Toxicity symptoms of nickel in common bean

Abstract

Despite the importance of nickel (Ni) in the N metabolism of legumes, common bean (Phaseolus vulgaris L.) is considered very sensitive to Ni doses. The objective in this study was to characterize the toxicity symptoms of Ni in common bean cv. Pérola. The experiment was conducted in greenhouse in the campus of the Universidade Estadual do Norte Fluminense - Darcy Ribeiro, Campos dos Goytacazes - RJ. Solutions containing 0; 20; 40; 60 and 100 mg L^-1 of Ni, in the form of nickel chloride hexahydrate (NiCl₂.6H₂O), were applied to shoots of common bean plants at the rate of 2.5 mL of solution per plant of common bean, 25 days after sowing. Plants of common bean treated with 0; 20; 40 and 60 mg L^-1 of Ni showed no toxicity symptoms. Plants treated with 100 mg L^-1 of Ni showed chlorotic leaves with gray spots that coalesced and became necrotic in a more advanced stage.