Propagation Characteristics of the Rare Endemic Rhododenderon micranthum Turcz.

Abstract

This study was conducted to examine the effect of plant growth regulators on the rooting and growth of Rhododendron micranthum Turcz., a rare plant in South Korea. Indole-3-butyric acid (IBA) 150, 250, 350 mg·L−1 and α-naphthaleneacetic acid (NAA) 50, 150, 250 mg·L−1 treatment groups were established and cutting was performed in a commercial growth medium in March 2021 with 3 replications of 10 plants per group. After 70 days, the longest initial root growth was observed under the NAA 150 and 250 mg·L−1 treatments. Moreover, the number of roots and percentage of rooting were slightly higher in NAA 150 and 250 mg·L−1, indicating that these treatments were more effective in promoting plant growth. The above-ground part of plants treated with NAA 150 and 250 mg·L−1 had a taller plant height, longer and wider leaves, and a greater number of leaves compared to other groups. Accordingly, the survival rate of plants treated with NAA 150 and 250 mg·L−1 was higher than 80%, suggesting well-established roots and excellent above-ground growth. Therefore, treatment with growth regulator NAA at 150 and 250 mg·L−1 is considered beneficial for the cutting of R. micranthum Turcz.