Microsporogenesis in angiosperms producing pantoporate pollen

Prieu, Charlotte; Toghranegar, Zohreh; Gouyon, Pierre‐Henri; Albert, Béatrice

doi:10.1080/23818107.2019.1652849

Cited by 6 publications

(3 citation statements)

References 31 publications

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“…Matamoro-Vidal et al (2016) report that tetrads formed in S. latifolia are 81.5% tetrahedral, 17.9% rhomboidal, and 0.5% isobilateral. Also, Prieu et al (2019) report that tetrads were 81% tetrahedral and 19% rhomboidal in S. pendula. In this study, the decussate tetrad type is reported for the first time in the genus Silene.…”

Section: Discussionmentioning

confidence: 95%

Male gametophyte development of <i>Silene sangaria</i> Coode & Cullen (Caryophyllaceae), an endemic species from Turkey

Kartal,

Agirman

2023

CYTOLOGIA

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In this study, microspore formation (microsporogenesis), gamete formation (microgametogenesis), and pollen features of Silene sangaria, a species endemic to Turkey, was examined cytoembryologically and histochemically. The species is distributed along the Black Sea coast of Turkey. The materials were collected from the coast of Igneada village (Kirklareli province). The anthers, separated by size, were passed through ethyl alcohol concentration series, and embedded in historesin. Sections were sliced using a rotary microtome and stained with toluidine blue O for general histological observations, Coomassie brilliant blue for proteins, and periodic acid-Schiff for insoluble polysaccharides. The aceto-orcein squash technique was used for cytological observations, and lactophenol-aniline blue solution was used to assess pollen viability. The anthers of S. sangaria are tetrasporangiate, and its anther wall development is of basic type. The tapetum is secretory type, and cytokinesis is simultaneous type. As a result of meiotic division of microspore mother cells, 43.5% decussate, 28.2% rhomboidal, 21.1% tetrahedral and 7.2% isobilateral tetrads occur. The released microspores first pass through the first pollen mitosis to form vegetative and generative cells, then the generative cell passes through the second pollen mitosis to form two sperm cells. Pollen grains are three-celled when released from the anther. Pollen viability rate is high (91.82%). Mature pollen grain contains a high concentration of insoluble polysaccharide and protein.

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Section: Discussionmentioning

confidence: 95%

Male gametophyte development of <i>Silene sangaria</i> Coode & Cullen (Caryophyllaceae), an endemic species from Turkey

Kartal,

Agirman

2023

CYTOLOGIA

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“…Recent progress in developmental genetics has revealed that fine mechanisms of pollen aperture development are to some extent conserved among lineages as distantly related as Brassicaceae ( Arabidopsis ) and grasses (e.g., rice and maize), which represent highly derived eudicots and monocots respectively (Dobritsa and Coerper, 2012; Li et al, 2018; Wang and Dobritsa, 2018; Zhang et al, 2020; Lee et al, 2021; Zhou et al, 2021). Deletion of the INP1 protein is correlated with formation of inaperturate pollen in some lineages (Dobritsa and Coerper, 2012; see also Prieu et al, 2019). It will be interesting to discover whether a homologue of the Arabidopsis gene INP1 is involved in regulation of pollen aperture formation in Aponogeton , Ruppia , and Althenia .…”

Section: Discussionmentioning

confidence: 99%

Pollen in water of unstable salinity: Evolution and function of dynamic apertures in monocot aquatics

Severova

Rudall

Macfarlane³

et al. 2022

American J of Botany

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Premise: The sporoderm of seed-plant pollen grains typically has apertures in which the outer sporopollenin-bearing layer is relatively sparse. The apertures allow regulation of the internal volume of the pollen grain during desiccation and rehydration (harmomegathy) and also serve as sites of pollen germination. A small fraction of angiosperms undergo pollination in water or at the water surface, where desiccation is unlikely. Their pollen grains commonly lack apertures, though with some notable exceptions. We tested a hypothesis that in some angiosperm aquatics that inhabit water of unstable salinity, the pollen apertures accommodate osmotic effects that occur during pollination in such conditions. Methods: Pollen grains of the tepaloid clade of the monocot order Alismatales, which contains ecologically diverse aquatic and marshy plants, were examined using light microscopy and scanning electron microscopy. We used Ruppia as a model to test pollen grain response in water of various salinities. Pollen aperture evolution was also analyzed using molecular tree topologies. Results: Phylogenetic optimizations demonstrated an evolutionary loss and two subsequent regains of the aperturate condition in the tepaloid clade of Alismatales. Both of the taxa that have reverted to aperturate pollen (Ruppia, Ruppiaceae; Althenia, Potamogetonaceae) are adapted to changeable water salinity. Direct experiments with Ruppia showed that the pollen apertures have a role in a harmomegathic response to differences in water salinity. Conclusions: Our results showed that the inferred regain of pollen apertures represents an adaptation to changeable water salinity. We invoke a loss-and-regain scenario, prompting questions that are testable using developmental genetics and plant physiology.

