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 H 2 S (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 H 2 S exposure only slightly affected the rate and level of SH‐accumulation. H 2 S fumigation did not affect the water‐soluble SH‐content of the roots. Glutathione was the sole water‐soluble SH‐compound accumulating upon exposure to H 2 S. It was calculated that during the first hour of exposure to 380 μg m −3 H 2 S 39% of the possible absorbed H 2 S was converted into glutathione. The SH‐content of the water‐soluble proteins of the shoots was not affected by H 2 S 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 H 2 S, SO 2 fumigation did not result in a rapid accumulation of glutathione in spinach shoots. The possible role of glutathione accumulation during H 2 S fumigation is discussed.