Tibetan sedges sequester more carbon belowground than grasses: a 13C labeling study

Mou, Xiao Ming; Li, Xiao Gang; Zhao, Ningning; Yu, Ying; Kuzyakov, Yakov

doi:10.1007/s11104-018-3634-5

Cited by 32 publications

(9 citation statements)

References 56 publications

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“…Leymus secalinus is one of the key grass species in alpine grasslands of the QTP (Mou et al, 2018). Through field investigation in our study site, we found that L. secalinus is the most dominant grass species accounting for nearly 50% of the total coverage under each treatment.…”

Section: Introductionmentioning

confidence: 75%

Effects of Warming and N Deposition on the Physiological Performances of Leymus secalinus in Alpine Meadow of Qinghai-Tibetan Plateau

Shen

Dong

et al. 2020

Front. Plant Sci.

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Warming and Nitrogen (N) deposition are key global changes that may affect ecophysiological process of territorial plants. In this paper, we examined the effects of warming, N deposition, and their combination effect on the physiological performances of Leymus secalinus. Four treatments were established in an alpine meadow of Qinghai-Tibetan plateau: control (CK), warming (W), N deposition (N), and warming plus N deposition (NW). Warming significantly decreased the photosynthetic rate (A net), stomatal conductance (g s), intercellular CO 2 concentration (C i), and transpiration rate (T r), while N deposition and warming plus N deposition significantly increased those parameters of L. secalinus. Warming significantly increased the VPD and L s , while N deposition and warming plus N deposition had a significant positive effect. Warming negatively reduced the leaf N content, Chla, Chlb, and total Chl content, while N deposition significantly promoted these traits. Warming, N deposition, and their combination significantly increased the activity of SOD, POD, and CAT. Besides, warming and warming plus N deposition significantly increased the MDA content, while N deposition significantly decreased the MDA content. N deposition and warming plus N deposition significantly increased the Rubisco activity, while warming showed no significant effect on Rubisco activity. N deposition and warming plus N deposition significantly increased the Fv/Fm, FPSII, qP, and decreased NPQ, while warming significantly decreased the Fv/Fm, FPSII, qP, and increased NPQ. N deposition strengthened the relations between g s , Chl, Chla, Chlb, Rubisco activity, and A net. Under warming, only g s showed a significantly positive relation with A net. Our findings suggested that warming could impair the photosynthetic potential of L. secalinus

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Section: Introductionmentioning

confidence: 75%

Effects of Warming and N Deposition on the Physiological Performances of Leymus secalinus in Alpine Meadow of Qinghai-Tibetan Plateau

Shen

Dong

et al. 2020

Front. Plant Sci.

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“…The slower decomposition of sedge litters implies that plant-derived C stays longer in soil for sedges than for grasses. Taking account of the greater allocation of photosynthetic assimilates belowground under sedges than under grasses (Mou et al, 2018), we demonstrated that the ongoing replacement of sedges by grasses in the vast Tibetan alpine meadows is unfavourable for the maintenance of SOC storage. Our results are opposites of Chen et al (2017) and Liu et al (2018).…”

Section: Discussionmentioning

confidence: 88%

“…The litter materials of shoots and roots at community and species levels were sampled from a pasture near the Gansu Agricul- A remarkable feature of vegetation in this pasture was the patchiness of species distribution, possibly due to grazing by domestic animals and root foraging by subterranean burrowing rodents such as zokor (Myospalax baileyi), or undulations in the microrelief (Li et al, 2009;Wen et al, 2013). In July 2016, we conducted a 13 C labelling experiment in this pasture to compare the allocation of photosynthetic C in various plant and soil pools between sedge and grass communities (patches) (Mou et al, 2018).…”

Section: Litter Materialsmentioning

confidence: 99%

Sedge replacement by grasses accelerates litter decomposition and decreases organic matter formation in alpine meadow soils

