Effects of salt stress on PSII function and photoinhibition in the cyanobacterium Spirulina platensis

Cong Ming Lu, Jianhua ZHANG*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

The changes in PSII function and susceptibility to photoinhibition in the cyanobacterium Spirulina platensis adapted to 0.75 mol/L NaCl were evaluated by use of chlorophyll fluorescence. In salt-stressed cells, photochemical quenching (q(p)) decreased while the proportion of Q(B)-non-reducing PSII reaction centres increased. However, salt stress had small effect on the maximal efficiency of PSII photochemistry (F(v)/F(m)) and the efficiency of excitation energy capture by open PSII reaction centres (F(v)/F(m')). These results suggest that the decreased quantum yield of PSII electron transport (Φ(PSII)) in salt-stressed cells was mainly due to the decreased qp, which can be explained by an increase in the proportion of O(B)-non-reducing PSII reaction centres. On the other hand, increased susceptibility to photoinhibition was observed in salt-stressed cells when exposed to high light (600 μmol m-2 s-1). Such increased susceptibility was reflected by a greater decrease in F(v)/F(m), F(v')/F(m'), q(p) and Φ(PSII), as well as in a greater increase in the proportion of Q(B)-non-reducing PSII reaction centres. No significant difference in non-photochemical quenching (q(N)) was observed between control cells and salt-stressed cells. Our results suggest that an increase in the proportion of Q(B)-non-reducing PSII reaction centres induced by salt stress may be responsible for increased susceptibility of PSII to photoinhibition.

Original languageEnglish
Pages (from-to)740-745
Number of pages6
JournalJournal of Plant Physiology
Volume155
Issue number6
DOIs
Publication statusPublished - Dec 1999

Scopus Subject Areas

  • Physiology
  • Agronomy and Crop Science
  • Plant Science

User-Defined Keywords

  • Chlorophyll fluorescence
  • Photoinhibition
  • Photosystem II
  • Salt stress
  • Spirulina platensis (cyanobacterium)

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