Alternative carbohydrate supplementation with honey in the in vitro propagation of Dendrobium antennatum (Lindl.)

Abstract Dendrobium antennatum (Lindl.), or antelope orchid, is a species of significant horticultural and conservation value. In this study, the effects of honey were investigated as an alternative carbohydrate source in the in vitro propagation of D. antennatum . Honey is a complex, underutilized organic additive in orchid tissue culture. It was hypothesized that its nutritional composition could support plant development similarly to, or better than, traditional sucrose. Four media treatments were prepared: a control (20.0 g L −1 sucrose), a combined treatment of 15.0 g L −1 honey with 10 g L −1 sucrose, 30.0 g L −1 honey alone, and 60.0 g L −1 honey alone. After 120 d, plant performance was assessed by shoot length, root condition, and fresh weight. The best results were obtained with 30.0 g L −1 honey and the combined honey–sucrose treatment, both showing significantly improved growth compared to control. The highest fresh weight was recorded in the 30.0-g L −1 treatment, which exceeded the control by 277%, while shoot length increased by 150%. In contrast, the 60.0-g L −1 honey treatment inhibited growth, suggesting a toxic or stress-inducing effect. To better understand the plant responses to high sugar levels, proline content, photosynthetic pigments, and peroxidase enzyme activity were measured as biochemical stress markers. Although no statistically significant differences were observed among treatments for these parameters, trends indicated increased stress at higher honey concentrations. This study demonstrated the potential of honey as an effective and sustainable alternative to sucrose in orchid micropropagation with practical implications for commercial cultivation and ex situ conservation.