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American Journal of Botany

Siri Fjellheim, Jill C Preston
No abstract text is available yet for this article.
March 15, 2018: American Journal of Botany
Katharine L Cary, Jarmila Pittermann
PREMISE OF THE STUDY: The pygmy forest, a plant community of severely stunted conifers and ericaceous angiosperms, occurs on patches of highly acidic, nutrient-poor soils along the coast of Northern California, USA. This system is an excellent opportunity to study the effect of severe nutrient deficiency on leaf physiology in a naturally-occurring ecosystem. In this study, we seek to understand the physiological mechanisms stunting the plants' growth and their implications for whole plant function...
January 2018: American Journal of Botany
Anushree Sanyal, Jonathan Lenoir, Carmel O'Neill, Frederic Dubois, Guillaume Decocq
PREMISE OF THE STUDY: Nearly all seed plants rely on stored seed reserves before photosynthesis can commence. Natural selection for seed oil traits must have occurred over 319 million years of evolution since the first seed plant ancestor. Accounting for the biogeographic distribution of seed oil traits is fundamental to understanding the mechanisms of adaptive evolution in seed plants. However, the evolution of seed oils is poorly understood. We provide evidence of the adaptive nature of seed oil traits at the intraspecific and interspecific levels in Brassicaceae-an oilseed-rich and economically important plant family...
January 2018: American Journal of Botany
Dmitry D Sokoloff, Margarita V Remizowa, Richard M Bateman, Paula J Rudall
No abstract text is available yet for this article.
January 2018: American Journal of Botany
Michael Song, Li-Yaung Kuo, Layne Huiet, Kathleen M Pryer, Carl J Rothfels, Fay-Wei Li
PREMISE OF THE STUDY: Gene space in plant plastid genomes is well characterized and annotated, yet we discovered an unrecognized open reading frame (ORF) in the fern lineage that is conserved across flagellate plants. METHODS: We initially detected a putative uncharacterized ORF by the existence of a highly conserved region between rps16 and matK in a series of matK alignments of leptosporangiate ferns. We mined available plastid genomes for this ORF, which we now refer to as ycf94, to infer evolutionary selection pressures and assist in functional prediction...
January 2018: American Journal of Botany
David M Spooner, Holly Ruess, Carlos I Arbizu, Flor Rodríguez, Claudia Solís-Lemus
PREMISE OF THE STUDY: The species boundaries of wild and cultivated potatoes are controversial, with most of the taxonomic problems in the cultivated potato clade. We here provide the first in-depth phylogenetic study of the cultivated potato clade to explore possible causes of these problems. METHODS: We examined 131 diploid accessions, using 12 nuclear orthologs, producing an aligned data set of 14,072 DNA characters, 2171 of which are parsimony-informative. We analyzed the data to produce phylogenies and perform concordance analysis and goodness-of-fit tests...
January 2018: American Journal of Botany
(no author information available yet)
No abstract text is available yet for this article.
January 2018: American Journal of Botany
Lindsay D Leverett, George F Schieder Iv, Kathleen Donohue
PREMISE OF THE STUDY: Phenology, the seasonal timing of development, can alter biotic interactions. Emergence from dormant or quiescent stages often occurs earlier when neighbors are present, which may reduce the neighbors' competitive effects. Delayed emergence in response to neighbors also has been observed, but the potential benefits of such delays are unclear. Further, emergence time may respond to neighbors experienced by parents, which may predict future competition in offspring...
January 2018: American Journal of Botany
Pamela K Diggle, Theresa M Culley
No abstract text is available yet for this article.
January 2018: American Journal of Botany
Tiina Särkinen, Sören Kottner, Wolfgang Stuppy, Farah Ahmed, Sandra Knapp
PREMISE OF THE STUDY: Fossils provide minimum age estimates for extant lineages. Here we critically evaluate Cantisolanum daturoides Reid & Chandler and two other early putative seed fossils of Solanaceae, an economically important plant family in the Asteridae. METHODS: Three earliest seed fossil taxa of Solanaceae from the London Clay Formation (Cantisolanum daturoides) and the Poole and Branksome Sand Formations (Solanum arnense Chandler and Solanispermum reniforme Chandler) were studied using x-ray microcomputed tomography (MCT) and scanning electron microscopy (SEM)...
