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Warming decreased and grazing increased plant uptake of amino acids in an alpine meadow.

Ma S, Zhu X, Zhang J, Zhang L, Che R, Wang F, Liu H, Niu H, Wang S, Cui X - Ecol Evol (2015)

Bottom Line: Grazing alone significantly increased organic N absorption by 15%, whereas under warming condition grazing did not affect organic N uptake by the Kobresia humilis community on Tibetan Plateau.These results suggested warming promoted soil microbial activity and dissolved organic N mineralization.Grazing stimulated organic N uptake by plants, which counteracted the effect of warming.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences University of Chinese Academy of Sciences Beijing 100049 China.

ABSTRACT
Organic nitrogen (N) uptake by plants has been recognized as a significant component of terrestrial N cycle. Several studies indicated that plants have the ability to switch their preference between inorganic and organic forms of N in diverse environments; however, research on plant community response in organic nitrogen uptake to warming and grazing is scarce. Here, we demonstrated that organic N uptake by an alpine plant community decreased under warming with (13)C-(15)N-enriched glycine addition method. After 6 years of treatment, warming decreased plant organic N uptake by 37% as compared to control treatment. Under the condition of grazing, warming reduced plant organic N uptake by 44%. Grazing alone significantly increased organic N absorption by 15%, whereas under warming condition grazing did not affect organic N uptake by the Kobresia humilis community on Tibetan Plateau. Besides, soil NO 3-N content explained more than 70% of the variability observed in glycine uptake, and C:N ratio in soil dissolved organic matter remarkably increased under warming treatment. These results suggested warming promoted soil microbial activity and dissolved organic N mineralization. Grazing stimulated organic N uptake by plants, which counteracted the effect of warming.

No MeSH data available.


The relationship between soil NO3–N and tracer 15N recovered in plants. Each symbol represents one soil sample. There is a significant, positive correlation between the two variables (y = 267.68x − 870.47, r² = 0.53, P = 0.0115).
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ece31646-fig-0009: The relationship between soil NO3–N and tracer 15N recovered in plants. Each symbol represents one soil sample. There is a significant, positive correlation between the two variables (y = 267.68x − 870.47, r² = 0.53, P = 0.0115).

Mentions: The N content of plants was significantly higher under warming treatment (P < 0.05; Fig. 5). However, both DON and DIN contents were significantly lower under warming in 0–10 cm soil layer (P < 0.05; Fig. 6). Soil organic matter C:N ratio did not differ among treatments, whereas warming highly significantly increased dissolved organic matter (DSOM) C:N ratio (DOC:DON, P < 0.001; Fig. 7). Warming and grazing did not affect soil MBC or MBN (Fig. 8). Only NO3–N alone was recognized as explanatory variable through the multiple stepwise regression analysis. Correlation analysis showed that NO3–N explained more than 70% of the variation of plant glycine uptake among treatments (Fig. 9).


Warming decreased and grazing increased plant uptake of amino acids in an alpine meadow.

Ma S, Zhu X, Zhang J, Zhang L, Che R, Wang F, Liu H, Niu H, Wang S, Cui X - Ecol Evol (2015)

The relationship between soil NO3–N and tracer 15N recovered in plants. Each symbol represents one soil sample. There is a significant, positive correlation between the two variables (y = 267.68x − 870.47, r² = 0.53, P = 0.0115).
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4588656&req=5

ece31646-fig-0009: The relationship between soil NO3–N and tracer 15N recovered in plants. Each symbol represents one soil sample. There is a significant, positive correlation between the two variables (y = 267.68x − 870.47, r² = 0.53, P = 0.0115).
Mentions: The N content of plants was significantly higher under warming treatment (P < 0.05; Fig. 5). However, both DON and DIN contents were significantly lower under warming in 0–10 cm soil layer (P < 0.05; Fig. 6). Soil organic matter C:N ratio did not differ among treatments, whereas warming highly significantly increased dissolved organic matter (DSOM) C:N ratio (DOC:DON, P < 0.001; Fig. 7). Warming and grazing did not affect soil MBC or MBN (Fig. 8). Only NO3–N alone was recognized as explanatory variable through the multiple stepwise regression analysis. Correlation analysis showed that NO3–N explained more than 70% of the variation of plant glycine uptake among treatments (Fig. 9).

Bottom Line: Grazing alone significantly increased organic N absorption by 15%, whereas under warming condition grazing did not affect organic N uptake by the Kobresia humilis community on Tibetan Plateau.These results suggested warming promoted soil microbial activity and dissolved organic N mineralization.Grazing stimulated organic N uptake by plants, which counteracted the effect of warming.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences University of Chinese Academy of Sciences Beijing 100049 China.

ABSTRACT
Organic nitrogen (N) uptake by plants has been recognized as a significant component of terrestrial N cycle. Several studies indicated that plants have the ability to switch their preference between inorganic and organic forms of N in diverse environments; however, research on plant community response in organic nitrogen uptake to warming and grazing is scarce. Here, we demonstrated that organic N uptake by an alpine plant community decreased under warming with (13)C-(15)N-enriched glycine addition method. After 6 years of treatment, warming decreased plant organic N uptake by 37% as compared to control treatment. Under the condition of grazing, warming reduced plant organic N uptake by 44%. Grazing alone significantly increased organic N absorption by 15%, whereas under warming condition grazing did not affect organic N uptake by the Kobresia humilis community on Tibetan Plateau. Besides, soil NO 3-N content explained more than 70% of the variability observed in glycine uptake, and C:N ratio in soil dissolved organic matter remarkably increased under warming treatment. These results suggested warming promoted soil microbial activity and dissolved organic N mineralization. Grazing stimulated organic N uptake by plants, which counteracted the effect of warming.

No MeSH data available.