Effects of chlorine dioxide on the germination, oxidative metabolism and growth of barley seedlings (Hordeum vulgare L.)

The effects of chlorine dioxide, ClO2, on the germination, oxidative metabolism and growth of barley seedlings were investigated. Barley seeds were separately treated with 0, 500, 1000 and 2000 mg.L−1 ClO2 solutions. Differences in the percentage of seed germination were observed in treatments with 1000 and 2000 mg.L−1 ClO2 solutions only. However, 1000 and 2000 mg.L−1 ClO2 significantly decreased the germination percentage. No significant difference in the MDA content, electrolyte leakage and amount of chlorophyll was observed in seedlings germinated from seeds treated with 0, 500 and 1000 mg.L−1 of ClO2. Similarly, POD and CAT activities showed no significant differences in seedlings germinated from seeds treated with 0 and 500 mg.L−1 while with 1000 mg.L−1 ClO2 there was an increase of these activities. Although there was no significant difference in the above ground part fresh weight between barley seedlings in which seeds were treated with distilled water and ClO2, the fresh weight of barley roots in which seeds were treated with ClO2 was significantly higher than that of control. The total length of barley roots and the number of roots were also increased. The lignin content of barley roots was markly reduced. Staining with Evans blue indicated that barley roots were not obviously damaged. Furtherly, the stimulation of the cell membrane H+-ATPase activity and root activity were observed to be induced by ClO2.