Thidiazuron-induced morphogenetic response in petiole cultures of Pelargonium x hortorum and Pelargonium x domesticum and its histological analysis.

The possibility of inducing somatic embryogenesis in petiole cultures of two cultivars of Pelargonium x hortorum and of one cultivar of Pelargonium x domesticum using thidiazuron (TDZ) was investigated. Petioles were cultivated on a modified Murashige and Skoog medium with different concentrations and application periods of TDZ. Regeneration was achieved with all TDZ treatments for all cultivars and was highly variable. Shoots of different shapes and somatic embryo-like structures were observed. Histological examination revealed that no somatic embryos were formed, and regenerants had to be classified as shoots and shoot-like or leaf-like structures. The importance of these results on the classification of regeneration induced by TDZ in these species and on the propagation of these pelargoniums is discussed.