Morfoanatomía de las plántulas de dos especies de lupinos graníferos: Lupinus albus y L. angustifolius (Fabaceae, Faboideae)

Abstract

The morphoanatomy of seedlings of two cultivated grain lupines is described and compared ( Lupinus albus L. and L. angustifolius L.). To obtain the seedlings, 60 seeds of each species were sown in terrines with a coarse sand substrate. After 20 days from sowing, 15 seedlings were selected and the lengths of hypocotyl, epycotyl were measured as well as, the length and width of leaflets, which showed significant differences except in the lengths of the leaflets. Optical microscope slides were done for the epidermis and cross-sections of primary root, hypocotyl, epycotyl, petiole and leaflet, the sections were analyzed, illustrated and photographed. Both species share the same structure of diarch root, glabrous adaxial face and anfistomatics characteristics with anomocytic stomata in leaflets epidermal layers. The most noticeable differences between the species seedlings are the presence of a laminar collenchyma layer and the larger number of vascular bundles in the hypocotyl and epycotyl of L. angustifolius and a starchy layer sheath in the hypocotyl of L. albus . The cordate form and the two lobes emerging from a center channel in the petiole of L. angustifolius, reaffirm other morphological similarities with the species L. gibertianus . The major differences in the leaflets are the width and the structure of the mesophyll which is dorsiventral in L. albus and is isobilateral in L. angustifolius . The structure of an epitricopodium in tricelular trichomes are described for the first time for the genus Lupinus . The anatomical structures were com- pared and discussed with those of other species of the genus, with environmental conditions and with modifications by plant breeding. This work serves as a basic knowledge for further research to find if there are relationship between support tissues and transport system with the plant protection strategies against pathogen infections and water stress.