Chin J Plant Ecol ›› 2019, Vol. 43 ›› Issue (1): 46-54.DOI: 10.17521/cjpe.2018.0100

• Research Articles • Previous Articles     Next Articles

Nitrogen and phosphorus stoichiometric homoeostasis in leaves of dominant sand-fixing shrubs in Horqin Sandy Land, China

NING Zhi-Ying1,2,LI Yu-Lin1,*(),YANG Hong-Ling1,2,ZHANG Zi-Qian1,2   

  1. 1 Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resource, Chinese Academy of Sciences, Lanzhou 730000, China
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-05-04 Accepted:2018-12-24 Online:2019-01-20 Published:2019-04-23
  • Contact: LI Yu-Lin
  • Supported by:
    Supported by the National Natural Science Foundation of China(31270501);the National Key R&D Program of China(2016YFC0500907)

Abstract:

Aims Sand-fixing shrubs play an irreplaceable role in ecological restoration and eco-environmental protection in arid and semiarid regions of northern China. Determination of the stoichiometric homoeostasis of dominant sand-fixing shrubs along soil nutrient gradients could provide insights into ecological adaptability and pattern of changes of sand-fixing vegetation in Horqin Sandy Land.
Methods We measured N and P concentrations in leaves of two dominant sand-fixing shrubs Caragana microphylla and Artemisia halodendron, and the total and available N and P concentrations in soils beneath the canopy of each shrub. The differences between the two shrubs in N and P concentrations and N:P of leaves and soils as well as in stoichiometric homoeostasis were examined.
Important findings Caragana microphylla had higher leaf N concentration and lower leaf P concentration, thereby higher leaf N:P, than A. halodendron. Soils beneath the shrub canopies, regardless of the species, had higher total and available N and P concentrations relative to soils outside the canopy cover. Moreover, the total and available N and P concentrations in soils beneath the C. microphylla canopy were higher than that beneath the A. halodendron canopy. The stoichiometric homoeostasis indexes (H) were ranked in the order of HP > HN:P > HN in A. halodendron and HN:P > HN > HP in C. microphylla, respectively, suggesting N limitation in A. halodendron and P limitation in C. microphylla. Therefore, Caragana microphylla could be used as nursing plants in degraded N-limiting soil because of high HN. However, due to excessive uptake of N, Caragana microphylla might suffer from P limitation, and adequate P supply should be considered during the restoration process in sandy land.

Key words: Horqin Sandy Land, shrub, leaf, soil, stoichiometric homoeostasis