Pollen wall stratification and pollination

Hesse, Michael

doi:10.1007/bf00984093

Cited by 56 publications

(11 citation statements)

References 89 publications

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“…The basic and most common type is tricolpate, which is observed in most of the Ranunculus species. Pollen structures have developed in other genera as an adaptation to pollination mechanisms (Proctor & al., 1996;Hesse, 2000;Tanaka & al., 2004). Characters of the perianth are probably based on a shared developmental program, and may be highly dynamic according to activation or de-activation of gene expression patterns (Rasmussen & al., 2009).…”

Section: Taxonomic Conclusionmentioning

confidence: 99%

A molecular phylogeny, morphology and classification of genera of Ranunculeae (Ranunculaceae)

Emadzade

Lehnebach

Lockhart

et al. 2010

TAXON

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Ranunculeae represent a highly diverse and cosmopolitan tribe within Ranunculaceae. Because of the great diversity of morphological features and lack of molecular phylogeny for the tribe, the classification of its genera has always been controversial. We report here molecular phylogenetic analyses based on nuclear and plastid markers (nrITS, matK, trnK, psbJ-petA) that provide a framework for understanding relationships and character evolution within the tribe. Maximum parsimony analyses suggest a weakly supported basal dichotomy, while Neighbor Net analysis indicates strong support for five distinct lineages. Both methods revealed several well-supported, small terminal clades which correspond to previously described genera, characterised by unique morphological features and character combinations. Anatomical structures of the achenes suggested relationships with greatest concordance to those in the molecular phylogeny. Macroscopic analysis of achene morphology often indicated parallel evolution of structures related to certain dispersal mechanisms. Characters of perianth, androecium, gynoeceum and pollen are highly homoplasious, but several features characteristic of small terminal clades and terminal branches can be observed. Geographic isolation and adaptions may have triggered the evolution of morphological characters. We conclude that a classification accepting several small genera (Arcteranthis, and a large genus Ranunculus s.str. (including Batrachium, Aphanostemma and Gampsoceras) reflects best the molecular phylogeny and morphological diversity of the tribe.

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Section: Taxonomic Conclusionmentioning

confidence: 99%

A molecular phylogeny, morphology and classification of genera of Ranunculeae (Ranunculaceae)

Emadzade

Lehnebach

Lockhart

et al. 2010

TAXON

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“…Therefore, it seems evident that stigma shape and organization are highly associated with the type of pollination (Edlund et al, 2004). However, much greater effort has been expended on elucidating the relationship between pollen and pollination (e.g., Banks and Rudall, 2016;Hesse, 2000;Osborn et al, 1991) than between stigma and pollination (Heslop-Harrison, 1992). The study of the diversity of stigmata related to various types of pollination (Basso-Alves et al, 2011;Jousselin and Kjellberg, 2001) and breeding systems (Katinas et al, 2016;Lora et al, 2011) is thus of great interest in general and for obligate mutualisms such as between fig trees (Ficus) and their agaonid pollinating wasps in particular (Galil and Eisikowitch, 1968).…”

Section: Introductionmentioning

confidence: 99%

Morphological diversity and function of the stigma in Ficus species (Moraceae)

et al. 2018

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The stigma plays several roles such as pollen hydration and selection, and pollen tube nutrition. In the Ficus-fig wasp mutualism, stigmata have an additional, almost unknown, function by representing a physical interface for both plant and wasp reproduction. We used light and electron microscopy to compare the detailed morphology of the stigmata of nine Ficus species of different sections and with different pollination modes and sexual expressions. Figs were collected at the stage when the stigmata were receptive for pollination. Stigmata in actively pollinated monoecious species have well developed papillae concentrated on the adaxial surface exposed towards the fig cavity. Conversely, the passively pollinated monoecious species have the whole surface of the stigmata covered by somewhat smaller papillae. In both actively and passively pollinated monoecious species these features are consistent, irrespective of style length. In all actively pollinated gynodioecious species, the stigmata of pistillate flowers were tubular or infundibuliform whereas in almost all actively pollinated monoecious species (except F. racemosa) the stigmata were filiform, with one branch or two asymmetric branches. In gynodioecious species the short-styled flowers in "male" figs show a limited receptive surface with small papillae, while the stigmata of long-styled flowers in "female" figs are covered by papillae that extend down the sides of the style, increasing the stigmatic surface. In actively pollinated species, stigmata are cohesive, forming a common surface for pollen tube germination (= synstigma). The synstigma arrangement was quite variable: lax, cohesive or very cohesive, with entanglement by stigmatic papillae and stylar trichomes. Entanglement by stylar trichomes is common in gynodioecious species. The synstigma arrangement did not correlate with phylogeny or breeding system. This study is the first to report a very loose synstigma in actively pollinated monoecious Ficus species. Our analyses revealed that, in Ficus, the synstigma is functionally analogous to an extra-gynoecial compitum. Comparative studies will be required to test further hypotheses about the evolutionary determinants of such variation.

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“…Besides this, there is a direct correlation between the exine ornamentation/thickness and pollinators. A detailed review of this subject can be found in Ferguson and Skvarla (1982), Philbrick and Osborn (1994), and Hesse (2000). The exine thickness is also an important parameter regarding pollen conservation, because it directly influences the desiccation and rupture of the pollen grains (Souza et al, 2015).…”

Section: Resultsmentioning

confidence: 99%

Pollen morphology and viability ofTillandsia(Bromeliaceae) species by light microscopy and scanning electron microscopy

Souza

Oliveira

Aona

et al. 2020

Microscopy Res & Technique

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Tillandsia is the bromeliad genus containing the largest number of species, with wide geographic dispersion and an important ecological role in the ecosystems. Investigations of pollen morphology are important to support taxonomic and conservation studies as well as to choose promising species for cross‐pollination to obtain hybrids. The objective of this study was to evaluate the morphology, production, and viability of pollen grains of 24 Tillandsia species that naturally occur in the state of Bahia, Brazil. Pollen grains were acetolized and analyzed by scanning electron microscopy. The pollen were germinated in vitro in two culture media (BM and BKM) and collected at three floral development stages (pre‐anthesis, anthesis and post‐anthesis). Pollen viability also was analyzed by staining with Alexander's solution and acetocarmine in three floral development stages. Variations in the ornamentation and size of the pollen were observed among the species studied, with the majority having medium size, while T. polystachia and T. juncea had large grains and the subgenera Diaphoranthema and Phytarrhiza had small grains. The pollen of the majority of species had bilateral symmetry, with a single irregularly shaped colpus, semitectate exine and reticulated‐heterobrochate surface. The pollen presented high germination percentage, tube length and viability according to the histochemistry, except for T. recurvata, T. usneoides and T. loliacea. The BKM medium and collection of pollen during anthesis produced the best results for the Tillandsia species. The results can support studies of the taxonomy and conservation of these species, which have great environmental importance and high value for ornamental purposes.

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Pollen wall stratification and pollination

Cited by 56 publications

References 89 publications

A molecular phylogeny, morphology and classification of genera of Ranunculeae (Ranunculaceae)

A molecular phylogeny, morphology and classification of genera of Ranunculeae (Ranunculaceae)

Morphological diversity and function of the stigma in Ficus species (Moraceae)

Pollen morphology and viability ofTillandsia(Bromeliaceae) species by light microscopy and scanning electron microscopy

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