Abstract: [Objective] The aim of this study was to improve the rooting rate of cutting of M. wufengensis, and provide theoretical support and guidance for the rapid propagation, cultivation and promotion of M. wufengensis.[Method] The semi-lignified branches from 5-year-old Magnolia wufengensis seedlings were collected as the propagation materials. A completely randomized block design with two factors, including four types of plant growth regulators of GGR₆,NAA,IBA,and IAA, and six concentrations of 200,500,800,1 000,2 000,3 000 mg·L^-1,were used. The effects of different types and concentrations of plant growth regulars on rooting parameters of M. wufengensis, i.e. rooting rate, number of adventitious roots, average root length, average root diameter, and root effective traits rate, were investigated. And then the principal component analysis was used to comprehensively evaluate the effects of each treatment combination on rooting.[Result] The results showed that the rooting rate and root morphology of NAA solution treatment was all at a high level among the four plant growth regulators. When the cuttings was soaked in 1 000 mg·L^-1 NAA solution, the cutting root had the best quality. The average number of adventitious roots was 13.3, which was 12 more than that of the control group treated with water. The average root length was 14.33 cm, which was about 2.7 times of the control group. The average root diameter was 2.44 mm,which was 0.60 mm thicker than that of the control group. The root effective traits rate was 55.4%, which was 22.1% higher than that of the control group. The rooting rate of NAA 1 000 mg·L^-1 treatment was the highest, reaching 53.3%, significantly different from other concentrations, and 16 times higher than that of the control group.[Conclusion] The NAA solution had the better rooting effects than the other three types of growth regulator, and the best concentration of NAA was 1 000 mg·L^-1. The research has greatly increased the rooting rate of M. wufengensis, and has provided theoretical basis and technical guidance for the large-scale propagation of germplasm resources of M. wufengensis.

Key words: Magnolia wufengensis, cuttage propagation, plant growth regulators, rooting rate, root morphology parameter