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

• Main Authors: Ma, Shuang, Zhu, Xiaoxue, Zhang, Jing, Zhang, Lirong, Che, Rongxiao, Wang, Fang, Liu, Hanke, Niu, Haishan, Wang, Shiping, Cui, Xiaoyong
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2015
• Subjects: C-13-n-15-glycine; Amino Acid Uptake; Grazing; Plant Community; Qinghai-tibetan Plateau; Warming; Science & Technology; Life Sciences & Biomedicine; SOIL MICROBIAL BIOMASS; ORGANIC NITROGEN; TIBETAN PLATEAU; CARBON AVAILABILITY; INORGANIC NITROGEN; EXTRACTION METHOD; N AVAILABILITY; BOREAL FORESTS; ARCTIC TUNDRA; ROOT UPTAKE; Environmental Sciences & Ecology; Ecology; Arctic; Tundra
• Online Access: http://210.75.249.4/handle/363003/5512

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 C-13-N-15-enriched glycine addition method. After 6years 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 NO3-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. 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 C-13-N-15-enriched glycine addition method. After 6years 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%, ...