Micropropagation of self-heading Philodendron via direct shoot regeneration

The present study describes a direct shoot regeneration-based micropropagation procedure for the self-heading cultivars of Philodendron. Three types of explant (i.e. leaf lamina, petiole, stem nodal segment) were screened for their shoot induction potential following a three months treatment with 0.5 mg l−1 of either 2,4-dichlorophenoxyacetic acid (2,4-D), thidiazuron (TDZ) or both. Results indicated that the leaf laminas were poor candidates for shoot induction whereas the petioles showed potential for adventitious shoot production at frequencies of 2.8–11.1% in two of the cultivars tested. Stem nodal segments were the most responsive among the three as shoots formed directly following the TDZ treatment at frequencies of 16.7–41.7% depending on the cultivar. When comparing the effectiveness of different cytokinins to induce shoot proliferation on stem nodal segments, it was found that the 0.5 and 1 mg l−1 of kinetin (Kn) and 6-benzyladenine (BA) treatments resulted in higher shoot formation percentages compared to the 0.5 and 1 mg l−1 of TDZ treatments in two of the three cultivars. Furthermore, more shoots were produced on BA than on Kn-supplemented media in all the three cultivars. Shoots derived from the 0.5 mg l−1 of BA treatment can be induced to root following one month incubation with 0.1–1 mg l−1 of indole-3-butyric-acid (IBA). The rooted shoots showed 100% survival after acclimatization in the greenhouse. The procedure reported in the present study can assist in the large-scale multiplication of elite self-heading cultivars of Philodendron in the future.