Zinc toxicity-induced variation of mineral element composition in hydroponically grown bush bean plants

Bush bean plants (Phaseolus vulgaris L. cv Contender) were grown for twenty days in nutrient solution (pH=5), containing 0.13, 0.3, 0.5 or 0.75 mg 1–1 Zn as ZnS04-7H20. The plant yield decreased linearly with the increase of the Zn concentration supplied. The phytotoxic threshold content (for 10% growth reduction) was about 486, 242, 95 and 134≺ μg Zn g 1 for roots, stems, mature primary and trifoliate leaves, and developing leaves, respectively. High inverse correlation coefficients with the Zh concentration supplied were found for the Mn content of all organs, for the P content of roots, and for the Cu and Ca contents of developing leaves. Significant positive relations were found for the Fe, Zn and Cu contents in roots and for the Zn contents in stems and fully expanded leaves. The ratios of the mineral contents between organs suggest inhibition of uptake of Mn and P, and inhibition of translocation of Fe, Cu and Ca. The relation between dry weight decrease and Zn-induced nutrient content disorders were discussed. © 1987, Taylor & Francis Group, LLC. All rights reserved.