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Phenotypic plasticity of Artemisia ordosica seedlings in response to different levels of calcium carbonate in soil 被引量:1
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作者 XUE Pingping ZHAO Xuelai +1 位作者 GAO Yubao he xingdong 《Journal of Arid Land》 SCIE CSCD 2019年第1期58-65,共8页
Plant phenotypic plasticity is a common feature that is crucial for explaining interspecific competition, dynamics and biological evolution of plant communities. In this study, we tested the effects of soil CaCO_3(cal... Plant phenotypic plasticity is a common feature that is crucial for explaining interspecific competition, dynamics and biological evolution of plant communities. In this study, we tested the effects of soil CaCO_3(calcium carbonate) on the phenotypic plasticity of a psammophyte, Artemisia ordosica, an important plant species on sandy lands in arid and semi-arid areas of China, by performing pot experiments under different CaCO_3 contents with a two-factor randomized block design and two orthogonal designs. We analyzed the growth responses(including plant height, root length, shoot-leaf biomass and root biomass) of A. ordosica seedlings to different soil CaCO_3 contents. The results revealed that, with a greater soil CaCO_3 content, A. ordosica seedlings gradually grew more slowly, with their relative growth rates of plant height, root length, shoot-leaf biomass and root biomass all decreasing significantly. Root N/P ratios showed significant negative correlations with the relative growth rates of plant height, shoot-leaf biomass and root length of A. ordosica seedlings; however, the relative growth rate of root length increased significantly with the root P concentration increased, showing a positive correlation. These results demonstrate that soil CaCO_3 reduces the local P availability in soil, which produces a non-adaptive phenotypic plasticity to A. ordosica seedlings. This study should prove useful for planning and promoting the restoration of damaged/degraded vegetation in arid and semi-arid areas of China. 展开更多
关键词 ARTEMISIA ORDOSICA N/P ratio PHENOTYPIC plasticity relative growth rate SOIL CaCO3 SOIL P availability ARID and SEMI-ARID areas
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新发展格局下我国生鲜农产品流通体系运行机理与重构对策 被引量:2
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作者 贺兴东 高君宇 《商业经济研究》 北大核心 2023年第14期5-8,共4页
生鲜农产品流通事关国民生计,是构建新发展格局的重要支撑,本文通过分析构建新发展格局对我国生鲜农产品流通的新要求,剖析了生鲜农产品流通运行的主要问题,重点研究了新发展格局下我国生鲜农产品流通运行机理,提出了推动我国生鲜农产... 生鲜农产品流通事关国民生计,是构建新发展格局的重要支撑,本文通过分析构建新发展格局对我国生鲜农产品流通的新要求,剖析了生鲜农产品流通运行的主要问题,重点研究了新发展格局下我国生鲜农产品流通运行机理,提出了推动我国生鲜农产品流通体系重构的对策建议。 展开更多
关键词 生鲜农产品 流通体系 运行机理 供需适配
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平茬处理对小叶锦鸡儿灌丛邻居植物群落空间格局的影响 被引量:12
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作者 丁新峰 郝广 +6 位作者 董轲 王宇坤 高韶勃 陈磊 何兴东 赵念席 高玉葆 《生态学报》 CAS CSCD 北大核心 2019年第11期4011-4020,共10页
