Phenylacetic acid-induced somatic embryogenesis in cultured hypocotyl explants of geranium (Pelargonium x hortorum Bailey).

The effect of a non-indole compound, phenylacetic acid (PAA), on the induction of somatic embryogenesis in tissue cultures of geranium (Pelargonium x hortorum Bailey cv. Scarlet Orbit Improved) was investigated. Hypocotyl explants derived from young, dark-grown seedlings were cultured on Murashige and Skoog (1962) medium (MS) supplemented with PAA or IAA (0.01-120 μM) alone or in combination with BAP (8 μM). Somatic embryogenesis was induced by both PAA and IAA at 0.01-20 μM with 8 μM BAP, however, the optima differed considerably for the two compounds. Maximal activity of IAA for somatic embryogenesis was found at 0.1-2.5 μM, whereas PAA gave best results at 10 and 20 μM under identical culture conditions. Higher concentrations (30-120 μM) of IAA or PAA in the medium induced callusing in the explants, but the callus was neither embryogenic nor morphogenic.