Medicinal and Aromatic Plants (MAP): How Do They Adapt to the Environment?

Abstract

Taking the best out of plants, namely from medicinal and aromatic plants (MAP), involves understanding their structural and chemical features, in connection with their biological roles, and, no less important, realizing the principles behind their use by plants. Plants are exquisitely sensitive to biotic and abiotic environmental changes. Nevertheless, plants are unique in their renewal capacity, since they can produce meristems during their life time, and in showing developmental plasticity, i.e., the ability to change its development in response to diverse factors. This means that a plant can very often survive, despite having been partially eaten, and/or that a single plant genotype can be expressed under different phenotypes, and the one(s) expressed will depend on local environmental stimuli. From man point of view this may have importance, as these different phenotypes can be associated to different chemotypes, which may have a tremendous implication on the biological activity of plant man-valued products and on their commercial value. Some of the structural and chemical traits involved in plant-abiotic and plant-biotic defence, and in attraction interactions, with some examples on how man uses some of these traits and mechanisms to his benefit, are here revised. Apoplastic barriers, glandular or non-glandular structures, mimicry, plant, or plant parts, movements, abiotic environmental relationships, interaction with pathogens and phytophagous and attraction of pollinators and seed dispersers, are discussed. In each case, plants use both constitutive, as well as inducible traits. Nevertheless, it is noteworthy that constitutive traits are not always constant. Indeed, constitutive structural and chemical features can be permanent or transient, depending on the plant developmental stage. Despite all available traits, plants are endowed with self-defence mechanisms against their own toxins. The awareness of plant structural and chemical adaptative features purposes can complement the knowledge derived from evolutionary studies, and provide us the know-how to project and develop plants with improved traits, or procedures based on their modus operandi and/or better plant (nano-)products.