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Designing ex-situ conservation strategies for seeds storage of Piper aduncum and P. hispidinervum through cryopreservation and low-temperature techniques

ABSTRACT Piper aduncum and Piper hispidinervum are species found primarily in the Amazon region, and have been highlighted by the fact that they contain, in their essential oils, significant amounts of dillapiol and safrole. The aim of this work was to assess the seed behavior of P. aduncum and P. hispidinervum and to develop strategies for medium—to long-term storage of the species at sub-zero and cryogenic temperatures. In the first experiment, seeds were desiccated and their water content was determined. Then, the seeds were kept at −20°C for up to 90 days. In the second experiment, seeds were stored for up to 24 h in liquid nitrogen (LN; −196°C), with and without the use of cryoprotectants. Finally, for assessing the efficiency of these techniques, seeds were stored at −20°C and in LN for up to 360 days. The germination rate was more than 90% for both species when stored at −20°C or LN, without compromising their viability and development. The results suggest that P. aduncum and P. hispidinervum have seeds with orthodox behavior, which can be stored for the medium to long term at sub-zero and cryogenic temperatures without the need for use of cryoprotectants.