اثر میدان مغناطیسی بر اندام زایی مستقیم ریزنمونه بنفشه آفریقایی (Saintpaulia ionantha) در محیط فاقد و دارای تنظیم کننده های رشد

To study intermittence of duration of exposure to magnetic field or MF (0.9 mT) on direct organogenesis of African violet explant in medium with and without PGRs these experiments performed. First experiment performed as completely randomized design (CRD) with three level of MF exposure (control, 5 day continuous and 5 day discontinuous) in PGR- free medium included via 6 repeat. The second experiment performed as factorial in CRD.  Factors included auxin and cytokenin as two PGRs in 1mg Lit and 3mg Lit IBA and BAP levels and 3 levels of MF exposure as well as first experiment with 6 repeat. The results showed that explants exposed to a discontinuous MF with and without PGRs produced the highest shoot number (7.08) and the lowest number was produced in the control (2.35). Plantlets length was not affected by the MF but it was affected inside of PGRs. The leaf number in the continuous (4.4) and discontinuous (4.7) magnetic field was approximately doubled in comparison with control (2.77). The fresh and dry weight revealed better values in the MF discontinuous (0.49 and 0.03 mg) than continuous (0.35 and 0.02 mg) in PGRs-free medium. Results showed the fresh weight of plantlets was significantly higher for 1mgl-1 PGRs than 3 mgl-1 PGRs, when exposed to 0.9 mT MF for 5 days continuously, as well as for dry weight. It seems that the MF as a light abiotic stress can simulate the cell division and elongation and eventually the plant growth.