In vitro propagation of Asparagus maritimus – A rare Mediterranean salt-resistant species

Abstract

Asparagus maritimus L. Miller is a rare species growing of the Mediterranean region and is morphologically similar to A. officinalis. In order to establish an efficient in vitro propagation protocol, explants were excised from spear segments and cultured on Murashige and Skoog (1962) medium containing 3% sucrose and various concentrations of growth regulators. The best shoot initiation (3–4 per explant) was achieved on a medium containing 0.88 μM N⁶-benzyladenine (BA), 0.93 μM kinetin, 1.07 μM α-naphthaleneacetic acid (NAA) and 3.90 μM ancymidol. Shoot initiation could also be achieved without ancymidol but the shoots were thinner and longer. A very high shoot multiplication rate was achieved on media supplemented with 3% sucrose, 1.07 μM NAA, 0.93 μM kinetin, 0.44 μM BA and various concentrations of ancymidol. The lowest concentration of ancymidol (0.39 μM) significantly promoted the highest shoot multiplication rate (11.9 shoots/crown). For root formation, media were supplemented with 6% sucrose, 1.07 μM NAA and various concentrations of ancymidol. Rooting frequency increased with higher ancymidol concentration up to 5.07 μM (82.0% rooting). The number of ex vitro shoots formed was strongly correlated (r=0.66) with the length of roots formed in vitro, which was the highest at a 1.95 μM ancymidol.