The effect of short‐term H₂S fumigation on water‐soluble sulphydryl and glutathione levels in spinach

Abstract

Short-term fumigation of Spinacia oleracca with 380/ig m"'' H2S (250 ppb) resulted in a rapid accumulation of water-soluble SH-compounds in the shoots. After 1 h exposure a substantial inctease in the SH-content was already detectable and maxitnal accumulation, three-to four-fold that in control plants, was observed after 24 h of exposure. Irradiation during H2S exposure only slightly affected the rate and level of SH-accumulation. H2S fumigation did not affect the water-soluble SHcontent of the roots. Glutathione was the sole watersoluble SH-cornpound accutiiulating upon exposure to H2S. It was calculated that during the first hour of exposure to 380/tg m~-^ H2S 39% of the possible absorbed H2S was converted into glutathione. The SH-content of the water-soluble proteins of the shoots was not affected by H2S exposure. When futnigation was stopped, a rapid decrease in glutathione content was observed and after 48 h the content was comparable to that of the control plants. Contrary to H2S, SO2 fumigation did not result in a rapid accumulation of glutathione in spinach shoots. The possible role of glutathione accumulation during HjS fumigation is discussed.

Variação sazonal em antioxidantes em folhas de plantas jovens de Caesalpinia echinata Lam. (pau-brasil)

“…0,2 mL de DTNB 0,04% em tampão fosfato (0,02 M pH 7,0), 0,2 mL de tampão fosfato (0,02 M pH 7,0) e 1,1 mL de tampão trisHCl (pH 8,0), 0,3 mL de albumina (1%), 0,01 mL de glioxilase I e 0,09 mL de metil-glioxal (0,1 M), e foram mantidos por 15 min em temperatura ambiente, visando a conversão da glutationa em S-lactonil glutationa. O conteúdo de GSH foi, então, calculado pela diferença entre as concentrações obtidas nos extratos desproteinizados e naqueles incubados com glioxalase I e metil-glioxial (De Kok et al 1985). Atividade das peroxidases (POD) -As folhas congeladas (0,3 g) foram homogeneizadas com tampão fosfato (0,1 M, pH 7,0) e polivinilpolipirrolidona (PVPP) 2% e centrifugadas (40.000 g, 30 min, a 2 ºC).…”

Alteration of Extracellular Enzymes in Pinto Bean Leaves upon Exposure to Air Pollutants, Ozone and Sulfur Dioxide

“…The total SH-content of the extracellular fluid was assayed as described by DeKok et al (7). Sulfhydryl was determined in 0.2 M Tris-HCl, 1 mM K-phosphate buffer (pH 8.0), 2% SDS, and 0.5 mm 5,5'-dithio-bis (2-nitrobenzoic Acid) (DTNB).…”

Hydrogen sulfide causes excision of a genomic island in Pseudomonas syringae pv. phaseolicola

“…Dedicated enzymes in plants generate H 2 S, such as desulhydrases (Alvarez et al 2010). The effects in plants include increased germination rates (Dooley et al 2013), alteration of glutathione levels (de Kok et al 1985) and mediating the responses to a range of stresses (reviewed by Lisjak et al 2013). It has been reported that H 2 S causes the opening of stomata on plants (Lisjak et al 2010(Lisjak et al , 2011, although closure induced by H 2 S has also been reported (García-Mata and Lamattina 2010), the difference probably due to the plant growth conditions.…”