Abstract:

The demand for plant hormones varies in different stages of asexual rapid propagation of Dendrobium officinale. The paper aims to further explore the relationship between exogenous hormone ratio and tissue culture seedling growth. The segmented stem segments of D. officinale from Tianmushan of Zhejiang were used as explants to conduct experiments on induction, proliferation, and rooting of clustered buds of D. officinale. The effects of different hormone ratios on the growth of D. officinale at different stages were compared, and the optimal hormone conditions for rapid propagation of D. officinale stem segments were selected to establish an asexual rapid propagation system of D. officinale stem segments. The results showed that the optimal hormone conditions for inducing clustered buds were 1.0 mg/L NAA+ 2.0 mg/L 6-BA, with a germination rate of 97.8% and robust buds. The optimal hormone conditions for the proliferation of clustered buds of D. officinale were 0.5 mg/L NAA+ 2.0 mg/L 6-BA, with a proliferation rate of 86.9% and good growth. The optimal hormone conditions for the rooting of clustered buds of D. officinale were 1.0 mg/L NAA+ 1.0 mg/L IBA, with a rooting rate of 83.4% and a robust and developed root system. The study confirmed that hormone ratio and medium salt concentration synergistically regulated the morphogenesis of D. officinale, and the 7-8 leaf stage was the key node of physiological response. The hormone combinations screened in this study can provide theoretical basis and technical reference for large-scale tissue culture of orchid medicinal plants.

Key words: Dendrobium officinale, rapid propagation of stem segments, exogenous hormones, induction, clustered buds, proliferation, rooting