Details
| Original language | English |
|---|---|
| Pages (from-to) | 1193-1203 |
| Number of pages | 11 |
| Journal | Land Degradation and Development |
| Volume | 33 |
| Issue number | 8 |
| Early online date | 4 May 2022 |
| Publication status | Published - 15 May 2022 |
Abstract
Root exudates can significantly modify microbial activity and soil organic matter (SOM) mineralization. However, how root exudates and their C/N stoichiometric ratios control rice field (paddy) soil C mineralization is poorly understood. This study used a mixture of glucose, oxalic acid, and alanine as root exudate mimics for three C/N stoichiometric ratios (CN6, CN10, and CN80) to explore the underlying mechanisms involved in SOM mineralization. The input of root exudates enhanced CO2 emissions by 1.8–2.3-fold that of soil with only C additions (C-only). Artificial root exudates with low C/N ratios (CN6 and CN10) increased the metabolic quotient (qCO2) by 12% over those with higher stoichiometric ratios (CN80 and C-only), suggesting a relatively high energy demand for microorganisms to acquire organic N from SOM by increasing N-hydrolase production. The increase of stoichiometric ratios of C- to N-hydrolase [β-1,4-glucosidase to β-1,4-N-acetyl glucosaminidase (NAG)] promoted SOM degradation compared to those involved in organic C- and N-degradation, which had a significant positive correlation with qCO2. The stoichiometric ratios of microbial biomass were positively correlated with C use efficiency, indicating root exudates with higher C/N ratios provide an undersupply of N for microorganisms that trigger the release of N-degrading extracellular enzymes. Our findings showed that the C/N stoichiometry of root exudates controlled SOM mineralization by affecting the specific response of the microbial biomass through the activity of C- and N-releasing extracellular enzymes to adjust the microbial C/N ratio.
Keywords
- carbon use efficiency, extracellular enzymes, metabolic quotients, microbial biomass, root exudates, stoichiometric ratios
ASJC Scopus subject areas
- Environmental Science(all)
- Environmental Chemistry
- Social Sciences(all)
- Development
- Environmental Science(all)
- General Environmental Science
- Agricultural and Biological Sciences(all)
- Soil Science
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In: Land Degradation and Development, Vol. 33, No. 8, 15.05.2022, p. 1193-1203.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Root exudates with low C/N ratios accelerate CO2 emissions from paddy soil
AU - Cai, Guan
AU - Shahbaz, Muhammad
AU - Ge, Tida
AU - Hu, Yajun
AU - Li, Baozhen
AU - Yuan, Hongzhao
AU - Wang, Yi
AU - Liu, Yuhuai
AU - Liu, Qiong
AU - Shibistova, Olga
AU - Sauheitl, Leopold
AU - Wu, Jinshui
AU - Guggenberger, Georg
AU - Zhu, Zhenke
N1 - Funding information: National Natural Science Foundation of China, Grant/Award Numbers: 41877104, 41977156, 42177330, 42177334; the Alexander von Humboldt Foundation of Germany, Grant/Award Number: The grants or other support to Tida Ge from the Al; the Natural Science Foundation of Hunan Province, Grant/Award Number: 2020JJ4653; The Youth Innovation Promotion Association of the Chinese Academy of Sciences, Grant/Award Number: 2019357
PY - 2022/5/15
Y1 - 2022/5/15
N2 - Root exudates can significantly modify microbial activity and soil organic matter (SOM) mineralization. However, how root exudates and their C/N stoichiometric ratios control rice field (paddy) soil C mineralization is poorly understood. This study used a mixture of glucose, oxalic acid, and alanine as root exudate mimics for three C/N stoichiometric ratios (CN6, CN10, and CN80) to explore the underlying mechanisms involved in SOM mineralization. The input of root exudates enhanced CO2 emissions by 1.8–2.3-fold that of soil with only C additions (C-only). Artificial root exudates with low C/N ratios (CN6 and CN10) increased the metabolic quotient (qCO2) by 12% over those with higher stoichiometric ratios (CN80 and C-only), suggesting a relatively high energy demand for microorganisms to acquire organic N from SOM by increasing N-hydrolase production. The increase of stoichiometric ratios of C- to N-hydrolase [β-1,4-glucosidase to β-1,4-N-acetyl glucosaminidase (NAG)] promoted SOM degradation compared to those involved in organic C- and N-degradation, which had a significant positive correlation with qCO2. The stoichiometric ratios of microbial biomass were positively correlated with C use efficiency, indicating root exudates with higher C/N ratios provide an undersupply of N for microorganisms that trigger the release of N-degrading extracellular enzymes. Our findings showed that the C/N stoichiometry of root exudates controlled SOM mineralization by affecting the specific response of the microbial biomass through the activity of C- and N-releasing extracellular enzymes to adjust the microbial C/N ratio.
AB - Root exudates can significantly modify microbial activity and soil organic matter (SOM) mineralization. However, how root exudates and their C/N stoichiometric ratios control rice field (paddy) soil C mineralization is poorly understood. This study used a mixture of glucose, oxalic acid, and alanine as root exudate mimics for three C/N stoichiometric ratios (CN6, CN10, and CN80) to explore the underlying mechanisms involved in SOM mineralization. The input of root exudates enhanced CO2 emissions by 1.8–2.3-fold that of soil with only C additions (C-only). Artificial root exudates with low C/N ratios (CN6 and CN10) increased the metabolic quotient (qCO2) by 12% over those with higher stoichiometric ratios (CN80 and C-only), suggesting a relatively high energy demand for microorganisms to acquire organic N from SOM by increasing N-hydrolase production. The increase of stoichiometric ratios of C- to N-hydrolase [β-1,4-glucosidase to β-1,4-N-acetyl glucosaminidase (NAG)] promoted SOM degradation compared to those involved in organic C- and N-degradation, which had a significant positive correlation with qCO2. The stoichiometric ratios of microbial biomass were positively correlated with C use efficiency, indicating root exudates with higher C/N ratios provide an undersupply of N for microorganisms that trigger the release of N-degrading extracellular enzymes. Our findings showed that the C/N stoichiometry of root exudates controlled SOM mineralization by affecting the specific response of the microbial biomass through the activity of C- and N-releasing extracellular enzymes to adjust the microbial C/N ratio.
KW - carbon use efficiency
KW - extracellular enzymes
KW - metabolic quotients
KW - microbial biomass
KW - root exudates
KW - stoichiometric ratios
UR - http://www.scopus.com/inward/record.url?scp=85127414234&partnerID=8YFLogxK
U2 - 10.1002/ldr.4198
DO - 10.1002/ldr.4198
M3 - Article
AN - SCOPUS:85127414234
VL - 33
SP - 1193
EP - 1203
JO - Land Degradation and Development
JF - Land Degradation and Development
SN - 1085-3278
IS - 8
ER -