Mutagenic treatments of cotyledons for in vitro plant regeneration in oilseed rape

摘要

Ultraviolet (UV) irradiation, mutagenic agents ethylmethane sulphonate (EMS) and sodium azide (NaN3) were applied to cotyledons of two Brassica napus cultivars N1 and N6 in vitro. Cotyledons were exposed to the UV radiation for different time intervals (30, 60, 120, 180, 240 s). The results showed that UV had some promotive effect on cotyledon regenerations. The highest rates of callus induction (85.71 and 83.33%) and plant regeneration (67.86 and 50.00 %) were observed from UV treatment of 120 and 60 sec in genotypes N1 and N6 respectively. With the increase of UV radiation intervals, the rate of plant regeneration decreased gradually although the rate of callus induction was not much affected. There was no difference in the rates of callus induction and plant regeneration between the treatment of lower EMS concentration (0.01% for 5 h) and the control. However, with the increase in concentrations and prolongation of treatment intervals, the rate of induced calli and the rate of regenerated plants decreased progressively in both genotypes. No plant was regenerated when the EMS concentration reached 1% and the exposure time lasted for 25 h. After NaN3 treatment, the rate of callus induction was not much affected or even higher than that of the control. As for the plant regeneration, there was no obvious difference between the treatment of lower NaN3 concentration (10 μM) and the control in both genotypes. Higher concentrations of NaN3 (100 and 1000 μM) inhibited the plant regeneration, and no plant was produced when its concentration reached 1000 μM and the exposure time lasted for 25 h.