Roots from beech (Fagus sylvatica L.) and ash (Fraxinus excelsior L.) differentially affect soil microorganisms and carbon dynamics
Roots from beech (Fagus sylvatica L.) and ash (Fraxinus excelsior L.) differentially affect soil microorganisms and carbon dynamics
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DOI：
10.1016/j.soilbio.2013.02.003
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发表时间：
2013-06-01
影响因子：
9.7
通讯作者：
Scheu, Stefan
中科院分区：
文献类型：
--
作者：
Cesarz, Simone;Fender, Ann-Catrin;Scheu, Stefan
关于活根对土壤分解过程的影响的知识很少，但需要了解土壤中的碳动态。我们研究了中欧森林植被中的优势落叶乔木--欧洲山毛榉(Fagus Halvatica L)和欧洲白蜡树(Fraxinus Excelsior L)对土壤生物群和碳动态的影响，并区分了根和叶凋落物介导的影响。以富含C-13和N-15的枯枝落叶为材料，研究了山毛榉和白蜡树苗木、混合树种和不种植植物对照的双分根根管中C-13和N-15含量的变化。利用稳定同位素和化合物特定脂肪酸分析(C-13-PLFA)跟踪稳定同位素在微生物、土壤动物和植物中的掺入。利用16S rRNA基因扩增产物的焦磷酸测序分析细菌群落组成。虽然山毛榉根系生物量显着低于水曲柳，但培养475天后，只有山毛榉显著降低了土壤碳、氮浓度。此外，山毛榉显著降低了微生物碳的利用效率，表现为较高的比呼吸量。较低的土壤pH可能会增加细菌的比呼吸量，这表明山毛榉根系沉积诱导了微生物呼吸量的增加，从而导致了土壤碳的损失。与山毛榉三角洲C-13和三角洲N-15相比，灰树根际革螨的特征量显着较高，表明凋落物来源的碳和氮含量较高，从而达到较高的营养水平。细菌和细根的相似的增量C-13特征表明，主要是细菌在山毛榉根际生物体内吸收了根源碳。结果表明，山毛榉和灰木对土壤过程的影响不同，山毛榉通过根系分泌物以及与之相关的根际微生物和碳动态的变化，对地下系统的影响比山毛榉更强烈。(C)2013爱思唯尔有限公司。保留所有权利。
Knowledge about the influence of living roots on decomposition processes in soil is scarce but is needed to understand carbon dynamics in soil. We investigated the effect of dominant deciduous tree species of the Central European forest vegetation, European beech (Fagus sylvatica L) and European ash (Fraxinus excelsior L), on soil biota and carbon dynamics differentiating between root- and leaf litter-mediated effects. The influence of beech and ash seedlings on carbon and nitrogen flow was investigated using leaf litter enriched in C-13 and N-15 in double split-root rhizotrons planted with beech and ash seedlings as well as a mixture of both tree species and a control without plants. Stable isotope and compound-specific fatty acid analysis (C-13-PLFA) were used to follow the incorporation of stable isotopes into microorganisms, soil animals and plants. Further, the bacterial community composition was analyzed using pyrosequencing of 16S rRNA gene amplicons. Although beech root biomass was significantly lower than that of ash only beech significantly decreased soil carbon and nitrogen concentrations after 475 days of incubation. In addition, beech significantly decreased microbial carbon use efficiency as indicated by higher specific respiration. Low soil pH probably increased specific respiration of bacteria suggesting that rhizodeposits of beech roots induced increased microbial respiration and therefore carbon loss from soil. Compared to beech delta C-13 and delta N-15 signatures of gamasid mites in ash rhizotrons were significantly higher indicating higher amounts of litter-derived carbon and nitrogen to reach higher trophic levels. Similar delta C-13 signatures of bacteria and fine roots indicate that mainly bacteria incorporated root-derived carbon in beech rhizotrons. The results suggest that beech and ash differentially impact soil processes with beech more strongly affecting the belowground system via root exudates and associated changes in rhizosphere microorganisms and carbon dynamics than ash. (C) 2013 Elsevier Ltd. All rights reserved.