Best defined function of manganese in green plants is

Step-by-step solution

Photolysis of water requires light energy, an Oxygen Evolving Complex (OEC) and electron carrier 1/2. OEC complex was formerly called Z-enzyme. It has four Mn ions. Light energy brings about changes in Mn ( Mn ⁺², Mn ³⁺, Mn ⁺⁴ ) which helps in removing electrons from OH ⁻ component of water forming oxygen. Liberation of oxygen also requires Cl ⁻ and Ca ⁺² .