Micromorphologie des épidermes foliaires chez quelques espèces de Medicago

Abstract

The micromorphology of the abaxial epidermis of the first and sixth leaf has been studied in seven annual species of Medicago L. The pattern of the epidermal cells and of the stomatal complex does not allow differentiation of the taxa. Three main types of trichomes are recognized on the two foliar levels; their localization on the first leaf epidermis allows identification of five taxa out of seven. Four quantitative variables are also examined: stomatal density, trichome density, guard cell length, and stomatal index. The variable having the best discriminant value is the guard cell length on the first leaf. It is possible to identify each of the seven species by a combination of two features: the localization of the types of trichomes on the first leaf and the stomatal density on the sixth leaf.