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1.
Interest in reciprocal floral polymorphisms, such as heterostyly, has increased in recent decades because they can be used as suitable model systems to study mechanisms of outbreeding and disassortative mating in plants. Heterostylous plants are characterised by the presence of discrete morphs that differ in sex organ position and in some other ancillary traits. As regards sex organ deployment, different types of polymorphisms have been described, depending on number and type of discrete classes present in populations and degree of reciprocity between them. However, a clear-cut characterisation of stylar polymorphisms does not appear to be the best approach when there is great variability among populations because of continuous variation of some of traits examined. A recent study in Lithodora sensu lato (recently split into two separate genera, Lithodora and Glandora) showed a wide variation in sex organ position across species in the genus, which warrants precise population analysis of stylar polymorphism and its reciprocity. We provide a detailed morphometric analysis of flower sexual traits and include those considered to be ancillary characters. We report a wide variation in these traits in populations of Lithodora s.l. and highlight the subjectivity of the former characterisation of style polymorphism based on visual inspection. Ancillary traits appear repeatedly in Lithodora and Glandora, particularly in the latter. The appearance of these traits seems to be related to greater reciprocity between sexual whorls in Glandora, with the exception of G.?prostrata. These results agree with evolutionary steps proposed in the build-up of heterostyly according to some evolutionary models. We also examined variation in polymorphisms in light of current models for evolution of heterostyly, and, more specifically, we sought to verify the prediction that flower traits as a whole (i.e., flower integration) respond to selective pressure to assure the exact location of pollen on the pollinator body. Most reciprocal populations and species, where between-morph pollen transfer is expected to be higher, would show greater integration. Our results confirm this hypothesis. 相似文献
2.
Fabio Pinheiro Donata Cafasso Salvatore Cozzolino Giovanni Scopece 《Annals of botany》2015,116(3):457-467
Background and Aims The evolution of interspecific reproductive barriers is crucial to understanding species evolution. This study examines the contribution of transitions between self-compatibility (SC) and self-incompatibility (SI) and genetic divergence in the evolution of reproductive barriers in Dendrobium, one of the largest orchid genera. Specifically, it investigates the evolution of pre- and postzygotic isolation and the effects of transitions between compatibility states on interspecific reproductive isolation within the genus.Methods The role of SC and SI changes in reproductive compatibility among species was examined using fruit set and seed viability data available in the literature from 86 species and ∼2500 hand pollinations. The evolution of SC and SI in Dendrobium species was investigated within a phylogenetic framework using internal transcribed spacer sequences available in GenBank.Key Results Based on data from crossing experiments, estimations of genetic distance and the results of a literature survey, it was found that changes in SC and SI significantly influenced the compatibility between species in interspecific crosses. The number of fruits produced was significantly higher in crosses in which self-incompatible species acted as pollen donor for self-compatible species, following the SI × SC rule. Maximum likelihood and Bayesian tests did not reject transitions from SI to SC and from SC to SI across the Dendrobium phylogeny. In addition, postzygotic isolation (embryo mortality) was found to evolve gradually with genetic divergence, in agreement with previous results observed for other plant species, including orchids.Conclusions Transitions between SC and SI and the gradual accumulation of genetic incompatibilities affecting postzygotic isolation are important mechanisms preventing gene flow among Dendrobium species, and may constitute important evolutionary processes contributing to the high levels of species diversity in this tropical orchid group. 相似文献
3.
Background and Aims
Salvia is the largest genus in Lamiaceae and it has recently been found to be non-monophyletic. Molecular data on Old World Salvia are largely lacking. In this study, we present data concerning Salvia in Africa. The focus is on the colonization of the continent, character evolution and the switch of pollination systems in the genus.Methods
Maximum likelihood and Bayesian inference were used for phylogenetic reconstruction. Analyses were based on two nuclear markers [internal transcribed spacer (ITS) and external transcribed spacer (ETS)] and one plastid marker (rpl32-trnL). Sequence data were generated for 41 of the 62 African taxa (66 %). Mesquite was used to reconstruct ancestral character states for distribution, life form, calyx shape, stamen type and pollination syndrome.Key Results
Salvia in Africa is non-monophyletic. Each of the five major regions in Africa, except Madagascar, was colonized at least twice, and floristic links between North African, south-west Asian and European species are strongly supported. The large radiation in Sub-Saharan Africa (23 species) can be traced back to dispersal from North Africa via East Africa to the Cape Region. Adaptation to bird pollination in southern Africa and Madagascar reflects parallel evolution.Conclusions
The phenotypic diversity in African Salvia is associated with repeated introductions to the continent. Many important evolutionary processes, such as colonization, adaptation, parallelism and character transformation, are reflected in this comparatively small group. The data presented in this study can help to understand the evolution of Salvia sensu lato and other large genera. 相似文献4.
