Ontogeny Elucidates the Double Calyx of Leandra melastomoides (Miconieae, Melastomataceae)

Autor(es)

Basso-Alves, Joao Paulo ^{[1, 2]} ; Goldenberg, Renato ^[3] ; Teixeira, Simone Padua ^[2]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Inst Biol, Programa Posgrad Biol Vegetal, BR-13083970 Campinas, SP - Brazil

^[2] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Ciencias Farmaceut, Ave Cafe S-N, BR-14040903 Sao Paulo - Brazil

^[3] Univ Fed Parana, Dept Bot, Ctr Politecn, Setor Ciencias Biol, BR-81531970 Curitiba, Parana - Brazil

• Tipo de documento: Artigo Científico
• Fonte: INTERNATIONAL JOURNAL OF PLANT SCIENCES; v. 178, n. 9, p. 740-752, NOV-DEC 2017.
• Citações Web of Science: 1

Resumo

Premise of research.The flower of Leandra melastomoides (Melastomataceae) exhibits a singular condition that is the presence of two distinct and opposite portions in the sepals forming what is known as a double calyx. These portions may correspond to individual sepals, explaining the recognition of two calyx whorls. No studies resolving this structure are available in the literature. Thus, we aimed to elucidate the nature of the double calyx of L. melastomoides by analyzing its ontogeny. This approach allowed us to test hypotheses about how this structure developed.Methodology.Flowers and buds were preserved and prepared for observation in LM and SEM.Pivotal results.The sepals originate in the margin of the floral apex as six spherical primordia in a single outer whorl. The growth is unidirectional until a basal protuberance arises on the ventral surface of each primordium, which allows us to distinguish an upper and a lower part of this structure. The upper portion later takes on a dorsal position. The lower portion shows laminar growth, various vascular traces, and nonglandular emergences. The dorsal portion becomes conical, is lined with nonglandular emergences, and is supplied by a single vascular trace. The vascularization of each part of a sepal has a common origin from the radial divergence of the same trace that emerges from the vascular ring of the hypanthium.Conclusions.The calyx of L. melastomoides actually consists of only one whorl, because both dorsal and laminar parts of a sepal originate from a single primordium in a peripheral region of the floral meristem. The dorsal projection is similar to that described in the literature under the term Vorlauferspitze. The understanding of the existence of two distinct ontogenetic modules for the same organ allows us to compare it with other organs and taxonomic groups and to search for a better descriptive terminology for the structure in this group. (AU)

• Processo FAPESP: 08/10793-0 - Embriologia em espécies de Miconia (Melastomataceae) com diferentes sistemas reprodutivos
• Beneficiário: Sandra Maria Carmello-Guerreiro
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 11/02701-0 - Desenvolvimento floral em espécies de Melastomataceae Juss.
• Beneficiário: João Paulo Basso Alves
• Modalidade de apoio: Bolsas no Brasil - Doutorado