The effects of paraquat on cabbage (Brassica oleracea var. capitata L.) cultured in vitro

Considering the great toxicity paraquat has to a wide range of plant and animal species, including man, we have investigated the possible use of cabbage in vitro cultures as a model system suitable to study this pesticide. The main aim of this study was to investigate the effect of paraquat on growth and development of cabbage shoot cultures. Special attention was paid to the detection of eventual means by which cultures can overcome the detrimental effect of the chemical, and also to investigate if some of the genotypes coming from the breeding program have an increased tolerance to paraquat. Promising domestic genotypes P194, P295, P6p, P44 were investigated in the rooting stage. A root induction medium containing MS inorganic salts and 5.0 mgl(-1) IBA was also supplemented with Paraquat at 0.5, 2.0, 10.0, 50.0 mgl-(1). Shoots were treated for 24 hours and then transferred to a hormone free medium. After 28 days we measured shoot length, number of internodes, percentage of rooting, root length and formation of laterals. Paraquat decreased all the parameters which were followed. On leaves it induced lesions. Genotypes P44 and P6p were more tolerant to paraquat then the other two genotypes. Genotype P44 was interesting since in some plants lateral shoot formation occurred.