Enzymatic antioxidants—Relevant or not to protect the photosynthetic system against cadmium-induced stress in Massai grass supplied with sulfur?

Made available in DSpace on 2019-10-04T12:30:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-11-01 Brazilian Federal Government Agency Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Research Foundation Flanders - FWO Exposure to cadmium (Cd) can cause oxidative stress and injuries to the photosynthetic apparatus of plants. Otherwise, plant metabolism impaired by Cd toxicity can be aided by a proper sulfur (S) nutrition, since S is a component of antioxidants and photosynthetic systems. In this sense, our aim in this study was to evaluate the effect of S supply (0.1, 1.9 and 3.7 mmol L-1) on the antioxidant and photosynthetic systems of Massai grass exposed to Cd (0.0, 0.1 and 0.5 mmol L-1) as a prerequisite for studies of Cd phytoextraction. Plants supplied with 3.7 mmol L-1 S showed the lowest growth and the highest Cd concentrations when exposed to 0.5 mmol L-1 Cd. However, Massai grass grown without S deprivation showed the highest GSH + GSSG concentrations in all tissues and the lowest lipid peroxidation in stems and sheaths and roots. In general, the activities of SOD, CAT, APX, GPOX and GR did not increase in Massai grass exposed to Cd, even with proper S supply. Severe Cd exposure halted the photosynthetic system of Massai grass, although well-nourished plants with S exhibited greatest photosynthetic rate probably due to the action of GSH in the control of the oxidative stress. Univ Sao Paulo, Ctr Nucl Energy Agr, BR-13416000 Piracicaba, Brazil Hasselt Univ, Ctr Environm Sci, B-3590 Diepenbeek, Belgium Univ Fed Acre, BR-69920900 Rio Branco, Brazil Univ Sao Paulo, Luiz de Queiroz Coll Agr, BR-13418900 Piracicaba, Brazil Sao Paulo State Univ, BR-17602496 Tupa, Brazil Sao Paulo State Univ, BR-17602496 Tupa, Brazil CAPES: 1332394 FAPESP: 2014/16731-7 FAPESP: 2014/18735-0 FAPESP: 2015/21562-2 FAPESP: 2017/12367-7