Rate of Gametophyte Maturation in Sexual and Apogamous Forms of Pellaea glabella

Whittier, P.

doi:10.2307/1546272

Cited by 25 publications

(29 citation statements)

References 7 publications

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“…). Comparative studies on germination of other allopolyploid ferns and their parents also found no differences (Quintanilla and Escudero, ) or higher germination percentages in the polyploid (Whittier, ; Kott and Peterson, ; Pangua et al., ; Testo et al., ). We did find differences among populations in germination percentage, which makes it advisable to include several populations in future studies comparing cytotypes.…”

Section: Discussionmentioning

confidence: 97%

Fitness of an allopolyploid rupicolous fern compared with its diploid progenitors: from sporogenesis to sporophyte formation

Pangua

Pajarón

Quintanilla

2019

American J of Botany

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Premise When two populations of related cytotypes grow in sympatry, the rarer cytotype tends to be excluded due to a frequency‐dependent mating disadvantage. Evolutionary models predict that polyploids, which are typically the rarer cytotype upon first formation, should have higher relative fitness and/or higher selfing rates to establish and then coexist with diploid parents. Methods Performance during early recruitment was compared among three co‐occurring rupicolous fern species: the allotetraploid Cheilanthes tinaei and its diploid ancestors, C. hispanica and C. maderensis. In culture experiments, fresh spores and samples of soil spore banks were tested for variation among cytotypes in germination, survival, fecundity, and mating system of gametophytes. Results Compared with its diploid parents, C. tinaei fresh spores had higher abortion percentages, lower dispersal ability as a result of its larger spores, and similar vigor at germination. For gametophytes from soil spore banks, C. tinaei had high survival similar to C. maderensis, but its sex expression resembled that of C. hispanica, with a high proportion of males. Patterns of sporophyte formation by females and bisexuals indicate that the polyploid does not have an increased gametophytic selfing rate. Gametophytes were larger in C. tinaei, but its reproductive success (sporophyte formation) was intermediate relative to diploids. Conclusions Our results show no evidence of higher selfing or fitness advantage of the allopolyploid over both diploid parents at any stage of early recruitment. These two unexpected findings suggest that further factors, such as niche differentiation, play a more important role in cytotype coexistence.

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Section: Discussionmentioning

confidence: 97%

Fitness of an allopolyploid rupicolous fern compared with its diploid progenitors: from sporogenesis to sporophyte formation

Pangua

Pajarón

Quintanilla

2019

American J of Botany

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“…Cheilanthes tomentosa has been counted repeatedly, and the majority of published reports indicate that this species is an apogamous triploid with n ϭ 2n ϭ 90 (Knobloch, 1966(Knobloch, , 1967Whittier, 1970;Knobloch et al, 1975). The conflict in this case involves counts of 2n ϭ 87 and n ϭ c. 89 published by Wagner et al (1970) and Lloyd (1966), respectively.…”

Section: Bommeria-the Only Previous Report For B Elegans (As Hemionimentioning

confidence: 98%

Chromosome studies of cheilanthoid ferns (Pteridaceae: Cheilanthoideae) from the western United States and Mexico

Windham

Yatskievych

2003

American J of Botany

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Although analyses of chromosome numbers represent a fundamental step in the study of any group of organisms, the xeric-adapted cheilanthoid ferns (Pteridaceae: subfamily Cheilanthoideae) have received little attention from cytogeneticists due to the difficulty in obtaining samples and accurate chromosome counts. In an effort to clarify patterns of chromosomal evolution in this group, we present 131 chromosome counts representing 75 taxa of cheilanthoid ferns from the western United States and Mexico. First reports are provided for 24 taxa, including the first count for the genus Cheiloplecton. Nine other taxa yielded numbers that had not been reported previously. Our data suggest that chromosome base numbers are more stable than previously thought and that much of the reported variation may involve erroneous counts. When coupled with published DNA sequence data, our counts suggest that the plesiomorphic base number of subfamily Cheilanthoideae is x = 30 and that x = 29 has arisen just once or twice among the taxa studied.

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“…In part this is because they defy the stereotypic view of ferns as plants of cool, mesic woodlands by thriving in the xeric and semixeric habitats that are at least seasonally characteristic of this region. The apogamous lifestyle (Gastony and Windham 1989) of many of these taxa minimizes the impact of hot, dry conditions on the relatively delicate gametophyte generation because apogamy both shortens the time from spore to sporophyte (Whittier 1970) and eliminates gametophytic dependence on free water for fertilization by motile sperm. Among the features thought to adapt many cheilanthoid sporophytes to such habitats are an indument of wax or insulating scales or trichomes on the leaves, reflexion of the leaf margin to form a false indusium over the sori, and the ability to die back to the rhizome and survive the driest periods in dormant condition.…”

Section: Introductionmentioning

confidence: 99%

Cheilanthoid Ferns (Pteridaceae: Cheilanthoideae) in the Southwestern United States and Adjacent Mexico-A Molecular Phylogenetic Reassessment of Generic Lines

Gastony¹,

Rollo²

1998

aliso

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Cheilantho ids are the most commonl y e ncountered fe rn species of the arid southwest and other xeric habitats throughout the world. Cheilanthes, Notholaena, Pellaea, and Bommeria are the best known southwestern genera, but some authors recogni ze segregate genera such as Argyrochosma, Aspidotis, Astrolepis, and Pentag ramma. Others reject di stinctions among some of these genera as artificial, leaving cheil antho id generic concepts in a state of flu x. This unsettl ed taxonomy is often attributed to morpholog ical homoplasy associated with adaptation to xeric habitats , suggesting the need for new analyses that do not depend o n potentially mi sleading morphology. Nucleotide sequences of the maternally inherited, chloroplast-encoded rbcL gene from 57 species that bear on the relationships of the cheilanthoids of the southwest were c1adistically analyzed under the optimality criterion of max imum parsimony. The results provide new insights into phylogeneti c re lationships and ge neric circumscriptio ns of these ferns. Mexican Llavea cordifolia is rejected from the cheilantho ids, traditio nal Cheilanthes, Notholaena, and Pellaea are polyphyletic, and the segregati ons of A rgyrochosma, Aspidotis, Astrolepis, and Pentag ramma are supported. To assess confidence in these conclusions, results of the rbcL-based analys is are compared with those based on ITS sequences of biparentall y inherited nucl ear ribosomal DNA (nrDNA) for a subset of cheil anthoid taxa. These two data sets yield remarkabl y congruent topologies at shall owe r phylogenetic levels, suggesting that previous taxonomic proble ms in thi s g roup may indeed be attributable to diffi culties in inte rpreting the taxonomic significance of morphological characters . Disagreement at deeper levels of the topologies suggests the need to incorporate data from less rapidly evolving nrDNA regions.

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Rate of Gametophyte Maturation in Sexual and Apogamous Forms of Pellaea glabella

Cited by 25 publications

References 7 publications

Fitness of an allopolyploid rupicolous fern compared with its diploid progenitors: from sporogenesis to sporophyte formation

Fitness of an allopolyploid rupicolous fern compared with its diploid progenitors: from sporogenesis to sporophyte formation

Chromosome studies of cheilanthoid ferns (Pteridaceae: Cheilanthoideae) from the western United States and Mexico

Cheilanthoid Ferns (Pteridaceae: Cheilanthoideae) in the Southwestern United States and Adjacent Mexico-A Molecular Phylogenetic Reassessment of Generic Lines

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