Resumen

BENITEZ, Carmen  y  FERRAROTTO, María. Comparative anatomy of the petiole in Solanum species section Geminata. Polibotánica [online]. 2012, n.34, pp.177-190. ISSN 1405-2768.

The Geminata Section of the genus Solanum is integrated by 126 species, from which 35 are represented in Venezuela. These are very homogeneous regarding its morphology andgeneral growth habit with simpodial branching. In the searching of other features that allow their identification and/or separation, a study of petiole anatomy considering micromorphoanatomics characters that can conform a taxonomic criterion for delimitation at specific level. For this first article, 18 species were considered using fresh and herborized material from MER, MY and VEN. Petiole transverse sections from adult leaves were hand made, stained and mounted in semipermanent slides for observationunder a compound microscope. The dimension of transversal and longitudinal axis of sections, the trichome type and density, stomata type and density, number of epidermal layers and cell shape, bundle sheath form, dimensions and wings length were registered. The most contrasting petioles micromorphological features between the studied species were the quantitative referred to trichomes number with high densities for S. chlamydogynum, S. microleprodes and S. oblongifolium with 36 trichomes.mm^-2 and petiole wing length to 1700 μm in S. obovalifolium. The rest quantitative characters studied and all the qualitative features have a lack of significanceto relate these species. In addition, the presence of collenchyma only in S. nudum and S. obovalifolium petiole, as well as abundant sandy crystals only six species would differentiate them from the rest of those considered.

Palabras llave : micromorphology; anatomy; petiole; Solanum section Geminata.