Reproductive biology of the "Brazilian pine" (Araucaria angustifolia-Araucariaceae): the pollen tube growth and the seed cone development.

Autor: Kuhn SA; Laboratório de Anatomia Vegetal (LAVeg), Instituto de Biociências, Departamento de Botânica, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves, 9500, Porto Alegre, RS, Brazil. sofia.kuhn@ufrgs.br., Nogueira FM; Laboratório de Biologia Molecular de Plantas, Departamento de Biologia, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto (FFCLRP) - Universidade de São Paulo-USP, Av. Bandeirantes 3900, Ribeirão Preto, 14040-901, Brazil., Schürer T; Laboratório de Anatomia Vegetal (LAVeg), Instituto de Biociências, Departamento de Botânica, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves, 9500, Porto Alegre, RS, Brazil., Mariath JEA; Laboratório de Anatomia Vegetal (LAVeg), Instituto de Biociências, Departamento de Botânica, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves, 9500, Porto Alegre, RS, Brazil.
Jazyk: angličtina
Zdroj: Plant reproduction [Plant Reprod] 2024 Mar; Vol. 37 (1), pp. 1-13. Date of Electronic Publication: 2023 Jul 14.
DOI: 10.1007/s00497-023-00473-8
Abstrakt: Key Message: In Araucaria angustifolia, the seed scale is part of the ovule, the female gametophyte presents a monosporic origin and arises from a coenocytic tetrad, and the pollen tube presents a single axis. The seed cone of conifers has many informative features, and its ontogenetic data may help interpret relationships among function, development patterns, and homology among seed plants. We reported the seed cone development, from pollination to pre-fertilization, including seed scale, ovule ontogeny, and pollen tube growth in Araucaria angustifolia. The study was performed using light microscopy, scanning electron microscopy, and X-ray microcomputed tomography (μCT). During the pollination period, the ovule arises right after the seed scale has emerged. From that event to the pre-fertilization period takes about 14 months. Megasporogenesis occurs three weeks after ovule formation, producing a coenocytic tetrad. At the same time as the female gametophyte's first nuclear division begins, the pollen tube grows through the seed scale adaxial face. Until maturity, the megagametophyte goes through the free nuclei stage, cellularization stage, and cellular growth stage. Along its development, many pollen tubes develop in the nucellar tissue extending straight toward the female gametophyte. Our observations show that the seed scale came out of the same primordia of the ovule, agreeing with past studies that this structure is part of the ovule itself. The formation of a female gametophyte with a monosporic origin that arises from a coenocytic tetrad was described for the first time in conifers, and the three-dimensional reconstruction of the ovule revealed the presence of pollen tubes with only one axis and no branches, highlighting a new pattern of pollen tube growth in Araucariaceae.
(© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
Databáze: MEDLINE
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