Mou

Zhao

et al. 2022

Land Degrad Dev

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The dominance of sedges in Tibetan meadows is decreasing with the increasing abundance of grasses, mainly due to anthropogenic activities, nitrogen deposition, and climate warming. We investigated the effects of this vegetation shift on litter decomposition (in the field), mineralization to CO2, and litter carbon (C) incorporation into microorganisms (under laboratory conditions) under sedges and grasses at community and species levels. Litter C incorporation into soil organic carbon (SOC) was estimated using 13C labelling of the vegetation community. After one year of field incubation, a smaller proportion of shoot litter C was lost in sedges than in grasses at the species level and smaller proportions of root C were lost under sedges at community and species levels. Roots decomposed markedly slower than shoots across communities or species under sedges and grasses. Smaller proportions of the shoot and root C from sedges were incorporated into SOC than from grasses, and root C was less incorporated into the SOC than shoot C across communities. Over the 38‐day laboratory incubation, total microbial respiration and assimilation of litter C changed similarly to the C loss between litter types under the field condition. Across community and species levels, litter C loss in the field and incorporation of litter C into microorganisms under laboratory conditions all increased with initial phosphorus content in the litter and decreased with lignin content. Considering greater allocation of photosynthates belowground by sedges than grasses, we demonstrated that the ongoing replacement of sedges by grasses in the vast Tibetan alpine meadows is unfavorable for the maintenance of SOC storage.

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“…A previous study had shown that Cyperaceae and Poaceae had the highest photosynthetic rate and water use efficiency among all of the function groups, and the photosynthetic rate of Polygonaceae was the lowest (Liu et al, 2015 ). Meanwhile, a study based on isotope labeling also found that Cyperaceae plants have a stronger ability to assimilate CO 2 and transfer more C to roots and soil, because Cyperaceae plants had a high primary carbon assimilation tissue area when compared with Poaceae (Mou et al, 2018 ).…”

Section: Discussionmentioning

confidence: 99%

Seasonal and Inter-Annual Variations of Carbon Dioxide Fluxes and Their Determinants in an Alpine Meadow

Wang

Chen

et al. 2022

Front. Plant Sci.

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The alpine meadow is one of the most important ecosystems on the Qinghai-Tibet Plateau (QTP) due to its huge carbon storage and wide distribution. Evaluating the carbon fluxes in alpine meadow ecosystems is crucial to understand the dynamics of carbon storage in high-altitude areas. Here, we investigated the carbon fluxes at seasonal and inter-annual timescales based on 5 years of observations of eddy covariance fluxes in the Zoige alpine meadow on the eastern Tibetan Plateau. We found that the Zoige alpine meadow acted as a faint carbon source of 94.69 ± 86.44 g C m−2 y−1 during the observation periods with large seasonal and inter-annual variations (IAVs). At the seasonal scale, gross primary productivity (GPP) and ecosystem respiration (Re) were positively correlated with photosynthetic photon flux density (PPFD), average daily temperature (Ta), and vapor pressure (VPD) and had negative relationships with volumetric water content (VWC). Seasonal variations of net ecosystem carbon dioxide (CO2) exchange (NEE) were mostly explained by Ta, followed by PPFD, VPD, and VWC. The IAVs of GPP and Re were mainly attributable to the IAV of the maximum GPP rate (GPPmax) and maximum Re rate (Remax), respectively, both of which increased with the percentage of Cyperaceae and decreased with the percentage of Polygonaceae changes across years. The IAV of NEE was well explained by the anomalies of the maximum CO2 release rate (MCR). These results indicated that the annual net CO2 exchange in the alpine meadow ecosystem was controlled mainly by the maximum C release rates. Therefore, a better understanding of physiological response to various environmental factors at peak C uptake and release seasons will largely improve the predictions of GPP, Re, and NEE in the context of global change.

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Tibetan sedges sequester more carbon belowground than grasses: a 13C labeling study

Cited by 32 publications

References 56 publications

Effects of Warming and N Deposition on the Physiological Performances of Leymus secalinus in Alpine Meadow of Qinghai-Tibetan Plateau

Effects of Warming and N Deposition on the Physiological Performances of Leymus secalinus in Alpine Meadow of Qinghai-Tibetan Plateau

Sedge replacement by grasses accelerates litter decomposition and decreases organic matter formation in alpine meadow soils

Seasonal and Inter-Annual Variations of Carbon Dioxide Fluxes and Their Determinants in an Alpine Meadow

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