5.
Background and Aims
In sub-alpine habitats, patchiness in snowpack produces marked, small-scale variation in flowering phenology. Plants in early- and late-melting patches are therefore likely to experience very different conditions during their flowering periods. Mertensia fusiformis is an early-flowering perennial that varies conspicuously in style length within and among populations. The hypothesis that style length represents an adaptation to local flowering time was tested. Specifically, it was hypothesized that lower air temperatures and higher frost risk would favour short-styled plants (with stigmas more shielded by corollas) in early-flowering patches, but that the pollen-collecting behaviour of flower visitors in late-flowering patches would favour long-styled plants.Methods
Floral morphology was measured, temperatures were monitored and pollinators were observed in several matched pairs of early and late populations. To evaluate effects of cold temperatures on plants of different style lengths, experimental pollinations were conducted during mornings (warm) and evenings (cool), and on flowers that either had or had not experienced a prior frost. The effectiveness of different pollinators was quantified as seed set following single visits to plants with relatively short or long styles.Key Results
Late-flowering populations experienced warmer temperatures than early-flowering populations and a different suite of pollinators. Nectar-foraging bumble-bee queens and male solitary bees predominated in early populations, whereas pollen-collecting female solitary bees were more numerous in later sites. Pollinators differed significantly in their abilities to transfer pollen to stigmas at different heights, in accordance with our prediction. However, temperature and frost sensitivity did not differ between long- and short-styled plants. Although plants in late-flowering patches tended to have longer styles than those in early patches, this difference was not consistent.Conclusions
Seasonal change in pollinator-mediated selection on style length may help maintain variation in this trait in M. fusiformis, but adaptation to local flowering time is not apparent. The prevalence of short styles in these populations requires further explanation. 相似文献6.
Backgrounds and Aims
The spatial separation of stigmas and anthers (herkogamy) in flowering plants functions to reduce self-pollination and avoid interference between pollen dispersal and receipt. Little is known about the evolutionary relationships among the three main forms of herkogamy – approach, reverse and reciprocal herkogamy (distyly) – or about transitions to and from a non-herkogamous condition. This problem was examined in Exochaenium (Gentianaceae), a genus of African herbs that exhibits considerable variation in floral morphology, including the three forms of herkogamy.Methods
Using maximum parsimony and maximum likelihood methods, the evolutionary history of herkogamic and non-herkogamic conditions was reconstructed from a molecular phylogeny of 15 species of Exochaenium and four outgroup taxa, based on three chloroplast regions, the nuclear ribosomal internal transcribed spacer (ITS1 and 2) and the 5·8S gene. Ancestral character states were determined and the reconstructions were used to evaluate competing models for the origin of reciprocal herkogamy.Key results
Reciprocal herkogamy originated once in Exochaenium from an ancestor with approach herkogamy. Reverse herkogamy and the non-herkogamic condition homostyly were derived from heterostyly. Distylous species possessed pendent, slightly zygomorphic flowers, and the single transition to reverse herkogamy was associated with the hawkmoth pollination syndrome. Reductions in flower size characterized three of four independent transitions from reciprocal herkogamy to homostyly.Conclusions
The results support Lloyd and Webb''s model in which distyly originated from an ancestor with approach herkogamy. They also demonstrate the lability of sex organ deployment and implicate pollinators, or their absence, as playing an important role in driving transitions among herkogamic and non-herkogamic conditions. 相似文献7.
