RESUMEN
BACKGROUND: Drimys brasiliensis Miers is native to Brazil, where it is mainly found in montane forests and flooded areas in the South and Southeast regions of the country. The objectives of the present study were to compare the leaf anatomy and the chemical constitution of the essential oils from D. brasiliensis present in two altitude levels (1900 and 2100 m), in a Montane Cloud Forest, in Itamonte, MG, Brazil. RESULTS: A higher number of sclereids was observed in the mesophyll of the leaves at 1900 m altitude. At 2100 m, the formation of papillae was observed on the abaxial surface of the leaves, as well as an increase in the stomatal density and index, a reduction in leaf tissue thickness, an increase in the abundance of intercellular spaces in the mesophyll and an increase in stomatal conductance and in carbon accumulation in the leaves. Fifty-nine constituents have been identified in the oils, with the predominance of sesquiterpenes. Two trends could be inferred for the species in relation to its secondary metabolism and the altitude. The biosyntheses of sesquiterpene alcohols at 1900 m, and phenylpropanoids and epi-cyclocolorenone at 2100 m, were favored. CONCLUSIONS: D. brasiliensis presented a high phenotypic plasticity at the altitude levels studied. In relation to its leaf anatomy, the species showed adaptive characteristics, which can maximize the absorption of CO2 at 2100 m altitude, where a reduction in the partial pressure of this atmospheric gas occurs. Its essential oils presented promising compounds for the future evaluation of biological potentialities.
