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Paula J. Rudall - One of the best experts on this subject based on the ideXlab platform.
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Microsporogenesis is simultaneous in the early divergent grass streptochaeta but successive in the closest grass relative ecdeiocolea
Grana, 2009Co-Authors: Maria Das Graças Sajo, Carol A Furness, Paula J. RudallAbstract:Simultaneous Microsporogenesis is described for the first time in a grass, Streptochaeta spicata Schrad., a tropical Brazilian species that belongs in the early‐divergent subfamily Anomochlooideae. Microsporogenesis is successive in all other Poaceae examined so far, and most other members of the order Poales, to which grasses belong. The only other reports of simultaneous Microsporogenesis in Poales are in Rapateaceae and some members of the cyperid clade (Juncaceae, Cyperaceae, Prionium and Thurnia). Among the graminids, Ecdeiocolea (the putative closest relative to Poaceae) is successive, as are Joinvillea, Flagellaria and all other Poaceae, indicating that the simultaneous condition is autapomorphic in Streptochaeta, though Anomochloa has yet to be examined. Anther wall development in Streptochaeta is of the reduced type, as also in another early‐divergent grass Pharus, though most other Poales, including most grasses, have the monocot type. In Streptochaeta, as in Pharus, the endothecium lacks thicke...
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Microsporogenesis is simultaneous in the early‐divergent grass Streptochaeta, but successive in the closest grass relative, Ecdeiocolea
Grana, 2009Co-Authors: Maria Das Graças Sajo, Carol A Furness, Paula J. RudallAbstract:Simultaneous Microsporogenesis is described for the first time in a grass, Streptochaeta spicata Schrad., a tropical Brazilian species that belongs in the early‐divergent subfamily Anomochlooideae. Microsporogenesis is successive in all other Poaceae examined so far, and most other members of the order Poales, to which grasses belong. The only other reports of simultaneous Microsporogenesis in Poales are in Rapateaceae and some members of the cyperid clade (Juncaceae, Cyperaceae, Prionium and Thurnia). Among the graminids, Ecdeiocolea (the putative closest relative to Poaceae) is successive, as are Joinvillea, Flagellaria and all other Poaceae, indicating that the simultaneous condition is autapomorphic in Streptochaeta, though Anomochloa has yet to be examined. Anther wall development in Streptochaeta is of the reduced type, as also in another early‐divergent grass Pharus, though most other Poales, including most grasses, have the monocot type. In Streptochaeta, as in Pharus, the endothecium lacks thicke...
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Microsporogenesis and anther development in Bromeliaceae
Grana, 2005Co-Authors: M. Graça Sajo, Christina J. Prychid, Paula J. RudallAbstract:Bromeliaceae possess several features of pollen and anther wall development that are plesiomorphic for Poales, consistent with their putatively basal or near‐basal placement in this order. For example, successive Microsporogenesis and the monocotyledonous type of anther wall formation are both plesiomorphic features that occur commonly in other Poales, with a few notable exceptions, notably the simultaneous type of Microsporogenesis in Rapateaceae. The intermediate type of tapetum development in Bromeliaceae was probably derived secondarily from a secretory type, which occurs in most other Poales except Typhaceae.
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Evolution of Microsporogenesis in Angiosperms
International Journal of Plant Sciences, 2002Co-Authors: Carol A Furness, Paula J. Rudall, F. Bruce SampsonAbstract:Microsporogenesis is highly labile in early‐branching angiosperms, i.e., those with mostly sulcate pollen, compared with the tricolpate and tricolpate‐derived eudicots. New records of Microsporogenesis in basal angiosperms (19 taxa were examined), together with a review of the literature, demonstrate that the existing typology has been too strictly applied; several basal angiosperms have apparently intermediate forms and therefore do not fit easily into simultaneous or successive categories. Intermediate forms include the “modified simultaneous” type, where ephemeral cell plates are formed after the first meiotic division but then disperse, and simultaneous cleavage follows the second meiotic division. This relative diversity reflects a range of variation in number and position of pollen apertures in basal angiosperms, although both monosulcate and inaperturate pollen may occur in conjunction with either simultaneous or successive Microsporogenesis. However, many taxa with inaperturate pollen have success...
