Chin J Plant Ecol ›› 2017, Vol. 41 ›› Issue (6): 610-621.DOI: 10.17521/cjpe.2016.0329

Special Issue: 青藏高原植物生态学:植物-土壤-微生物

• Research Articles • Previous Articles     Next Articles

Effects of nitrogen enrichment on root exudative carbon inputs in Sibiraea angustata shrubbery at the eastern fringe of Qinghai-Xizang Plateau

Wei HE1,2, Xue-Ying YANG3, Juan XIAO4, Zi-Liang ZHANG1,2, Zheng JIANG1,2, Yuan-Shuang YUAN1,2, Dong WANG1,2, Qing LIU1, Hua-Jun YIN1,4,*()   

  1. 1Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China;

    2University of Chinese Academy of Sciences, Beijing 100049, China

    3Lixian Forestry Bureau, Lixian, Sichuan 623100, China
    4College of Environmental Science and Engineering, China West Normal University, Nanchong, Sichuan 637000, China
  • Received:2017-04-05 Accepted:2016-10-21 Online:2017-06-10 Published:2017-07-19
  • Contact: Hua-Jun YIN
  • About author:KANG Jing-yao(1991-), E-mail:


Aims Understanding the responses of root exudative carbon (C) to increasing nitrogen deposition is important for predicting carbon cycling in terrestrial ecosystems. However, fewer studies have investigated the dynamics of root exudation in shrubbery ecosystems compared to forests and grassland ecosystems. This objective of this study was to determine the effects of nitrogen fertilization on the rate and C flux of root exudates.Methods Three levels of nitrogen addition treatments were applied to a Sibiraea angustata shrubbery ecosystem situated at the eastern fringe of Qinghai-Xizang Plateau, including N0 (without nitrogen application), N5 (nitrogen addition rate of 5 g·m-2·a-1), and N10 (nitrogen addition rate of 10 g·m-2·a-1), respectively, in 5 m ´ 5 m plots. Root exudates were collected in June, August and October of 2015, using a modified culture-based cuvette system. Root biomass in each plot was measured with root core method.Important findings The rates of root exudates on biomass, length, and surface area basis all displayed apparent seasonal variations during the experimental period, with the magnitude ranked in the order of: August > June > October, consistent with changes in soil temperature at 5 cm depth. With increases in the nitrogen addition rate, the rate of root exudates on biomass, length, and area basis all trended lower. Compared with the control (N0), the N5 and N10 treatments significantly reduced fine root biomass in the Sibiraea angustata shrubbery, by 23.36% and 33.84%, respectively. The decreasing root exudation and fine root biomass in response to nitrogen addition significantly decreased C flux of root exudates. Our results provide additional evidences toward a robust theoretical foundation for better understanding soil C-nutrient cycling process mediated by root exudation inputs in Alpine shrubbery ecosystems under various environmental changes.

Key words: Sibiraea angustata shrubbery, nitrogen addition, root exudation, root biomass, root exudation flux