UV-B response of green and etiolated barley seedlings
2007
Fedina, I.,Bulgarian Academy of Sciences, Sofia (Bulgaria). Acad. M. Popov Inst. of Plant Physiology | Velitchkova, M.,Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Biophysics | Georgieva, K.,Bulgarian Academy of Sciences, Sofia (Bulgaria). Acad. M. Popov Inst. of Plant Physiology | Demirevska, K.,Bulgarian Academy of Sciences, Sofia (Bulgaria). Acad. M. Popov Inst. of Plant Physiology | Simova, L.,Bulgarian Academy of Sciences, Sofia (Bulgaria). Acad. M. Popov Inst. of Plant Physiology
Seven-d-old etiolated and green barley seedlings (Hordeum vulgare cv. Alfa) were irradiated with UV-B for 30 min and then kept for 24 h in light or darkness. Chlorophyll (Chl) synthesis was inhibited by about 30% as a result of UV-B irradiation, but there were no significant changes in photochemical activity measured by variable to maximum fluorescence ratio (Fv/Fm), quantum yield and oxygen evolution rate. Electron transport of etiolated seedlings was similar to that of green ones, nevertheless, the Chl content was more then 2-fold lower. Ribulose-1,5-bisphosphate carboxylase/oxygenase large and small subunits were diminished as a result of UV-B irradiation in both etiolated and green plants, especially in those kept in the darkness. Catalase activity decreased and total superoxide dismutase activity increased in both types of plants following UV-B treatment. When benzidine was used as a substrate, an isoform located between guaiacol peroxidases 2 and 3 (guaiacol peroxidase X) appeared, which was specific for UV-B treatment. As a result of irradiation, the contents of UV-B absorbing and UV-B induced compounds increased in green seedlings but not in etiolated ones.
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