Gibberellic Acid–Induced Germination and the Effect of Cytokinin Type on Early Seedling Development in Mirabilis jalapa L.

Processes of seed germination and early seedling development in Mirabilis jalapa L. are closely associated with dormancy mechanisms and hormonal regulation. The present study investigated the effects of different plant growth regulators on the germination and early seedling morphology of M. jalapa. Germination experiments were conducted in Petri dishes containing 25 seeds each, placed on filter paper, using gibberellic acid (GA₃) at concentrations of 100 and 200 µM. Furthermore, the effects of mechanical scarification, hot water treatment, and cold stratification on germination were evaluated. An assessment was made of early seedling development in media supplemented with 0.5 mg L-1 6-benzylaminopurine (BAP) and 0.5 mg L-1 kinetin.Treatments with gibberellic acid (GA3) resulted in limited germination, with rates of 15% at 100 µM and 25% at 200 µM. The process of germination was initiated between days 28 and 32, and was concluded by day 56. No germination was observed in seeds subjected to mechanical, thermal, or cold stratification treatments. The application of cytokinin primarily exerted an influence on the post-germination morphology of seedlings, as opposed to the process of germination itself. Treatment with kinetin resulted in higher mean values for shoot length, leaf number, leaf size, and root length in comparison with BAP. In contrast, BAP induced a more compact shoot architecture while restricting root development. The results of this study underscore the significance of selecting appropriate plant growth regulators, taking into account the developmental stage, for the effective propagation of M. jalapa.