... characteristics and productivity, on one hand, and taxon, on the other hand. The genus Populus is a member of the Salicaceae fam-ily and is subdivided into six taxonomically distinct sec-tions [18,21]. There ... result of the combined effects of irradiance and leaf aging, leaves at the base of the stems being the oldest ones and age decreasingfrom the bottom to the top of the stem. The variations in ... the thickness of the abaxial epidermis (EbT). The leaves of the genotypes of the Tacamahaca (T, T×B) and Tacamahaca× Aigeiros (T×D) sections were thicker than the leaves of the genotypes of the...