Direct organogenesis from immature female inflorescence of date palm by gradual reduction of 2,4-D concentration

Abstract

Inflorescences represent an alternative explant source for superior date palm trees, especially those that do not produce offshoots. They provide large numbers of explants free of fungal and bacterial contamination for successful tissue culture initiation. Furthermore, they are characterized by the capacity of plant regeneration within a short time as compared to other explant types. This chapter focuses on the procedures employed for plant regeneration by direct organogenesis using immature female inflorescence explants, including initiation of adventitious buds, differentiation, multiplication, shoot elongation, rooting, and acclimatization. Adding 5 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) into the initiation medium and gradually reducing it to 1 and then to 0.5 mg/L in the subsequent 2 subcultures, respectively, are determining factors in direct adventitious bud formation from the inflorescence. Bud differentiation is obtained on MS medium containing 0.25 mg/L kinetin (Kin), 0.25 mg/L benzyladenine (BA), 0.25 mg/L abscisic acid (ABA), 0.1 mg/L naphthaleneacetic acid (NAA), and 0.2 g/L activated charcoal (AC). Regenerated shoots exhibit sufficient root formation on MS medium supplemented with 2 mg/L indole butyric acid (IBA) and 1 mg/L NAA and subsequent survival in the greenhouse.