)模型鼠脊髓背角胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)、N-甲基-D-天冬氨酸(N-methyl-D-aspartate,NMDA)受体2B亚...目的通过观察推拿对坐骨神经慢性压迫性损伤(chronic constriction injury of the sciatic nerve,CCI)模型鼠脊髓背角胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)、N-甲基-D-天冬氨酸(N-methyl-D-aspartate,NMDA)受体2B亚基(NR2B)表达的影响,探讨推拿治疗神经病理性疼痛的镇痛机制。方法建立CCI模型,将大鼠分为假手术组、模型组、推拿组,每组12只,采用按摩推拿手法模拟仪定性、定量模拟点法、拨法、揉法,对推拿组大鼠右侧的殷门、承山、阳陵泉穴进行干预,通过机械缩足反射阈值和累计疼痛评分评价大鼠机械痛敏反应和疼痛强度变化;通过透射电镜对大鼠脊髓背角突触超微结构进行观察;采用免疫荧光双重标记法观察脊髓背角GFAP、NR2B的共定位表达。结果推拿可以提高CCI模型鼠机械缩足反射阈值、降低累计疼痛评分(P<0.01);同时也能改变大鼠脊髓背角突触的形态结构:与模型组相比,推拿组脊髓背角突触形态结构恢复,膜较完整、线粒体肿胀程度轻、突触后致密区变长。干预20天后,与模型组比较,推拿组大鼠脊髓背角GFAP、NR2B平均荧光强度显著降低(P<0.05)。结论推拿可以改善大鼠的行为学和形态学结果,改变脊髓背角突触可塑性来抑制痛觉敏化;还可以通过抑制星型胶质细胞活化,降低脊髓背角GFAP和NR2B的表达来镇痛。展开更多
了解植被物候与城市化之间的关系对于认识人类活动对生态系统的影响至关重要。基于呼和浩特市近20 a MODIS的两种植被指数数据,利用动态阈值法提取了植被物候,结合城市化指标,研究了2001—2020年呼和浩特市植被物候对城市化的响应。研...了解植被物候与城市化之间的关系对于认识人类活动对生态系统的影响至关重要。基于呼和浩特市近20 a MODIS的两种植被指数数据,利用动态阈值法提取了植被物候,结合城市化指标,研究了2001—2020年呼和浩特市植被物候对城市化的响应。研究表明:森林和灌木地返青期(Start of growing season,SOS)发生较早(平均值第132 d),但其枯黄期(End of growing season,EOS)也较早(第265 d)。SOS较晚的是耕地(第168 d),EOS较晚的是草地(第275 d),表明研究区木本植物SOS和EOS均早于草本植物。人造地表植被物候年际变化较大,在SOS和EOS的物候变化率分别为每10 a提前4.1 d和推迟0.7 d。此外,以人造地表比率和城乡梯度信息(即从城市核心到周边农村地区的同心环)为城市化指标,探讨了呼和浩特市中心城区植被物候对城市化的响应。研究发现SOS随人造地表比率上升而提前,EOS则出现相反的趋势。从城乡梯度上看,在特定范围内,远离城市中心SOS波动上升,即距城市中心越远植被SOS越晚,而EOS逐渐下降,即距城市中心越远植被EOS越早。总之,不同的城市化指标显示了植被物候对城市化的非线性响应。展开更多
基金jointly supported by the National Natural Science Foundation of China(42361024,42101030,42261079,and 41961058)the Talent Project of Science and Technology in Inner Mongolia of China(NJYT22027 and NJYT23019)the Fundamental Research Funds for the Inner Mongolia Normal University,China(2022JBBJ014 and 2022JBQN093)。
文摘Gross primary productivity(GPP)of vegetation is an important constituent of the terrestrial carbon sinks and is significantly influenced by drought.Understanding the impact of droughts on different types of vegetation GPP provides insight into the spatiotemporal variation of terrestrial carbon sinks,aiding efforts to mitigate the detrimental effects of climate change.In this study,we utilized the precipitation and temperature data from the Climatic Research Unit,the standardized precipitation evapotranspiration index(SPEI),the standardized precipitation index(SPI),and the simulated vegetation GPP using the eddy covariance-light use efficiency(EC-LUE)model to analyze the spatiotemporal change of GPP and its response to different drought indices in the Mongolian Plateau during 1982-2018.The main findings indicated that vegetation GPP decreased in 50.53% of the plateau,mainly in its northern and northeastern parts,while it increased in the remaining 49.47%area.Specifically,meadow steppe(78.92%)and deciduous forest(79.46%)witnessed a significant decrease in vegetation GPP,while alpine steppe(75.08%),cropland(76.27%),and sandy vegetation(87.88%)recovered well.Warming aridification areas accounted for 71.39% of the affected areas,while 28.53% of the areas underwent severe aridification,mainly located in the south and central regions.Notably,the warming aridification areas of desert steppe(92.68%)and sandy vegetation(90.24%)were significant.Climate warming was found to amplify the sensitivity of coniferous forest,deciduous forest,meadow steppe,and alpine steppe GPP to drought.Additionally,the drought sensitivity of vegetation GPP in the Mongolian Plateau gradually decreased as altitude increased.The cumulative effect of drought on vegetation GPP persisted for 3.00-8.00 months.The findings of this study will improve the understanding of how drought influences vegetation in arid and semi-arid areas.
文摘目的通过观察推拿对坐骨神经慢性压迫性损伤(chronic constriction injury of the sciatic nerve,CCI)模型鼠脊髓背角胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)、N-甲基-D-天冬氨酸(N-methyl-D-aspartate,NMDA)受体2B亚基(NR2B)表达的影响,探讨推拿治疗神经病理性疼痛的镇痛机制。方法建立CCI模型,将大鼠分为假手术组、模型组、推拿组,每组12只,采用按摩推拿手法模拟仪定性、定量模拟点法、拨法、揉法,对推拿组大鼠右侧的殷门、承山、阳陵泉穴进行干预,通过机械缩足反射阈值和累计疼痛评分评价大鼠机械痛敏反应和疼痛强度变化;通过透射电镜对大鼠脊髓背角突触超微结构进行观察;采用免疫荧光双重标记法观察脊髓背角GFAP、NR2B的共定位表达。结果推拿可以提高CCI模型鼠机械缩足反射阈值、降低累计疼痛评分(P<0.01);同时也能改变大鼠脊髓背角突触的形态结构:与模型组相比,推拿组脊髓背角突触形态结构恢复,膜较完整、线粒体肿胀程度轻、突触后致密区变长。干预20天后,与模型组比较,推拿组大鼠脊髓背角GFAP、NR2B平均荧光强度显著降低(P<0.05)。结论推拿可以改善大鼠的行为学和形态学结果,改变脊髓背角突触可塑性来抑制痛觉敏化;还可以通过抑制星型胶质细胞活化,降低脊髓背角GFAP和NR2B的表达来镇痛。