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Microsporogenesis and systematics of Aristolochiaceae
Botanical Journal of the Linnean Society, 2001Co-Authors: Favio González, Paula J. Rudall, Carol A FurnessAbstract:Within Aristolochiaceae, a secretory tapetum and orbicules are ubiquitous, but both simultaneous and successive types of Microsporogenesis occur. Simultaneous cytokinesis is apparently plesiomorphic within the order Piperales, in which Aristolochiaceae are now placed. Successive Microsporogenesis was found only in species of Aristolochia confined to a crown clade in the proposed phylogeny of this genus. In contrast to many other taxa, within Aristolochiaceae there is no strict relationship between Microsporogenesis type and tetrad configuration, which is strongly influenced by spindle orientation, especially during meiosis II. There is also no direct correlation between Microsporogenesis type and the aperture of mature pollen grains.
Carol A Furness - One of the best experts on this subject based on the ideXlab platform.
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Microsporogenesis is simultaneous in the early divergent grass streptochaeta but successive in the closest grass relative ecdeiocolea
Grana, 2009Co-Authors: Maria Das Graças Sajo, Carol A Furness, Paula J. RudallAbstract:Simultaneous Microsporogenesis is described for the first time in a grass, Streptochaeta spicata Schrad., a tropical Brazilian species that belongs in the early‐divergent subfamily Anomochlooideae. Microsporogenesis is successive in all other Poaceae examined so far, and most other members of the order Poales, to which grasses belong. The only other reports of simultaneous Microsporogenesis in Poales are in Rapateaceae and some members of the cyperid clade (Juncaceae, Cyperaceae, Prionium and Thurnia). Among the graminids, Ecdeiocolea (the putative closest relative to Poaceae) is successive, as are Joinvillea, Flagellaria and all other Poaceae, indicating that the simultaneous condition is autapomorphic in Streptochaeta, though Anomochloa has yet to be examined. Anther wall development in Streptochaeta is of the reduced type, as also in another early‐divergent grass Pharus, though most other Poales, including most grasses, have the monocot type. In Streptochaeta, as in Pharus, the endothecium lacks thicke...
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Microsporogenesis is simultaneous in the early‐divergent grass Streptochaeta, but successive in the closest grass relative, Ecdeiocolea
Grana, 2009Co-Authors: Maria Das Graças Sajo, Carol A Furness, Paula J. RudallAbstract:Simultaneous Microsporogenesis is described for the first time in a grass, Streptochaeta spicata Schrad., a tropical Brazilian species that belongs in the early‐divergent subfamily Anomochlooideae. Microsporogenesis is successive in all other Poaceae examined so far, and most other members of the order Poales, to which grasses belong. The only other reports of simultaneous Microsporogenesis in Poales are in Rapateaceae and some members of the cyperid clade (Juncaceae, Cyperaceae, Prionium and Thurnia). Among the graminids, Ecdeiocolea (the putative closest relative to Poaceae) is successive, as are Joinvillea, Flagellaria and all other Poaceae, indicating that the simultaneous condition is autapomorphic in Streptochaeta, though Anomochloa has yet to be examined. Anther wall development in Streptochaeta is of the reduced type, as also in another early‐divergent grass Pharus, though most other Poales, including most grasses, have the monocot type. In Streptochaeta, as in Pharus, the endothecium lacks thicke...
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successive Microsporogenesis in eudicots with particular reference to berberidaceae ranunculales
Plant Systematics and Evolution, 2008Co-Authors: Carol A FurnessAbstract:The eudicot clade of angiosperms is characterised by simultaneous Microsporogenesis and tricolpate pollen apertures. Successive Microsporogenesis, where a distinct dyad stage occurs after the first meiotic division, is relatively rare in eudicots although it occurs in many early branching angiosperms including monocots. An extensive literature survey shows that successive Microsporogenesis has arisen independently at least six times in eudicots, in five different orders, including Berberidaceae (Ranunculales). Microsporogenesis and pollen apertures were examined here using light and transmission electron microscopy in eleven species representing six genera of Berberidaceae. Successive Microsporogenesis is a synapomorphy for the sister taxa Berberis and Mahonia (and possibly also Ranzania), the remaining genera are simultaneous. Callose wall formation in Berberis and Mahonia is achieved by centripetal furrowing, though centrifugal cell plates are more usual for this Microsporogenesis type. This discrepancy could reflect the fact that the successive type in Berberidaceae is derived from the simultaneous type, and centripetal furrowing has been retained. Eudicots with successive Microsporogenesis usually produce tetragonal or decussate tetrads, though occasional tetrahedral or irregular tetrads in Berberis and Mahonia indicate that the switch from simultaneous to successive division is incomplete or “leaky”. In contrast, linear tetrads produced by successive Microsporogenesis in Asclepiadoideae (Apocynaceae s.l.) are the result of a highly specialised developmental pathway leading to the production of pollinia. Pollen in successive eudicots is dispersed as monads, dyads, tetrads, and as single grains in pollinia. Apertures are diverse, and patterns include spiraperturate, clypeate, irregular, monocolpate, diporate and inaperturate. It is possible that successive Microsporogenesis, although rare, potentially occurs in other eudicots, for example, in species where pollen is inaperturate.
