Effects of benzyladenine and alpha-Naphthaleneacetic acid on the formationof protocorm-like bodies (PLBs) from explants of outer tissue of CymbidiumPLBs cultured in vitro

Explants of outer tissue (OT) excised from protocorm-like bodies (PLBs) of Cymbidium produced PLBs on Murashige and Skoog (MS) medium without any horm one, or those containing benzyladenine (BA) and alpha-naphthaleneacetic aci d (NAA). The combination of 0.5 or 5.0 mu M NAA and 2.5 or 5.0 mu M BA yiel ded PLBs by 77.5% OT explants in Gym. Thanksgiving 'Nativity'. In Gym. Luck y Rainbow 'Lapine Dancer' a treatment with 2.5 mu M BA yielded PLBs from 73 .7% OT explants and faster on a medium with BA or BA + NAA than on a hormon e-free medium. An addition of NAA alone inhibited PLB formation significant ly. Thus, PLB formed from OT faster on MS media supplemented with BA or a c ombination of BA and NAA than on a hormone-free medium. In media supplemented with NAA or BA, there was a high negative correlation between PLB size and yield from an outer tissue (r=-0.893, r=-0.843). BA p romoted formation of small sized PLBs, whereas NAA suppressed PLB formation . However, once the PLBs were formed, NAA tended to increase their sizes.