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Glomalin-related soil protein responses to elevated CO2 and nitrogen addition in a subtropical forest : Potential consequences for soil carbon accumulation

Zhang, Jing LU ; Tang, Xuli; He, Xinhua and Liu, Juxiu (2015) In Soil Biology and Biochemistry 83. p.142-149
Abstract

According to the economy theory, plants should preferentially allocate photosynthate to acquire below-ground resources under elevated atmospheric carbon dioxide (eCO2) but decrease below-ground C allocation when nitrogen (N) is sufficient for plant growth. Arbuscular mycorrhizae (AM) represent a critical mechanism of below-ground nutrient acquisition for plants. The dynamics of arbuscular mycorrhizal fungi (AMF) could therefore reflect the response of plant C allocation under eCO2 and N addition. We examined the responses of glomalin-related soil protein (GRSP) to eCO2 (approximately 700μmolmol-1 CO2) and/or N addition (100kgNha-1yr-1 as... (More)

According to the economy theory, plants should preferentially allocate photosynthate to acquire below-ground resources under elevated atmospheric carbon dioxide (eCO2) but decrease below-ground C allocation when nitrogen (N) is sufficient for plant growth. Arbuscular mycorrhizae (AM) represent a critical mechanism of below-ground nutrient acquisition for plants. The dynamics of arbuscular mycorrhizal fungi (AMF) could therefore reflect the response of plant C allocation under eCO2 and N addition. We examined the responses of glomalin-related soil protein (GRSP) to eCO2 (approximately 700μmolmol-1 CO2) and/or N addition (100kgNha-1yr-1 as NH4NO3) in a modeled subtropical forest to better understand its potential influence on soil C storage. We hypothesized that GRSP would increase under eCO2 and decrease under N addition. Furthermore, the positive effects of eCO2 on GRSP would be offset by extra N addition, and GRSP would remain unchanged under combined eCO2 and N addition. Our results showed that the mean concentrations of easily extractable GRSP (EE-GRSP) and total GRSP (T-GRSP) were 0.35±0.05 and 0.72±0.13mgCcm-3, respectively, which accounted for 2.76±0.53% and 5.67±0.92% of soil organic carbon (SOC) in the 0-10cm soil layer. Elevated CO2 significantly increased T-GRSP by 35.02% but decreased EE-GRSP by 5.09% in the top 10cm soil layer. The opposite responses of T-GRSP and EE-GRSP to eCO2 might result from an unchanged photosynthate investment to AMF with possible changes in their decomposition rates. The effect of N on GRSP was contrary to our hypothesis, i.e., there was a 1.72%-48.49% increase in T-GRSP and a slightly increase in EE-GRSP. Both EE-GRSP and T-GRSP concentrations increased under the combination of eCO2 and N addition, which was inconsistent with our hypothesis. The significant increase of EE-GRSP under the combination of eCO2 and N addition was partly caused by more rapid plant growth and reduced microbial diversity, and the marginal increase of T-GRSP indicated that the interaction between eCO2 and N addition offset their independent effects. In addition, the relatively higher accumulation ratios of GRSP (22.6±13.6%) compared with SOC (15.9±9.4%) indicated that more rapid GRSP deposition in the soil might accelerate SOC accumulation under eCO2 and N addition. Our results will improve the understanding of the functioning of GRSP in soil C sequestration under global environmental change scenarios.

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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Elevated CO, Glomalin, N deposition, Soil organic carbon, Subtropical forest
in
Soil Biology and Biochemistry
volume
83
pages
8 pages
publisher
Elsevier
external identifiers
  • Scopus:84923063159
ISSN
0038-0717
DOI
10.1016/j.soilbio.2015.01.023
language
English
LU publication?
no
id
f2234384-df4b-4a0e-9a82-fbf57fc1d69b
date added to LUP
2016-10-17 15:56:41
date last changed
2016-11-13 04:42:47
@misc{f2234384-df4b-4a0e-9a82-fbf57fc1d69b,
  abstract     = {<p>According to the economy theory, plants should preferentially allocate photosynthate to acquire below-ground resources under elevated atmospheric carbon dioxide (eCO<sub>2</sub>) but decrease below-ground C allocation when nitrogen (N) is sufficient for plant growth. Arbuscular mycorrhizae (AM) represent a critical mechanism of below-ground nutrient acquisition for plants. The dynamics of arbuscular mycorrhizal fungi (AMF) could therefore reflect the response of plant C allocation under eCO<sub>2</sub> and N addition. We examined the responses of glomalin-related soil protein (GRSP) to eCO<sub>2</sub> (approximately 700μmolmol<sup>-1</sup> CO<sub>2</sub>) and/or N addition (100kgNha<sup>-1</sup>yr<sup>-1</sup> as NH<sub>4</sub>NO<sub>3</sub>) in a modeled subtropical forest to better understand its potential influence on soil C storage. We hypothesized that GRSP would increase under eCO<sub>2</sub> and decrease under N addition. Furthermore, the positive effects of eCO<sub>2</sub> on GRSP would be offset by extra N addition, and GRSP would remain unchanged under combined eCO<sub>2</sub> and N addition. Our results showed that the mean concentrations of easily extractable GRSP (EE-GRSP) and total GRSP (T-GRSP) were 0.35±0.05 and 0.72±0.13mgCcm<sup>-3</sup>, respectively, which accounted for 2.76±0.53% and 5.67±0.92% of soil organic carbon (SOC) in the 0-10cm soil layer. Elevated CO<sub>2</sub> significantly increased T-GRSP by 35.02% but decreased EE-GRSP by 5.09% in the top 10cm soil layer. The opposite responses of T-GRSP and EE-GRSP to eCO<sub>2</sub> might result from an unchanged photosynthate investment to AMF with possible changes in their decomposition rates. The effect of N on GRSP was contrary to our hypothesis, i.e., there was a 1.72%-48.49% increase in T-GRSP and a slightly increase in EE-GRSP. Both EE-GRSP and T-GRSP concentrations increased under the combination of eCO<sub>2</sub> and N addition, which was inconsistent with our hypothesis. The significant increase of EE-GRSP under the combination of eCO<sub>2</sub> and N addition was partly caused by more rapid plant growth and reduced microbial diversity, and the marginal increase of T-GRSP indicated that the interaction between eCO<sub>2</sub> and N addition offset their independent effects. In addition, the relatively higher accumulation ratios of GRSP (22.6±13.6%) compared with SOC (15.9±9.4%) indicated that more rapid GRSP deposition in the soil might accelerate SOC accumulation under eCO<sub>2</sub> and N addition. Our results will improve the understanding of the functioning of GRSP in soil C sequestration under global environmental change scenarios.</p>},
  author       = {Zhang, Jing and Tang, Xuli and He, Xinhua and Liu, Juxiu},
  issn         = {0038-0717},
  keyword      = {Elevated CO,Glomalin,N deposition,Soil organic carbon,Subtropical forest},
  language     = {eng},
  month        = {04},
  pages        = {142--149},
  publisher    = {ARRAY(0xa24eed8)},
  series       = {Soil Biology and Biochemistry},
  title        = {Glomalin-related soil protein responses to elevated CO<sub>2</sub> and nitrogen addition in a subtropical forest : Potential consequences for soil carbon accumulation},
  url          = {http://dx.doi.org/10.1016/j.soilbio.2015.01.023},
  volume       = {83},
  year         = {2015},
}