Abstract: The variant cell line of Onobrychis viciaefolia Scop. (ONmetr) resistant to 80 mmol/L methionine was isolated from calli which was treated with NAN3. This ONmet cell line was induced to regenerate plantlets. After growing for 6 months on a medium without selection pressure, the ONmetr cell line was still highly resistant to methionine being 5.6-fold higher than that of the wild type. The variant cell line also expressed high level of cross-resistance to ethionine which was 6. b-fold higher than that of the wild type. The contents of total methionine (Met) ,lysine (Lys) ,threonine (Thr) in ONmetr calli were 4.00,1.09,1.50-fold respectively higher than those of the wild type. The contents of total Met、 Lys、 Thr、 Ile (isoleucine) in ONmetr regenerants were-2.0, 3.5,3. 5,2. 5-fold respectively higher than those of the wild type. Two new bands appeared in SDS-PAGE profile as well as in the superoxidase isoenzymes electrophoresis pattern of the soluble proteins of ONmetr calli, thus indicated that the variant had carried the products of the changed genes.

Key words: Onobrychis viciaefolia, Methionine, Variant selection, Regenerated plantlet