Optimizing micropropagation of Miscanthus sinensis 'Gold Bar' by shortening the production cycle and reducing acclimation stress through the use of selected growth regulators.

Miscanthus, with its decorative qualities and low cultivation requirements in terms of soil fertility and temperature, is the most popular grass in gardens and urban areas. For years, micropropagation has been regarded as an effective method of its production. However, in order to meet the demands of customers and provide adequate quantities of high-quality planting materials, it is necessary to develop more efficient methods of Miscanthus production. The present study evaluated the influence of different media on Miscanthus sinensis (Thunb.) Andersson (silver grass) multiplication as well as assessing the effect of different concentrations of selected cytokinins and auxins on multiplication and rhizogenesis. To shorten the production cycle and reduce costs, ex vitro rooting was combined with acclimatization, and selected growth regulators were used to decrease stress associated with external conditions. Biochemical analyses were conducted at each stage to determine the content of basic organic compounds, hydrogen peroxide (H₂O₂) and catalase activity. Stomatal function was assessed at the acclimatization stage. The obtained results allowed for the production cycle of plants propagated in tissue culture to be shortened by simultaneous rooting and acclimatization of microcuttings sprayed with abscisic acid (ABA). This regulator has been shown to effectively reduce plant stress associated with acclimatization by reducing H₂O₂ concentration and increasing assimilation pigment content. Growth regulators reduced the number of stomata that developed on the leaves of silver grass and led to lower stomatal conductance. H₂O₂ should be considered not only a stress marker but a vital signaling molecule.Key message: Combining acclimatization and ex vitro rooting in a one-step process significantly shortens the production cycle, while abscisic acid and brassinosteroids can support this. [ABSTRACT FROM AUTHOR]