In vitro propagation of triploid Toxicodendron vernicifluum (Stokes) F. A. Barkl

Triploid lacquer trees have a higher yield of raw lacquer and greater stress resistance; however, it is challenging to develop efficient and rapid seedling culture techniques because of the influence of metabolites with raw lacquer. In this study, the stem segments of a triploid lacquer tree were used to investigate the effects of explant sterilization treatment, different combinations of exogenous hormone concentrations on the induction of axillary buds, seedling development, and rooting, as well as transplanting substrate ratios. The results showed that the optimal combination of disinfection treatment for triploid Toxicodendron vernicifluum (Stokes) F. A. Barkl explants involves 75% alcohol immersion for 10 s, followed by 2.0% benzalkonium chloride treatment for 1 min and 0.1% HgCl₂ treatment for 4 min. The suitable medium for axillary bud induction was Murashige and Skoog (MS) containing 0.1 mg•L⁻¹ zeatin (ZT) and 0.1 mg•L⁻¹ 6-benzylaminopurine (6-BA), resulting in a high induction rate of 95.0%. Use of 1/2 MS supplemented with 0.5 mg•L⁻¹ 6-BA and 0.3 mg•L⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D) was the most effective for axillary bud proliferation. The combination of 1/2 MS containing 0.1 mg•L⁻¹ 6-BA, 0.5 mg•L⁻¹ 2,4-D, 0.5 mg•L⁻¹ indole-3-butyric acid (IBA), and 0.2% activated carbon (AC) was an optimum for hardening-off. With woody plant medium (WPM) supplemented with 0.5 mg•L⁻¹ naphthaleneacetic acid (NAA) and 0.5 mg•L⁻¹ 2,4-D and 0.5 g•L⁻¹ AC as a rooting medium, the rooting rate was 67.8%. Also, the appropriate transplanting substrate ratio for triploid Toxicodendron vernicifluum (Stokes) F. A. Barkl was grass charcoal:laterite:humus = 1:1:1. Collectively, the results provided the technical assurance for seedling scale multiplication and propagation, facilitating its application in production.