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Phylogenetic comparative analysis of Microsporogenesis in angiosperms with a focus on monocots
American Journal of Botany, 2008Co-Authors: Sophie Nadot, Carol A Furness, Béatrice Albert, Julie Sannier, Laurent Penet, Sarah Triki-teurtroy, Adrienne RessayreAbstract:This paper presents the first broad overview of three main features of Microsporogenesis (male meiosis) in angiosperms: cytokinesis (cell division), intersporal wall formation, and tetrad form. A phylogenetic comparative approach was used to test for correlated evolution among these characters and to make hypotheses about evolutionary trends in Microsporogenesis. The link between features of Microsporogenesis and pollen aperture type was examined. We show that the pathway associated with successive cytokinesis (cytoplasm is partitioned after each meiotic division) is restricted to wall formation mediated by centrifugally developing cell plates, and tetragonal (or decussate, T-shaped, linear) tetrads. Conversely, much more flexibility is observed when cytokinesis is simultaneous (two meiotic divisions completed before cytoplasmic partitioning). We suggest that the ancestral type of Microsporogenesis for angiosperms, and perhaps for all seed plants, associated simultaneous cytokinesis with centripetal wall formation, resulting in a large diversity in tetrad forms, ranging from regular tetrahedral to tetragonal tetrads, including rhomboidal tetrads. From this ancestral pathway, switches toward successive cytokinesis occurred among basal angiosperms and monocots, generally associated with a switch toward centrifugal intersporal wall formation, whereas eudicots evolved toward an almost exclusive production of regular tetrahedral tetrads. No straightforward link is found between the type of Microsporogenesis and pollen aperture type.
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Evolution of Microsporogenesis in Angiosperms
International Journal of Plant Sciences, 2002Co-Authors: Carol A Furness, Paula J. Rudall, F. Bruce SampsonAbstract:Microsporogenesis is highly labile in early‐branching angiosperms, i.e., those with mostly sulcate pollen, compared with the tricolpate and tricolpate‐derived eudicots. New records of Microsporogenesis in basal angiosperms (19 taxa were examined), together with a review of the literature, demonstrate that the existing typology has been too strictly applied; several basal angiosperms have apparently intermediate forms and therefore do not fit easily into simultaneous or successive categories. Intermediate forms include the “modified simultaneous” type, where ephemeral cell plates are formed after the first meiotic division but then disperse, and simultaneous cleavage follows the second meiotic division. This relative diversity reflects a range of variation in number and position of pollen apertures in basal angiosperms, although both monosulcate and inaperturate pollen may occur in conjunction with either simultaneous or successive Microsporogenesis. However, many taxa with inaperturate pollen have success...
Sophie Nadot - One of the best experts on this subject based on the ideXlab platform.
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Diversity and evolution of Microsporogenesis in Bromeliaceae
Botanical Journal of the Linnean Society, 2014Co-Authors: Béatrice Albert, Zohreh Toghranegar, Sophie NadotAbstract:In this study, we explore the features of Microsporogenesis in Bromeliaceae and, in particular, the diversity and evolution of additional callose deposits. Cytokinesis type, cell wall formation, tetrad form and patterns of additional callose deposition after intersporal wall formation were studied in 12 species of Bromeliaceae (each from a different genus) presenting four different aperture patterns. Microsporogenesis is highly conserved, with successive cytokinesis, centrifugal cell plate formation and predominantly tetragonal and decussate tetrads, as in many monocots, but five different patterns of additional callose deposition were recorded. The optimization of patterns of additional callose deposition on the phylogeny of Bromeliaceae reveals convergences. Additional callose deposition is a variable and labile feature of Microsporogenesis in Bromeliaceae and is linked, to some extent, to aperture pattern. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176, 36–45.
