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作 者 ：周正朝¹;上官周平^1,2

期 刊 ：应用生态学报 2006年 17卷 11期 页码：2175-2178

关键词：红豆；

摘 要 ：在封闭的植物培养箱中，通过盆栽实验，研究了红豆草和土壤氮含量对CO₂浓度增加的响应.结果表明，与正常CO₂浓度(355～370 μmol·mol^-1)相比，CO₂浓度升高(700 μmol·mol^-1)，植物生物量增加25.1%(P＜0.01)，但植物体氮浓度降低25.3%(P＜0.001)，植物全氮没有显著的变化.经3个月盆栽实验后，与原始土壤相比，两种CO₂浓度处理土壤全N、NO₃^--N和NH₄⁺-N都有所降低，而土壤微生物氮则显著增加，这可能与植物生长有关.不同CO₂浓度处理土壤NH₄⁺-N浓度基本一致，但在高CO₂浓度下，土壤NO₃^--N浓度显著降低，而微生物生物氮显著增加.对整个土壤-植物系统而言，盆栽实验后，整个系统全氮有少量增加，但变化不显著，特别是在高CO₂浓度条件下，土壤-植物系统全氮最大，这可能与培养材料红豆草为豆科植物，而且在高CO₂浓度下生物量增加，导致氮的固定量增加有关.

Abstract:The effects of elevated CO₂ on terrestrial ecosystem processes are highly
related to the N cycling in the ecosystem. In two closed chambers with different
CO₂ concentration (ambient CO₂ 355～370 μmol·mol^-1, and elevated CO₂ 700 μmol·mol^-1), pot experiments were conducted to study the responses of Onobrychis viciaefolia Scop and soil nitrogen contents to elevated CO₂. The
results showed that compared with ambient CO₂, elevated CO₂ increased the
plant dry biomass by 25.1% (P<0.01), but decreased the plant N concentration
by 25.3% (P<0.001), resulting in little change of total plant N. After three
months experiment, soil total N, NO₃^--N and NH₄⁺-N under both ambient and elevated CO₂ conditions decreased, while soil microbial biomass N increased
significantly. Soil NH₄⁺-N concentration had little difference under ambient and elevated CO₂ conditions, but under elevated CO₂ condition, soil NO₃^--N concentration decreased significantly, while microbial biomass N increased
significantly. By the end of the experiment, the total N content of whole soil-plant ecosystem had a slight increase, especially under elevated CO₂
condition, which was probably due to the higher N-fixation capability of O. viciaefolia Scop under CO₂ enrichment.

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