NITRIC OXIDE (NO) PROTECTIVE EFFECT IN UV-B IRRADIATED MAIZE SEEDLING

TOSSI, V; LAMATTINA, L.; CASSIA, R.

Rosario, Argentina

Congreso; XLII Reunión de la Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular; 2006

Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular

PL-P40 NITRIC OXIDE (NO) PROTECTIVE EFFECT IN UV-B IRRADIATED MAIZE SEEDLING Tossi, V.E.; Lammatina, L.; Cassia, R.O. Instituto de Investigaciones Biológicas, FCEN, UNMDP.CC1245 (7600) Mar del Plata. E-mail: vanesa_e_tossi@yahoo.com.ar To determine the role of NO in the protection of plants against UV-B, maize seedlings were maintained for 10 days in normal conditions (H), or were pre-treated with Sodium Nitropruside (SNP), a NO donor (N). After that, H and N seedlings were irradiated 8 h with 3 W/m-2 of UV-B (Hi and Ni respectively). Twenty four hours after the UV-B irradiation, Hi and Ni seedlings displayed the same macroscopic aspect than non-irradiated ones. However, DAB staining showed a high concentration of reactive oxygen species (ROS) in Hi seedlings. Ni seedlings contained a greater concentration of NO detected with the fluorescent probe DAF-FM. and a strong reduction in the ROS amount compared to Hi. Five days after the UV irradiation, Hi seedlings displayed an important reduction of the leaves length, an increase of the cellular permeability and a high ROS content. Those effects were considerably attenuated in Ni. Five days after the UV irradiation, flavonoids in organic solvent extracts increase 25% in Hi and 50% in Ni, and anthocyanins increase 41% in Hi and 82% in Ni respect to the non-irradiated controls. Seedlings with alterations in flavonoids and anthocyanins synthesis did not respond to SNP. Our results indicate that NO reduces the oxidative stress generated by UV-B, scavenging the ROS and increasing the concentration of other ROS sacavengers like flavonoids and anthocyanins.