Chin J Plant Ecol ›› 2010, Vol. 34 ›› Issue (1): 23-28.DOI: 10.3773/j.issn.1005-264x.2010.01.005

Special Issue: 生态化学计量

• Special feature: Ecological Stoichiometry • Previous Articles     Next Articles

Seasonal variations of leaf nitrogen and phosphorus stoichiometry of three herbaceous species in Hangzhou Bay coastal wetlands, China

WU Tong-Gui*(), WU Ming**(), LIU Li, XIAO Jiang-Hua   

  1. Research Institute of Sub-tropical Forestry, Chinese Academy of Forestry, Fuyang, Zhejiang 311400, China
  • Received:2008-09-25 Accepted:2009-02-16 Online:2010-09-25 Published:2010-01-01
  • Contact: WU Ming


Aims Homeostasis constrains the elemental composition of individual species within narrow bounds no matter the chemical composition of the environment or the resource base. Our objective was to determine the dynamics of leaf stoichiometry during the growth period of plants and the optimum time for stoichiometry study.

Methods We monitored leaf N, P stoichiometry of Scirpus mariqueter, Carex scabrifolia and Phragmites australis, the dominant species in Hangzhou Bay coastal wetlands, at different growth stages from May to October 2007.

Important findings Leaf N, P stoichiometry of the Scirpus, Carex and Phragmites species showed differences: 7.41-17.12, 7.47-13.15 and 6.03-18.09 mg·g-1 for N, 0.34-2.60, 0.41-1.10 and 0.35-2.04 mg·g-1 for P, and 7.19-30.63, 11.58-16.81 and 8.62-21.86 for N:P ratios, respectively. The arithmetic means for the three species were (11.69 ± 2.66), (10.17 ± 1.53) and (11.56 ± 3.19) mg·g-1 for N, (0.93 ± 0.62), (0.74 ± 0.23) and (0.82 ± 0.53) mg·g-1 for P, and 16.83 ± 8.31, 14.53 ± 3.91 and 16.49 ± 5.51 for N:P, respectively, but there was no significant difference of N, P stoichiometry (p > 0.05). It showed high N, P concentrations at the early stage of growth because of small biomass and then decreased greatly with leaf expansion during the fast growth period, increased as leaf growth became stable and decreased again with leaf senescence. Leaf N:P was low at the early stage of growth and then increased, decreased strongly at the fast growth period, and became stable after leaf maturation.

Key words: Hangzhou Bay coastal wetlands, N and P stoichiometry, seasonal variations