In contrast to climax ecosystems, (3) Gram-positive bacteria obviously play an important role in N-limited soil systems during litter degradation, mainly of the recalcitrant fraction. According to Jenny (1941), a persistent soil
microbial community profile is influenced by different soil-forming factors such as climate, parent material, vegetation and time, which interact with each other closely. BIRB 796 ic50 The results from this study illustrate the importance of vegetation as a soil-forming factor, but suggest that interactions between climate and time should be addressed in future studies. Transferred to in situ conditions, the findings may indicate that L. corniculatus exert a strong influence on the structure of the microbial community through the quality of its litter, which in turn creates nutrient-rich patches under the L. corniculatus vegetation. Such nutrient-rich patches may indirectly facilitate
the colonization with coexisting plants like C. epigejos, which often tolerate nutrient-poor soil conditions, but enhance growth and reproduction rates under N-rich conditions (Brezina et al., 2006; Tůma et al., 2009). The authors thank C. Kollerbaur for the excellent work in the PLFA buy LBH589 analyses and R. Fuß for providing mathematical support. This study is part of the Transregional Collaborative Research Centre 38 (SFB/TRR 38), which is financially supported by the Deutsche Forschungsgemeinschaft (DFG, Megestrol Acetate Bonn) and the Brandenburg Ministry of Science, Research and Culture (MWFK, Potsdam). The authors also thank Vattenfall Europe Mining AG for providing the research sites and the soil for the experiments. The intensive and constructive reviews by two anonymous reviewers are gratefully acknowledged. Fig. S1. To obtain labelled plant litter, in a greenhouse experiment, 2 g of Lotus corniculatus and 0.3 g of Calamagrostis epigejos seeds were sown in plastic pans (12×55×35 cm) in a mixture of potting soil,
expanded clay and silica sand (2 : 1 : 1, v/v/v). Table S1. PLFA composition (mol%) relative to total PLFA in soil samples of control, Lotus corniculatus (LOT) and Calamagrostis epigejos (CAL) treatments 4, 12 and 40 weeks after litter application (n=5; means±SD). Table S2. Relative distribution (%) of added 13C among PLFA in soil samples of Lotus corniculatus (LOT) and Calamagrostis epigejos (CAL) treatments 4, 12 and 40 weeks after litter application (n=5; means±SD). Please note: Wiley-Blackwell is not responsible for the content or functionality of any supporting materials supplied by the authors. Any queries (other than missing material) should be directed to the corresponding author for the article.