High-frequency Plant Regeneration from Cultured Flower Bud Receptacles of Allium hookeri L.

Abstract

Allium hookeri L. (Alliaceae family) is an important ethnomedicinal plant native to the Himalayan region of Asia. The aim of this research was to establish a high-frequency plant regeneration system for in vitro propagation of A. hookeri. Among the tissue types examined, receptacle explants derived from immature flower buds showed the highest regeneration rate of shoots (<TEX>$93.33{\pm}4.63%$</TEX>), roots (<TEX>$76.67{\pm}7.85%$</TEX>), and calli (<TEX>$80.00{\pm}7.43%$</TEX>) when cultured on Gamborg B5 (B5) medium containing <TEX>$10{\mu}M$</TEX> 6-benzylaminopurine (BA) + <TEX>$1{\mu}M$</TEX> naphthalene acetic acid (NAA), <TEX>$0.5{\mu}M$</TEX> BA + <TEX>$5{\mu}M$</TEX> NAA, and <TEX>$1{\mu}M$</TEX> BA + <TEX>$10{\mu}M$</TEX> NAA, respectively. Shoot multiplication was superior when cultured in liquid rather than on solid medium and relatively high concentrations of BA, ranging from 5 to <TEX>$10{\mu}M$</TEX>. Efficient bulblet formation following root induction from shoot clumps was achieved with culture in liquid B5 medium containing 7% (w/v) sucrose. Regenerated bulblets were successfully acclimatized to ex vitro conditions with a greater than 95% survival rate. By this method, a maximum of 62 plantlets per receptacle could be propagated within 9 weeks of initial culture. The in vitro propagation system established in this study will promote A. hookeri biotechnology, including large-scale production of healthy and aseptic clones, preserving parental genotypes with desirable traits, and genetic manipulation to enhance medicinal value.