『Abstract
To determine how plant species richness impacts microbial assimilation
of new photosynthate, and how this may be modified by atmospheric
N deposition, we analyzed the microbial assimilation of recent
photosynthate in a 6-year-long field experiment in which plant
species richness, atmospheric N deposition, and atmospheric CO2 concentration were manipulated in concert. The
depleted δ13C of fumigaion CO2
enabled us to investigate the effect of plant species richness
and atmospheric N deposition on the metabolism of soil microbial
communities in the elevated CO2 treatment.
To accomplish this, we determined the δ13C of bacterial,
actinobacterial, and fungal phospholipid fatty acids (PLFAs).
In the elevated CO2 conditions of this study, the δ13C
of bacterial PLFAs (i15:0, i16:0, 16:1ω7c, 16:1ω9c, 10Me16:0,
and 10Me18:0) and the fungal PLFA 18:1ω9c was significantly lower
in species-rich plant communities than in species-poor plant communities,
indicating that microbial incorporation of new C increased with
plant species richness. Despite an increase in plant production,
total PLFA decreased under N deposition. Moreover, N deposition
also decreased fungal relative abundance in species-rich plant
communities. In our study, plant species richness directly increased
microbial incorporation of new photosynthate, providing a mechanistic
link between greater plant detritus production in species-rich
plant communities and larger and more active soil microbial community.
Keywords: Atmospheric N deposition; 13C; Grassland
ecosystems; Phospholipid fatty acid (PLFA); Plant species richness;
Soil microorganisms』
Abbreviations
Introduction
Methods
Experimental design and sampling procedures
Phospholipid fatty acid analysis
Statistical analyses
Results
Microbial assimilation of new photosynthate
Total PLFA and relative abundance of microbial PLFAs
Discussion
Acknowledgments
References