Limits...
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.


Plant community in the manipulated field system. Photo credit: Jichuang Duan.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4588656&req=5

ece31646-fig-0001: Plant community in the manipulated field system. Photo credit: Jichuang Duan.

Mentions: As the same with arctic, boreal, alpine, and other cold ecosystems, nitrogen is a limiting nutrient for plants in the alpine meadow on the Qinghai–Tibetan Plateau (Liu et al. 2013). Xu et al. (2004) found that alpine plants on this plateau could uptake organic N, which may play an important part in N nutrient. Besides, historical climate records show that the Qinghai–Tibetan Plateau has been experiencing substantial warming (i.e., 0.32°C per decade; Liu and Chen 2000), and this trend will likely continue in the future (Wang et al. 2014). This study examines the effects of warming and grazing on plant FAA–N uptake in a manipulated field system in an alpine meadow on the Qinghai–Tibetan Plateau (Fig. 1). We hypothesized that plant uptake of organic N decreased under warming and grazing probably due to plant–microbe competition on substrate (DON and DIN).


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)

Plant community in the manipulated field system. Photo credit: Jichuang Duan.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

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

ece31646-fig-0001: Plant community in the manipulated field system. Photo credit: Jichuang Duan.
Mentions: As the same with arctic, boreal, alpine, and other cold ecosystems, nitrogen is a limiting nutrient for plants in the alpine meadow on the Qinghai–Tibetan Plateau (Liu et al. 2013). Xu et al. (2004) found that alpine plants on this plateau could uptake organic N, which may play an important part in N nutrient. Besides, historical climate records show that the Qinghai–Tibetan Plateau has been experiencing substantial warming (i.e., 0.32°C per decade; Liu and Chen 2000), and this trend will likely continue in the future (Wang et al. 2014). This study examines the effects of warming and grazing on plant FAA–N uptake in a manipulated field system in an alpine meadow on the Qinghai–Tibetan Plateau (Fig. 1). We hypothesized that plant uptake of organic N decreased under warming and grazing probably due to plant–microbe competition on substrate (DON and DIN).

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.