Premium
Temperature/light dependent development of selective resistance to photoinhibition of photosystem I
Author(s) -
Ivanov A.G,
Morgan R.M,
Gray G.R,
Velitchkova M.Y,
Huner N.P.A
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00681-4
Subject(s) - photoinhibition , photosystem ii , biophysics , chemistry , photosystem i , botany , photosynthesis , photochemistry , biology
Exposure of winter rye leaves grown at 20°C and an irradiance of either 50 or 250 μmol m −2 s −1 to high light stress (1600 μmol m −2 s −1 , 4 h) at 5°C resulted in photoinhibition of PSI measured in vivo as a 34% and 31% decrease in ΔA 820 /A 820 (P700 + ). The same effect was registered in plants grown at 5°C and 50 μmol m −2 s −1 . This was accompanied by a parallel degradation of the PsaA/PsaB heterodimer, increase of the intersystem e − pool size as well as inhibition of PSII photochemistry measured as F v /F m . Surprisingly, plants acclimated to high light (800 μmol m −2 s −1 ) or to 5°C and moderate light (250 μmol m −2 s −1 ) were fully resistant to photoinhibition of PSI and did not exhibit any measurable changes at the level of PSI heterodimer abundance and intersystem e − pool size, although PSII photochemistry was reduced to 66% and 64% respectively. Thus, we show for the first time that PSI, unlike PSII, becomes completely resistant to photoinhibition when plants are acclimated to either 20°C/800 μmol m −2 s −1 or 5°C/250 μmol m −2 s −1 as a response to growth at elevated excitation pressure. The role of temperature/light dependent acclimation in the induction of selective tolerance to PSI photoinactivation is discussed.