Functions of carotenoids in leaves of higher plants (an overview)

The structural diversity and multifunctionality of carotenoids is an urgent problem for many areas of biological and medical research. The interaction of carotenoids in cyclic reactions made it possible to understand their role in redox processes and their participation in the basic physicochemical, physiological, and biochemical functions of a plant organism. The contribution of carotenoids to the formation of the structure of the photosynthetic apparatus (PSA) of plants, participation in the absorption of light energy and protection of chlorophyll molecules from reactive oxygen species is analyzed. The mechanisms of the participation of zeaxanthin in the process of energy dissipation and the protective role of carotenoids as antioxidants in the lipid phase of membranes are considered. The function of violaxanthin cycle (VC) pigments in the block of water photolysis reactions as participants in the utilization of the released oxygen is discussed. A hypothesis is proposed about the participation of balance transformations of VC pigments (at sub-threshold illumination) in maintaining the mechanisms of "plant memory" when switching to high illumination is necessary. Environmental studies have shown that in response to a wide range of stress factors, the photoprotection mechanism of the photosynthetic apparatus is activated, which is associated with the activation of non-photochemical quenching as a component of the system of non-specific reactions of the plant organism.