Diplospory and obligate apomixis in Miconia albicans (Miconieae, Melastomataceae) and an embryological comparison with its sexual congener M. chamissois

Caetano, Ana Paula Souza; Simão, Daniela Guimarães; Carmo-Oliveira, Renata; Oliveira, Paulo Eugênio

doi:10.1007/s00606-013-0793-y

Cited by 24 publications

(31 citation statements)

References 37 publications

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“…Bithecal and tetrasporangiate anthers, endothecium without parietal fibrous thickenings and grains released in monads in the bicellular stage are conserved conditions frequently reported for Melastomataceae, regardless of the type of stamen (Tobe & Raven 1983;Luo et al 2008;Caetano et al 2013a;Cortez et al 2015). Particularly regarding the pollen grains, even though the parameters analyzed indicated great similarity of the grains from different types of anthers, some Melastomataceae species may differ in shape, size, pattern of wall ornamentation, viability and content of pollen grains of the feeding and pollination anthers (Forbes 1882;Luo et al 2008;.…”

Section: Discussionmentioning

confidence: 79%

Anther specializations related to the division of labor in Microlicia cordata (Spreng.) Cham. (Melastomataceae)

et al. 2018

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In heterantherous flowers, some anthers have an attraction and feeding function, while others are related to plant reproduction. Microlicia cordata has dimorphic stamens organized in two cycles: the antesepalous one with large stamens and pink anthers, and the antepetalous one with small stamens and yellow anthers. Division of labor was analyzed using the parameters of structure, composition, amount and estimated viability of pollen, and the color of floral parts. The anthers of the pollinating stamens were larger than the anthers of the feeding stamens, although anatomically similar. There was a difference in the amount of pollen produced by the anthers of the two cycles, but no difference was found in pollen viability. Considering a bee color vision model, the color of the anthers of the pollinating stamens contrasted less with that of the corolla, and thus is probably less attractive to visitors. Conversely, the anthers of the feeding stamens and the ventral appendage of the connective of the pollinating stamens contrasted more with the corolla, presenting the same color to the pollinators. These results are in accordance with the idea of division of labor among anthers of heterantherous flowers, especially regarding the quantity of pollen and the color of the floral parts.

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Section: Discussionmentioning

confidence: 79%

Anther specializations related to the division of labor in Microlicia cordata (Spreng.) Cham. (Melastomataceae)

et al. 2018

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“…In the facultative apomictic species, the balance between apomictic and sexual events seems to be dependent on genetic (Asker & Jerling ; Hanna ) and cytological factors (Caetano et al . ,b). Facultative apomictic species such as M. hyemalis and T. sellowiana may maintain the ability to attract pollinators (Hanna ; Jefferson & Bicknell ; Koltunow et al .…”

Section: Discussionmentioning

confidence: 99%

“…) and is generally associated with polyploidy and hybridisation (Mendes‐Rodrigues & Oliveira ; Caetano et al . ,b), which in turn are related to different levels of low pollen viability or even complete pollen sterility (Mogie ; Richards ; Goldenberg & Shepherd ; Goldenberg & Varassin ). On the other hand, sexual species have high pollen viability (Goldenberg & Shepherd ; Goldenberg & Varassin ; Hoffmann & Varassin ).…”

Section: Introductionmentioning

confidence: 99%

Apomixis does not affect visitation to flowers of Melastomataceae, but pollen sterility does

2015

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Apomixis is an asexual seed reproduction mechanism thorough which embryos are originated from material tissues inside the ovules, without precedent fertilisation. It allows plants to colonise new habitats, even in places where flower visitors are scarce or where plants are isolate. Apomixis seems to be related to pollen sterility and, in species with flowers that offer pollen as a reward for pollinators, the amount or quality of the pollen offered by these species may influence the amount of the visits and specific composition of the visitors. In order to test this hypothesis, we studied breeding systems of 16 species of Melastomataceae and their flower visitors, evaluating composition and abundance of the visits to apomictic and sexual species. Apomictic plants with no viable pollen or with pollen with low viability did not receive visits from pollinators, and consequently probably produce strictly apomictic fruits. On the other hand, apomictic and sexual plants with high pollen viability do receive visits; in this case, apomictic plants may produce fruits and seeds through both sexual and apomictic methods. The species composition of insects visiting Melastomataceae with high pollen viability was similar, regardless of whether the plants were apomictic or not. It seems that pollen viability levels are important to determine visits to the flowers irrespective of breeding system.

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“…In Melastomataceae, apomictic species are prevalent in Miconieae (Renner ; Borges ; Goldenberg & Shepherd ; Goldenberg & Varassin ; Santos ; Fracasso & Sazima ; Caetano et al. ), but have also been reported in some Microlicieae, such as Trembleya (Silva ) and Microlicia (Santos et al. ).…”

Section: Are the Septa Persistent Until Anther Dehiscence And What Ismentioning

confidence: 99%

“…A population of M. fasciculata from another area of "campo rupestre" in Southeastern Brazil is apomictic, with approximately 2% of pollen viability (Santos et al 2012). In Melastomataceae, apomictic species are prevalent in Miconieae (Renner 1989;Borges 1991;Goldenberg & Shepherd 1998;Goldenberg & Varassin 2001;Santos 2003;Fracasso & Sazima 2004;Caetano et al 2013), but have also been reported in some Microlicieae, such as Trembleya (Silva 2000) and Microlicia (Santos et al 2012). These abnormal pollen grains could be related to the breeding system, not to the polysporangiate anther.…”

Section: Are the Septa Persistent Until Anther Dehiscence And What Ismentioning

confidence: 99%

Polysporangiate anthers in Microlicia D.Don (Melastomataceae Juss.)

2018

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Polysporangiate anthers are found in a small number of Microlicia species, a genus of Melastomataceae with a large number of endemic species in Brazil. This study describes for the first time the processes of formation and degeneration of the septa found in these particular anthers of Microlicia, providing relevant information about the structure and the functional role of septate anthers in the genus, which is an uncommon condition in angiosperms. The formation of septa begins when some initial cells enlarge and differentiate into sporogenous tissue, while other, more peripheral cells, are not affected by this increase and form the parenchymatous septum. The septa are present up until microgametogenesis, degenerating after the formation of the pollen grains. The mechanism of pollen release in stages, as suggested previously by some authors, could not be demonstrated for the studied species since the septa degenerated at flower anthesis. Thus, we propose that the transverse septa present during the formation of the sporogenous tissue and microspores are associated with providing better nutritional conditions for pollen development.

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Diplospory and obligate apomixis in Miconia albicans (Miconieae, Melastomataceae) and an embryological comparison with its sexual congener M. chamissois

Cited by 24 publications

References 37 publications

Anther specializations related to the division of labor in Microlicia cordata (Spreng.) Cham. (Melastomataceae)

Anther specializations related to the division of labor in Microlicia cordata (Spreng.) Cham. (Melastomataceae)

Apomixis does not affect visitation to flowers of Melastomataceae, but pollen sterility does

Polysporangiate anthers in Microlicia D.Don (Melastomataceae Juss.)

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