Hormonal Requirements Trigger Different Organogenic Pathways on Tomato Nodal Explants

Abstract

In this work, nodal-disk segments (4-6 mm in diameter × 5-6 mm in length) were obtained from established shoot culture, resulted from disinfected tomato seedlings, and they were suitable to induce different organogenic pathway under the influence of specific hormonal treatment. Application of BAP (1-2.5 mg/l) alone or in combination of 0.5 mg/l NAA resulted in induction of shoot formation. Somatic embryogenesis was rarely appeared (6%) when relatively low concentration of BAP (1.5 mg/l) with low concentration of IAA (0.5 mg/l IAA) was applied. Root induction was triggered when nodal explants or shoot cuttings were cultured on MS medium with (1 mg/l IAA, IBA or NAA) or without auxins, but the best result was obtained when 1 mg/l IAA was used. Application of 0.5 mg/l NAA stimulated callus formation but the best result was obtained when the three different phytohormoes were used (0.5 mg/l 2,4-D + 1 mg/l NAA + 0.5 mg/l BAP). These results indicated that nodal segments, as described in this protocol, can be used as alternative to other types of explants such as cotyledon, hypocotyl and leaf explants.