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Variation of Microsporogenesis in monocots producing monosulcate pollen grains
Annals of Botany, 2013Co-Authors: Zohreh Toghranegar, Sophie Nadot, Béatrice AlbertAbstract:† Background and Aims Microsporogenesis leading to monosulcate pollen grains has already been described for a wide range of monocot species. However, a detailed study of additional callose deposition after the completion of the cleavage walls has been neglected so far. The study of additional callose deposition in monosulcate pollen grain has gained importance since a correlation between additional callose deposition and aperture location has recently been revealed. † Methods Microsporogenesis is described for 30 species belonging to eight families of the monocots: Acoraceae, Amaryllidaceae, Alstroemeriaceae, Asparagaceae, Butomaceae, Commelinaceae, Liliaceae and Xanthorrhoeaceae. † Key Results Five different Microsporogenesis pathways are associated with monosulcate pollen grain. They differ in the type of cytokinesis, tetrad shape, and the presence and shape of additional callose deposition. Four of them present additional callose deposition. † Conclusions In all these different Microsporogenesis pathways, aperture location seems to be linked to the last point of callose deposition.
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Correlation between pollen aperture pattern and callose deposition in late tetrad stage in three species producing atypical pollen grains
American Journal of Botany, 2011Co-Authors: Béatrice Albert, Adrienne Ressayre, Sophie NadotAbstract:Premise of the study: Pollen grains of fl owering plants display a fascinating diversity of forms, in spite of their minute size. The observed diversity is determined by the developmental mechanisms implicated in the establishment of pollen morphological features. Pollen grains are generally surrounded by an extremely resistant wall interrupted in places by apertures that play a key role in reproduction, being the places at which pollen tube growth is initiated. Aperture shape, number, and position are determined during Microsporogenesis (male meiosis), the earliest step in pollen ontogeny. We investigate in detail the unfolding of Microsporogenesis in three species that present uncommon aperture pattern (i.e., disulculate in Calycanthus fl oridus [Calycanthaceae, magnoliids], tetraporate in Hohenbergia stellata [Bromeliaceae, monocots], and monoporate in Typha latifolia [Typhaceae, monocots]). Methods: We performed a comparative analysis of Microsporogenesis and aperture distribution within tetrads in these species with contrasting aperture arrangements. This was done using aniline blue coloration and UV light microscope observations. Keys results: We show that aperture localization and features of callose deposition on intersporal walls produced during cytokinesis coincide in all three species examined. Such a correlation suggests that patterns of callose deposition are strongly involved in determining aperture localization. Conclusion: In fl owering plants, patterns of male meiosis and especially callose deposition following meiosis may be implicated in the diversity of pollen aperture patterns.
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Phylogenetic comparative analysis of Microsporogenesis in angiosperms with a focus on monocots
American Journal of Botany, 2008Co-Authors: Sophie Nadot, Carol A Furness, Béatrice Albert, Julie Sannier, Laurent Penet, Sarah Triki-teurtroy, Adrienne RessayreAbstract:This paper presents the first broad overview of three main features of Microsporogenesis (male meiosis) in angiosperms: cytokinesis (cell division), intersporal wall formation, and tetrad form. A phylogenetic comparative approach was used to test for correlated evolution among these characters and to make hypotheses about evolutionary trends in Microsporogenesis. The link between features of Microsporogenesis and pollen aperture type was examined. We show that the pathway associated with successive cytokinesis (cytoplasm is partitioned after each meiotic division) is restricted to wall formation mediated by centrifugally developing cell plates, and tetragonal (or decussate, T-shaped, linear) tetrads. Conversely, much more flexibility is observed when cytokinesis is simultaneous (two meiotic divisions completed before cytoplasmic partitioning). We suggest that the ancestral type of Microsporogenesis for angiosperms, and perhaps for all seed plants, associated simultaneous cytokinesis with centripetal wall formation, resulting in a large diversity in tetrad forms, ranging from regular tetrahedral to tetragonal tetrads, including rhomboidal tetrads. From this ancestral pathway, switches toward successive cytokinesis occurred among basal angiosperms and monocots, generally associated with a switch toward centrifugal intersporal wall formation, whereas eudicots evolved toward an almost exclusive production of regular tetrahedral tetrads. No straightforward link is found between the type of Microsporogenesis and pollen aperture type.
