Which element is required photosynthetic evolution of oxygen?

Manganese is required for the photosynthetic evolution of oxygen.
Mn plays a vital role in the oxygen-evolving complex of photosynthesis; four atoms are required to split water.
manganese in nature is its involvement in oxygen evolution in green plant photosynthesis, a process essential for the maintenance of life and of critical importance for the production of food and other commodities for man.