Seed development in Malpighiaceae species with an emphasis on the relationships between nutritive tissues.
Malpighiaceae ovules have a well-developed nucellus; previous observations indicate that during seed development, the endosperm does not proliferate, thus, remaining scarce. This study aimed at identifying the nutritive tissues during seed development in Malpighiaceae, focusing especially on the endosperm. We analysed the seed development of Janusia mediterranea, J. occhionii, Mascagnia cordifolia, and Tetrapterys chamaecerasifolia, which were collected and processed by traditional methods for light microscopy. Ovules are subcampylotropous, crassinucellate and unitegmic in Janusia and bitegmic in M. cordifolia and T. chamaecerasifolia. The nucellus is well developed and protrudes through the micropyle, touching the funicular obturator. During development, a pachychalaza is formed, and the integuments coalesce in bitegmic species. Through a series of nucellar cell divisions, the perisperm is formed. In Janusia species, the endosperm is not produced. In M. cordifolia and T. chamaecerasifolia, the endosperm is nuclear, but it is scarce and ephemeral. The mature seed is exalbuminous, and the perisperm is consumed, and thus, the mature embryo is total. The absence of endosperm in Janusia is newly observed for the family and indicates functional transfer for the abundant perisperm.
Departamento de Biologia, Centro de Ciências e Tecnologias para Sustentabilidade, UFSCar-Universidade Federal de São Carlos, campus Sorocaba, Sorocaba, São Paulo, Brasil; Programa de Pós-Graduação em Ciências Biológicas (Botânica), Instituto de Biociências, UNESP-Universidade Estadual Paulista, Botucatu, São Paulo, Brasil.
Letícia Silva
LS
Souto
Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brasil. Electronic address: dmtoliveira@icb.ufmg.br.
Denise Maria Trombert
DM
Oliveira
D001938:Brazil; D056625:Endosperm; D035264:Flowers / Q000737:chemistry; D005638:Fruit / Q000737:chemistry; D006651:Histocytochemistry; D029581:Malpighiaceae / Q000235:genetics / Q000502:physiology*; D009753:Nutritive Value; D056771:Ovule / Q000737:chemistry; D012639:Seeds / Q000737:chemistry / Q000254:growth & development*
Endosperm absence; Janusia; Mascagnia; Perisperm; Tetrapterys