Uptake and Recovery of Soil Nitrogen by Bryophytes and Vascular Plants in an Alpine Meadow  

作　　者：WANG Jin-niu SHI Fu-sun XU Bo WANG Qian WU Yan WU Ning 

机构地区：[1]Key Laboratory of Mountain Ecological Restoration and Bioresource [2]Utilization & Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences [3]University of Chinese Academy of Sciences [4]International Centre for Integrated Mountain Development (ICIMOD), G.P.O. Box 3226, Khumaltar, Kathmandu, Nepal

出　　处：《Journal of Mountain Science》2014年第2期475-484,共10页山地科学学报（英文）

基　　金：the National Natural Science Foundation Youth Project of China (Grant No.31100358);the "Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues" of the Chinese Academy of Sciences (Grant No. XDA05050307);Key Projects in the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period"Vegetation Stabilization Techniques of Alpine Forest-Grassland Ecotone" (Grant No. 2011BAC09 B04-02-03);International Science & Technology Cooperation Program of China (Grant No. 2013DFR90670) for fund support

摘　　要：Due to their particular physiology and life history traits, bryophytes are critical in regulating biogeochemical cycles and functions in alpine ecosystem. Hence, it is crucial to investigate their nutrient utilization strategies in comparison with vascular plants and understand their responses to the variation of growing season caused by climate change. Firstly, this study testified whether or not bryophytes can absorb nitrogen(N) directly from soil through spiking three chemical forms of 15N stable isotope tracer. Secondly, with stronger ability of carbohydrates assimilation and photosynthesis, it is supposed that N utilization efficiency of vascular plants is significantly higher than that of bryophytes. However, the recovery of soil N by bryophytes can still compete with vascular plants due to their greater phytomass. Thirdly, resource acquisition may be varied from the change of growing season, during which N pulse can be manipulated with 15N tracer addition at different time. Both of bryophytes and vascular plants contain more N in a longer growing season, and prefer inorganic over organic N. Bryophytes assimilate more NH4+ than NO3– and amino acid, which can be indicated from the greater shoot excess 15N of bryophytes. However, vascular plants prefer to absorb NO3– for their developed root systems and vascular tissue. Concerning the uptake of three forms N by bryophytes, there is significant difference between two manipulated lengths of growing season. Furthermore, the capacity of bryophytes to tolerate N-pollution may be lower than currently appreciated, which indicates the effect of climate change on asynchronous variation of soil N pools with plant requirements.

关 键 词：Plant functional groups N pulse Alpine meadow N uptake N recovery 

分 类 号：Q948[生物学—植物学] S812.2[农业科学—草业科学]