Establishment of Iris laevigata Tissue Culture Using Hypocotyl and Root Explants

Iris laevigata is an ornamental plant and so its wild genetic resources need to be protected. However, traditional inefficient propagation limits its landscape applications. In this study, we assessed the effects of phytohormones on growth of I. laevigata at various culture stages using roots and hypocotyls as explants and established an efficient micropropagation system. The highest callus induction of hypocotyl (75.0%) was obtained using Murashige and Skoog medium containing 6-benzylaminopurine (6-BA), 0.5 mg L^-1 + 2,4-dichlorophenoxyacetic acid (2,4-D), 1.0 mg L^-1 + 1-naphthylacetic acid (NAA), and 0.4 mg L^-1. Similarly, the highest callus induction (73.3%) of roots was achieved with 6-BA 0.5 mg L^-1 + 2,4-D 0.5 mg L^-1 + NAA 0.4 mg L^-1. The calli induced from hypocotyl and root tissues achieved 39.7% and 49.5% adventitious shoot induction on a medium containing indole-3-butyric acid (IBA) 0.5 mg L^-1 + 6-BA 1.5 mg L^-1 + NAA 1.0 mg L^-1 and 6-BA 2.0 mg L^-1 + NAA 0.4 mg L^-1 + kinetin (KT) 1.0 mg L^-1, respectively. The rooting of adventitious shoots reached 93.3% in the medium supplemented with NAA 0.2 mg L^-1. The survival of regenerated plants reached 90.0% after being transplanted into soil. This study provides an efficient and reliable propagation method for I. laevigata for landscape applications and the preservation of wild genetic material.