近几十年来,内蒙古典型草原小叶锦鸡儿(Caragana microphylla)灌丛化现象普遍发生,严重影响了草地生产力。平茬作为灌丛化草地主要管理方式之一,已受到广泛关注;然而平茬如何影响灌丛邻居植物群落的格局动态及其下土壤理化性质变化,仍... 近几十年来,内蒙古典型草原小叶锦鸡儿(Caragana microphylla)灌丛化现象普遍发生,严重影响了草地生产力。平茬作为灌丛化草地主要管理方式之一,已受到广泛关注;然而平茬如何影响灌丛邻居植物群落的格局动态及其下土壤理化性质变化,仍缺少相应研究。以内蒙古草原小叶锦鸡儿灌丛化草地为研究对象,进行平茬处理,并依据距离小叶锦鸡儿灌丛的远近位置(远-2.5 m,近-0.5 m)设置样方进行植物群落调查和土壤样品的采集,经分析发现:(1)平茬处理显著提高了灌丛邻居植物群落均匀度及邻居植物群落下土壤全碳、全氮含量。(2)借助零模型(Null-model)分析,得出未平茬处理条件下,距离灌丛远近两种位置群落均表现为竞争性格局;而平茬处理条件下,群落竞争性格局作用弱化,且距离灌丛2.5 m位置处群落表现为促进性格局。(3)调查群落中物种间的关系多为中性作用;仅有少数物种对表现为显著正(或负)相互作用关系,且多由群落中优势物种组成;平茬处理条件下群落中显著负相互作用关系物种对比例下降,支持群落整体竞争性格局弱化这一结论。所得结果不仅为小叶锦鸡儿灌丛平茬处理条件下邻居植物群落及土壤环境的动态变化的探讨提供了实验依据,而且对灌丛化草地的恢复具有一定的实践指导意义。 展开更多
关键词 小叶锦鸡儿 平茬处理 零模型 空间分布格局 物种对 种间关系
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沙地土壤C∶N∶P比对早期植物群落物种多样性的影响 被引量:13
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作者 杨祥祥 李梦琦 +4 位作者 何兴东 尤万学 余殿 张彩华 陈娜 《土壤学报》 CAS CSCD 北大核心 2019年第1期242-249,共8页
为揭示土壤碳∶氮∶磷(C∶N∶P)比对植物群落物种多样性的影响,以宁夏哈巴湖国家级自然保护区内沙地植物群落(沙柳群落和油蒿群落)为研究对象,调查计算了沙地植物群落的物种多样性,测定了群落中土壤C、N、P含量,分析讨论了土壤C∶N∶P... 为揭示土壤碳∶氮∶磷(C∶N∶P)比对植物群落物种多样性的影响,以宁夏哈巴湖国家级自然保护区内沙地植物群落(沙柳群落和油蒿群落)为研究对象,调查计算了沙地植物群落的物种多样性,测定了群落中土壤C、N、P含量,分析讨论了土壤C∶N∶P比与沙地植物群落物种多样性之间的关系。结果表明,分布于流动、半固定沙地的沙柳群落其土壤C∶N∶P比对物种多样性的影响不显著,而分布于半固定、固定沙地的油蒿群落其土壤C∶N∶P比对物种多样性的影响显著。这说明沙地植物群落生物量不断增大的同时,枯枝落叶增多,土壤C、N、P显著增多,较大的土壤C∶N比与N∶P比与不断增大的物种多样性有趋同变化,因此,土壤的C∶N∶P比能够影响沙地植物群落的物种多样性。 展开更多
关键词 沙地植物群落 土壤C∶N∶P比 物种多样性 宁夏哈巴湖国家级自然保护区
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Effects of soil stoichiometry of the CaCO_3/available phosphorus ratio on plant density in Artemisia ordosica communities 被引量:2
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作者 ZHAO XueLai he xingdong +7 位作者 XUE PingPing ZHANG Ning WU Wei LI Rong CI HuaCong XU JingJing GAO YuBao ZHAO HaLin 《Chinese Science Bulletin》 SCIE CAS 2012年第5期492-499,共8页
In soil, CaCO3 can reduce the availability of phosphorus in arid and semi-arid regions, thereby influencing plant growth. However, the effects of soil stoichiometry of the CaCO3/available phosphorus ratio (CaCO3/AP ra... In soil, CaCO3 can reduce the availability of phosphorus in arid and semi-arid regions, thereby influencing plant growth. However, the effects of soil stoichiometry of the CaCO3/available phosphorus ratio (CaCO3/AP ratio) on plant density are unknown. In this study, we examined 4 Artemisia ordosica communities located in arid and semi-arid regions, and performed a pot experiment with an orthogonal design to examine the relationships between the soil CaCO3/AP ratio and plant density. The results showed that the soil stoichiometry of the CaCO3/AP ratio had a greater effect on growth of A. ordosica than either CaCO3 or AP as single factor. The influence of the soil CaCO3/AP ratio on density of A. ordosica was related to the climatic zone and the types and/or amplitudes of increases in the soil CaCO3/AP ratio. When the soil CaCO3/AP ratio was within the same amplitude and was less than 2.5, the A. ordosica density increased in the semi-arid region, whereas the density decreased with increasing soil CaCO3/AP ratios in the arid region. In the semi-arid region, when the soil CaCO3/AP ratio was within the same amplitude and the increase in the soil CaCO3 content was greater than the increase in soil AP, the A. ordosica density increased with increasing soil CaCO3/AP ratios. This means that the relationship between the soil CaCO3/AP ratio and the A. ordosica density remained the same. In the arid region, an increase in the soil CaCO3/AP ratio as a result of increased soil CaCO3 content and decreased soil AP resulted in increased density of A. ordosica. Therefore, the relationship between soil CaCO3/AP ratios and density of A. ordosica was altered by these changes in soil chemistry. Thus, the soil stoichiometry of the CaCO3/AP ratio is an important factor affecting the density of A. ordosica in arid and semi-arid regions. 展开更多
