<p>Ptants are in charge of essential metabolic processes. They have the responsibility of generating oxygen and nutritious compounds through photosynthesis, starting from water, dioxide of carbon and solar energy. Therefore, they are essential to maintain life on earth. The place they are developed becomes the source of information to determine the quantity and quality of the crop. The light is heterogeneous and changing, therefore they are exposed to radiations unfavourable to its metabolic processes. Thus they have developed a series of structural and physiologic adaptations which allow them to Support and to take advantage of the available radiation. The ultraviolet solar energy is inhibitor and it can cause some biosynthetic unbalances which in turn, through secondary metabolism routs, can generate especial properties instilling typology in those types produced in tropical cold climates, with regional characteristics or with Denomination of Origin. The secondary biosynthesis is usually restricted to specific phases of plant development and to stress situations. Such conditions induce to the expression of genes that code several enzyme in the biosynthetic route of fenilpropanoid compounds.</p>