Low molecular weight thiols and chromosomal aberrations in Picea omorika upon exposure to two concentrations of H2S

Three years old spruce trees (Picea omorika) were exposed to 100 and 225 nl l(-1) H2S for three weeks. Contents of glutathione and cysteine in needles and fine roots as well as the number of chromosomal aberrations and the mi totic index in the root tips were determined. H2S exposure resulted in a su bstantial increase of the cyst(e)ine (up to 7-fold) and total glutathione c ontent (up to 3-fold) of the needles, whereas in fine roots there was solel y and increase in the glutathione content (2-fold) at 225 nl l(-1). Glutath ione was predominantly present in its reduced form, also upon H2S exposure. The number of chromosomal aberrations in the root tips increased significa ntly upon H2S, it was 2-fold higher than that in control roots. However, th e mitotic index was not affected by H2S.