Showing papers by "Beatriz G. Galati published in 2014"
TL;DR: The first functional EFN of each secondary axis of the inflorescence reaches its maturity when both the pollen grains and the embryo sacs are completely developed and the flowers begin to open and the secretion is granulocrine.
Abstract: The inflorescences of the genus Vigna Savi have extrafloral nectaries (EFNs) among the flowers whose origin is still unknown. The disposition, anatomy and morphology, as well as the ontogeny of the extrafloral nectaries (EFNs) associated with the inflorescences of Vigna adenantha (G.F.W. Meyer) Marechal, Mascherpa & Stainier (Leguminosae, Papilionoideae, Phaseolae) were studied. Besides, the ultrastructure of the secretory stage was described. The inflorescence, a raceme, bears a brief globose secondary axis in each node with 2 flowers and 5–7 EFNs, which develop in acropetal direction. Each EFN originates from the abscission of a flower bud that interrupts its development, resulting in an elevated EFN. This secretory structure is formed by a ring of epidermal and parenchymatic cells surrounding a group of elongated central cells. The nectary is irrigated by phloem and xylem. Four developmental stages proceed; each one relates to a different embryological stage of the flowers in each secondary axis. The first functional EFN of each secondary axis of the inflorescence reaches its maturity when both the pollen grains and the embryo sacs are completely developed and the flowers begin to open. The secretion is granulocrine. The following EFNs develop in the same way.
9 citations
TL;DR: This is the first embryological report of the Grewioideae subfamily, contributing to the characterization of the genera studied and the results are discussed in relation to the known data for the family.
Abstract: Anther development, microsporogenesis and microgametogenesis of six species of the genera Corchorus, Heliocarpus, Luehea and Triumfetta were analysed. The genera were found to share the following characters: ontogeny of anther wall of basic type; simultaneous microsporogenesis, resulting mainly in tetrahedral tetrads; secretory tapetum and pollen grains shed at the bicellular stage. Moreover, the characters that differentiate them are: presence of uninucleate tapetal cells in Heliocarpus and Triumfetta; binucleate cells in Corchorus and multinucleate cells in Luehea; differentiation of the thickenings of the endothecium at free microspores stage in Corchorus, Heliocarpus and Triumfetta, whereas in Luehea differentiation occurs at the mature pollen grains stage; late disintegration of sporogenous tissue cell walls in Luehea; and the presence of orbicules, absent only in Corchorus. This is the first embryological report of the Grewioideae subfamily, contributing to the characterization of the genera studied...
5 citations
TL;DR: The aim of the present study is to provide detailed morphological descriptions of the seed coat in 10 species of Oxalis from Buenos Aires Province, Argentina, using light microscopy and scanning electron microscopy.
Abstract: The aim of the present study is to provide detailed morphological descriptions of the seed coat in 10 species of Oxalis from Buenos Aires Province, Argentina, using light microscopy and scanning electron microscopy. The seed is ovate and brown, and its surface is smooth. Oxalis has a mechanism of spermobolia by which a part of the seed coat is detached by the rupture of cells, leaving exposed a layer of opened cells, generally with oxalate crystals. This new coat surface has different characteristics in the species studied in this work. Three types are recognized, mostly on the basis of anatomical and ultrastructural characteristics of the seed coat. The species grouped in each of the 3 types of seeds belong to different sections of the genus; thus, the seed morphology could be of taxonomic value for the genus Oxalis.
3 citations