EFFECTS OF IRON AND DIFFERENT FORMS OF NITROGEN ON UPTAKE AND DISTRIBUTION OF MINERAL ELEMENTS IN CORN PLANTS Ⅱ. On the Fe, Mn, Cu and Zn

The effects of Fe and two forms of nitrogen on uptake and distribution of microelements in corn plants was studied in nutrient solution under controlled conditions. The results demonstrated that Fe supply improved Fe content in young leaves obviuosly and decreased Mn, Zn content in young leaves no matter what kind of nitrogen was supplied. At the same time, different forms of nitrogen could also influence the contents of Fe, Mn, Cu, Zn in plants. Compared to NO3--N, NH4+-N supply could improve Fe content in young leaves and decrease Mn, Zn, Cu content under Fe-deficient condition. Though there was lower Fe content in the roots of NH4+-N fed plants comparing to NO3--N supply, there was higher Fe content in young leaves. Moreover, Fe and NH4+-N supply decreased the contents of active Mn and Zn in young leaves of corn plants. The influence of iron and nitrogen supply on contents and distribution of Fe, Mn. Zn and Cu in old leaves, stem and roots was also discussed.