Sorbents of phenols as a components of the nutritional medium in microclonal reproduction of plants

In the process of microclonal reproduction, plants secrete various substances into the nutrient medium, for example, phenolic compounds, which act as inhibitors of growth processes and, accordingly, prevent the normal development of explants in vitro . Plant tissues are treated with stabilizing substances, and various sorbents are also used as components of the nutrient medium to neutralize the negative effects of phenols. This paper presents an overview of the approved methods for solving the problem of sorption of phenolic compounds during microclonal propagation of plants. Various studies are considering the addition of certain components to the nutrient medium that prevent the release of harmful growth-inhibiting substances. Most often, various carbon compounds, such as activated carbon, are used as an adsorbent. The authors, based on the analysis of domestic and foreign literature on this topic, conclude that the most effective and frequently used are carbon compounds and the polymer polyvinyl pyrrolidone, less common is the use of the following inhibitory substances: ascorbic and citric acids, silver nitrate and mercury chloride. According to the results of the conducted analytical studies, the prospects of using such substances as thermally expanded graphite (TEG) and colloidal silicon dioxide as sorbents in the composition of the drug “Polysorb” were revealed. Due to the inhomogeneous porous structure, including both micropores and meso- or macropores, TEG is able to adsorb pollutants both from the solution and from the water surface, which makes it a potential sorbent for phenolic compounds. The effect of silicon dioxide, in amorphous form, on plants in vitro has already been successfully tested by some researchers, which indicates the prospects of its study.