Chin J Plant Ecol ›› 2009, Vol. 33 ›› Issue (1): 141-149.DOI: 10.3773/j.issn.1005-264x.2009.01.016

• Research Articles • Previous Articles     Next Articles

PHYSIOLOGICAL RESPONSES OF THREE BRYOPHYTE SPECIES OF SOUTH CHINA TO SIMULATED NITROGEN DEPOSITION

LIU Bin-Yang1, LIU Wei-Qiu1,*(), LEI Chun-Yi2, ZHANG Yi-Shun1   

  1. 1School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
    2Heishiding Nature Reserve, Zhaoqing, Guangdong 526536, China
  • Received:2007-11-01 Accepted:2007-12-10 Online:2007-11-01 Published:2009-01-30
  • Contact: LIU Wei-Qiu
  • About author:*E-mail: lsslwq@mail.sysu.edu.cn

Abstract:

Aims Increasing global N deposition will lead to severe damage to bryophytes due to their sensitivity to N deposition. Our objective is to examine the responses of three species of bryophytes, widely distributed in South China, to simulated N deposition.
Methods Four N addition treatments (Control, 20, 40 and 60 kg N·hm-2) in three replicates were established for Reboulia hemisphaerica, Hypnum plumaeforme, and Pogonatum cirratum subsp. fuscatum. The N additions were divided into four applications.
Important findings With N addition treatments in the range of 0-60 kg N·hm -2 for H. plumaeforme, photosynthesis, concentrations of starch, soluble sugars, total N and soluble proteins all increased with increasing N addition. Inducible nitrate reductase activity (NRA) of H. plumaeforme at control conditions was very high, indicating its N-limited situation. K + leakage of H. plumaeforme increased at 20 kg N·hm -2 treatment, but did not further increase at higher N addition concentrations. Most of the physiological indices of P. cirratum subsp. fuscatum showed similar trends within an N treatment of 0-40 kg N·hm -2, but showed opposite trends at >40 kg N·hm -2. Inducible NRA of P. cirratum subsp. fuscatum at the control condition was 2.20 µg N·g -1 FW·h-1, but decreased dramatically when treated with N. Its K+ leakage only increased significantly at the 60 kg N·hm-2 N addition treatment. Soluble sugars and soluble proteins of R. hemisphaerica were not significantly different at different N treatments, but photosynthesis and the starch concentration were lower at 20 and 40 kg N·hm -2treatments than at control and 60 kg N·hm-2 treatments, while the total N concentration changed inversely. The inducible and constituted NRA of R. hemisphaerica were both very low for all treatments, indicating its restricted ability to utilize nitrates. K + leakage of R. hemisphaerica increased significantly only at an N addition of 60 kg N·hm -2.

Key words: nitrogen deposition, bryophytes, physiological response