TY - JOUR
T1 - Role of light in the response of PSII photochemistry to salt stress in the cyanobacterium Spirulina platensis
AU - Lu, Congming
AU - ZHANG, Jianhua
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2000/5
Y1 - 2000/5
N2 - The role of light in the effect of salt stress on PSII photochemistry in the cyanobacterium Spirulina platensis grown at 50 μmol m-2 s-1 was investigated. The time-course of changes in PSII photochemistry in response to high salinity (0.8 M NaCl) incubated in the dark and at 30, 50 and 100 μmol m-2 s-1 was composed of two phases. The first phase, which was independent of light, was characterized by a rapid decrease (20-50%) in the maximal efficiency of PSII photochemistry (F(v)/F(m)), the efficiency of excitation energy capture by open PSII reaction centres (F'(v)/F'(m)), photochemical quenching (q(p)), and the quantum yield of PSII electron transport (Φ(PSI)) in the first 15 min, followed by a recovery of up to about 86-92% of their initial levels after 4 h of incubation. The second phase took place after 4 h, in which a further decline in the above parameters occurred only in the light but not in the dark, reaching levels as low as 32-56% of their initial levels after 12 h. Moreover, the higher incubation light intensity, the greater the decrease in the above parameters. At the same time, Q(B)-non-reducing PSII reaction centres increased significantly in the first 15 min and then recovered to the initial level during the first phase, but increased again in the light in the second phase. Photosynthetic oxygen evolution activity decreased sharply by 70% in the first 5 min, and then kept largely constant until 12 h. The changes in oxygen evolution activity were independent of light intensity during both phases.
AB - The role of light in the effect of salt stress on PSII photochemistry in the cyanobacterium Spirulina platensis grown at 50 μmol m-2 s-1 was investigated. The time-course of changes in PSII photochemistry in response to high salinity (0.8 M NaCl) incubated in the dark and at 30, 50 and 100 μmol m-2 s-1 was composed of two phases. The first phase, which was independent of light, was characterized by a rapid decrease (20-50%) in the maximal efficiency of PSII photochemistry (F(v)/F(m)), the efficiency of excitation energy capture by open PSII reaction centres (F'(v)/F'(m)), photochemical quenching (q(p)), and the quantum yield of PSII electron transport (Φ(PSI)) in the first 15 min, followed by a recovery of up to about 86-92% of their initial levels after 4 h of incubation. The second phase took place after 4 h, in which a further decline in the above parameters occurred only in the light but not in the dark, reaching levels as low as 32-56% of their initial levels after 12 h. Moreover, the higher incubation light intensity, the greater the decrease in the above parameters. At the same time, Q(B)-non-reducing PSII reaction centres increased significantly in the first 15 min and then recovered to the initial level during the first phase, but increased again in the light in the second phase. Photosynthetic oxygen evolution activity decreased sharply by 70% in the first 5 min, and then kept largely constant until 12 h. The changes in oxygen evolution activity were independent of light intensity during both phases.
KW - Chlorophyll fluorescence
KW - Cyanobacterium
KW - Light effect
KW - PSII photochemistry
KW - Salt stress
KW - Spirulina platensis
UR - http://www.scopus.com/inward/record.url?scp=0034114585&partnerID=8YFLogxK
U2 - 10.1093/jxb/51.346.911
DO - 10.1093/jxb/51.346.911
M3 - Journal article
C2 - 10948217
AN - SCOPUS:0034114585
SN - 0022-0957
VL - 51
SP - 911
EP - 917
JO - Journal of Experimental Botany
JF - Journal of Experimental Botany
IS - 346
ER -