Atmospheric nitrogen deposition has complex effects on individual plants and terrestrial ecosystems. We synthesized results from 39 published papers (16 papers in English and 23 papers in Chinese) and conducted a meta-analysis to evaluate the general responses of tree root traits to nitrogen addition, and further analyzed the difference of N-induced results between English papers and Chinese papers. Our results showed that N addition significantly increased fine root diameter (+6.7%), fine root N content (+8.9%), and root respiration rate (+17.5%), but did not affect fine root biomass, fine root length, specific root length, fine root C content, and fine root C:N ratio. Different climatic zone and fertilizer types had different effects on the experimental results. In addition, experimental results published in English papers were generally more significant than those in Chinese papers. We summarized the general effects of N addition on tree root systems, and further analyzed the mechanisms underlying the effects of N enrichment on forest ecosystem carbon cycle.
大气氮沉降对植物个体及整个生态系统都具有复杂的影响.本文共搜集39篇(16篇英文、23篇中文)已发表期刊论文的数据,通过整合分析方法分析了氮添加对树木根系特性的影响,并对比了发表在中、英文期刊上的结果差异.结果表明: 氮添加显著增加了细根直径(+6.7%)、细根氮含量(+8.9%)和细根呼吸速率(+17.5%),对细根生物量、细根长度、比根长、细根碳含量以及细根碳氮比的影响并不显著.不同的气候带类型和肥料类型对试验结果也具有不同的影响.另外,发表于英文期刊的试验结果的显著性普通高于发表在中文期刊上的结果.本文总结了氮添加对树木根系特性影响的普适性规律,以此分析了氮添加对森林生态系统碳循环影响的主要机理.
Keywords: autotrophic respiration; forest ecosystem; nitrogen addition; root biomass; root morphology.