In vitro regeneration and conservation of the lentisk (Pistacia lentiscus L.)

Pistacia lentiscus L. (lentisk or mastic tree) is an economically important member of the genus Pistacia due to its valuable mastic resin. Shoot tips and nodal segments were used as explant sources from in vitro-germinated seeds of lentisk. Shoot tips were found to be suitable for multiple shoot formation. Thereafter, the influences of different growth regulators [N6-benzyladenine (BA), gibberellic acid (GA3), naphthalene acetic acid (NAA), or jasmonic acid (JA)] together with various elicitors [silver nitrate (AgNO3) or phloroglucinol (PG)] were assessed to develop efficient micropropagation protocol. Our results showed that the combination of all tested concentrations of GA3 with 1.0 mg/L BA resulted in enhancement of multiple shoot formation. The maximum number of shoots per explant (3.95) was recorded on MS medium containing 1.0 mg/L BA and 0.3 mg/L GA3. In contrast, JA had a negative influence, while AgNO3 had no significant effect on multiple shoot formation. In terms of synthetic seed production, it was possible to encapsulate shoot tips at 4 °C in darkness for up to 6 months with a frequency of 87.5% plant regrowth. In vitro-propagated microshoots, including plantlets derived from synthetic seeds, were transferred to MS medium containing different concentrations (1.0, 2.0, or 4.0 mg/L) of indole butyric acid for rooting and successfully acclimatized to ex vitro conditions. The presented data suggest an efficient in vitro regeneration system and conservation via synthetic seed production for lentisk.