After a brief exposure to supra-saturating light, leaves of a tobacco trans
formant, in which chloroplastic NAD(P)H dehydrogenase (NDH) Tvas defective,
showed more severe photoinhibition than the wild-type, when judged by the
parameter of chlorophyll fluorescence Fv/Fm, Repeated application of supra-
saturating light eventually resulted in chlorosis in the NDH-defective muta
nt, while the mild-type sustained less photodamage and was able to recover
from it. The mechanism of the phenomena is discussed with respect to the po
tential role of NDH in photosynthesis. (C) 1999 Federation of European Bioc
hemical Societies.