I Plant nitrogen Uptake of NH4 may be brought about by the facilitated diffusion(by the electropotential difference and cation selective channels). With Nhat nutrition recycling of ht back into the cytosol is restricted and the ht/pumped out of the cell and remain mainly outside and hence the pH is depressed.Uptake of NH4 + may be brought about by the facilitated diffusion (by the electropotential difference and cation selective channels). With NH4 + nutrition recycling of H+ back into the cytosol is restricted and the H+ /pumped out of the cell and remain mainly outside and hence the pH is depressed. I Plant nitrogen