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American Journal of Botany

Ivan Prieto, Isabelle Litrico, Cyrille Violle, Philippe Barre
PREMISE OF THE STUDY: Current ecological theory can provide insight into the causes and impacts of plant domestication. However, just how domestication has impacted intraspecific genetic variability (ITV) is unknown. We used 50 ecotypes and 35 cultivars from five grassland species to explore how selection drives functional trait coordination and genetic differentiation. METHODS: We quantified the extent of genetic diversity among different sets of functional traits and determined how much genetic diversity has been generated within populations of natural ecotypes and selected cultivars...
January 12, 2017: American Journal of Botany
Meng Wu, Jamicia Lewis, Richard C Moore
PREMISE OF THE STUDY: The red flesh of some papaya cultivars is caused by a recessive loss-of-function mutation in the coding region of the chromoplast-specific lycopene beta cyclase gene (CYC-b). We performed an evolutionary genetic analysis of the CYC-b locus in wild and cultivated papaya to uncover the origin of this loss-of-function allele in cultivated papaya. METHODS: We analyzed the levels and patterns of genetic diversity at the CYC-b locus and six loci in a 100-kb region flanking CYC-b and compared these to genetic diversity levels at neutral autosomal loci...
January 12, 2017: American Journal of Botany
Pamela K Diggle
No abstract text is available yet for this article.
January 12, 2017: American Journal of Botany
Rachel Rock-Blake, Melissa K McCormick, Hope E A Brooks, Cynthia S Jones, Dennis F Whigham
PREMISE OF THE STUDY: Symbioses are almost universal, but little is known about how symbiont abundance can affect host performance. Many orchids undergo vegetative dormancy and frequent and protracted dormancy have been associated with population declines. If mycorrhizal fungi affect host plant performance, those effects are likely to alter patterns of vegetative dormancy. The goal of this study was to determine whether the abundance of mycorrhizal fungi is related to the likelihood of entering dormancy and whether fungal abundance varied with dormancy duration in the federally listed threatened orchid Isotria medeoloides...
January 6, 2017: American Journal of Botany
Shi-Jun Wang, Richard M Bateman, Alan R T Spencer, Jun Wang, Longyi Shao, Jason Hilton
PREMISE OF THE STUDY: Noeggerathiales are an extinct group of heterosporous shrubs and trees that were widespread and diverse during the Pennsylvanian-Permian Epochs (323-252 Ma) but are of controversial taxonomic affinity. Groups proposed as close relatives include leptosporangiate ferns, sphenopsids, progymnosperms, or the extant eusporangiate fern Tmesipteris. Previously identified noeggerathialeans lacked anatomical preservation, limiting taxonomic comparisons to their external morphology and spore structure...
January 6, 2017: American Journal of Botany
Elizabeth W McCarthy, Andrea E Berardi, Stacey D Smith, Amy Litt
PREMISE OF THE STUDY: Both polyploidy and shifts in floral color have marked angiosperm evolution. Here, we investigate the biochemical basis of the novel and diverse floral phenotypes seen in allopolyploids in Nicotiana (Solanaceae) and examine the extent to which the merging of distinct genomes alters flavonoid pigment production. METHODS: We analyzed flavonol and anthocyanin pigments from Nicotiana allopolyploids of different ages (N. tabacum, 0.2 million years old; several species from Nicotiana section Repandae, 4...
January 5, 2017: American Journal of Botany
Vanessa Suaza-Gaviria, Favio González, Natalia Pabón-Mora
PREMISE OF THE STUDY: Loranthaceae, Santalaceae, and Viscaceae are the most diversified hemiparasitic families of Santalales in the Andes. Their partial inflorescences (PIs) vary from solitary flowers, or dichasia in most Santalales, to congested floral groups along articles in most Viscaceae. The atypical articled inflorescences in Phoradendreae (Viscaceae), a phylogenetic novelty restricted to this tribe, have been variously described as racemes, spikes, fascicles, or as intercalary inflorescences, but no developmental studies have been performed to compare them with the construction of PIs across Santalales...
January 5, 2017: American Journal of Botany
Adrian C Brennan
No abstract text is available yet for this article.
January 5, 2017: American Journal of Botany
Victoria Ferrero, Spencer C H Barrett, Danny Rojas, Juan Arroyo, Luis Navarro
PREMISE OF THE STUDY: Populations of heterostylous species are characterized by two or three floral morphs with reciprocal positioning of stigmas and anthers. Theoretical models predict equal morph frequencies (isoplethy) when disassortative mating is prevalent in populations, but biased morph ratios may occur when variation in the expression of heterostyly causes deviations from intermorph mating. METHODS: We explore the role of sex-organ deployment in governing morph ratios in two closely related genera of Boraginaceae, exhibiting striking variation in floral traits associated with the heterostylous syndrome...
December 30, 2016: American Journal of Botany
Xiaofeng Yin, Roger D Meicenheimer
PREMISE OF THE STUDY: Fibonacci phyllotactic patterns in seed plants are well documented, but whether such predominance holds true for lower vascular plants is relatively unknown. We investigated Diphasiastrum digitatum (Lycopodiaceae) phyllotaxis throughout its ontogeny to extend our knowledge of pattern frequency of lower vascular plants and to measure quantitative variables associated with discontinuous phyllotactic transitions. These investigations allowed us to test whether the same mechanisms inherent in shoot apical meristem (SAM) development of seed plants are applicable to early-diverged lower vascular plants SAM development...