Background and aims
Tribe Orchideae (Orchidaceae: Orchidoideae) comprises around 62 mostly terrestrial genera, which are well represented in the Northern Temperate Zone and less frequently in tropical areas of both the Old and New Worlds. Phylogenetic relationships within this tribe have been studied previously using only nuclear ribosomal DNA (nuclear ribosomal internal transcribed spacer, nrITS). However, different parts of the phylogenetic tree in these analyses were weakly supported, and integrating information from different plant genomes is clearly necessary in orchids, where reticulate evolution events are putatively common. The aims of this study were to: (1) obtain a well-supported and dated phylogenetic hypothesis for tribe Orchideae, (ii) assess appropriateness of recent nomenclatural changes in this tribe in the last decade, (3) detect possible examples of reticulate evolution and (4) analyse in a temporal context evolutionary trends for subtribe Orchidinae with special emphasis on pollination systems.Methods
The analyses included 118 samples, belonging to 103 species and 25 genera, for three DNA regions (nrITS, mitochondrial cox1 intron and plastid rpl16 intron). Bayesian and maximum-parsimony methods were used to construct a well-supported and dated tree. Evolutionary trends in the subtribe were analysed using Bayesian and maximum-likelihood methods of character evolution.Key Results
The dated phylogenetic tree strongly supported the recently recircumscribed generic concepts of Bateman and collaborators. Moreover, it was found that Orchidinae have diversified in the Mediterranean basin during the last 15 million years, and one potential example of reticulate evolution in the subtribe was identified. In Orchidinae, pollination systems have shifted on numerous occasions during the last 23 million years.Conclusions
The results indicate that ancestral Orchidinae were hymenopteran-pollinated, food-deceptive plants and that these traits have been dominant throughout the evolutionary history of the subtribe in the Mediterranean. Evidence was also obtained that the onset of sexual deception might be linked to an increase in labellum size, and the possibility is discussed that diversification in Orchidinae developed in parallel with diversification of bees and wasps from the Miocene onwards. 相似文献8.
9.
Timoth��e Le P��chon Jean-Yves Dubuisson Thomas Haevermans Corinne Cruaud Arnaud Couloux Luc D. B. Gigord 《Annals of botany》2010,106(2):343-357
Background and Aims
In the Mascarenes, a young oceanic archipelago composed of three main islands, the Dombeyoideae (Malvaceae) have diversified extensively with a high endemism rate. With the exception of the genus Trochetia, Mascarene Dombeyoideae are described as dioecious whereas Malagasy and African species are considered to be monocline, species with individuals bearing hermaphrodite/perfect flowers. In this study, the phylogenetic relationships were reconstructed to clarify the taxonomy, understand the phylogeographic pattern of relationships and infer the evolution of the breeding systems for the Mascarenes Dombeyoideae.Methods
Parsimony and Bayesian analysis of four DNA markers (ITS, rpl16 intron and two intergenic spacers trnQ-rsp16 and psbM-trnD) was used. The molecular matrix comprised 2985 characters and 48 taxa. The Bayesian phylogeny was used to infer phylogeographical hypotheses and the evolution of breeding systems.Key Results
Parsimony and Bayesian trees produced similar results. The Dombeyoideae from the Mascarenes are polyphyletic and distributed among four clades. Species of Dombeya, Trochetia and Ruizia are nested in the same clade, which implies the paraphyly of Dombeya. Additionally, it is shown that each of the four clades has an independent Malagasy origin. Two adaptive radiation events have occurred within two endemic lineages of the Mascarenes. The polyphyly of the Mascarene Dombeyoideae suggests at least three independent acquisitions of dioecy.Conclusions
This molecular phylogeny highlights the taxonomic issues within the Dombeyoideae. Indeed, the limits and distinctions of the genera Dombeya, Trochetia and Ruizia should be reconsidered. The close phylogeographic relationships between the flora of the Mascarenes and Madagascar are confirmed. Despite their independent origins and a distinct evolutionary history, each endemic clade has developed a different breeding systems (dioecy) compared with the Malagasy Dombeyoideae. Sex separation appears as an evolutionary convergence and may be the consequence of selective pressures particular to insular environments. 相似文献10.
Background and Aims
Leptochloa (including Diplachne) sensu lato (s.l.) comprises a diverse assemblage of C4 (NAD-ME and PCK) grasses with approx. 32 annual or perennial species. Evolutionary relationships and a modern classification of Leptochloa spp. based on the study of molecular characters have only been superficially investigated in four species. The goals of this study were to reconstruct the evolutionary history of Leptochloa s.l. with molecular data and broad taxon sampling.Methods
A phylogenetic analysis was conducted of 130 species (mostly Chloridoideae), of which 22 are placed in Leptochloa, using five plastid (rpL32-trn-L, ndhA intron, rps16 intron, rps16-trnK and ccsA) and the nuclear ITS 1 and 2 (ribosomal internal transcribed spacer regions) to infer evolutionary relationships and revise the classification.Key results
Leptochloa s.l. is polyphyletic and strong support was found for five lineages. Embedded within the Leptochloa sensu stricto (s.s.) clade are two Trichloris spp. and embedded in Dinebra are Drake-brockmania and 19 Leptochloa spp.Conclusions
The molecular results support the dissolution of Leptochloa s.l. into the following five genera: Dinebra with 23 species, Diplachne with two species, Disakisperma with three species, Leptochloa s.s. with five species and a new genus, Trigonochloa, with two species. 相似文献11.
