A Contribution to the Life History of Casuarina

Swamy, B. G. L.

doi:10.2307/20023517

Cited by 23 publications

(41 citation statements)

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“…Essas células são bastante diferenciadas, entretanto, fazem parte de um tecido originalmente totipotente que é o nucelo, o que justifica sua capacidade de dar origem às PEA. Devido à sua localização, as células da hipóstase podem participar ativamente na translocação de nutrientes para o saco embrionário em desenvolvimento (Swamy 1941, Tilton 1980, o que também pode influenciar no alto número de PEA aí encontradas. O fato de não haver deposição de lignina nas células da hipóstase é menos comum (Tilton 1980), entretanto isto favorece a sua diferenciação em PEA.…”

Section: Discussionunclassified

“…A embriogenia de T. ochracea é do tipo Onagrado, de acordo com o sistema de classificação de Johansen (1950), como também foi observado em diversos trabalhos com a família Bignoniaceae, o de Souèges (1940) para Catalpa kaempferi Sieb. & Zucc., de Swamy (1941) para Bignonia megapotamica Spreng., de Ghatak (1956) para Oroxylum indicum (L.) Vent. e de Mehra & Kulkarni (1985) para Tabebuia rosea, Millingtonia hortensis L., Dolichandrone falcata Seem., Heterophragma adenophyllum (Wall.…”

Section: Discussionunclassified

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Poliembrionia e aspectos da embriogênese em Tabebuia ochracea (Chamisso) Standley (Bignoniaceae)

Costa¹,

Sampaio²,

Paoli³

et al. 2004

Rev. bras. Bot.

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-(Polyembryony and aspects of embryogenesis in Tabebuia ochracea (Chamisso) Standley (Bignoniaceae)). The origin of the extranumerary embryos and the embryogeny of Tabebuia ochracea were analysed. Extranumerary apomictic embryos are of adventitious origin from hypostase cells and from the integument of ovule micropilar region. The embryogeny corresponds to Onagrad type. Among 233 dissected seeds, 81.37% presented polyembryony and up to seven embryos were detected in a single seed. Sexual and adventitious embryos can develop together in a single seed. Some of the adventitious embryos show severe morphoanatomical anomalies that can affect their development into seedlings.Key words -apomixis, Bignoniaceae, polyembryony, Tabebuia ochracea RESUMO -(Poliembrionia e aspectos da embriogênese em Tabebuia ochracea (Chamisso) Standley (Bignoniaceae)). A origem dos embriões supranumerários e a embriogenia de Tabebuia ochracea foram analisadas. Embriões supranumerários apomíticos têm origem adventícia a partir de células da hipóstase e do tegumento da região micropilar do óvulo. A embriogenia corresponde ao tipo Onagrado. Das 233 sementes dissecadas 81,37% apresentaram poliembrionia e foram encontrados até sete embriões em uma mesma semente. Aparentemente, embriões sexuais e adventícios podem se desenvolver juntos, numa mesma semente. Alguns dos embriões adventícios apresentam alterações morfoanatômicas graves que podem prejudicar seu desenvolvimento em plântulas.

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Section: Discussionunclassified

Poliembrionia e aspectos da embriogênese em Tabebuia ochracea (Chamisso) Standley (Bignoniaceae)

Costa¹,

Sampaio²,

Paoli³

et al. 2004

Rev. bras. Bot.

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“…Both carpels are fertile and each has two ovules in Gymnostoma, although mature fruits are always one-seeded (unpublished data). In Allocasuarina and Casuarina, one of the two carpels is sterile and the carpel has a single ovule (Swamy 1948, Barlow 1958. Ticodendron also has a bicarpellate gynoecium and each carpel has two fertile ovules (Tobe 1991).…”

