Ancymidol Increases In Vitro Multiplication Rate of Hosta in Liquid Media

Abstract

The main and interactive effects of plant growth regulators were assayed to optimize multiplication rate for Hosta in liquid media. Two varieties of Hosta were run through three 4-week subculture cycles in shake flasks. When Hosta `Blue Cadet' was grown on three concentrations of cytokinin (1, 2.25, and 5 μM BA), three concentrations of auxin (0.1, 1.0, and 10 μM IAA), and four concentrations of an anti-gibberellin growth regulator (0.0, 0.1, 0.32, and 1.0 μM ancymidol), multiplication rates improved markedly during the first two subculture cycles in liquid, (1.7 and 3.6x, respectively) before stabilizing at third subculture. BA and ancymidol both increased multiplication rate. IAA interacted antagonistically with BA. An optimal multiplication medium with 2.25 μM BA, 1.0 μM IAA, and 1.0 μM ancymidol, provided a high rate of multiplication with well-defined shoot morphology and minimal root growth. Media consisting of 1.0 μM BA, 10.0 μM IAA, and 0.32 μM ancymidol was effective in producing leafy plantlets, with root initials, ready for transfer to mist bed acclimatization. When Hosta `Stilletto' was grown on concentrations of cytokinin (1, 2.25, and 5 μM BA), auxin (0.1, 1.0, and 10 μM IAA) and ancymidol (0.0, 1.0, and 3.2 μM), multiplication rates improved markedly during the first two subculture cycles in liquid (1.9 and 2.4x, respectively) before stabilizing at third subculture. Ancymidol increased multiplication rate at either level; the interactive effect with BA showed highest multiplication rates at lowest BA levels in the presence of ancymidol. Lower BA concentrations promoted better culture morphology and lesser BA induced root inhibition.