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

Abstract

Abstract. Short‐term fumigation of Spinacia oleracea with 380 μg m−3 H2S (250 ppb) resulted in a rapid accumulation of water‐soluble SH‐compounds in the shoots. After 1 h exposure a substantial increase in the SH‐content was already detectable and maximal 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 SH‐content of the roots. Glutathione was the sole water‐soluble SH‐compound accumulating upon exposure to H2S. It was calculated that during the first hour of exposure to 380 μg m−3 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 fumigation 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 H2S fumigation is discussed.