Optimization of In Vitro Propagation of Artemisia pontica Through Integrated Morphophysiological, Biochemical, and SEM Analysis Under GA3 and MeJA

Comparative Enhancement of Glycyrrhizin Content in Callus Cultures of Achras sapota L. and Taverniera cuneifolia (Roth) Arn. Through Optimization of Plant Growth Regulator Combinations

The present investigation was carried out to evaluate the effects of different combinations of plant growth regulators (PGRs) on callus induction, biomass accumulation, and glycyrrhizin production in Achras sapota L. and Taverniera cuneifolia (Roth) Arn. Stem explants were cultured on Murashige and Skoog (MS) medium supplemented with various concentrations of α-naphthaleneacetic acid (NAA), Kinetin (Kn), 6-benzylaminopurine (BAP), and 2,4- dichlorophenoxyacetic acid (2,4-D). Callus cultures were maintained for eight weeks under controlled photoperiodic conditions and analyzed for glycyrrhizin content using High-Performance Liquid Chromatography (HPLC). Among the six tested treatments, the ternary combination of NAA (1.0 mg/L) + Kn (1.0 mg/L) + BAP (2.0 mg/L) (T6) produced the highest callogenesis frequency and glycyrrhizin accumulation. Maximum glycyrrhizin content of 6.42 mg/g dry weight (DW) and 9.84 mg/g DW was observed in Achras sapota and Taverniera cuneifolia, respectively, under T6—representing 3.13-fold and 2.64-fold enhancement over field-grown plants. The study demonstrates that strategic optimization of auxin–cytokinin balance significantly enhances secondary metabolite production in vitro, offering a sustainable biotechnological approach for commercial-scale glycyrrhizin biosynthesis.

Effects of mannitol-induced drought stress on the growth of Phalaenopsis amabilis (L.) blume plantlets under in vitro conditions

Phalaenopsis amabilis (L.) Blume is an ornamental orchid with high aesthetic and economic value and is recognized as the national flower of Indonesia. However, its growth and physiological performance are highly susceptible to drought stress. This study aimed to evaluate the effects of mannitol-induced drought stress on the growth of P. amabilis plantlets under in vitro conditions and to determine the highest mannitol concentration that could be tolerated. Mannitol was applied as an osmotic agent at five concentrations (0, 50, 100, 150, and 200 mM) in Vacin and Went (VW) medium using a completely randomized design with five replications. The evaluated parameters included plantlet survival percentage, morphological characteristics, chlorophyll content, and stomatal density. Data were analyzed using analysis of variance (ANOVA) at the 5% significance level, followed by Tukey's test when significant differences were detected. The results showed that all treatments maintained a 100% plantlet survival rate throughout the four-week culture period. Mannitol application had no significant effect on morphological characteristics or chlorophyll content. In contrast, stomatal density was significantly reduced with increasing mannitol concentrations. Plantlets cultured on medium containing 50 mM mannitol exhibited the greatest tolerance and maintained normal growth, whereas concentrations of 150–200 mM induced more pronounced drought stress responses. These findings indicate that 50 mM mannitol is the optimum concentration for simulating mild drought stress while maintaining the growth of P. amabilis plantlets under in vitro conditions.

Leaf anatomy, chlorophyll content and growth performance of chokeberry (Aronia mitschurinii) plants ex vitro rooted using floating perlite bed at different incubation periods

Optimization of In Vitro Conditions for Micropropagation of Dieffenbachia exotica cv. Tropic Snow

