Physiological role of carotenoids and other antioxidants in plants and application to turfgrass stress management

Reactive oxygen species (ROS) are highly destructive chemicals within plant systems. Antioxidants are important photoprotective chemicals that guard plants from oxidative stress. Antioxidants can be classified into two groups: enzymatic and non-enzymatic. Of the non-enzymatic antioxidants, carotenoids have received relatively little attention in turfgrass research. However, carotenoids are vital antioxidants for buffering of singlet oxygen, dissipation of excess light energy through non-photochemical quenching, and harvesting light energy and channeling to the photosystem. Greater emphasis on carotenoids in turfgrass research could provide several benefits. For example, new cultivars could be selected that have improved high light tolerance owing to greater zeaxanthin production. Additionally, xenobiotics could potentially increase carotenoid production, thereby increasing turfgrass survivability under oxidative stress. Previous research indicates turfgrass species have robust carotenoid pool levels comparable to vegetables and herbs consumed for their phytonutrient benefits.