Do oxidative stress conditions impairing photosynthesis in the light manifest as photoinhibition?
We compared the effect of photoinhibition by excess photosynthetically active radiation (PAR), UV-B irradiation combined with PAR, low temperature stress and paraquat treatment on photosystem (PS) II. Although the experimental conditions ensured that the four studied stress conditions resulted in approximately the same extent of PS II inactivation, they clearly followed different molecular mechanisms. Our results show that singlet oxygen production in inactivated PS II reaction centres is a unique characteristic of photoinhibition by excess PAR. Neither the accumulation of inactive PS II reaction centres (as in UV-B or chilling stress), nor photo-oxidative damage of PS II (as in paraquat stress) is able to produce the special oxidizing conditions characteristic of acceptor-side-induced photoinhibition.
Hideg
E
E
Institute of Plant Biology, Biological Research Centre, Szeged, Hungary.
Kálai
T
T
Hideg
K
K
Vass
I
I
D004579:Electron Transport; D008027:Light; D015394:Molecular Structure; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis / Q000502:physiology*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism* / Q000528:radiation effects; D045332:Photosystem II Protein Complex; D018515:Plant Leaves / Q000378:metabolism; D010947:Plants, Toxic; D026082:Singlet Oxygen; D014026:Nicotiana; D014466:Ultraviolet Rays
D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D026082:Singlet Oxygen; D010100:Oxygen