Dieffenbachia is widely used in indoor landscaping due to its variegated leaf structure and high adaptability to indoor conditions. This study aimed to evaluate the effects of combinations of cytokinins (BAP) and auxins (NAA and 2,4-D) on vegetative growth during the in vitro micropropagation of Dieffenbachia sp. Single-node shoot explants were transferred to MS medium. Basic morphological parameters such as shoot length, number of leaves, number of roots, and root length were evaluated in the study. Statistically significant differences were found among the treatments (p<0.05). The highest shoot growth was observed in the T1 (6.00 cm) treatment, whereas the T1 (5.00 per plantlet) and T3 (5.00 per plantlet) treatments exhibited a higher number of leaves. In terms of rooting performance, the highest number of roots (8.08 per plantlet) occurred in the T2 treatment, while the longest roots occurred in the T1 treatment (8.67 cm). No vegetative growth occurred in the treatments containing a high concentration (0.6 mg/L) 2,4D (T14, T16, T18, T20). This study demonstrates that low and moderate levels of cytokinin-auxin combinations enhance in vitro regeneration efficiency in Dieffenbachia exotica cv. Tropic Snow. in in vitro regeneration and provides an important basis for optimizing protocols the commercial micropropagation of this species.

Morphological, physiological, and anatomical responses of Cattleya labiata Lindl. plantlets to mannitol-induced drought stress under in vitro conditions

Cattleya labiata Lindl. is a high-value ornamental orchid whose growth and development are highly dependent on adequate water availability. Drought stress disrupts cellular water balance, reduces photosynthetic activity, and restricts plant growth. Under in vitro conditions, drought stress can be simulated by incorporating mannitol into the culture medium as an osmotic agent. This study evaluated the effects of different mannitol concentrations on the morphological, physiological, and anatomical responses of C. labiata plantlets cultured in vitro. The experiment was arranged in a Completely Randomized Design (CRD) with five mannitol concentrations (0, 50, 100, 150, and 200 mM), each with five replications. The evaluated parameters included plantlet survival, morphological characteristics (root length, plantlet height, and leaf number), chlorophyll content, and stomatal density. Quantitative data were analyzed using analysis of variance (ANOVA), followed by Tukey’s Honestly Significant Difference (HSD) test at the 5% significance level. Mannitol concentrations ranging from 50 to 200 mM did not significantly affect plantlet survival, morphological growth, or chlorophyll content. In contrast, stomatal density decreased significantly with increasing mannitol concentration, indicating that anatomical responses were more sensitive to osmotic stress than morphological and physiological traits during the three-week culture period. These findings demonstrate that mannitol effectively induced drought stress responses in C. labiata plantlets under in vitro conditions, although the applied concentrations were insufficient to produce significant morphological and physiological alterations within the experimental period.

Effects of Different Concentrations of 6-Benzylaminopurine (BAP) on the In Vitro Growth of Dendrobium spectabile (Blume) Miq. Plantlets

Dendrobium spectabile (Blume) Miq. is an ornamental orchid with high economic value and considerable potential for commercial cultivation. However, conventional propagation is relatively slow, making in vitro culture an effective alternative for producing large numbers of uniform plantlets. This study aimed to evaluate the effects of different concentrations of 6-benzylaminopurine (BAP) on the growth of D. spectabile plantlets and to determine the optimal BAP concentration for in vitro plantlet development. The experiment was arranged in Completely Randomized Design (CRD) consisting of five BAP concentrations (0, 0.5, 1.0, 1.5, and 2.0 mg/L) using Vacin and Went (VW) medium. The observed parameters included plantlet survival percentage, visual appearance, plantlet height, number of leaves, number of shoots, root length, number of roots, and fresh weight. Data were analyzed using analysis of variance (ANOVA), followed by Tukey’s test at the 5% significance level. The results showed that BAP concentrations significantly affected the growth of D. spectabile plantlets. A concentration of 1.5 mg/L BAP was the most effective for promoting plantlet height, number of leaves, number of shoots, and fresh weight, whereas 0.5 mg/L BAP produced the greatest root length and number of roots. These findings indicate that 1.5 mg/L BAP is the optimal concentration for enhancing shoot growth, while 0.5 mg/L BAP is more suitable for root development of D. spectabile plantlets cultured on VW medium.