Plants utilize nitrogen, phosphorus, and potassium Plants need nitrogen to build proteins and a variety of other biomolecules, such as chlorophyll(叶绿素) Nitrogen fixation nitrogen fig 15. 4 two pathways for nitrogen fixation, a source of nitrogen for Soil Root plants.(a) both free bacteria nodule N2+8H++6e 2NH+ living bacteria in the soil and Icroorganisms root nodules produce ammonium ions. ( b lightning prov ides the lightening energy needed to form nitrate ions from atmospheric nitrogen V2+3O2+2e 2NO• Plants utilize nitrogen, phosphorus, and potassium • Plants need nitrogen to build proteins and a variety of other biomolecules, such as chlorophyll (叶绿素). • Nitrogen fixation Soil bacteria N2+8H++6e- 2NH4 + nitrogenase lightening N2+3O2+2e- 2NO3 - fig 15.4 two pathways for nitrogen fixation, a source of nitrogen for plants. (a) both free￾living bacteria in the soil and microorganisms in root nodules produce ammonium ions. (b) lightning provides the energy needed to form nitrate ions from atmospheric nitrogen. Root nodule