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“…Sin embargo, este patrón de microsporogénesis por lo general determina la formación de granos de polen con tres aberturas, que es el más común en eudicotiledóneas y se explica por los puntos de contacto de las microsporas en la tétrada (Furness & Rudall, 2004). No obstante, los granos de polen de A. rosea son pantoporados, lo cual no se podría explicar por el modelo de contacto de las microsporas y al parecer está determinado por la presencia de acumulaciones regulares de calosa durante la formación de la tétrada (Prieu et al, 2019). Durante la microsporogénesis en plantas el depósito de la esporodermis es centrípeto, es decir, primero se deposita la exina formada principalmente de esporopolenina y posteriormente se forma la intina que está formada por componentes de pared primaria (Blackmore et al, 2007;Pacini & Hesse, 2012).…”

Section: Discussionunclassified

Microsporogénesis y micromorfología del polen de la planta Alcea rosea (Malvaceae)

Barón

Torres-Rodríguez²,

Passarelli³

et al. 2021

Rev. Biol. Trop.

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Introducción: Los estudios sobre microsporogénesis, micromorfología y estructura de los granos de polen en Malvaceae son escasos. Objetivos: Describir el proceso de microsporogénesis y aspectos micromorfológicos de los granos de polen en A. rosea. Métodos: Se procesaron más de 30 andróforos de acuerdo con los protocolos estándar para incrustar y seccionar en parafina. Las secciones obtenidas se tiñeron con azul de Safranina-Alcian, las anteras inmaduras y no fijadas se tiñeron con azul de anilina. Se procesaron secciones de resina adicionales de los andróforos y se tiñeron con azul de toluidina. Se observaron secciones ultrafinas con microscopía electrónica de transmisión (TEM). Para la observación con microscopía electrónica de barrido (SEM), el material se fijó y deshidrató en 2,2 dimetoxipropano, luego se secó hasta un punto crítico y se recubrieron con oro. Resultados: las anteras se diferencian de una masa celular en los extremos distales de los filamentos del estambre. La pared de la antera madura presenta una capa externa de células epidérmicas y una capa interna, el endotecio. Las células madre de microesporas se dividen por mitosis y luego experimentan meiosis para formar tétradas. El tapete es inicialmente celular y forma una sola capa de células y luego pierde integridad celular al invadir el lóculo de microsporangio, formando un periplasmodio. Durante la formación de la esporodermis, primero se deposita la exina y luego la intina. Para el momento de la liberación de los granos de polen, el tapete se ha degenerado por completo. Los granos de polen son pantoporados, apolares, con simetría radial, esferoidales, con espinas, bacula, gránulos y microgránulos. El tectum está perforado con foveolea dispuesta homogéneamente en toda la superficie y con polenkit. La exina es ancha (5-6 µm) y consta de una endexina gruesa de 3.5 a 4 µm y una ektexina fina (0.6-0.7 µm). La ultraestructura muestra columelas claramente definidas formando el infratectum. Se aprecian tricomas nectaríferos unicelulares glandulares capitados (TG) cubriendo toda la superficie de los filamentos de los estambres. Conclusiones: La estructura y desarrollo de las anteras sigue los patrones conocidos de las angiospermas. La microsporogénesis simultánea y el depósito centrípeto de la esporodermis se han descrito previamente para Malvaceae.

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Microsporogenesis in angiosperms producing pantoporate pollen

Cited by 6 publications

References 31 publications

Male gametophyte development of <i>Silene sangaria</i> Coode & Cullen (Caryophyllaceae), an endemic species from Turkey

Male gametophyte development of <i>Silene sangaria</i> Coode & Cullen (Caryophyllaceae), an endemic species from Turkey

Pollen in water of unstable salinity: Evolution and function of dynamic apertures in monocot aquatics

Microsporogénesis y micromorfología del polen de la planta Alcea rosea (Malvaceae)

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