Benko-Iseppon et al. 2015 (Conference Paper) Bromeliaceae

An overview and abstracts of the First World Congress on Bromeliaceae Evolution

Author(s):—A.M. Benko-Iseppon, M. Alves & R. Louzada

Publication:— (2015). — DOI

Abstract:—CAM plants have the capacity to deal with highly changing environments due to the flexibility of reversible morphological and physiological adaptations to multiple stresses. However, little is known about the signalling pathway of ROS in plants with 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 of Guzmania monostachia . The exposure of G . monostachia plants to 10 days of water deficit led to a decrease in the leaf relative water content (RWC) from 75% to 50% in all leaf portions (apical, middle and basal); hence, it was concluded that plants 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 ten days of CAM induction, H 2 O 2 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. The analysis showed that the middle and basal portions of the leaves increased the activity of superoxide dismutase (SOD) at 12pm 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 compared to 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 an- tioxidant 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. Funding: FAPES

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