In vitro selection and propagation of salt tolerant Sesbania rostrata Brem & Oberm.

Propagation of Sesbania rostrata Brem. & Oberm. was studied from germinated seeds on MS medium supplemented with 11 mg/l BA for 14 days. Sotyledonary nodes were excised and cultured on MS with 0, 1, 3 and 5 mg/l BA incombination with 0, 0.05, 0.1 and 0.2 mg/l NAA for 30 days. MS with 1 mg/l BA and 0.05 mg/l NAA could induce the highest shoot number of 9.3 shoots/explant. Root induction was conducted on MS with 0, 1, 3 and 5 mg/l NAA or IBA for 30 days. The highest number of 10.6 roots/shoot was obtained on MS with 5 mg/l IBA. The plantlets were hardening off before transplanting and the survival rate was 85 percent. Seeds were imbibed in NaCl solution at 0, 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75 and 2.0 percent NaCl for one night and then were transferred on MS with the same concentrations of NaCl for 15 days. Growth of seedlings, by number of normal seedlings, fresh weight, dry weight and shoot lenght, were decreased when increased NaCl concentration. The results showed that when the percentage of NaCl exceeded 1 percent the number of normal seedlings were decreased more than 50 percent compared to the control. Salt tolerance seeds were selected and propagated by imbibing seeds in water with 0, 0.25, 0.75 and 1.0 percent NaCl for one night and then transferred on MS with 11 mg/l BA at the same concentrations of NaCl for 14 days. The number of seedlings from 1.0 percent NaCl medium decreased more than 50 percent compared to the control. Cotyledonary nodes were excised and placed on MS with 1 mg/l BA and 0.05 mg/l NAA for 30 days and had shoot number of 10.2, 8.4, 7.2 and 4.2 shoots/explant, respectively. Then shoots were cultured on MS with 5 mg/l IBA within 30 days for root induction. Salt tolerance test was divided into 2 experiments: One was the control, plantlets obtained from free-salt medium, and the second one, plantlet obtained from the medium supplemented with 0, 0.5, 0.75 and 1.0 percent NaCl. They were propagated and then tested on the MS medium supplemented with 0, 0.5, 0.75 and 1.0 percent NaCl for 60 days. Plantlets which came from salt-medium has survival rate of 100, 93.3, 53.3 and 26.7 percent compared to the control and had higher survival percentage than plantlets which came from free-salt medium that had survival rate of 100, 86.7, 33.3 and 20 percent compared to the control.