In vitro propagation of the endangered orchid Paphiopedilum dianthum: Effects of plant growth regulators and organic additives on shoot
1Faculty of Biology, Hanoi Pedagogical University 2, Hanoi, Vietnam. 2Faculty of Agriculture and Forestry, Thai Nguyen University of Agriculture and Forestry (TUAF), Thai Nguyen, Vietnam. 3Thai Nguyen University – Lao Cai Campus, Lao Cai, Vietnam. Corresponding e-mail: phamphuongthu@hpu2.edu.vn
DOI: https://doi.org/10.37855/jah.2025.v27i04.110
This study aimed to develop an in vitropropagation protocol for Paphiopedilum dianthum, an endemic Vietnamese orchid currently under severe threat in its natural habitat due to overexploitation and habitat degradation. This study presents the first optimized protocol for the mass propagation of P. dianthum in vitro. The full-strength MS medium was identified as optimal for asymbiotic seed germination, achieving a germination rate of 76.67% and protocorm formation within 70–84 days. During shoot regeneration from protocorms, the addition of 1.0 mg L-1 BAP resulted in the highest regeneration rate (83.17%) and produced morphologically uniform shoots. Furthermore, a combination of 1.0 mg L-1 BAP and 0.5 mg L-1 TDZ yielded a favorable shoot multiplication rate (1.47) while maintaining shoot quality. Organic additives such as 20 mL L-1 coconut water or 30 g L-1 banana pulp enhanced shoot height and leaf number, indicating the stimulatory effects of natural hormone sources. For rooting, 1.0 mg L-1 IBA was the most effective auxin, producing superior root number and length. During acclimatization, a substrate mixture of pine bark, charcoal, sawdust (1:1:1), and forest moss led to the highest survival rate. This protocol contributes to the conservation and propagation of the rare and endangered orchid species P. dianthum in Vietnam.
