Chin J Plant Ecol ›› 2017, Vol. 41 ›› Issue (3): 325-336.DOI: 10.17521/cjpe.2016.0230

• Research Articles • Previous Articles     Next Articles

Effects of different nitrogen:phosphorus levels on the growth and ecological stoichiometry of Glycyrrhiza uralensis

Ju-Ying HUANG1,*(), Hai-Long YU2, Li-Li WANG2, Kai-Bo MA2, Yang-Mei KANG2, Ya-Xian DU2   

  1. 1Institute of Environmental Engineering, Ningxia University, Yinchuan 750021, China
    and
    2College of Resources and Environment, Ningxia University, Yinchuan 750021, China
  • Online:2017-03-10 Published:2017-04-12
  • Contact: Ju-Ying HUANG
  • About author:KANG Jing-yao(1991-), E-mail: kangjingyao_nj@163.com

Abstract:

Aims The increase in atmospheric nitrogen (N) deposition has accelerated N cycling of ecosystems, probably resulting in increases in phosphorus (P) demand of ecosystems. Studies on the effects of artificial N:P treatment on the growth and carbon (C), N, P ecological stoichiometry of desert steppe species could provide not only a new insight into the forecasting of how the interaction between soils and plants responses to long-term atmospheric N deposition increase, but also a scientific guidance for sustainable management of grassland in northern China under global climate change. Methods Based on a pot-cultured experiment conducted for Glycyrrhiza uralensis (an N-fixing species) during 2013 to 2014, we studied the effects of different N:P supply ratios (all pots were treated with the same amount of N but with different amounts of P) on aboveground biomass, root biomass, root/shoot ratio, and C:N:P ecological stoichiometry both in G. uralensis (leaves and roots) and in soils. Additionally, through the correlation analyses between biomass and C:N:P ecological stoichiometry in leaves, roots, and soils, we compared the differences among the C:N:P ecological stoichiometry of the three pools, and discussed the indication of C:N:P ecological stoichiometry in soils for the growth and nutrient uptake of G. uralensis. Important findings The results showed that, reducing N:P decreased C:P and N:P ratios both in G. uralensis (leaves and roots) and in soils but increased aboveground biomass and root biomass of G. uralensis, indicating that low to moderate P addition increased P availability of soils and P uptake of G. uralensis. However, excessive low N:P (high P addition) led to great decreases in soil C:P and N:P ratios, thus hindering N uptake and the growth of G. uralensis. C:N:P ratios in the two pools of G. uralensis (especially in leaves) had close correlations with soil C:N:P ratio, indicating that the change in soil C:N:P ratio would have a direct influence on plants. Our results suggest that, through regulating C:N:P ratio in leaves and soils, appropriate amounts of P addition could balance soil P supply and plant P demand and compensate the opposite influences of long-term atmospheric N deposition increase on the structure of desert steppe.

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Key words: ecological stoichiometry, desert steppe, Glycyrrhiza uralensis, phosphorus addition