Hydrogen sulphide increase the tolerance to alkalinity stress in cabbage plants (Brassica oleracea L. 'Bronco')

The present study investigates how the application of hydrogen sulphide (0.5 mM of NaHS) in Brassica oleracea L. 'Bronco' influences the processes involved in glutathione homeostasis and tolerance to alkaline stress (50 mM NaHCO3:Na2CO3). According to our results, alkaline stress increases the O2− content, lipid peroxidation, and the activities of the enzymes glyoxalase I (Gly I) and glyoxalase II (Gly II) that detoxify methylglyoxal (MG) while decreasing biomass, the activity of superoxide dismutase (SOD), the activity of enzymes involved in glutathione (GSH) synthesis and in the AsA-GSH cycle, as well as the content in reduced glutathione and the different forms of ascorbate (AsA). On the other hand, the application of NaHS improved the antioxidant response, inducing SOD activity and improving processes involved in glutathione homeostasis, boosting the reduced GSH content as well as the activity of key enzymes in glutathione synthesis and in the AsA-GSH cycle. Consequently, the application of H2S in the form of NaHS at a concentration of 0.5 mM could fortify the tolerance of Brassica oleracea L. 'Bronco' against alkaline stress.