Morphology and anatomy of the diaspores and seedling of Paspalum (Poaceae, Poales)

Abstract

The knowledge regarding of the diaspore and post-seminal development of Paspalum L. is important for grassland biodiversity conservation, based on their representativeness and genetic improvement of forage. The morphology of the diaspore and the post-seminal development of Paspalum dilatatum Poir. (rhizomatous), P. mandiocanum Trin. var. subaequiglume Barreto (stoloniferous), P. pumilum Nees. (decumbent caespitose) and P. urvillei Steud. (erect caespitose) was described to distinguish species with different growth forms and to survey the characters useful for taxonomy. P. dilatatum differs by presenting oval diaspores larger than the others, with five prominent nerves and trichomes; P. urvillei presents diaspores with one central nerve that is more developed than the two lateral nerves and trichomes; P. mandiocanum var. subaequiglume presents diaspores with trichomes only in the margin; and P. pumilum differs by presenting glabrous diaspores. The caryopsis involves the seed that presents the differentiated embryo and disposed laterally, an elliptical hilum in all of the studied species and a rostellum in P. dilatatum and P. mandiocanum var. subaequiglume. The post-seminal development is similar in the four species and begins with germination that is marked by the emergence of the coleorhiza, followed by the coleoptile. These characteristics are common to other Poaceae previously studied, indicating a pattern to the family and do not distinguish the growth forms.

Relationship of the lateral embryo (in grasses) to other monocot embryos: a status up-grade

“…The first thing to emerge from a grass seed during germination is the coleorhiza, which is subsequently ruptured by an emerging adventitious root (Eichemberg and Scatena, 2013). In some species, two or more roots are in the coleorhiza (Tillich, 2007).…”