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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.


Related in: MedlinePlus

The relationship between 13C excess and 15N excess in roots and shoots of plants supplied with 13C–15N‐glycine. The regression of 13C excess on 15N excess of glycine‐treated plants is shown. The lowercase letters a, b, c, d represent CK, G, W, WG, respectively.
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ece31646-fig-0002: The relationship between 13C excess and 15N excess in roots and shoots of plants supplied with 13C–15N‐glycine. The regression of 13C excess on 15N excess of glycine‐treated plants is shown. The lowercase letters a, b, c, d represent CK, G, W, WG, respectively.

Mentions: Enrichment of 13C and 15N in plant samples was detected in mini‐quadrats supplying 13C/15N glycine at all of the four treatments (CK, G, W, and WG; Fig. 2). The slopes of regressions of 13C excess against 15N excess ranged 0.15–0.27, which indicated that 7.5–13.5% of the 13C/15N labeled glycine was absorbed intact into plants (Näsholm et al. 1998). Correlation coefficients were high for all treatments, except for CK, due to one value with low 13C: 15N ratio. For sieved soil from the treated plots (Fig. 3), significant regression was found between excess 13C and 15N (P < 0.0001), and 37% of the 13C label was lost from the plots.


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 13C excess and 15N excess in roots and shoots of plants supplied with 13C–15N‐glycine. The regression of 13C excess on 15N excess of glycine‐treated plants is shown. The lowercase letters a, b, c, d represent CK, G, W, WG, respectively.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

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

ece31646-fig-0002: The relationship between 13C excess and 15N excess in roots and shoots of plants supplied with 13C–15N‐glycine. The regression of 13C excess on 15N excess of glycine‐treated plants is shown. The lowercase letters a, b, c, d represent CK, G, W, WG, respectively.
Mentions: Enrichment of 13C and 15N in plant samples was detected in mini‐quadrats supplying 13C/15N glycine at all of the four treatments (CK, G, W, and WG; Fig. 2). The slopes of regressions of 13C excess against 15N excess ranged 0.15–0.27, which indicated that 7.5–13.5% of the 13C/15N labeled glycine was absorbed intact into plants (Näsholm et al. 1998). Correlation coefficients were high for all treatments, except for CK, due to one value with low 13C: 15N ratio. For sieved soil from the treated plots (Fig. 3), significant regression was found between excess 13C and 15N (P < 0.0001), and 37% of the 13C label was lost from the plots.

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.


Related in: MedlinePlus