The aim of this study was to determine the influence of biostimulants on the content of selected microelements in the skin and flesh of potato tubers. Five potato cultivars were grown: Irga, Satina (with cream- and yellow-colored flesh), Valfi, Blaue St. Galler (with purple-colored flesh) and Highland Burgundy Red - HB Red (with red-colored flesh). Potatoes were treated with the following biostimulants: Asahi SL, Bio-Algeen S 90, Kelpak SL and Trifender WP. Control plants were not treated with biostimulants. Samples of potato tubers were analyzed immediately after the harvest and after 5 months of storage (4°C). The highest content of micronutrients in the skin and flesh of potato tubers was determined at harvest in the driest 2015 year. In all years of the experiment, micronutrient concentrations were lower in the flesh than in the skin of potato tubers, and the greatest differences were noted in the content of Fe. The concentrations of Zn, Mn and Fe in the skin and flesh of potato tubers increased as a response to the Bio-Algeen S 90 biostimulant, and the content of Fe was also higher in the skin of potatoes treated with Kelpak SL. In general, the skin and flesh of potatoes cvs. Valfi, Blaue St. Galler and HB Red were more abundant in microelements than cvs. Irga and Satina potatoes. Content of Zn and Mn increased and the content of Cu and Fe decreased (excluding the first year of the study) in the skin and flesh of stored potatoes. The skin and flesh of stored potato tubers treated with biostimulants were characterized by Mn concentrations that were higher or similar to those recorded in the control treatment (excluding the skin of potatoes treated with Bio-Algeen S 90) and a smaller decrease in Cu content.

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