Effects of alginate encapsulated divalent ions (Zn2+, Cu2+ and Ca2+) on mustard (Brassica juncea (L.) Czern.) seed germination and seedling growth

Abstract

Encapsulation of agrochemicals allows growers to precisely control the conditions under which the active ingredient is released. Since zinc, copper, and calcium ions are essential micronutrients in crop production, the goal of our work was to incorporate them into alginate-based capsules, and to investigate the impact of their release on seed germination and seedling growth. Oriental mustard (Brassica juncea (L.) Czern.) was selected as a model crop. Among the tested ions, Cu²⁺ exhibited the greatest increase, followed by Zn²⁺, whereas Ca²⁺ showed the smallest increase, and its concentration declined over time when calcium-based capsules were applied. Performed studies demonstrate that released cations from the capsules into soil solution significantly affected seeds germination and biomass of mustard sprouts in laboratory tests. The release of Cu²⁺ and Zn²⁺ negatively influenced radicle development, with Cu²⁺ almost completely suppressing radicle elongation, and Zn²⁺ exhibiting a progressive inhibitory effect with increasing incubation time. Although, Ca²⁺ stimulated radicle elongation, it did not significantly affect total sprout and cotyledon biomass