Evaluating the Impact of Exogenous Application of Jasmonic Acid on in vitro Growth and Development of Rose Micropropagules

Background: Rose (Rosa hybrida L.) micropropagules were studied to assess the impact of jasmonic acid (JA) on their in vitro growth, biomass accumulation and biochemical parameters. The study also investigated the effects of two JA incorporation methods-pre-autoclaving and post-autoclaving (filter sterilization). Methods: Micropropagules were cultivated in vitro on Murashige and Skoog (MS) medium supplemented with jasmonic acid at concentrations of (0, 5, 10, 25, 50, 75 and 100 mg L-1). Growth parameters, including shoot number, shoot length, fresh weight anddry weight, were measured. Biochemical analyses included total carbohydrates, proteins, phenols and chlorophyll content. The influence of JA concentration and incorporation method was evaluated. Result: JA application method (pre or post-autoclaving) did not significantly affect growth parameters. Low concentrations of jasmonic acid (5 and 10 mg L-1) increased total chlorophyll content in rose micropropagules when applied using the pre-autoclaving method, with the highest accumulation observed at 25 mg L-1 (0.46±0.02 mg g-1 fwt). In contrast, post-autoclaving application resulted in a marked reduction in chlorophyll content across all concentrations. The highest biochemical improvements were observed at 25 mg L-1 JA, while concentrations above 50 mg L-1 negatively impacted growth and biochemical attributes. These findings highlight JA’s effectiveness as a regulator for improving rose micropropagules’ growth and biochemical properties, with optimal results achieved at moderate concentrations and slight variations in response based on the incorporation method.