| 摘要: |
The 18O-labelled water approach has been widely used to estimate microbial carbon use efficiency (CUE). However, this approach assumes that oxygen in microbial DNA synthesis is 100% from water while this assumption has not been tested. We tested this assumption using 18O-labelled glucose and 18O-labelled water to see their contributions to the oxygen in microbial DNA synthesis. Results showed microbes used less than 8.3% glucose-oxygen and more than 91.7% water-oxygen for their DNA synthesis. The 18O-labelled water method for estimation of CUE has proven to be reliable under low enrichment of 18O in soil water. We suggest to use a correction factor (i.e., 1.1 in this study) to account for oxygen incorporated into DNA from other sources than water. |
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