Carotenoids in Thermal Adaptation of Plants and Animals

Abstract

The support of carotenoids in photosynthesis is well documented. However, what is their role in parts of plants where there is no photosynthesis such as in fruits or stems or even in parts which are not exposed to the light at all, such as seeds or roots? Why are carotenoids essential for all animals and humans and present in almost every tissue in their body? The answer is that carotenoids can make complexes with lipids, which results in an increase of lipid thermal energy absorption and a reduction of viscosity. These changes help to expand the temperature range for the functionality of lipid structures, improve the capacity of thermal homeostasis and support adaptation and survival of living species to environmental stress and in particular to temperature variations. Working as “thermal antennas” carotenoids can increase lipid thermal energy conductivity, heat storage and heat retaining capacity. This, on the one hand, can reduce the freezing/melting points of plant and animal lipids and makes carotenoids work as antifreezers in microorganisms, plants or ectothermic animals. On the other hand, the thermal antennas can help absorb, transmit and accumulate external thermal energy essential to activate and support cellular metabolism. In addition, we describe how these properties of carotenoids can affect lipid parameters in nutrition, physiology and pathology.