Embryogenic callus formation from the petioles of Spathiphyllum wallisii

For micropropagation or various breeding objectives, an efficient regeneration protocol is an indispensable tool. In vitro Spathiphyllum wallisii leaves cannot be regenerated. Regeneration from petioles was attempted as an alternative for anther filament or internode regeneration. Wounded petiole explants from cultivars ‘Daniel’ and ‘Domino’ were introduced on half strength Murashige and Skoog medium with 3% sucrose, 0.7% agarose and different compositions of TDZ, 2iP and 2,4-D. 16-68% Petioles from ‘Daniel’ treated with TDZ and 2,4-D yielded calli. In case of ‘Domino’, only 16-40% of petioles turned into calli. Shoots and roots were directly formed on 2iP + 2,4-D treated petioles without callus phase. The mean weight of calli is 0.25-0.77 g and 0.65-0.74 g for ‘Daniel’ and ‘Domino’ respectively. All the calli produced through the above mentioned way are compact, creamy white colored and regenerative. The optimal concentration of TDZ and 2,4-D varies according to the genotypes. For example, petioles of ‘Daniel’ regenerate best (68%) after a combination of 1 mg/L TDZ and 0.2 mg/L 2,4-D but ‘Domino’ petioles (40%) prefer 2 mg/L TDZ and 1 mg/L 2,4-D. Whether through formation of embryogenic callus and subsequent shoot formation on a TDZ-embedded medium or through direct organogenesis on a 2iP embedded medium, petioles of both Spathiphyllum wallisii cultivars could thus be used to establish an efficient regeneration system.