Effects of Benzyladenine and .ALPHA.-Naphthaleneacetic Acid on the Formation of Protocorm-like Bodies(PLBs) from Explants of Outer Tissue of Cymbidium PLBs Cultured In Vitro.

Abstract

Explants of outer tissue (OT) excised from protocorm-like bodies (PLBs) of Cymbidium produced PLBs on Murashige and Skoog (MS) medium without any hormone, or those containing benzyladenine (BA) and α-naphthaleneacetic acid (NAA). The combination of 0.5 or 5.0 μM NAA and 2.5 or 5.0 μM BA yielded PLBs by 77.5% OT explants in Cym. Thanksgiving 'Nativity'. In Cym. Lucky Rainbow 'Lapine Dancer' a treatment with 2.5 μM BA yielded PLBs from 73.7% OT explants and faster on a medium with BA or BA+NAA than on a hormone-free medium. An addition of NAA alone inhibited PLB formation significantly. Thus, PLB formed from OT faster on MS media supplemented with BA or a combination 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 promoted formation of small sized PLBs, whereas NAA suppressed PLB formation. However, once the PLBs were formed, NAA tended to increase their sizes.