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我国环境土壤中的重要超铀核素分布 被引量:3
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作者 郭秋菊 倪有意 李思璇 《原子能科学技术》 EI CAS CSCD 北大核心 2019年第10期2083-2091,共9页
Pu、Am、Np是3种重要的超铀核素,环境中的这些核素主要来源于人类的核活动,包括大气层核武器试验、核设施排放和核事故释放等。这些超铀核素不仅具有放射性,还兼具化学毒性。我国地域辽阔,环境土壤类型丰富,在当前核电事业蓬勃发展的背... Pu、Am、Np是3种重要的超铀核素,环境中的这些核素主要来源于人类的核活动,包括大气层核武器试验、核设施排放和核事故释放等。这些超铀核素不仅具有放射性,还兼具化学毒性。我国地域辽阔,环境土壤类型丰富,在当前核电事业蓬勃发展的背景下,建立和扩大我国环境土壤中这些重要超铀核素的“准本底”数据库是辐射环境安全评价的重要组成部分,也是公众关心的热点问题。近30多年来,研究人员对我国不同环境土壤中这几种超铀核素从不同科学角度开展了调查测量研究。本文对此进行整理和分析,对我国环境土壤中这些重要超铀核素(主要是Pu核素,还包括241Am和237Np)的来源、浓度水平和分布特征进行讨论和综述,为辐射环境安全评价奠定基础。 展开更多
关键词 土壤 Pu核素 241Am 237Np 分布特征 全球沉降 中国核试验
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Native woody legumes respond more negatively to extreme drought than invasive ones 被引量:4
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作者 Zhengkuan Lu Xue Zhang +1 位作者 Hongxiang Zhang Yanjie Liu 《Journal of Plant Ecology》 SCIE CSCD 2022年第3期485-493,共9页
Plant invasion potentially will be affected by increased extreme drought events and deposition of atmospheric N.However,results from previous research indicate that it is not clear as to how extreme drought,N depositi... Plant invasion potentially will be affected by increased extreme drought events and deposition of atmospheric N.However,results from previous research indicate that it is not clear as to how extreme drought,N deposition and their interaction affect alien plant invasion,in particular for the invasive woody legumes.We conducted a greenhouse experiment with three invasive and three native woody species of legumes(Fabaceae).We grew plants in extreme drought and in well-watered conditions combined with low and high levels of N and compared plant height,number of leaves and biomass production and allocation.Growth of native woody legumes was suppressed more by extreme drought than that of invasive woody legumes.Although an increase in soil N availability decreased the root mass fraction of plants of all species,it did not affect their overall performance.We found that invasive woody legumes can tolerate the adverse effects of the prolonged extreme drought better than native woody legumes.These results enhance our understanding of the effects of drought due to climate change on the invasion of alien woody legumes. 展开更多
关键词 FABACEAE global warming N deposition plant invasion water availability
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Neutral responses of plant community Ca concentration to nitrogen enrichment in a semiarid grassland 被引量:1
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作者 Shuang-Li Hou Xiao-Tao Lü Jun-Jie Yang 《Journal of Plant Ecology》 SCIE CSCD 2022年第2期286-293,共8页
Calcium(Ca)is an essential nutrient for plant growth and Ca concentrations in forage have important implications for ruminant diet and health.It remains an open question whether forage Ca concentration would be decrea... Calcium(Ca)is an essential nutrient for plant growth and Ca concentrations in forage have important implications for ruminant diet and health.It remains an open question whether forage Ca concentration would be decreased by increasing nitrogen(N)deposition.We manipulated the increasing rates of N addition(2008–2015)in a semiarid grassland,northern China.Plant Ca concentrations for all species were examined in each plot under N treatment.The Ca concentrations at functional group and community levels were calculated based on the concentration of each species presented and their relative biomass in each plot.We found that community-level Ca concentration remained stable across a gradient of wide-ranged N addition rates,although Ca concentration at both species and functional group levels showed negative responses to N enrichment.Given that forbs had higher Ca concentration than grasses,the increasing relative biomass of forbs canceled out the negative responses of species-level and functional group-level Ca concentration.Our results further showed that community Ca pool showed a positive but saturating response to N addition,with a threshold at the rate of 10 g N m^(−2)yr^(−1).Our findings highlight the role of changes in plant relative biomass in controlling the responses of forage Ca concentration and stock to N enrichment. 展开更多
关键词 calcium stock community composition ecological processes global changes nitrogen deposition temperate steppe
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