Section: (Gymnostoma (Ceuthostoma (Casuarina-allocasuarina)))mentioning

confidence: 99%

Molecular Phylogeny of Casuarinaceae Based on rbcL and matK Gene Sequences

et al. 2001

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We present the first overall molecular phylogenetic study of Casuarinaceae on the basis of sequences of two chloroplast genes, rbcL (1310 bp) and matK (1014 bp), using 15 species representing the family. The study included analyses of Ticodendron (Ticodendraceae) and three species of Betulaceae as close relatives, and one species each of Juglandaceae and Myricaceae as outgroups. Analyses based on matK gene sequences, which provided a much better resolution than the analyses based on rbcL gene sequences alone, resulted in a single most parsimonious tree whose topology is almost identical with the strict consensus tree generated by the combined data set of rbcL and matK gene sequences. Results showed that Casuarinaceae are monophyletic, comprising four distinct genera, A//ocasuarina, Casuarina, Ceuthostoma and Gymnostoma, which were not recognized until recently. Within the family, Gymnostoma is positioned at the most basal position and sister to the remainder. Within the remainder Ceuthostoma is sister to the A//ocasuarina-Casuarina clade. Morphologically the basalmost position of Gymnostoma is supported by plesiomorphies such as exposed stomata in the shallow longitudinal furrows of the branchlets, a basic chromosome number x=8 and the gynoecium composed of two fertile, biovulate carpels. The three other genera, A//ocasuarina, Casuarina, and Ceuthastoma, have invisible stomata in the deep longitudinal furrows of the branchlets, a higher basic chromosome number x=9 or 10-14 (unknown in Ceuthostoma), the gynoecium composed of one fertile and one sterile carpel with a single ovule (unknown in Ceuthastoma). The diversity of infructescence morphology found in the latter three genera suggests that they may have evolved in close association with the elaboration of fruit dispersal mechanisms.

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“…However, in contrast to Arabidopsis and Torenia as well as to most other angiosperms, species of Casuarinaceae have an unusual and distinctive time difference (more than 1 month) between pollination and fertilization. In addition, species of Casuarinaceae are known to show chalazogamy (e.g., Swamy 1948;Barlow 1958), a mode of fertilization by which the pollen tube passes through the chalaza instead of a micropyle (porogamy) as found in a majority of angiosperms.…”

Section: Introductionmentioning

confidence: 99%

Pollen-tube growth pattern and chalazogamy in Casuarina equisetifolia (Casuarinaceae)

Sogo

Noguchi

Jaffré³

et al. 2004

Journal of Plant Research

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For a better understanding of pollen-tube guidance in relation to pollen-pistil interaction, we investigated the mode of pollen-tube growth in pistils of Casuarina equisetifolia, a monoecious, wind-pollinated species that undergoes chalazogamous fertilization. The pistil is bicarpellate, but only one of the two carpels develops with two ovules. One of these ovules develops more than four embryo sacs. Pistils usually require more than 1 month to reach maturity after pollen grains have been deposited on the stigmas. During that period, pollen-tube growth proceeds discontinuously in five distinct steps that lead up to fertilization: (1) from the stigma to the upper region of the style, (2) from the upper region of the style to a septum in the ovary, (3) from the septum to the surface of the funiculus, (4) from the funiculus to chalaza in the ovule, and (5) from the chalaza to an egg apparatus. Probably because of competitive interaction between male and female gametophytes (or ovules), one pollen tube is selected from among many during the first step (just before the second step), one ovule from the two during the second and third steps, and one embryo sac from more than four during the fourth and fifth steps. On the basis of our results, erroneous drawings and explanations reported in earlier publications on chalazogamy in Casuarinaceae should be brought into question.

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A Contribution to the Life History of Casuarina

Cited by 23 publications

References 0 publications

Poliembrionia e aspectos da embriogênese em Tabebuia ochracea (Chamisso) Standley (Bignoniaceae)

Poliembrionia e aspectos da embriogênese em Tabebuia ochracea (Chamisso) Standley (Bignoniaceae)

Molecular Phylogeny of Casuarinaceae Based on rbcL and matK Gene Sequences

Pollen-tube growth pattern and chalazogamy in Casuarina equisetifolia (Casuarinaceae)

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