Embryology in Relation to Systematics of Gramineae

Bhanwra, R. K.

doi:10.1093/oxfordjournals.aob.a087653

Cited by 30 publications

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“…The unreduced female gametophytes that accompanied the sexual ones also potentially can undergo development. These structures resembling unorganized aposporous and also incomplete monopolar female gametophytes without antipodes, with polar nuclei and an egg cell and a synergid, or with polar nuclei only (Bhanwra, 1988;Ma and Huang, 2007;Guohua et al, 2009) observed in M. ×giganteus may be interpreted as a tendency toward apomixis (apospory). Although apomixis could have been inherited from M. sinensis (Chou et al, 2000), apomictic female gametophytes were arrested at an early stage of development or else degenerated and did not develop embryos.…”

Section: Discussionmentioning

confidence: 95%

Sterility of Miscanthus × Giganteus Results from Hybrid Incompatibility

Słomka¹,

Kuta²,

Płażek³

et al. 2012

Acta Biologica Cracoviensia Series Botanica

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Miscanthus ×giganteus Greef et Deu. (Poaceae), a hybrid of Miscanthus sinensis and M. sacchariflorus native to Japan, is an ornamental and a highly lignocellulosic bioenergy crop, cultivated in the European Union as an alternative source of energy. This grass reproduces exclusively vegetatively, by rhizomes or via expensive in vitro micropropagation. The present study was aimed at finding the barriers that prevent sexual seed production, based on detailed embryological analyses of the whole generative cycle, including microsporogenesis, pollen viability, megasporogenesis, female gametophyte development, and embryo and endosperm formation. Sterility of M. ×giganteus results from abnormal development of both male and female gametophytes. Disturbed microsporogenesis (laggard chromosomes, univalents, micronuclei) was further highlighted by low pollen staining. The frequency of stainable pollen ranged from 13.9% to 55.3% depending on the pollen staining test, and no pollen germination was observed either in vitro or in planta. The wide range of pollen sizes (25.5-47.6 μm) clearly indicated unbalanced pollen grain cytology, which evidently affected pollen germination. Only 9.7% of the ovules developed normally. No zygotes nor embryos were found in any analyzed ovules. Sexual reproduction of M. ×giganteus is severely hampered by its allotriploid (2n=3x=57) nature. Hybrid sterility, a strong postzygotic barrier, prevents sexual reproduction and, therefore, seed formation in this taxon.K Ke ey y w wo or rd ds s: : Miscanthus ×giganteus, allotriploid, pollen viability, female gametophyte development, sterility.

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Section: Discussionmentioning

confidence: 95%

Sterility of Miscanthus × Giganteus Results from Hybrid Incompatibility

Słomka¹,

Kuta²,

Płażek³

et al. 2012

Acta Biologica Cracoviensia Series Botanica

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“…In addition, Bhanwra (1988) reported the presence of only four layers of microsporangium cells in Poaceae, one of the family synapomorphies. Bhanwra (1988) also stated that male embryological traits are common in the family.…”

Section: Introductionmentioning

confidence: 99%

Anther and pollen development in some species of Poaceae (Poales)

2010

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Anther and pollen development were studied in Olyra humilis Nees, Sucrea monophylla Soderstr, (Bambusoideae), Axonopus aureus P. Beauv., Paspalum polyphyllum Nees ex Trin. (Panicoideae), Eragrostis solida Nees, and Chloris elata Desv. (Chloridoideae). The objective of this study was to characterise, embryologically, these species of subfamilies which are considered basal, intermediate and derivate, respectively. The species are similar to each other and to other Poaceae. They present the following characters: tetrasporangiate anthers; monocotyledonous-type anther wall development, endothecium showing annular thickenings, secretory tapetum; successive microsporogenesis; isobilateral tetrads; spheroidal, tricellular, monoporate pollen grains with annulus and operculum. Nevertheless, the exine patterns of the species studied are distinct. Olyra humilis and Sucrea monophylla (Bambusoideae) show a granulose pattern, whereas in the other species, it is insular. In addition, Axonopus aureus and Paspalum polyphyllum (Panicoideae) have a compactly insular spinule pattern, while Chloris elata and Eragrostis solida (Chloridoideae) show a sparsely insular spinule pattern. The exine ornamentation may be considered an important feature at the infrafamiliar level.Keywords: Bambusoideae, Chloridoideae, Gramineae, microsporogenesis, Panicoideae. Desenvolvimento da antera e do grão de pólen em espécies de Poaceae (Poales)Resumo O desenvolvimento da antera e do grão de pólen de Olyra humilis Nees, Sucrea monophylla Soderstr. (Bambusoideae), Axonopus aureus P. Beauv., Paspalum polyphyllum Nees ex Trin. (Panicoideae), Eragrostis solida Nees and Chloris elata Desv. (Chloridoideae) foi estudado visando caracterizar embriologicamente essas espécies de subfamílias consideradas basal, intermediária e derivada, respectivamente. As espécies são similares entre si e entre as demais Poaceae. Apresentam os seguintes caracteres: anteras tetrasporangiadas; desenvolvimento da parede da antera do tipo monocotiledôneo, endotécio com espessamento de parede anelar, tapete secretor; microsporogênese sucessiva; tétrades isobilaterais; grãos de pólen esféricos, tricelulares, monoporados, com anel e opérculo. Por outro lado, o padrão de ornamentação da exina do grão de pólen é distinto. Olyra humilis e Sucrea monophylla (Bambusoideae) apresentam padrão granuloso e as demais espécies padrão insular. Axonopus aureus e Paspalum polyphyllum (Panicoideae) apresentam espínulos densamente agrupados, enquanto Chloris elata e Eragrostis solida (Chloridoideae) espínulos esparsamente agrupados. A ornamentação da exina dos grãos de pólen pode ser considerada caráter importante a nível infrafamiliar.

