
TY  - JOUR
A1  - Lu, Congming 
A1  - Zhang, Jianhua 
A1  - Vonshak, Avigad 
T1  - Inhibition of quantum yield of PS II electron transport in <emph type="2">Spirulina platensis</emph> by osmotic stress may be explained mainly by an increase in the proportion of the Q<emph tye="8">B</emph>-non-reducing PS II reaction centres
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 1998
VL  - 25
IS  - 6
SP  - 689
EP  - 694
KW  - chlorophyll fluorescence, cyanobacterium, osmotic stress, PS II, QB-non-reducing PS II reaction centres, Spirulina platensis
UR  - https://doi.org/10.1071/PP98043 
N2  - Modulated chlorophyll fluorescence and fluorescence induction kinetics were used to evaluate the PS II photochemistry in Spirulina platensis exposed to osmotic stress (0&#8211;0.8 M mannitol). Osmotic stress decreased the efficiency of excitation energy capture by open PS II reaction centres (Fv&#8242;/Fm&#8242;) and more significantly, decreased photochemical quenching (qP). Osmotic stress also decreased the maximal efficiency of PS II photochemistry (Fv/Fm). There was no significant change in non-photochemical quenching (qN), indicating that the decreased Fv&#8242;/Fm&#8242; was not due to an increase in qN. Analyses of the fast fluorescence induction kinetics indicated that osmotic stress caused a significant increase in the proportion of the QB-non-reducing PS II reaction centres. Based on the results in this study, we suggest that a substantial increase in the proportion of the QB-non-reducing PS II reaction centres may be responsible for the decrease in qP and Fv&#8242;/Fm&#8242;, of which both resulted in the decrease in the quantum yield of PS II electron transport (&Phi;PSII ). 
ER  -