Ludeña B Chabrillange N Aberlenc-Bertossi F Adam H Tregear JW Pintaud JC 《Annals of botany》2011,108(8):1433-1444
Background and Aims
Molecular phylogenetic studies of palms (Arecaceae) have not yet provided a fully resolved phylogeny of the family. There is a need to increase the current set of markers to resolve difficult groups such as the Neotropical subtribe Bactridinae (Arecoideae: Cocoseae). We propose the use of two single-copy nuclear genes as valuable tools for palm phylogenetics.Methods
New primers were developed for the amplification of the AGAMOUS 1 (AG1) and PHYTOCHROME B (PHYB) genes. For the AGAMOUS gene, the paralogue 1 of Elaeis guineensis (EgAG1) was targeted. The region amplified contained coding sequences between the MIKC K and C MADS-box domains. For the PHYB gene, exon 1 (partial sequence) was first amplified in palm species using published degenerate primers for Poaceae, and then specific palm primers were designed. The two gene portions were sequenced in 22 species of palms representing all genera of Bactridinae, with emphasis on Astrocaryum and Hexopetion, the status of the latter genus still being debated.Key Results
The new primers designed allow consistent amplification and high-quality sequencing within the palm family. The two loci studied produced more variability than chloroplast loci and equally or less variability than PRK, RPBII and ITS nuclear markers. The phylogenetic structure obtained with AG1 and PHYB genes provides new insights into intergeneric relationships within the Bactridinae and the intrageneric structure of Astrocaryum. The Hexopetion clade was recovered as monophyletic with both markers and was weakly supported as sister to Astrocaryum sensu stricto in the combined analysis. The rare Astrocaryum minus formed a species complex with Astrocaryum gynacanthum. Moreover, both AG1 and PHYB contain a microsatellite that could have further uses in species delimitation and population genetics.Conclusions
AG1 and PHYB provide additional phylogenetic information within the palm family, and should prove useful in combination with other genes to improve the resolution of palm phylogenies. 相似文献12.
Pralongyut Sripalwit Chalobol Wongsawad Thapana Chontananarth Somboon Anuntalabhochai Pheravut Wongsawad Jong-Yil Chai 《The Korean journal of parasitology》2015,53(2):201-207
This study aimed to investigate the infection status, worm development, and phylogenetic characteristics of the intestinal trematode, Stellantchasmus falcatus. The metacercariae of S. falcatus were detected only in the half-beak (Dermogenus pusillus) out of the 4 fish species examined. Their prevalence was 90.0%, and the intensity of infection was 919 metacercariae on average. Worms were recovered from 33 (97.1%) of 34 chicks that were experimentally infected with 200 S. falcatus metacercariae each, and the average recovery rate was 43.0%. The body size and inner organs of S. falcatus quickly increased in the experimental chicks over days 1-2 post-infection (PI). In addition, ITS2 sequence data of this parasite were analyzed to examine the phylogenetic relationships with other trematodes using the UPGMA method. The results indicated that the ITS2 sequence data recorded from trematodes in the family Heterophyidae appeared to be monophyletic. This study concluded that D. pusillus serves as a compatible second intermediate host of S. falcatus in Thailand and that S. falcatus can develop rapidly in the experimental chicks. Data collected from this study can help to close the gap in knowledge regarding the epidemiology, biology, and phylogenetic characteristics of S. falcatus in Thailand. 相似文献
13.
