Manganese toxicity in bush bean as affected by concentration of manganese and iron in the nutrient solution

Abstract

Abstract An experiment was conducted to clarify the relationship between Mn toxicity and Fe deficiency in bush snap bean (Phaseolus vulgaris L. cv. ‘Wonder Crop No. 2'). Seedlings were grown in full strength Hoagland No. 2 solution at pH 6.0 for ten days. Six concentrations of Mn as MnCl2.4H2O were used in combination with three concentrations of Fe as FeEDTA. Toxicity symptoms, induced by low levels of Mn (0.1 ppm and above), included: small brown necrotic spots and veinal necrosis on primary leaves; necrosis on primary leaf petioles; interveinal chlorosis, with or without brown necrotic spots, on trifoliate leaves; and brown necrotic spots on stipules. Manganese toxicity symptoms were alleviated or prevented by increasing Fe concentration in the nutrient solution. Manganese concentration in the leaves increased with increasing Mn and decreased with increasing Fe concentration in the nutrient solution, Iron concentration in the roots increased with increasing Fe concentration in the nutrient solution; ho...