December 30, 2016: American Journal of Botany
Jorge Cortés-Flores, Karen Beatriz Hernández-Esquivel, Antonio González-Rodríguez, Guillermo Ibarra-Manríquez
PREMISE OF THE STUDY: Analyses of the influence of temporal variation in abiotic factors on flowering phenology of tropical dry forest species have not considered the possible response of species with different growth forms and pollination syndromes, while controlling for phylogenetic relationships among species. Here, we investigated the relationship between flowering phenology, abiotic factors, and plant functional attributes, while controlling for phylogenetic relationship among species, in a dry forest community in Mexico...
December 28, 2016: American Journal of Botany
Ann Willyard, David S Gernandt, Kevin Potter, Valerie Hipkins, Paula Marquardt, Mary Frances Mahalovich, Stephen K Langer, Frank W Telewski, Blake Cooper, Connor Douglas, Kristen Finch, Hassani H Karemera, Julia Lefler, Payton Lea, Austin Wofford
PREMISE OF THE STUDY: Molecular genetic evidence can help delineate taxa in species complexes that lack diagnostic morphological characters. Pinus ponderosa (Pinaceae; subsection Ponderosae) is recognized as a problematic taxon: plastid phylogenies of exemplars were paraphyletic, and mitochondrial phylogeography suggested at least four subdivisions of P. ponderosa. These patterns have not been examined in the context of other Ponderosae species. We hypothesized that putative intraspecific subdivisions might each represent a separate taxon...
December 28, 2016: American Journal of Botany
Matti A Niissalo, Jana Leong-Škorničková, Gillian S Khew, Edward L Webb
PREMISE OF THE STUDY: Tropical plant communities in fragmented forests are likely to experience an extinction debt, i.e., the habitat cannot support as many species as are present due to reduced habitat size and connectivity. There are few estimates of the number of species that represent extinction debt, and the number of extinctions over time has rarely been recorded. We recorded population sizes to assess threats and extinctions in gingers (sensu Zingiberales) in fragmented rainforest in Singapore, ca...
December 28, 2016: American Journal of Botany
Katherine R Goodrich, Luis A Ortiz, David J Coughlin
PREMISE OF STUDY: Deciduous woody species invest considerable resources in the growth of new foliage and distal stems. This new growth is at risk for mechanical damage from high winds and storms. Pawpaw has large leaves borne distally on thin twigs. Following a storm, pawpaw branches sometimes exhibit a persistent "flipped" orientation, slowly returning upright over 24 h. We investigated biomechanical properties of pawpaw twigs, comparing them to co-occurring species with similarly high leaf areas and loads, which do not exhibit this "flipping"...
November 18, 2016: American Journal of Botany
Miranda K Melen, Julie A Herman, Jessica Lucas, Rachel E O'Malley, Ingrid M Parker, Aaron M Thom, Justen B Whittall
PREMISE OF THE STUDY: Self incompatibility (SI) in rare plants presents a unique challenge-SI protects plants from inbreeding depression, but requires a sufficient number of mates and xenogamous pollination. Does SI persist in an endangered polyploid? Is pollinator visitation sufficient to ensure reproductive success? Is there evidence of inbreeding/outbreeding depression? We characterized the mating system, primary pollinators, pollen limitation, and inbreeding/outbreeding depression in Erysimum teretifolium to guide conservation efforts...
November 18, 2016: American Journal of Botany
(no author information available yet)
No abstract text is available yet for this article.
November 18, 2016: American Journal of Botany
Pablo Riba-Hernández, Jorge Lobo Segura, Jenny Muñoz-Valverde
PREMISE OF THE STUDY: Factors related to pollen and resource limitation were evaluated to predict female fruit production in a tropical dioecious tree. Pollen limitation via variation in the male density at local scales is expected to limit female reproduction success in dioecious plants. METHODOLOGY: We modeled the roles of local male density, female crown size, crown illumination, and female flower production on female fruit initiation and mature fruit production in a continuous population (62 ha plot) of a tropical dioecious tree (Virola surinamensis)...
November 18, 2016: American Journal of Botany
Sandra Varga, Minna-Maarit Kytöviita
PREMISE OF THE STUDY: Sex lability (i.e., gender diphasy) in plants is classically linked to the larger resource needs associated with the female sexual function (i.e., seed production) compared to the male function (i.e., pollen production). Sex lability in response to the environment is extensively documented in dioecious species, but has been largely overlooked in gynodioecious plants. METHODS: Here, we tested whether environmental conditions induce sex lability in the gynodioecious Geranium sylvaticum...
November 18, 2016: American Journal of Botany
Yuka Ikezaki, Yoshihisa Suyama, Beth A Middleton, Yoshihiko Tsumura, Kousuke Teshima, Hidenori Tachida, Junko Kusumi
PREMISE OF THE STUDY: Studies of natural genetic variation can elucidate the genetic basis of phenotypic variation and the past population structure of species. Our study species, Taxodium distichum, is a unique conifer that inhabits the flood plains and swamps of North America. Morphological and ecological differences in two varieties, T. distichum var. distichum (bald cypress) and T. distichum var. imbricarium (pond cypress), are well known, but little is known about the level of genetic differentiation between the varieties and the demographic history of local populations...
November 14, 2016: American Journal of Botany
Lisi D P Alvarenga, Kátia C Pôrto, Maria L P Coelho, Charles E Zartman
PREMISE OF THE STUDY: Leaf-inhabiting organisms offer an experimentally tractable model system within which to investigate the influence of alternative reproductive strategies on plant metapopulation dynamics. We conducted a field study to determine whether (1) threshold colony sizes exist for the onset of sexual and asexual expression, and (2) alternative reproductive strategies differentially influence within-patch dynamics of the tropical pleurocarpous moss Crossomitrium patrisiae...
November 14, 2016: American Journal of Botany
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