Different forms of copper and kinetin impacted element accumulation and macromolecule contents in kidney bean (Phaseolus vulgaris) seeds

Abstract

The relationship between engineered nanomaterials and plant biostimulants is unclear. In this study, kidney bean (Phaseolus vulgaris) plantswere grown to maturity (90 days) in soil amendedwith nano copper (nCu), bulk copper (bCu), or copper chloride (CuCl2) at 0, 50, or 100mg kg−1, thenwatered with 0, 10, or 100 μMof kinetin (KN). Seeds were harvested and analyzed via ICP-OES and biochemical assays. While seed production was largely unaffected, nutritional valuewas significantly impacted. Accumulation of Cuwas enhanced by 5–10% fromcontrols by Cu-based treatments. Fe was the only macro/microelement significantly altered by nCu, which was ~29% lower than seeds fromuntreated plants. All forms of Cu combinedwith 10 μMKN reducedMg from9 to 12%. Application of KN plus bCu or CuCl2 elevated concentrations of Mn (31–41%) and S (19–22%), respectively. Protein content of seeds was stimulated (11–12%) by bCu, on average, and depressed by CuCl2 + KN (up to 22%). Variations in sugar and starch contentwere insignificant, compared to controls. Our results indicate that the interaction Cu × KN significantly altered the nutritional value of common beans, which has potential implications to agricultural practices incorporating Cu as either a pesticide or fertilizer.