Record ID No. |
4743 |
Author(s) |
I. V. Yevdokimov, A. A. Larionova, A. F. Stulin , 2013 |
Affiliation |
Institute of Physicochemical and Biological Problems of Soil Science, Russian Academy of Sciences, ul. Institutskaya 2, Pushchino, Moscow oblast, 142290, Russia, Email: ilyaevd@rambler.ru |
Title |
Turnover of “new” and “old” carbon in soil microbial biomass |
Source. Vol.(no):Page |
Microbiology 82(4): 505-516p. |
Categories |
Mycorrhiza General |
Subjects |
Physiology |
Host |
Zea mays |
Organism |
Microbes (bacteria, mycorrhizal fungi) |
Country |
Russia, Eastern Europe |
Abstracts |
The contributions of “new” carbon coming from plants with the C4-type of photosynthesis (maize) and “old” carbon from soil organic matter (SOM) formed under C3 vegetation as carbon sources for microorganisms was determined. Soil samples were taken from the plots of field experiments on Chernozem and Phaeozem. The values of δ13C were determined in evolved CO2, SOM, total microbial biomass (Cmic), and phospholipid fatty acids (PLFA), assuming that the PLFA markers for certain taxonomic groups of microorganisms enriched in C4 carbon indicated a more significant role of these microorganisms in the transformation of root exudates and plant residues. Carbon pools were arranged in the following order by the degree of their enrichment with “new” C: SOM < Cmic < CO2. Consequently, the “new” carbon proved to be a more preferable substrate for microbial growth than the “old” one. The share of C4 in the markers varied from 18 to 60% (on average 38%) in Phaeozem and from 15 to 40% in Chernozem (on average 28%). The groups of microorganisms in Phaeozem were arranged in the following order by the degree of their enrichment with “new” carbon: protozoa < saprotrophic fungi < actinomycetes < gram-positive bacteria < gramnegative bacteria < mycorrhizal fungi. In Chernozem, the contribution of C4 to the carbon composition of PLFA did not differ significantly for various groups of microorganisms. The C4 content within the PLFA markers of fungi and gram-negative bacteria did not demonstrate any crucial contribution of these groups of organisms to the transformation of “new” C. The long-term C3–C4 transition probably results in formation of a broad range of carbon pools similar in their C4 content but different in resistance to mineralization; therefore, gram-positive bacteria could assimilate C4 from resistant C pools. The low content of “new” carbon in the PLFA markers of fungi may be explained by a considerable portion of dormant forms. |