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“…Para as espécies de Poaceae, Dahlgren et al (1985) citaram óvulos ortótropos, anátropos, hemianátropos e campilótropos, sendo os três últimos os mais citados na literatura, para esta família (Narayanaswami 1954, Mengesha & Guard 1966, Bhanwra 1988. Para as espécies de Chloridoideae estudadas, o óvulo é campilótropo, devido à curvatura do megagametófito.…”

Section: Discussionunclassified

“…A divisão periclinal da epiderme nucelar que caracteriza os óvulos pseudocrassinucelados das espécies de Bambusoideae e Panicoideae estudadas foi descrita também para outras espécies de Panicoideae estudadas por Bhanwra (1988). O autor sugeriu ser essa uma característica exclusiva da subfamília Panicoideae.…”

Section: Discussionunclassified

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Desenvolvimento de óvulo, fruto e semente de espécies de Poaceae (Poales)

Nakamura¹,

Longhi-Wagner²,

Scatena³

2009

Rev. bras. Bot.

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-(Ovule, fruit and seed development in species of Poaceae (Poales)). We selected Olyra humilis Nees and Sucrea monophylla Soderstr. (Bambusoideae), Axonopus aureus P. Beauv. and Paspalum polyphyllum Nees ex Trin. (Panicoideae), Chloris elata Desv. and Eragrostis solida Nees (Chloridoideae) to study their ovule, fruit and seed development in order to characterize the embryology of these subfamilies within Poaceae. Like other Poaceae that have already been studied, these species present bitegmic ovule, micropyle formed by the inner integument, megagametophyte of the Polygonum type, starchy nuclear endosperm, and lateral, developed embryo. In specimens of Bambusoideae and Panicoideae, the ovule is hemianatropous and pseudocrassinucellate, whereas in Chloridoideae, it is campylotropous and tenuinucellate. The outer integument is restricted to the ovule base in Bambusoideae; it reaches up to one third of the nucellus in Panicoideae and extends to the micropyle in Chloridoideae. O. humilis and S. monophylla (Bambusoideae) present a more developed nucellus than the other species studied here. Each subfamily varies with regard to its mature caryopsis type. In Bambusoideae, the fruit has a phenolic endocarp and ategmic seeds; Panicoideae have compressed, adnate pericarp and tegmen; Chloridoideae present a free exocarp and a phenolic endotegmen. The overall features are diagnostic for the Poaceae subfamilies studied here.Key words -Bambusoideae, Chloridoideae, embryology, Panicoideae RESUMO -(Desenvolvimento do óvulo, fruto e semente de espécies de Poaceae (Poales)). O desenvolvimento de óvulo, fruto e semente de Olyra humilis Nees e Sucrea monophylla Soderstr. (Bambusoideae), Axonopus aureus P. Beauv. e Paspalum polyphyllum Nees ex Trin. (Panicoideae), Chloris elata Desv. e Eragrostis solida Nees (Chloridoideae) foram estudados visando à caracterização embriológica dessas subfamílias de Poaceae. As espécies apresentam óvulo bitegumentado, micrópila formada pelo tegumento interno, megagametófito tipo Polygonum, endosperma nuclear e amiláceo, embrião lateral e desenvolvido, caracteres comuns às demais espécies de Poaceae já estudadas. Destacam-se diferenças como: óvulo hemianátropo e pseudocrassinucelado nas espécies de Bambusoideae e Panicoideae, campilótropo e tenuinucelado, nas de Chloridoideae; tegumento externo restrito à base do óvulo em Bambusoideae, até um terço do nucelo em Panicoideae e próximo à região micropilar em Chloridoideae. O. humilis e S. monophylla (Bambusoideae) apresentam maior desenvolvimento do nucelo do que as demais espécies. A variação no tipo de cariopse separa as subfamílias de Poaceae estudadas, pois Bambusoideae apresenta endocarpo fenólico e semente ategumentada; Panicoideae apresenta pericarpo comprimido e adnato ao tégmen; e Chloridoideae apresenta exocarpo livre e endotégmen fenólico. Esses caracteres são diagnósticos para as subfamílias de Poaceae estudadas.

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Embryology in Relation to Systematics of Gramineae

Cited by 30 publications

References 0 publications

Sterility of Miscanthus × Giganteus Results from Hybrid Incompatibility

Sterility of Miscanthus × Giganteus Results from Hybrid Incompatibility

Anther and pollen development in some species of Poaceae (Poales)

Desenvolvimento de óvulo, fruto e semente de espécies de Poaceae (Poales)

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