Ion-exchange substrates based on the weakly acidic ion exchanger TOKEM-200

The possibility of using the carboxyl ion exchanger TOKEM-200 as a carrier of biogenic ions necessary for plant growth has demonstrated. The main objective of the study was to determine the ionic ratio of the content of K + , Mg 2+ , and Ca 2+ in it, the pH of the substrate solution and the total electrolytes concentration. Physiologically acceptable values of these parameters were determined. The corresponding substrates were obtained under laboratory conditions, and their suitability for growing the test plant – lettuce ( Lactuca sativa L.) – was tested. The test plants, grown on new 100% ion-exchange substrates BIONA, containing TOKEM-200 cation exchange resin, developed normally over three consecutive growing seasons. The yield of aboveground biomass of the plants was almost independent of the type of anionic component optimized for ionic composition. The plants contained nitrate ions in concentrations no higher than 680 mg/kg of green biomass.