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Constraints and selection: insights from Microsporogenesis in Asparagales
Evolution & Development, 2007Co-Authors: Laurent Penet, Pierre-henri Gouyon, Michel Laurin, Sophie NadotAbstract:SUMMARY Developmental constraints have been proposed to interfere with natural selection in limiting the available set of potential adaptations. Whereas this concept has long been debated on theoretical grounds, it has been investigated empirically only in a few studies. In this article, we evaluate the importance of developmental constraints during Microsporogenesis (male meiosis in plants), with an emphasis on phylogenetic patterns in Asparagales. Different developmental constraints were tested by character reshuffling or by simulated distributions. Among the different characteristics of Microsporogenesis, only cell wall formation appeared as constrained. We show that constraints may also result from biases in the correlated occurrence of developmental steps (e.g., lack of successive cytokinesis when wall formation is centripetal). We document such biases and their potential outcomes, notably the establishment of intermediate stages, which allow development to bypass such constraints. These insights are discussed with regard to potential selection on pollen morphology.
Xiangyang Kang - One of the best experts on this subject based on the ideXlab platform.
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megaspore chromosome doubling in eucalyptus urophylla s t blake induced by colchicine treatment to produce triploids
Forests, 2018Co-Authors: Jun Yang, Jianzhong Wang, Tao Xiong, Yun Li, Xiangyang KangAbstract:Triploids generally provide an advantage in vegetative growth in forest trees. However, the technique of triploid breeding is still an open field in the Eucalyptus tree species. This study aims to explore the colchicine treatment technique for megaspore chromosome doubling to establish triploids in this tree species. Cytological observation on Microsporogenesis and megasporogenesis was carried out to guide megaspore chromosome doubling induced by colchicine treatment. Ploidy level in progenies was detected by flow cytometry and somatic chromosome counting. A relationship between Microsporogenesis and megasporogenesis was established to guide the colchicine treatment. Seven triploids were obtained in the progenies, and the highest efficiency of triploid production was 6.25% when the flower buds underwent a 0.25% colchicine solution treatment for 6 h using an aspiration method seven days after the first observation of leptotene during Microsporogenesis on the floral branch. Cytological analysis showed that the megasporocyte from leptotene to diakinesis may be the optimal period for megaspore chromosome doubling by colchicine treatment. Plant height, ground diameter, leaf area, and the photosynthetic parameter of triploid eucalypt were significantly higher than those of the diploid plant at 6 months old. Hybridization with 2n megaspores induced by colchicine treatment is an effective way for Eucalyptus triploid breeding. These results should accelerate the development of advanced germplasms in this tree species.
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Microsporogenesis and Induction of Unreduced Pollen with High Temperatures in Rubber Tree Clone RRIM 600
Forests, 2017Co-Authors: Peng-qiang Yao, Qing-yi Long, Xiangyang KangAbstract:In order to induce unreduced pollens, Microsporogenesis and male flower bud (MFB) development were compared in rubber tree clone RRIM 600. We observed strong asynchronism in different MFBs in an inflorescence. Asynchronism of Microsporogenesis in different microsporangiums from a MFB was also observed. The relationship between Microsporogenesis and external morphology was examined, which was used to estimate Microsporogenesis stages of MFBs. Unreduced pollen was successfully induced by high temperature exposure in this study, with the highest production ratio of about 20.17% at 44 °C. Our findings showed that diplotene to metaphase I may be the most effective stage for unreduced pollen induction, and 42–44 °C may be the suitable treatment temperature in rubber trees. Thus, Microsporogenesis of MFBs has been elucidated in detail in the rubber tree clone RRIM 600 and will provide a reference for future breeding studies of rubber trees.
