Abstract: To investigate the optimal conditions for the rooting of Rhododendron cuttings and their anatomical structure characteristics, semi-lignified current-year branches of Rhododendron mucronatum and Rhododendron obtusum Dayuanyangjin were used as materials. The influencing factors of cutting rooting were analyzed from substrate types, plant growth regulator types and concentrations. Additionally, sectioning techniques were employed to observe anatomical structural changes during the rooting process. The results showed that the optimal external conditions for rooting in Rhododendron mucronatum were a peat∶perlite mixture(3∶1,V/V, the same below) supplemented with 800 mg/L α-naphthaleneacetic acid(NAA). For Rhododendron obtusum Dayuanyangjin, the optimal treatment was a peat∶perlite mixture(3∶1) supplemented with 400 mg/L indole-3-butyric acid(IBA)+NAA in a 1∶1 ratio(V/V). During the rooting process of Rhododendron mucronatum and Rhododendron obtusum Dayuanyangjin, the occurrence method of adventitious roots belonged to the induced root primordium rooting type, and the occurrence sites were both located in the cambium, belonging to the cortex rooting type.

Key words: Rhododendron mucronatum, Rhododendron obtusum Dayuanyangjin, cutting, rooting index, rooting type, anatomical structure