Floral reversion of mature inflorescence of date palm in vitro

Regeneration plants of date palm (Phoenix dactylifera L.) cultivar Siwi (semi-dry cv.) via reversion of mature female flower were studied. Mature female flowers were cultured on MS medium supplemented with different concentrations of paclobutrazol (PBZ) and abscisic acid (ABA) (0.0, 0.5, 1.0 and 2.0 mg l−1). Callus induction was achieved by all treatments from 8 to 16 weeks of culture. The highest formation of callus performed on MS medium containing 2.0 mg l−1 PBZ, which also gave the highest values of total soluble sugars and their fractions. This callus was initiated from different zones: the basal part of the flower, the surface of the perianth segments, carpels and the receptacle. Meanwhile, direct shoot and somatic embryos were only obtained by cultured explants on different concentrations of ABA which contained the highest concentration of total soluble sugars and their fractions. Shoots initiated from some meristematic cells occurred between the basal part of the petal and carpel. This protocol provides a simple and rapid way to regenerate date palm through reversion the mature female flower to the vegetative growth.