Long Wave UV-B Radiation and Asahi SL Modify Flavonoid Content and Radical Scavenging Activity of Zea mays var. saccharata Leaves

摘要

The experiment on Zea mays L. cv. Landmark (F1) plants was performed in a greenhouse with UV-B (305-315 nm). The pots with plants were divided into four groups: the first and the second groups were grown, respectively, at low (1.0 kJ m~(-2) d~(-1)) and high (3.0 kJ m~(-2) d~(-1)) biological effective dose of UV-B radiation. Half of the pots of each group were sprayed with 0.1% solution of Asahi SL (the third and fourth groups). The intensity of photosynthesis and transpiration, chlorophyll fluorescence, the content of UV-absorbing compounds and radical scavenging activity were measured using DPPH after four and six weeks of UV-B radiation. After six weeks of irradiation with a higher UV-B dose both flavonoid content and antioxidant activity increased by 112% and by 44%, respectively, compared to the plants grown at the lower dose. The plants treated with Asahi SL and exposed to the high dose of UV-B had the content of flavonoids 80% higher than the control ones. Asahi SL decreased scavenging activity in both groups of plants by 17% and 32%, respectively, in comparison with the untreated plants. The intensity of net photosynthesis, the transpiration rate and chlorophyll fluorescence parameters (Fv/Fo, ETR, Rfd) did not differ in most of variants.