LAUSR

Abstract In this study, possible effects of 24-epibrassinolide (24-epiBL) pretreatment against NaCl stress were investigated using in vitro shoot organogenesis from cotyledon and hypocotyl explants in M-28 tomato hybrid cultivar. The cotyledon and hypocotyl explants of 10-day sterile seedlings were treated with 1 μM and 2 μM 24-epiBL solutions (prepared with 70% acetone) for 30 seconds and applied explants were cultured on MS medium supplemented with 2 mg/l 6-benzylaminopurine (BAP) + NaCl (0, 20, 40, 60, 80 and 100 mM). It was determined that the regeneration percentage as well as the shoot number/explant, the shoot length and the leaf number/shoot derived from both explants suffered NaCl stress after 30 days. 24-epiBL pretreatment against NaCl stress showed ameliorative effects and hypocotyl explants gave better results than cotyledon explants for these growth parameters. Different stages of shoot organogenesis from hypocotyl explants applied with 24-epiBL under salt stress were observed with scanning electron microscopy. As a result, it was shown that 24-epiBL treatment against NaCl stress may play an effective role in salt tolerance in M-28 tomato hybrid cultivar.