Abstract: Objective: To study the oxidative stress and antioxidative response of Cinnamomum camphora seedlings exposed to nitrogen dioxide (NO₂) fumigation. Methods: Measurements were made up of the growth, chlorophyll content, chlorophyll fluorescence, antioxidant system and lipid peroxidation of one-year-old C. camphora seedlings exposed to NO₂ (0.1, 0.5, and 4 μl/L) fumigation in open top chambers over a period of 60 d. Results: After the first 30 d, 0.5 and 4.0 μl/L NO₂ showed insignificant effects on the growth of C. camphora seedlings. However, exposure to 0.5 and 4.0 μl/L NO₂ for 15 d significantly reduced their chlorophyll content (P<0.05), enhanced their malondialdehyde (MDA) content and superoxide dismutase (SOD) activity (P<0.05), and also significantly reduced the maximal quantum yield of PSII in the dark [the ratio of variable fluorescence to maximal fluorescence (F_v/F_m)] (P<0.05). In the latter 30 d, 0.5 μl/L NO₂ showed a positive effect on the vitality of the seedlings, which was reflected by a recovery in the ratio of F_v/F_m and chlorophyll content, and obviously enhanced growth, SOD activity, ascorbate (AsA) content and glutathione reductase (GR) activity (P<0.05); 4.0 μl/L NO₂ then showed a negative effect, indicated by significant reductions in chlorophyll content and the ratio of F_v/F_m, and inhibited growth (P<0.05). Conclusion: The results suggest adaptation of C. camphora seedlings to 60-d exposure to 0.1 and 0.5 μl/L NO₂, but not to 60-d exposure to 4.0 μl/L NO₂. C. camphora seedlings may protect themselves from injury by strengthening their antioxidant system in response to NO₂-induced oxidative stress.

Key words: Cinnamomum camphora, Fumigation, Growth, Chlorophyll content, Chlorophyll fluorescence, Antioxidant, Lipid peroxidation

Please provide your name, email address and a comment

Your Name: Affili: E-Mail Address:

Comment (Please comment in English):


Verification Code(click to change a pic):