TY - JOUR
T1 - Repetitive short-pulse light mainly inactivates photosystem i in sunflower leaves
AU - Sejima, Takehiro
AU - Takagi, Daisuke
AU - Fukayama, Hiroshi
AU - Makino, Amane
AU - Miyake, Chikahiro
N1 - Funding Information:
This work was supported by the Japan Society for the Promotion of Science [Scientific Research Grant No. 21570041 to C.M.]; the Ministry of Education, Culture, Sports, Science, and Technology in Japan [Scientific Research on Innovative Area No. 22114512 to C.M. and A.M.].
PY - 2014/6
Y1 - 2014/6
N2 - Under field conditions, the leaves of plants are exposed to fluctuating light, as observed in sunfleck. The duration and frequency of sunfleck, which is caused by the canopy being blown by the wind, are in the ranges from 0.2 to 50 s, and from 0.004 to 1 Hz, respectively. Furthermore, >60% of the sunfleck duration ranges from 0.2 to 0.8 s. In the present research, we analyzed the effects of repetitive illumination by short-pulse (SP) light of sunflower leaves on the photosynthetic electron flow. The duration of SP light was set in the range from 10 to 300 ms. We found that repetitive illumination with SP light did not induce the oxidation of P700 in PSI, and mainly inactivated PSI. Increases in the intensity, duration and frequency of SP light enhanced PSI photoinhibition. PSI photoinhibition required the presence of O2. The inactivation of PSI suppressed the net CO2 assimilation. On the other hand, the increase in the oxidized state of P700 suppressed PSI inactivation. That is, PSI with a reduced reaction center would produce reactive oxygen species (ROS) by SP light, leading to PSI photodamage. This mechanism probably explains the PSI photodamage induced by constant light.
AB - Under field conditions, the leaves of plants are exposed to fluctuating light, as observed in sunfleck. The duration and frequency of sunfleck, which is caused by the canopy being blown by the wind, are in the ranges from 0.2 to 50 s, and from 0.004 to 1 Hz, respectively. Furthermore, >60% of the sunfleck duration ranges from 0.2 to 0.8 s. In the present research, we analyzed the effects of repetitive illumination by short-pulse (SP) light of sunflower leaves on the photosynthetic electron flow. The duration of SP light was set in the range from 10 to 300 ms. We found that repetitive illumination with SP light did not induce the oxidation of P700 in PSI, and mainly inactivated PSI. Increases in the intensity, duration and frequency of SP light enhanced PSI photoinhibition. PSI photoinhibition required the presence of O2. The inactivation of PSI suppressed the net CO2 assimilation. On the other hand, the increase in the oxidized state of P700 suppressed PSI inactivation. That is, PSI with a reduced reaction center would produce reactive oxygen species (ROS) by SP light, leading to PSI photodamage. This mechanism probably explains the PSI photodamage induced by constant light.
KW - Photoinhibition
KW - Photosystem I
KW - Reactive oxygen species (ROS)
KW - Water-Water Cycle (WWC)
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U2 - 10.1093/pcp/pcu061
DO - 10.1093/pcp/pcu061
M3 - Article
C2 - 24793753
AN - SCOPUS:84902480138
SN - 0032-0781
VL - 55
SP - 1184
EP - 1193
JO - Plant and Cell Physiology
JF - Plant and Cell Physiology
IS - 6
ER -