Katie J. Field Jeffrey G. Duckett Duncan D. Cameron Silvia Pressel 《Annals of botany》2015,115(6):915-922
Background and Aims Following the consensus view for unitary origin and conserved function of stomata across over 400 million years of land plant evolution, stomatal abundance has been widely used to reconstruct palaeo-atmospheric environments. However, the responsiveness of stomata in mosses and hornworts, the most basal stomate lineages of extant land plants, has received relatively little attention. This study aimed to redress this imbalance and provide the first direct evidence of bryophyte stomatal responsiveness to atmospheric CO2.Methods A selection of hornwort (Anthoceros punctatus, Phaeoceros laevis) and moss (Polytrichum juniperinum, Mnium hornum, Funaria hygrometrica) sporophytes with contrasting stomatal morphologies were grown under different atmospheric CO2 concentrations ([CO2]) representing both modern (440 p.p.m. CO2) and ancient (1500 p.p.m. CO2) atmospheres. Upon sporophyte maturation, stomata from each bryophyte species were imaged, measured and quantified.Key Results Densities and dimensions were unaffected by changes in [CO2], other than a slight increase in stomatal density in Funaria and abnormalities in Polytrichum stomata under elevated [CO2].Conclusions The changes to stomata in Funaria and Polytrichum are attributed to differential growth of the sporophytes rather than stomata-specific responses. The absence of responses to changes in [CO2] in bryophytes is in line with findings previously reported in other early lineages of vascular plants. These findings strengthen the hypothesis of an incremental acquisition of stomatal regulatory processes through land plant evolution and urge considerable caution in using stomatal densities as proxies for paleo-atmospheric CO2 concentrations. 相似文献
14.
BACKGROUND AND AIMS: A new infrageneric rearrangement for Veronica has been proposed based on the most recent evidence from DNA sequence data, morphological evidence, and biogeographical considerations. Looking for morphological synapomorphies for each monophyletic subgenus has been problematic, due to difficulties arising from widespread homoplasy (mainly parallel evolution). In an attempt to overcome these difficulties, previously underexplored morphological characters are starting to be studied in more depth. METHODS: A molecular phylogenetic hypothesis was used based on sequences of ITS (nuclear ribosomal DNA) and plastid trnL-F regions, as a framework to test the use of seed coat ultrastructure (studied under scanning electron microscope) in the systematics of the genus. A sample of 132 taxa representing ten of the 13 subgenera in Veronica, excluding the species of the southern hemisphere Hebe complex and the exclusively North American subgenus Synthyris, was studied. KEY RESULTS AND CONCLUSIONS: The results demonstrate that, in many cases, the ultrastucture of the testa can be employed to assess relationships of taxa within the genus, and the character provides additional support for molecular trees. Further characters relevant for the classification of Veronica, i.e. base chromosome number, iridoid chemical data, life cycle, inflorescence position, have been taken into consideration in a discussion where an attempt is made to highlight the best traits to characterize each subgenus investigated. 相似文献
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16.
Moya M. Smith Zerina Johanson Thomas Butts Rolf Ericsson Melinda Modrell Frank J. Tulenko Marcus C. Davis Gareth J. Fraser 《Proceedings. Biological sciences / The Royal Society》2015,282(1805)
Ray-finned fishes (Actinopterygii) are the dominant vertebrate group today (+30 000 species, predominantly teleosts), with great morphological diversity, including their dentitions. How dental morphological variation evolved is best addressed by considering a range of taxa across actinopterygian phylogeny; here we examine the dentition of Polyodon spathula (American paddlefish), assigned to the basal group Acipenseriformes. Although teeth are present and functional in young individuals of Polyodon, they are completely absent in adults. Our current understanding of developmental genes operating in the dentition is primarily restricted to teleosts; we show that shh and bmp4, as highly conserved epithelial and mesenchymal genes for gnathostome tooth development, are similarly expressed at Polyodon tooth loci, thus extending this conserved developmental pattern within the Actinopterygii. These genes map spatio-temporal tooth initiation in Polyodon larvae and provide new data in both oral and pharyngeal tooth sites. Variation in cellular intensity of shh maps timing of tooth morphogenesis, revealing a second odontogenic wave as alternate sites within tooth rows, a dental pattern also present in more derived actinopterygians. Developmental timing for each tooth field in Polyodon follows a gradient, from rostral to caudal and ventral to dorsal, repeated during subsequent loss of teeth. The transitory Polyodon dentition is modified by cessation of tooth addition and loss. As such, Polyodon represents a basal actinopterygian model for the evolution of developmental novelty: initial conservation, followed by tooth loss, accommodating the adult trophic modification to filter-feeding. 相似文献
17.
