A study on the optimization of tissue culture parameters for the micropropagation of dendrobium sw. “Den 08.5.2”

Abstract

This study aimed to develop an efficient in vitro propagation protocol for the Dendrobium orchid “Den 08.5.2”. Apical buds were effectively sterilized using a 150 ppm nano-silver solution for 45 minutes, resulting in a high rate of aseptic culture establishment (72.22%). Optimal shoot multiplication was achieved on a medium supplemented with 2.5 g/L Hyponex, 0.5 mg/L BAP, 0.2 mg/L α-NAA, 0.2 g/L activated charcoal (AC), 100 mL/L coconut juice and 15 mg/L chitosan. This medium yielded a multiplication rate of 4.3 shoots per explant, with an average shoot length of 2.2 cm and fresh weight of 0.93 g per shoot. Subsequent root development was optimized on a medium containing 2.5 g/L Hyponex, 0.5 mg/L α-NAA, 0.3 g/L AC and 7.5 g/L milled banana, resulting in 5.38 roots per plantlet, with an average root length of 4.17 cm, shoot length of 5.75 cm, and leaf number of 3.56 per plantlet. Finally, plantlets were successfully acclimatized to ex vitro conditions using Sphagnum moss as a substrate, demonstrating a high survival rate of 98.8% and achieving a plant height of 7.82 cm. This optimized protocol provides a foundation for the mass propagation of this valuable orchid cultivar.