Effect of nitrogen and potassium supply on concentration of iron and manganese and activities of catalase, peroxidase and aconitase in pepper plants

Abstract

Pepper plants (Capsicum annuum L. cv. Lamuyo) grown in soil filled pots were fertilized with 4 levels of NH₄NO₃ (6, 12, 18 and 24 g/pot) and 3 levels of K₂SO₄ (4, 8 and 12 g/pot). The lowest concentrations (N₁ and K₁) were selected as controls. The foliar levels of Fe and Mn, both total and extractable, were measured, together with the activities of catalase, peroxidase and aconitase. The N and K treatments affected the Fe and Mn nutritional status of the leaves. The effects on the catalase and peroxidase activity showed an Fe‐Mn interaction more clearly than the concentrations of Fe and Mn in leaves. In the present experiment aconitase activity did not prove to be a good indicator for the Fe nutritional status of plants.