Genetic analyses using DNA sequences of nuclear ribosomal DNA ITS1 were conducted to determine the extent of genetic variation within and among Longidorus and Xiphinema species. DNA sequences were obtained from samples collected from Arkansas, California and Australia as well as 4 Xiphinema DNA sequences from GenBank. The sequences of the ITS1 region including the 3'' end of the 18S rDNA gene and the 5'' end of the 5.8S rDNA gene ranged from 1020 bp to 1244 bp for the 9 Longidorus species, and from 870 bp to 1354 bp for the 7 Xiphinema species. Nucleotide frequencies were: A = 25.5%, C = 21.0%, G = 26.4%, and T = 27.1%. Genetic variation between the two genera had a maximum divergence of 38.6% between X. chambersi and L. crassus. Genetic variation among Xiphinema species ranged from 3.8% between X. diversicaudatum and X. bakeri to 29.9% between X. chambersi and X. italiae. Within Longidorus, genetic variation ranged from 8.9% between L. crassus and L. grandis to 32.4% between L. fragilis and L. diadecturus. Intraspecific genetic variation in X. americanum sensu lato ranged from 0.3% to 1.9%, while genetic variation in L. diadecturus had 0.8% and L. biformis ranged from 0.6% to 10.9%. Identical sequences were obtained between the two populations of L. grandis, and between the two populations of X. bakeri. Phylogenetic analyses based on the ITS1 DNA sequence data were conducted on each genus separately using both maximum parsimony and maximum likelihood analysis. Among the Longidorus taxa, 4 subgroups are supported: L. grandis, L. crassus, and L. elongatus are in one cluster; L. biformis and L. paralongicaudatus are in a second cluster; L. fragilis and L. breviannulatus are in a third cluster; and L. diadecturus is in a fourth cluster. Among the Xiphinema taxa, 3 subgroups are supported: X. americanum with X. chambersi, X. bakeri with X. diversicaudatum, and X. italiae and X. vuittenezi forming a sister group with X. index. The relationships observed in this study correspond to previous genera and species defined by morphology. 相似文献
18.
Sunshine A. Van Bael Hermógenes Fernández-Marín Mariana C. Valencia Enith I. Rojas William T. Wcislo Edward A. Herre 《Proceedings. Biological sciences / The Royal Society》2009,276(1666):2419-2426
Interactions among the component members of different symbioses are not well studied. For example, leaf-cutting ants maintain an obligate symbiosis with their fungal garden, while the leaf material they provide to their garden is usually filled with endophytic fungi. The ants and their cultivar may interact with hundreds of endophytic fungal species, yet little is known about these interactions. Experimental manipulations showed that (i) ants spend more time cutting leaves from a tropical vine, Merremia umbellata, with high versus low endophyte densities, (ii) ants reduce the amount of endophytic fungi in leaves before planting them in their gardens, (iii) the ants'' fungal cultivar inhibits the growth of most endophytes tested. Moreover, the inhibition by the ants'' cultivar was relatively greater for more rapidly growing endophyte strains that could potentially out-compete or overtake the garden. Our results suggest that endophytes are not welcome in the garden, and that the ants and their cultivar combine ant hygiene behaviour with fungal inhibition to reduce endophyte activity in the nest. 相似文献
19.
Pattern and timing of diversification in Yucca (Agavaceae): specialized pollination does not escalate rates of diversification 总被引:1,自引:0,他引:1
Smith CI Pellmyr O Althoff DM Balcázar-Lara M Leebens-Mack J Segraves KA 《Proceedings. Biological sciences / The Royal Society》2008,275(1632):249-258
The yucca-yucca moth interaction is one of the most well-known and remarkable obligate pollination mutualisms, and is an important study system for understanding coevolution. Previous research suggests that specialist pollinators can promote rapid diversification in plants, and theoretical work has predicted that obligate pollination mutualism promotes cospeciation between plants and their pollinators, resulting in contemporaneous, parallel diversification. However, a lack of information about the age of Yucca has impeded efforts to test these hypotheses. We used analyses of 4322 AFLP markers and cpDNA sequence data representing six non-protein-coding regions (trnT-trnL, trnL, trnL intron, trnL-trnF, rps16 and clpP intron 2) from all 34 species to recover a consensus organismal phylogeny, and used penalized likelihood to estimate divergence times and speciation rates in Yucca. The results indicate that the pollination mutualism did not accelerate diversification, as Yucca diversity (34 species) is not significantly greater than that of its non-moth-pollinated sister group, Agave sensu latissimus (240 species). The new phylogenetic estimates also corroborate the suggestion that the plant-moth pollination mutualism has at least two origins within the Agavaceae. Finally, age estimates show significant discord between the age of Yucca (ca 6-10Myr) and the current best estimates for the age of their pollinators (32-40Myr). 相似文献
20.
Susanna A Galbany-Casals M Romaschenko K Barres L Martín J Garcia-Jacas N 《Annals of botany》2011,108(2):263-277