关键词 化学计量学 土壤化学 种植密度 油蒿群落 半干旱地区 碳酸钙含量 CaCO3含量 比例
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中美流通成本比较及建议
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作者 高君宇 贺兴东 《宏观经济管理》 北大核心 2023年第5期83-90,共8页
流通成本由物流环节成本和交易环节成本构成。我国宏观物流成本约为美国的2倍,主要与国土空间特点、资源禀赋与产业结构差异有关,受流通体系自身影响较小。我国单位物流活动成本约为美国的二分之一,原因在于充分竞争的物流市场和相对低... 流通成本由物流环节成本和交易环节成本构成。我国宏观物流成本约为美国的2倍,主要与国土空间特点、资源禀赋与产业结构差异有关,受流通体系自身影响较小。我国单位物流活动成本约为美国的二分之一,原因在于充分竞争的物流市场和相对低下的企业利润率水平。我国线上电商渠道流通活动的交易环节成本低于美国5~10个百分点,线下商超渠道流动活动的交易环节成本约为美国的40%,原因在于较低的人力、物流、平台运营等要素投入成本。建议坚持标本兼治、长短结合的流通降本增效思路。当务之急,应从加大助企纾困政策力度、改善营商环境入手,出硬招实招,助流通企业企稳向好。同时,针对短板环节,增强流通与生产消费的空间匹配度,提升流通运行全程组织化水平,推广扁平化流通渠道模式,降低流通企业经营的制度性成本,扩大流通成本优势。远期着眼优化流通体系,构建内畅外联流通网络,畅通现代流通发展链条,推动流通业态模式创新,推动流通顶层设计落地,建立促进我国流通综合降本增效长效机制。 展开更多
关键词 现代流通体系 流通成本 中美比较
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沙地植物群落功能多样性对物种多样性的影响 被引量:4
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作者 杨祥祥 李梦琦 +4 位作者 何兴东 尤万学 余殿 张彩华 陈娜 《南开大学学报(自然科学版)》 CAS CSCD 北大核心 2020年第4期75-80,共6页
功能多样性作为生物多样性的一个组分,它主要反映群落中物种间功能的差异程度,它是独立的,与传统生物多样性之间相互作用相互影响.为探讨沙地植物群落功能多样性对物种多样性的影响,调查了宁夏哈巴湖国家级自然保护区沙化封禁区37个群... 功能多样性作为生物多样性的一个组分,它主要反映群落中物种间功能的差异程度,它是独立的,与传统生物多样性之间相互作用相互影响.为探讨沙地植物群落功能多样性对物种多样性的影响,调查了宁夏哈巴湖国家级自然保护区沙化封禁区37个群落的物种多样性,测定分析了每一个群落中各植物的C、N、P含量,计算了物种多样性和功能多样性.结果表明,物种多样性Shannon-Wiener指数Simpson指数与功能均匀度和功能多样性Rao's二次熵指数之间有极显著的正相关关系,随功能均匀度指数和功能多样性指数的增大,物种多样性呈幂函数形式增大,但物种多样性与功能分歧度之间没有显著的相关关系.这表明,功能多样性能够影响群落的物种多样性. 展开更多
关键词 生物多样性 物种多样性 功能多样性 植物群落 沙地
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Drought resistance of four grasses using pressure-volume curve
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作者 he xingdong CONG Peifang +4 位作者 GAO Yubao LU Jianguo WANG Haitao XUE Pingping ZHANG Xu 《Frontiers in Biology》 CSCD 2007年第4期425-430,共6页
Pressure-volume curve(PV curve)technique is a major method for studying critical plant water potential and critical tissue water content when plasmolysis takes place.In the present study,a mathematical solution method... Pressure-volume curve(PV curve)technique is a major method for studying critical plant water potential and critical tissue water content when plasmolysis takes place.In the present study,a mathematical solution method is put forward to obtain parameters based on the PV curve.The cal-culated results for the parameters of Lolium perenne,Festuca arundinacea,Leymus chinensis and Stipa krylovii indicated that the mathematical solution method is convenient for actual research compared with the graphical method.Further analysis of the calculations suggested that drought resistance decreased in the following order:S.krylovii>F.arundinacea and L.chinensis>L.perenne. 展开更多
关键词 pressure-volume curve water potential of plant PLASMOLYSIS index of drought resistance
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