Rhizosphere priming effects differ between Norway spruce (Picea abies) and Scots pine seedlings cultivated under two levels of light intensity
(2020) In Soil Biology and Biochemistry 145.- Abstract
The rhizosphere priming effect (RPE), which occurs in the presence of growing plant roots, may either stimulate or reduce the decomposition of soil organic matter (SOM). The carbon and nitrogen cycling in forest soils could be more rapid or slower due to the RPE, depending on the tree species and their growing conditions. Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) are two commercially important tree species in the boreal region, and their photosynthetic rate depends upon light intensity. Since photosynthesis is an important determinant of below-ground plant C allocation and the root exudation rate, we hypothesized that the RPE would also differ between Norway spruce and Scots pine. The hypothesis was tested in a... (More)
The rhizosphere priming effect (RPE), which occurs in the presence of growing plant roots, may either stimulate or reduce the decomposition of soil organic matter (SOM). The carbon and nitrogen cycling in forest soils could be more rapid or slower due to the RPE, depending on the tree species and their growing conditions. Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) are two commercially important tree species in the boreal region, and their photosynthetic rate depends upon light intensity. Since photosynthesis is an important determinant of below-ground plant C allocation and the root exudation rate, we hypothesized that the RPE would also differ between Norway spruce and Scots pine. The hypothesis was tested in a greenhouse experiment using a combined 13CO2 pulse-chase and 15N pool-dilution approach designed to quantify the root exudation rate, SOM decomposition, gross N mineralization, and the RPE. We found that spruce induced a positive RPE while pine induced a negative RPE. Our results also showed that the light intensity could influence the RPE in a species-dependent way. Spruce induced higher priming of SOM decomposition and gross nitrogen mineralization when exposed to low light intensity, while there was no connection between the RPE and light intensity on soil carbon and nitrogen cycling processes under Pine. Furthermore, the species-specific variation in carbon and nitrogen cycling was related to soil nitrogen availability rather than root exudation rates, apparently because severe nitrogen limitation led to plant-microbial competition for nitrogen and reduced SOM decomposition and gross nitrogen mineralization rates. We conclude that the environmental factors that influence nitrogen availability need to be integrated into our understanding of the RPE in forest soils.
(Less)
- author
- Li, Jian LU ; Zhou, Moyan ; Alaei, Saeed LU and Bengtson, Per LU
- organization
- publishing date
- 2020
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Decomposition, Gross nitrogen mineralization, Nitrogen availability, Root exudation, Soil organic carbon
- in
- Soil Biology and Biochemistry
- volume
- 145
- article number
- 107788
- publisher
- Elsevier
- external identifiers
-
- scopus:85083078972
- ISSN
- 0038-0717
- DOI
- 10.1016/j.soilbio.2020.107788
- language
- English
- LU publication?
- yes
- id
- 44f88f17-da9d-4dd1-a10d-c830fedfef6c
- date added to LUP
- 2020-04-29 07:38:07
- date last changed
- 2022-04-18 21:56:20
@article{44f88f17-da9d-4dd1-a10d-c830fedfef6c,
abstract = {{<p>The rhizosphere priming effect (RPE), which occurs in the presence of growing plant roots, may either stimulate or reduce the decomposition of soil organic matter (SOM). The carbon and nitrogen cycling in forest soils could be more rapid or slower due to the RPE, depending on the tree species and their growing conditions. Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) are two commercially important tree species in the boreal region, and their photosynthetic rate depends upon light intensity. Since photosynthesis is an important determinant of below-ground plant C allocation and the root exudation rate, we hypothesized that the RPE would also differ between Norway spruce and Scots pine. The hypothesis was tested in a greenhouse experiment using a combined <sup>13</sup>CO<sub>2</sub> pulse-chase and <sup>15</sup>N pool-dilution approach designed to quantify the root exudation rate, SOM decomposition, gross N mineralization, and the RPE. We found that spruce induced a positive RPE while pine induced a negative RPE. Our results also showed that the light intensity could influence the RPE in a species-dependent way. Spruce induced higher priming of SOM decomposition and gross nitrogen mineralization when exposed to low light intensity, while there was no connection between the RPE and light intensity on soil carbon and nitrogen cycling processes under Pine. Furthermore, the species-specific variation in carbon and nitrogen cycling was related to soil nitrogen availability rather than root exudation rates, apparently because severe nitrogen limitation led to plant-microbial competition for nitrogen and reduced SOM decomposition and gross nitrogen mineralization rates. We conclude that the environmental factors that influence nitrogen availability need to be integrated into our understanding of the RPE in forest soils.</p>}},
author = {{Li, Jian and Zhou, Moyan and Alaei, Saeed and Bengtson, Per}},
issn = {{0038-0717}},
keywords = {{Decomposition; Gross nitrogen mineralization; Nitrogen availability; Root exudation; Soil organic carbon}},
language = {{eng}},
publisher = {{Elsevier}},
series = {{Soil Biology and Biochemistry}},
title = {{Rhizosphere priming effects differ between Norway spruce (Picea abies) and Scots pine seedlings cultivated under two levels of light intensity}},
url = {{http://dx.doi.org/10.1016/j.soilbio.2020.107788}},
doi = {{10.1016/j.soilbio.2020.107788}},
volume = {{145}},
year = {{2020}},
}