A rapid in vitro protocol for propagation of Piper aduncum and Piper hispidinervum, two species from Amazon region with multipurpose uses
The morphogenic potential of nodal explants of Piper aduncum and Piper hispidinervum (Piperaceae) was investigated and a protocol for rapid micropropagation is described. An experiment based on the saline formulation of Murashige and Skoog (MS) and Wood Plant medium (WPM) combined with different N6-benzylaminopurine (BAP) and 1-naphthalene acetic acid (NAA) concentrations was evaluated. After determining the optimal concentration of growth regulators, the multiplication rates for the species, which were distributed in five subcultures, was assessed, and the number of plantlets produced in this period was recorded. After assessing the plants from all five subcultures, plantlets with well-developed root and shoot systems were transferred to pots containing substrate for acclimatization. The culture of nodal segments of P. aduncum and P. hispidinervum on hormone-free medium was shown to be a suitable method for micropropagation due to the high multiplication rate and good plant development. The use of BAP or BAP + NAA resulted to formation of vitrified multiple shoots and callus formation at the base of the microcuttings. Even at concentrations lower than 1 mg L-1, the use of BAP resulted in vitrified multiple shoot and callus formation, without significantly improving the multiplication rates. For both species, the first subculture resulted in the greatest number of axillary buds, and mainly for P. hispidinervum, the MS medium was the most appropriate for in vitro multiplication of microcuttings. The species showed 100% root formation, and acclimatization of plants from the fifth subculture in a greenhouse resulted in 100% survival.
Key words: Spiked pepper, long pepper, micropropagation, dillapiol, safrole, morphogenesis, organogenesis.