Abreu et al. 2015 (Conference Paper) Guzmania

Reactive oxygen species and antioxidant enzyme activities in leaves of Guzmania monostachia plants under water deficit

Author(s):—Maria Elizabeth Abreu, Victória Carvalho & Helenice Mercier in Benko-Iseppon, A.M.; Alves, M. & Louzada, R. (2015) An overview and abstracts of the First World Congress on Bromeliaceae Evolution. Rodriguésia 66(2): A1-A66.

Publication:— (2015).

Abstract:—CAM plants have the capacity to deal with highly changing environments due to the flexibility of reversible morphologicaland physiological adaptations to multiple stresses. However, little is known about the signalling pathway of ROS in plantswith CAM metabolism, other than the knowledge that ROS production is limited in CAM plants. In the present study,we assessed the effects of drought stress on reactive oxygen species and antioxidant enzyme activities in leaf portions ofGuzmania monostachia. The exposure of G. monostachia plants to 10 days of water deficit led to a decrease in the leafrelative water content (RWC) from 75% to 50% in all leaf portions (apical, middle and basal); hence, it was concluded thatplants subjected to drought produced higher levels of reactive oxygen species (ROS) when compared with control plants.Significant variations to the formation of ROS were also identified in all leaf portions during the diurnal cycle. After tendays of CAM induction, H2O2 concentration increased significantly in contrast to control plants during the day-night cycle.In addition, the activity of antioxidant enzymes in processes related to the elimination of ROS was also evaluated. Theanalysis showed that the middle and basal portions of the leaves increased the activity of superoxide dismutase (SOD) at12pm when subjected to water deficit, while in the apical portion, this enzyme was most active at 8am in the control plants.Moreover, the plants with the water supply suspension showed greater activity of catalase (CAT) at 8am when comparedto control plants, which also showed an increase in CAT activity at 8pm in the basal portion. Ascorbate peroxidase (APX)was most active in the middle portion of plants under drought. Meanwhile, as a general tendency, a higher activity of antioxidant enzymes (SOD, CAT and APX) was observed in the middle portion of the leaves of G. monostachia that were subject to ten days of water deficit.

Keywords:—Reactive Oxygen Species; Antioxidant Enzymes; CAM Metabolism.