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comparative Microsporogenesis and flower development in eucalyptus urophylla e grandis
Journal of Forestry Research, 2016Co-Authors: Jun Yang, Peng-qiang Yao, Jun Lan, Zhen Huang, Xiangyang KangAbstract:Microsporogenesis and flower development in Eucalyptus urophylla × E. grandis were examined using chromosome tableting to provide a method to predict the meiotic stages in this species. Although Microsporogenesis was normal, cytokinesis during meiosis of pollen mother cells occurred simultaneously, with strong asynchronism observed in the two different lengths of stamens in a flower bud. In a single flower, the developmental period of Microsporogenesis in anthers on the longer stamens was always ahead of those on the shorter stamens. Flower development was also asynchronous at different locations on a branch. Flower buds on the upper side of the branch were larger in diameter than those on the lower side. In addition, a correlation was observed between Microsporogenesis development and flower bud diameter growth. The pachytene stage was first observed when the diameter of the flower buds increased to 3.0 mm, and the majority of the meiotic stages were observed when bud diameters ranged from 3.5 to 5.0 mm. This study showed that the developmental stages of Microsporogenesis in Eucalyptus urophylla × E. grandis could be distinguished readily, which may be applicable to future breeding studies.
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Comparative Microsporogenesis and flower development in Eucalyptus urophylla × E. grandis
Journal of Forestry Research, 2015Co-Authors: Jun Yang, Peng-qiang Yao, Jun Lan, Zhen Huang, Xiangyang KangAbstract:Microsporogenesis and flower development in Eucalyptus urophylla × E. grandis were examined using chromosome tableting to provide a method to predict the meiotic stages in this species. Although Microsporogenesis was normal, cytokinesis during meiosis of pollen mother cells occurred simultaneously, with strong asynchronism observed in the two different lengths of stamens in a flower bud. In a single flower, the developmental period of Microsporogenesis in anthers on the longer stamens was always ahead of those on the shorter stamens. Flower development was also asynchronous at different locations on a branch. Flower buds on the upper side of the branch were larger in diameter than those on the lower side. In addition, a correlation was observed between Microsporogenesis development and flower bud diameter growth. The pachytene stage was first observed when the diameter of the flower buds increased to 3.0 mm, and the majority of the meiotic stages were observed when bud diameters ranged from 3.5 to 5.0 mm. This study showed that the developmental stages of Microsporogenesis in Eucalyptus urophylla × E. grandis could be distinguished readily, which may be applicable to future breeding studies.
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Microsporogenesis and flower development in eucalyptus urophylla e tereticornis
Breeding Science, 2015Co-Authors: Jun Yang, Xiangyang KangAbstract:We compared Microsporogenesis and flower development in Eucalyptus urophylla × E. tereticornis. In this study, although Microsporogenesis and cytokinesis occurred simultaneously during meiosis of pollen mother cells, we observed a strong asynchronism in different anthers from a flower bud. The developmental period of Microsporogenesis in anthers originated from the long thrum before the short thrum. Flower development was also asynchronous at different locations on a branch. The flower buds grew on the lower side of the branch and showed greater increases in diameter. In addition, we observed a relationship between Microsporogenesis development and flower bud diameter growth. Generally, when the pachytene stage was first observed in a small single flower bud growing on top of a flowering branch, the remaining Microsporogenesis stages (from diplotene to tetrad) in the whole branch occurred over the next 5-9 days. Thus, the start of Microsporogenesis in E. urophylla × E. tereticornis could be determined, which may be applicable to future breeding studies.
Béatrice Albert - One of the best experts on this subject based on the ideXlab platform.
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Microsporogenesis in angiosperms producing pantoporate pollen
Botany Letters, 2019Co-Authors: Charlotte Prieu, Zohreh Toghranegar, Pierre-henri Gouyon, Béatrice AlbertAbstract:Pollen grains are produced during meiosis (Microsporogenesis), in the anthers of flower buds. Apertures are usually formed at the last points of contact between the microspores. However this mechan...
