Terpenoids of plants in arid environments.

Arid and desert environments are characterized by the sparse and discontinuous vegetation cover. Species that have been able to survive difficult bioclimatic conditions and adapt from generation to generation in these areas had to develop physiological and biochemical mechanisms of tolerance and/or resistance. The use of secondary metabolites, specifically terpenoids, is predominant in most of the biotic and abiotic interactions in which these plants are involved. Studies have shown their roles in the prevention of oxidative stress by intervening in thermo-tolerance, water stress, and salt stress generalized in a model of "the protective role of volatile compounds" explained by a single biochemical mechanism. Other studies have proven the functions of terpenoids in direct and indirect defenses against natural enemies, herbivores, and pathogenic microorganisms, in the attraction of pollinators, in competition and facilitation and other interactions between plants. This review mainly summarizes the recent research progress on the adaptation mechanisms of plants in arid environments and the biological and ecological roles of terpenoids in the various biotic and abiotic interactions.