5 research outputs found
UV-B response of greening barley seedlings
The relationship between the greening stage of barley seedlings and their response to UV-B irradiation
was studied. Etiolated barley seedlings (Hordeum vulgare L., cv. Alfa) greened 12, 24 and 48 h were
exposed to UV-B irradiation (312 nm) for 5 h. As a result of UV-B treatment the rate of CO2 fixation
and chlorophyll contents decreased but flavonoids, UV-B-induced compounds and carotenoids
increased. The inhibition of photosynthesis in green plants was lower in comparison to greening ones.
The 12 h greening plants were more sensitive to UV-B treatment than the plants greening 24 h and particularly
48 h, estimated by the quantum efficiency of PSII photochemistry and the oxygen production
rate. The levels of flavonoids and UV-B induced compounds enhanced with increasing the greening time.
Activity of antioxidant enzymes catalase, peroxidase and superoxide dismutase increased during the
seedlings greening and as a result of UV-B irradiation, but the pattern of isoforms remained similar to
those found in the controls. UV-B preferentially induced Cu,Zn-superoxide dismutase. Increase of UVB
induced synthesis of antioxidant enzymes is in line with their important role in the plant response to
UV-B stress. Data presented show that the response of barley seedlings to UV-B irradiation is related to
the development stage of photosynthetic apparatus