MUTANTS OF ARABIDOPSIS-THALIANA (L) HEYNH TOLERANT TO NORFLURASON, ANINHIBITOR OF CAROTENOID BIOSYNTHESIS

Mutant plants tolerant to the bleaching effect of the herbicide norflu rason (NF) were selected from M2 seeds of Arabidopsis thaliana (L.) He ynh., ecotype Dijon. Mutants had elevated stomatal conduction (nfzl, n fz2), reduced seed dormancy (nfz3), and increased (nfz2) or decreased (nfz3-1) sensitivity to exogenous abscisic acid (ABA) during the germi nation period. The content of the (+) ABA form was two times higher in these mutants than in the initial ecotype. It was shown that exogenou s ABA prevents bleaching caused by NF. This allowed the assumption tha t, in the mutants selected, tolerance to NF is related to an increased level of endogenous ABA or to higher sensitivity of plants to this ho rmone.