ABSTRACT
Labile carbon (C) inputs to soil affect organic C dynamics in soil and the pathway of energy metabolism in tissue of plants. However, studies focusing on orchard soil are still scarce. In this study, the fate of 13C-glucose in organic C components, and the C metabolism in root of Malus baccata (L.) Borkh. in response to exogenous glucose at two levels, 1.50 g kg−1 (GLC1) and 7.50 g kg−1 (GLC2), were evaluated. Glucose addition increased the δ13C values and contents of soil organic carbon (SOC) and active fractions including microbial biomass carbon (MBC), dissolved organic carbon (DOC) pools, and particulate organic carbon (POC). At the end of the experiment, the MBC, DOC, and POC contents in GLC1 were 3.20%, 14.26%, and 5.16% higher than those in GLC2, respectively. In addition, no marked difference was found for SOC content between these two glucose rates. At the end of incubation, glucose-C was mostly allocated to SOC (56.79–85.05%), followed by DOC (4.72–20.88%) and MBC (4.46–18.1%); the lowest percentage was in POC (3.86–5.77%). Exogenous glucose increased the contents of organic acids and activities of key enzymes related with C metabolism in roots of M. baccata. In addition, adenosine triphosphate content, the energy matter, in root under GLC1 was 22.35% higher than that under GLC2. Correlation analyses suggested that the soil organic C fractions were positively correlated with C metabolism parameters in the roots of M. baccata. Overall, glucose addition improved the C metabolism in roots and the allocation of glucose-derived C in soil.
Acknowledgments
This study was funded by the National Natural Science Foundation of China (31972359), the National Key Research and Development Program of China (2020YFD1000201), the China Agriculture Research System of MOF and MARA (CARS-27), and the Agricultural Research and Industrialization Projects of Liaoning Province (2020JH2/10200028).
Disclosure statement
No potential conflict of interest was reported by the author(s).
Supplementary material
Supplemental data for this article can be accessed online at https://doi.org/10.1080/00103624.2022.2094396
Author contributions
L.D. M: performed the experiments, analysed data, and wrote the original draft. L.D. G and Q.S. J: conceived and designed the study, review and edited manuscript, funding acquisition. H.J. L: review and edited manuscript. Z.Z. T: performed part of experiments. All authors read and approved the final version of the manuscript.