Poster: Oxidative stress

Abs # 96: UV-C light and antioxidant production in tobacco

Presenter:	Jennings, Dianne , Dianne.B.Jennings@pmusa.com
Authors	Jennings, Dianne  (A)   Parrish, Shelly  (B)   Krauss, Marc  (C)
Affiliations:	(A): Philip Morris USA Postgraduate Research Program (B): Philip Morris USA Research Center, Lancaster Labs (C): Philip Morris USA Research Center

A wide variety of stresses are known to induce the production of active oxygen species and in turn antioxidant systems in plants. While plants are not normally exposed to UV-C light (254nm) it has been used as a post-harvest treatment in fruit production to prevent disease formation in stored fruits. UV-C exposure is associated with increases in active oxygen species as well as induction of antioxidant defenses. Of particular interest in tobacco production is the potential correlation between increased antioxidants and reduced tobacco-specific nitrosamine formation. To investigate possible benefits of UV-C treatment, greenhouse grown Burley tobacco plants were exposed to two different dosages of UV-C light. Photosynthetic rates decreased in all UV-C treated plants by 24hrs after exposure but returned to control rates by 48-72hrs. In addition UV-C treatment caused shifts in the spectral reflectance of treated leaves. Tissue samples were also analyzed for changes in phenylalanine ammonia lyase (a known precursor of salicylic acid (defense signaling) and a key enzyme in phenylpropanoid metabolism) activity and antioxidant capacity.