Active Fe in young leaves
Fresh peanut leaves from each pot or district were mixed, and 1 g of leaf was taken and mixed with 10 ml of 1 M hydrochloric acid. The supernatant was shaken for 5 h at 150 rpm and then filtered with filter paper. The Fe concentration was measured by inductively coupled plasma–optical emission spectrometry (ICP-OES) using a 7300DV system (Perkin Elmer, USA).