Impact of oxidative stress on the sunflower seedling responses to water deficit

ANDRADE A.; VIGLIOCCO A.; PEREZ CHACA M.V.; MOLINA A.S.; ZIRULNIK F.; ALEMANO S.

Congreso; XXXV Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2017

One of the most important effects of environmental stresses on plants is overproduction and generating of reactive oxygen species (ROS). Our aim was to evaluate the content of hydrogen peroxide (H2O2) and the activity of three antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) in shoots and roots of seedlings of two sunflower inbred lines (B59 and B71, respectively sensitive and tolerant to water stress) in response to moderate water stress and subsequent re-watering. The H2O2 content was determined according to Sergiev et al. (1997) and SOD by Beauchamp y Fridovich, (1973). CAT activity was measured according to Aebi (1984) and APX activity according to Chen and Asada (1989). In response to water stress, higher content of H2O2 were detected in both lines. However, this increase was superior in shoot and roots of B59 seedlings. During re-watering period a decrease in H2O2 was observed in shoots of both lines. In response to water stress, CAT activity showed a high level in shoots of B59 respect to B71, SOD activity decreased in shoots and roots of B71 line, and the activity of APX was high in both shoots and roots of B71 tolerant line. In B71 tolerant line, the increase of SOD activity during re-watering would reduce the oxidative stress caused by water stress, which was evidenced as H2O2 content decrease. This finding could be used to choose hybrids from B71 line with better performance against water stress conditions in the Pampa Central-West.