Chin J Plan Ecolo ›› 2015, Vol. 39 ›› Issue (1): 92-103.DOI: 10.17521/cjpe.2015.0010

Special Issue: 入侵生态学

• Orginal Article • Previous Articles     Next Articles

Influence of three types of salt stress on photosynthesis in Spartina alterniflora and Phragmites australis

HU Chu-Qi, LIU Jin-Ke, WANG Tian-Hong, WANG Wen-Lin, LU Shan, ZHOU Chang-Fang*()   

  1. State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, China
  • Received:2014-07-21 Accepted:2014-12-09 Online:2015-01-10 Published:2015-01-22
  • Contact: Chang-Fang ZHOU
  • About author:

    # Co-first authors

Abstract: Aims

The invasion of Spartina alterniflora has imposed significant influences on structure and functioning of coastal saltmarshes. The Spartina marsh has been found to contain relatively higher sulfur content than the adjacent native Phragmites marsh. This research is aimed to investigate if sulfur helps with S. alterniflora in competition over Phragmites australis.


Seedlings of S. alterniflora and P. australis were grown in an imitated mesocosm on the campus of Nanjing University. Three common salts of the sea water, Na2SO4, Na2S and NaCl were respectively added to the cultural medium. Light response curves of the plants before and during the four days of treatments were obtained by measuring gas exchange with varying light levels. Maximum quantum yield of photosynthesis II (PSII) and light induction curves were also measured by chlorophyll fluorescence analysis.

<i>Important findings</i>

Among the three salts, Na2S caused the greatest difference in the response of photosynthesis between S. alterniflora and P. australis, and Na2SO4 had the least effect. The Na2S treatment significantly increased net photosynthetic rate (Pn) and light saturation point (Isat) in S. alterniflora, but decreased Pn in P. australis. The NaCl treatment also increased Pn in S. alterniflora to a less degree and decreased Pn in P. australis. The Na2SO4 treatment had little effect on Pn in both S. alterniflora and P. australis. The non-photochemical quenching (NPQ) in P. australis were promoted by all three salts, whereas it was only affected by Na2S and NaCl in S. alterniflora. Our results suggest that S. alterniflora has significantly greater tolerance to sulfate and sulfide than P. australis. Therefore, sulfuric compounds and especially sulfide in saltmarsh environments might benefit the competition of S. alterniflora over P. australis, which could contribute to the formation of the mono-specific vegetation of the invasive S. alterniflora.

Key words: biological invasion, saltmarsh ecosystem, Spartina alterniflora, Phragmites australis, sulfur enviroment, salt stress, photosynthesis