Heterogeneity of soil salinity is a prominent environmental characteristic in the intertidal zone of estuaries,affecting the plant growth and the shift of biotic interactions in the salt marsh.This study aims to exami...Heterogeneity of soil salinity is a prominent environmental characteristic in the intertidal zone of estuaries,affecting the plant growth and the shift of biotic interactions in the salt marsh.This study aims to examine the interactive effects of a salinity gradient and salinity fluctuations on intraspecific interactions of a euhalophyte.We assessed the impact of daily fluctuating salinity on the outcome of intraspecific interactions by cultivating seeds of Suaeda salsa(Chenopodiaceae)in river sand.The experiment was conducted in a greenhouse with three treatments:daily salinity fluctuations(static and fluctuating salinity),a salinity gradient(200 and 400 mmol L^(−1))and three planting densities(1,2 and 4 plants/pot).First,height and biomass of plants were measured at both the start and end of the experiment.Then,the growth indexes and log response ratio of S.salsa were analyzed.The outcome of intraspecific interactions of S.salsa shifted from competition in low salinity to facilitation in high salinity,and high conspecific density strengthened the competition and facilitation intensities.Daily salinity fluctuation did not significantly affect the plant growth and the outcome of intraspecific interactions,but did have a significant influence on belowground biomass.Our results suggest that the stress-gradient hypothesis may apply to predicting the variation of the intraspecific relationship of a salt-tolerant species along a salinity gradient,and the magnitude of this variation is density dependent.These findings help us understand how individuals and populations of a euhalophyte species respond to the natural variation or human modification of salinity conditions.展开更多
文摘目的探讨无症状低血糖2型糖尿病患者血糖波动特点及危险因素。方法选取2018年9月至2021年7月在安徽医科大学附属合肥医院内分泌科住院的2型糖尿病患者342例。通过连续动态血糖监测(continuous glucose monitoring,CGM)获取日内平均血糖波动幅度(mean amplitude of glycemic excursions,MAGE)、血糖变异系数(coefficient of variation,CV)、24 h平均血糖水平(24 hour mean blood glucose level,MG)、血糖在目标范围内时间(time in range,TIR)等相关指标,根据CGM结果及患者有无低血糖症状,分为无低血糖组、有症状低血糖组和无症状低血糖组;比较3组间血糖波动的差异;采用logistic回归分析2型糖尿病患者发生无症状低血糖的危险因素,通过受试者工作特征曲线分析MAGE对无症状低血糖的预测价值。结果与无低血糖组相比,无症状低血糖组TIR更高(Z=-2.042,P=0.041);与无低血糖组和有症状低血糖组相比,无症状低血糖组MG更低,MAGE和CV更高(均P<0.05)。多因素logistic回归分析显示,尿白蛋白/肌酐比值(urinary albumin/creatinine ratio,UACR)、MAGE、CV为无症状低血糖的危险因素,MG为保护因素。进一步校正其他危险因素,MAGE与无症状低血糖发生仍密切相关(OR=1.111,95%CI 0.999~1.235,P=0.049)。受试者工作特征曲线结果显示,MAGE对无症状低血糖预测的灵敏度为0.769,特异度为0.776。结论无症状低血糖患者血糖波动的特点为具有更高的TIR值,但MAGE更大,MAGE、UACR、CV为无症状低血糖的危险因素,且MAGE对无症状低血糖的发生有一定的预测价值。
基金supported by the Fundamental Research Funds for the Central Non-Profit Research Institution of Chinese Academy of Forestry(CAFYBB2016SY034,key technologies of functional restoration and directional improvement of mudflat wetland)the National Key R&D Program of China(2017YFC0506200)the Research on the synchronicity of dichogamy in Scirpus planiculmis based on population clonal structure(NSFC31800348).
文摘Heterogeneity of soil salinity is a prominent environmental characteristic in the intertidal zone of estuaries,affecting the plant growth and the shift of biotic interactions in the salt marsh.This study aims to examine the interactive effects of a salinity gradient and salinity fluctuations on intraspecific interactions of a euhalophyte.We assessed the impact of daily fluctuating salinity on the outcome of intraspecific interactions by cultivating seeds of Suaeda salsa(Chenopodiaceae)in river sand.The experiment was conducted in a greenhouse with three treatments:daily salinity fluctuations(static and fluctuating salinity),a salinity gradient(200 and 400 mmol L^(−1))and three planting densities(1,2 and 4 plants/pot).First,height and biomass of plants were measured at both the start and end of the experiment.Then,the growth indexes and log response ratio of S.salsa were analyzed.The outcome of intraspecific interactions of S.salsa shifted from competition in low salinity to facilitation in high salinity,and high conspecific density strengthened the competition and facilitation intensities.Daily salinity fluctuation did not significantly affect the plant growth and the outcome of intraspecific interactions,but did have a significant influence on belowground biomass.Our results suggest that the stress-gradient hypothesis may apply to predicting the variation of the intraspecific relationship of a salt-tolerant species along a salinity gradient,and the magnitude of this variation is density dependent.These findings help us understand how individuals and populations of a euhalophyte species respond to the natural variation or human modification of salinity conditions.
