Photoprotection by dissipation of excess light energy aided by xanthophyll cycle carotenoids.
The xanthophyll violaxanthin is converted to zeaxanthin (via the intermediate antheraxanthin) whenever chloroplasts absorb excess light. Zeaxanthin acts as a key facilitator of the dissipation of excess 1Chl*. Conversely, when light is not excessive, zeaxanthin is disengaged from energy dissipation and converted back to violaxanthin, thereby returning to an efficient utilization of light energy in photosynthesis.