CYCLOHEXIMIDE AND BUTHIONINE SULFOXIMINE PREVENT INDUCTION OF GENOTOXIC ADAPTATION BY CADMIUM SALT AGAINST METHYL MERCURIC-CHLORIDE IN EMBRYONIC SHOOT CELLS OF HORDIUM-VULGARE L

Presoaked seeds of barley Hordeum vulgare L. pretreated with cyclohexi mide (CH), 10(-6) M or bythionine sulfoximine (BSO), 10(-4) M, were ex posed to methyl mercuric chloride (MMCl), 10(-4) M, with or whitout pr ior conditioning with cadmium sulfate (CdSO4), 10(-4) M. Subsequently as the seeds germinated the endpoints measured were mitotic index, cel ls with mitotic aberrations and micronuclei (MNC) in embryonic shoot c ells fixed at 40, 44, 48 and 52 h of recovery. Indicated by the signif icant reduction (p less than or equal to 0.05) of the yield of cells w ith aberrations or MNC, the results confirmed that CdSO4-conditioning triggered an adaptive response to MMCl-challenge. Pretreatments of CH and BSO, whereas they potentiated the genotoxicity of MMCl, significan tly prevented (p less than or equal to 0.05) the Cd-induced genotoxic adaptation. That underscores a possible involvement of proteins in add ition to phytochelatins in the underlaying mechanisms.