Details
| Original language | English |
|---|---|
| Article number | 116810 |
| Number of pages | 9 |
| Journal | GEODERMA |
| Volume | 443 |
| Early online date | 10 Feb 2024 |
| Publication status | Published - Mar 2024 |
Abstract
Distribution of shrubs expanding in grasslands – shrubification – is ongoing worldwide in grasslands and is common on the Qinghai–Tibetan Plateau (QTP). But the consequences of shrubification for plant carbon (C) input and fate in soil are unclear. We used 13C pulse labelling in a meadow on the QTP to compare photosynthetic capacity and photosynthate distribution in shoots, roots, soil and microbial functional groups between herbaceous plants (herbs) and shrubby Potentilla fruticosa. During 3 h of labeling in 13CO2 atmosphere, the 13C amount assimilated by shrubs (0.81 g C/m−2) was only 38 % of that by herbs. Over 8 days after labeling, 13C amount respired jointly by roots and soil microorganisms under shrubs (0.049 g m−2) was less than half of that under herbs. The mean residence time of 13C for respiration jointly by roots and rhizosphere microorganisms was longer under shrubs (0.61 day) than under herbs (0.44 day). Within 22 days after labelling, 13C amounts in roots, soil, and microorganisms were consistently smaller under shrubs than those under herbs. Consequently, shrub P. fruticosa had not only smaller photosynthetic potential, but also allocated less photosynthate belowground and slowed down C cycling in soil compared with herbs. The distribution of total 13C in microbial functional groups indicated by PLFA analysis was similar between herbs and shrubs. Averaged over vegetation patch types, gram negative bacteria and AMF accounted for 22 % and 4 % of the total microbial PLFAs in the 0–20 cm, respectively, but these two functional groups took up 51 % and 23 % of the total 13C absorbed by microorganisms, respectively. This indicates that gram negative bacteria and AMF are major consumers of rhizodeposits. Concluding, shrubification leads to smaller C allocation belowground and slows down C cycling in the soil.
Keywords
- C pulse labelling, Herbaceous plants, phospholipid fatty acids (PLFAs), Photosynthate allocation belowground, Shrub expansion
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)
- Soil Science
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In: GEODERMA, Vol. 443, 116810, 03.2024.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Decreasing carbon allocation belowground in alpine meadow soils by shrubification
AU - Ming Mou, Xiao
AU - Li, Fen Can
AU - Jia, Bin
AU - Chen, Jie
AU - Guan, Zhen Huan
AU - Li, Yu Qiang
AU - Guggenberger, Georg
AU - Kuzyakov, Yakov
AU - Wang, Lin
AU - Gang Li, Xiao
N1 - Funding Information: This work was financed by the China Natural Science Foundation Program (Grant No. 42007078) and Youth Science and Technology Fund Program of Gansu Province (Grant No. 22JR5RA083). YK thanks the RUDN University Strategic Academic Leadership Program.
PY - 2024/3
Y1 - 2024/3
N2 - Distribution of shrubs expanding in grasslands – shrubification – is ongoing worldwide in grasslands and is common on the Qinghai–Tibetan Plateau (QTP). But the consequences of shrubification for plant carbon (C) input and fate in soil are unclear. We used 13C pulse labelling in a meadow on the QTP to compare photosynthetic capacity and photosynthate distribution in shoots, roots, soil and microbial functional groups between herbaceous plants (herbs) and shrubby Potentilla fruticosa. During 3 h of labeling in 13CO2 atmosphere, the 13C amount assimilated by shrubs (0.81 g C/m−2) was only 38 % of that by herbs. Over 8 days after labeling, 13C amount respired jointly by roots and soil microorganisms under shrubs (0.049 g m−2) was less than half of that under herbs. The mean residence time of 13C for respiration jointly by roots and rhizosphere microorganisms was longer under shrubs (0.61 day) than under herbs (0.44 day). Within 22 days after labelling, 13C amounts in roots, soil, and microorganisms were consistently smaller under shrubs than those under herbs. Consequently, shrub P. fruticosa had not only smaller photosynthetic potential, but also allocated less photosynthate belowground and slowed down C cycling in soil compared with herbs. The distribution of total 13C in microbial functional groups indicated by PLFA analysis was similar between herbs and shrubs. Averaged over vegetation patch types, gram negative bacteria and AMF accounted for 22 % and 4 % of the total microbial PLFAs in the 0–20 cm, respectively, but these two functional groups took up 51 % and 23 % of the total 13C absorbed by microorganisms, respectively. This indicates that gram negative bacteria and AMF are major consumers of rhizodeposits. Concluding, shrubification leads to smaller C allocation belowground and slows down C cycling in the soil.
AB - Distribution of shrubs expanding in grasslands – shrubification – is ongoing worldwide in grasslands and is common on the Qinghai–Tibetan Plateau (QTP). But the consequences of shrubification for plant carbon (C) input and fate in soil are unclear. We used 13C pulse labelling in a meadow on the QTP to compare photosynthetic capacity and photosynthate distribution in shoots, roots, soil and microbial functional groups between herbaceous plants (herbs) and shrubby Potentilla fruticosa. During 3 h of labeling in 13CO2 atmosphere, the 13C amount assimilated by shrubs (0.81 g C/m−2) was only 38 % of that by herbs. Over 8 days after labeling, 13C amount respired jointly by roots and soil microorganisms under shrubs (0.049 g m−2) was less than half of that under herbs. The mean residence time of 13C for respiration jointly by roots and rhizosphere microorganisms was longer under shrubs (0.61 day) than under herbs (0.44 day). Within 22 days after labelling, 13C amounts in roots, soil, and microorganisms were consistently smaller under shrubs than those under herbs. Consequently, shrub P. fruticosa had not only smaller photosynthetic potential, but also allocated less photosynthate belowground and slowed down C cycling in soil compared with herbs. The distribution of total 13C in microbial functional groups indicated by PLFA analysis was similar between herbs and shrubs. Averaged over vegetation patch types, gram negative bacteria and AMF accounted for 22 % and 4 % of the total microbial PLFAs in the 0–20 cm, respectively, but these two functional groups took up 51 % and 23 % of the total 13C absorbed by microorganisms, respectively. This indicates that gram negative bacteria and AMF are major consumers of rhizodeposits. Concluding, shrubification leads to smaller C allocation belowground and slows down C cycling in the soil.
KW - C pulse labelling
KW - Herbaceous plants
KW - phospholipid fatty acids (PLFAs)
KW - Photosynthate allocation belowground
KW - Shrub expansion
UR - http://www.scopus.com/inward/record.url?scp=85184838554&partnerID=8YFLogxK
U2 - 10.1016/j.geoderma.2024.116810
DO - 10.1016/j.geoderma.2024.116810
M3 - Article
AN - SCOPUS:85184838554
VL - 443
JO - GEODERMA
JF - GEODERMA
SN - 0016-7061
M1 - 116810
ER -