EFFECT OF PLANT-GROWTH REGULATORS AND BASAL MEDIA ON IN-VITRO SHOOT PROLIFERATION AND ROOTING OF MYRTUS-COMMUNIS L

The influence of macronutrients and growth regulators on in vitro shoo t proliferation and rooting of an East Spanish population of Myrtus co mmunis L. were studied. Preincubation of field material on a medium wi thout mineral salts prevented the browning from phenolic exudates. For multiplication, nodal segments of 5 mm from in vitro produced shoots were cultured on Murashige and Skoog (MS), Schenk and Hildebrandt (SH) and Heller (H) media (full strength or diluted to 1/2 or 1/4), with 6 -benzylaminopurine (BAP) at concentrations 4.4, 13.3 and 22.2 mu M or kinetin (K) at concentrations 4.7, 14.0 and 23.2 mu M. The optimum sho ot proliferation was on quarter-strength MS medium with 4.4 mu M BAP, whereas the maximum number of nodal segments was produced on half-stre ngth MS medium with 4.4 mu M BAP. Rooting of shoots was obtained by ad ding 2.5 - 24.6 mu M indole-3-butyric acid (IBA) and broad range of ma cronutrients; Lloyd and McCown (WPM) and Gresshoff and Doy (GD) media both full strength or diluted to 1/2 were optimum. No rooting was obta ined in the presence of alpha-naphthaleneacetic acid (NAA).