In vitro propagation and ex vitro acclimatization of Pittosporum angustifolium

Pittosporum angustifolium Lodd. is an Australian native evergreen, small weeping tree, drought and frost resistant, with potential ornamental and pharmaceutical use.
In Athens, Greece the plant produces fruit, which rarely bear seeds.
The aim of the present work was to develop a protocol for clonal in vitro propagation of the species.
In vitro cultures were established by shoot tip and nodal explants excised from young vegetation of an adult tree, cultured on solid MS medium with 2.0 mg L^‑1 6-benzyladenine (BA, 83-100% explant response, 1.4-1.7 shoots per responding explant). In following subcultures 1.0 or 2.0 mg L^‑1 BA were necessary for shoot multiplication (77-80% explant response, 2.7-2.9 shoots explant^-1), while micro-shoots had the tendency to produce axillary shoots.
Latter were mostly produced by cultures initiated by nodal explants compared to those initiated by shoot tip explants.
Shoot multiplication was further enhanced by increasing BA to 4.0 mg L^‑1 but shoot length was reduced.
Axillary shoot production was significantly increased (73-81% explant response, 3.8-4.7 axillary shoots explant^-1) in a medium with 2.0 or 4.0 mg L^‑1 BA by increasing the culture period from 35 to 90 days.
Micro-shoots 1 cm long rooted at 95% on half-strength MS medium with 4 mg L^‑1 IBA, in the dark, while 2 cm long micro-shoots rooted at 85% with 10 mg L^-1 IBA. Rooting under high IBA concentrations was inhibitory for the following ex vitro acclimatization of rooted micro-shoots.
The highest acclimatization (69-79%) was achieved in peat:perlite (1:1, v/v) when micro-shoots were rooted with 2.0 mg L^‑1 IBA with basal shoot darkening or in the dark.

IV International Symposium on Horticulture in Europe – SHE2021

M. Maniati, M. Papafotiou

axillary shoots, 6-benzyladenine, dark, Gumby, in vitro rooting, micropropagation, multiplication

https://doi.org/10.17660/ActaHortic.2021.1327.48