Activity of antioxidant enzymes during induction of morphogenesis of Fritillaria meleagris in bulb scale culture

We investigated the activity of 3 antioxidant enzymes: superoxide dismutase, catalase, and peroxidase during morphogenesis of Fritillaria meleagris L. in vitro in bulb scale culture. Bulb cultures of F. meleagris were established on nutrition medium supplemented with 1.0 mg L^–1 thidiazuron. Bulbs were grown at standard (24 °C) and low temperatures (4 °C) or at an increased sucrose concentration (4.5%) during the first 6 weeks (pretreatments). All bulbs were then grown for 4 weeks at standard temperature on 2, 4-dichlorophenoxyacetic acid and kinetin or thidiazuron (at concentrations of 1 mg L^–1 each) in order to examine the influence of the above-mentioned pretreatments and nutrient medium composition on enzyme activity. Enzyme activity was measured 7, 14, 21, and 28 days after the start of morphogenesis induction. Superoxide dismutase and catalase showed the highest activity at the beginning of morphogenesis in vitro. Peroxidase activity was the highest in bulb segments immediately after isolation following pretreatments and on both nutrition media. We also determined the effect of pretreatment coupled with low temperature (4 °C) on growth and development of F. meleagris in vitro and chlorophyll and carotenoids content.