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Diversity and evolution of Microsporogenesis in Bromeliaceae
Botanical Journal of the Linnean Society, 2014Co-Authors: Béatrice Albert, Zohreh Toghranegar, Sophie NadotAbstract:In this study, we explore the features of Microsporogenesis in Bromeliaceae and, in particular, the diversity and evolution of additional callose deposits. Cytokinesis type, cell wall formation, tetrad form and patterns of additional callose deposition after intersporal wall formation were studied in 12 species of Bromeliaceae (each from a different genus) presenting four different aperture patterns. Microsporogenesis is highly conserved, with successive cytokinesis, centrifugal cell plate formation and predominantly tetragonal and decussate tetrads, as in many monocots, but five different patterns of additional callose deposition were recorded. The optimization of patterns of additional callose deposition on the phylogeny of Bromeliaceae reveals convergences. Additional callose deposition is a variable and labile feature of Microsporogenesis in Bromeliaceae and is linked, to some extent, to aperture pattern. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176, 36–45.
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Variation of Microsporogenesis in monocots producing monosulcate pollen grains
Annals of Botany, 2013Co-Authors: Zohreh Toghranegar, Sophie Nadot, Béatrice AlbertAbstract:† Background and Aims Microsporogenesis leading to monosulcate pollen grains has already been described for a wide range of monocot species. However, a detailed study of additional callose deposition after the completion of the cleavage walls has been neglected so far. The study of additional callose deposition in monosulcate pollen grain has gained importance since a correlation between additional callose deposition and aperture location has recently been revealed. † Methods Microsporogenesis is described for 30 species belonging to eight families of the monocots: Acoraceae, Amaryllidaceae, Alstroemeriaceae, Asparagaceae, Butomaceae, Commelinaceae, Liliaceae and Xanthorrhoeaceae. † Key Results Five different Microsporogenesis pathways are associated with monosulcate pollen grain. They differ in the type of cytokinesis, tetrad shape, and the presence and shape of additional callose deposition. Four of them present additional callose deposition. † Conclusions In all these different Microsporogenesis pathways, aperture location seems to be linked to the last point of callose deposition.
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Correlation between pollen aperture pattern and callose deposition in late tetrad stage in three species producing atypical pollen grains
American Journal of Botany, 2011Co-Authors: Béatrice Albert, Adrienne Ressayre, Sophie NadotAbstract:Premise of the study: Pollen grains of fl owering plants display a fascinating diversity of forms, in spite of their minute size. The observed diversity is determined by the developmental mechanisms implicated in the establishment of pollen morphological features. Pollen grains are generally surrounded by an extremely resistant wall interrupted in places by apertures that play a key role in reproduction, being the places at which pollen tube growth is initiated. Aperture shape, number, and position are determined during Microsporogenesis (male meiosis), the earliest step in pollen ontogeny. We investigate in detail the unfolding of Microsporogenesis in three species that present uncommon aperture pattern (i.e., disulculate in Calycanthus fl oridus [Calycanthaceae, magnoliids], tetraporate in Hohenbergia stellata [Bromeliaceae, monocots], and monoporate in Typha latifolia [Typhaceae, monocots]). Methods: We performed a comparative analysis of Microsporogenesis and aperture distribution within tetrads in these species with contrasting aperture arrangements. This was done using aniline blue coloration and UV light microscope observations. Keys results: We show that aperture localization and features of callose deposition on intersporal walls produced during cytokinesis coincide in all three species examined. Such a correlation suggests that patterns of callose deposition are strongly involved in determining aperture localization. Conclusion: In fl owering plants, patterns of male meiosis and especially callose deposition following meiosis may be implicated in the diversity of pollen aperture patterns.
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Microsporogenesis variation in Codiaeum producing inaperturate pollen grain
Comptes Rendus Biologies, 2009Co-Authors: Béatrice Albert, Pierre-henri Gouyon, Adrienne RessayreAbstract:A study of Microsporogenesis (the earliest stage of pollen ontogeny) was undertaken in seven cultivars of Codiaeum variegatum var. pictum, a eudicot species that produces inaperturate pollen grains. Microsporogenesis appears highly variable for the developmental events suspected to be implicated in the determination of aperture pattern. Most eudicots have tri-aperturate pollen grains and Microsporogenesis is described as highly conserved in this clade. The observed burst of variation in C. variegatum therefore appears especially remarkable. A plausible hypothesis to explain the variation is that the pollen being inaperturate, the selective forces applying on the ontogeny of the aperture pattern are relaxed. To cite this article: B. Albert et al., C. R. Biologies ••• (••••).