Hs. Kang et al., EFFECTS OF LIGHT ENVIRONMENT DURING CULTURE ON UV-INDUCED CYCLOBUTYL PYRIMIDINE DIMERS AND THEIR PHOTOREPAIR IN RICE (ORYZA-SATIVA L.), Photochemistry and photobiology, 68(1), 1998, pp. 71-77
We examined the effects of a light environment during culture of rice
plants (Oryza sativa) on the steady-state cyclobutyl pyrimidine dimer
(CPD) level, CPD induction by challenge UVB exposure and the ability t
o photorepair CPD, The steady-state CPD level in plants grown under vi
sible radiation with supplemental UVB radiation in a growth chamber wa
s several times higher than in plants grown without supplemental UVB r
adiation, whereas in outdoor-grown plants, it was not enhanced by supp
lemental UVB radiation. The susceptibility to CPD induction by challen
ge UVB exposure was highest in dark-grown plants and decreased with in
creasing irradiance of visible radiation at low and high levels and ou
tdoors. Chronic UVB radiation reduced the susceptibility to UV-induced
CPD in plants grown both indoors and outdoors. There was a significan
t negative correlation between CPD levels induced by challenge UVB exp
osure and the content of UV-absorbing compounds. The UV-induced CPD co
uld be reduced by subsequent blue radiation in all samples except in d
ark-grown seedlings. The higher the irradiance of visible radiation in
the culture, the greater the ability to photorepair CPD. Chronic UVB
radiation did not increase the ability to photorepair CPD.