January 2018: American Journal of Botany
Amanda S Gallinat, Luca Russo, Eli K Melaas, Charles G Willis, Richard B Primack
PREMISE OF THE STUDY: Patterns of fruiting phenology in temperate ecosystems are poorly understood, despite the ecological importance of fruiting for animal nutrition and seed dispersal. Herbarium specimens represent an under-utilized resource for investigating geographical and climatic factors affecting fruiting times within species, patterns in fruiting times among species, and differences between native and non-native invasive species. METHODS: We examined over 15,000 herbarium specimens, collected and housed across New England, and found 3159 specimens with ripe fruits, collected from 1849-2013...
January 2018: American Journal of Botany
Brandon T Sinn, Dylan D Sedmak, Lawrence M Kelly, John V Freudenstein
PREMISE OF THE STUDY: As more plastomes are assembled, it is evident that rearrangements, losses, intergenic spacer expansion and contraction, and syntenic breaks within otherwise functioning plastids are more common than was thought previously, and such changes have developed independently in disparate lineages. However, to date, the magnoliids remain characterized by their highly conserved plastid genomes (plastomes). METHODS: Illumina HiSeq and MiSeq platforms were used to sequence the plastomes of Saruma henryi and those of representative species from each of the six taxonomic sections of Asarum...
January 2018: American Journal of Botany
Qing-Wei Wang, Lin Qi, Wangming Zhou, Cheng-Gang Liu, Dapao Yu, Limin Dai
PREMISE OF THE STUDY: The growth limitation hypothesis (GLH) and carbon limitation hypothesis (CLH) are two dominant explanations for treeline formation. The GLH proposes that low temperature drives the treeline through constraining C sinks more than C sources, and it predicts that non-structural carbohydrate (NSC) levels are static or increase with elevation. Although the GLH has received strong support globally for evergreen treelines, there is still no consensus for deciduous treelines, which experience great asynchrony between supply and demand throughout the year...
January 2018: American Journal of Botany
Ling-Yun Wu, Fang-Fang Chang, Shu-Juan Liu, W Scott Armbruster, Shuang-Quan Huang
PREMISE OF THE STUDY: Heterostyly, the reciprocal positioning of stigmas and anthers in different floral morphs, has long been thought to promote intermorph pollination. However, extensive intramorph pollination occurs commonly in heterostylous species, leading to recurrent questions about the functional and evolutionary significance of heterostyly. METHODS: To identify the sources of stigmatic pollen (autogamous [intraflower], geitonogamous [intraplant], vs. interplant), we emasculated either one flower or entire plants in experimental populations of the two closely related buckwheat species, distylous Fagopyrum esculentum and homostylous F...
January 2018: American Journal of Botany
Wenbin Mei, Markus G Stetter, Daniel J Gates, Michelle C Stitzer, Jeffrey Ross-Ibarra
No abstract text is available yet for this article.
January 2018: American Journal of Botany
Nicholas John Deacon, Jake Joseph Grossman, Anna Katharina Schweiger, Isabella Armour, Jeannine Cavender-Bares
PREMISE OF THE STUDY: Aspen groves along the Niobrara River in Nebraska have long been a biogeographic curiosity due to morphological differences from nearby remnant Populus tremuloides populations. Pleistocene hybridization between P. tremuloides and P. grandidentata has been proposed, but the nearest P. grandidentata populations are currently several hundred kilometers east. We tested the hybrid-origin hypothesis using genetic data and characterized putative hybrids phenotypically. METHODS: We compared nuclear microsatellite loci and chloroplast sequences of Niobrara River aspens to their putative parental species...
December 15, 2017: American Journal of Botany
Aysajan Abdusalam, Dunyan Tan, Shu-Mei Chang
PREMISE OF THE STUDY: Abiotic environmental factors are often considered to be important in the distribution and maintenance of variation in sexual systems in flowering plants. Associations between sexes and abiotic factors are well documented in dioecious systems, but much less is known about this relationship in other sexually polymorphic systems. Species that are highly variable in sexual expression and habitat distribution can provide insights into the role of abiotic factors in maintaining variation in sexual expression...
December 15, 2017: American Journal of Botany
Ghadeer Bukhari, Jingbo Zhang, Peter F Stevens, Wenheng Zhang
PREMISE OF THE STUDY: Observations of floral ontogeny indicated that floral organ initiation in pentapetalous flowers most commonly results in a median-abaxial (MAB) petal during early development, a median-adaxial (MAD) petal being less common. Such different patterns of floral organ initiation might be linked with different morphologies of floral zygomorphy that have evolved in Asteridae. Here, we provide the first study of zygomorphy in pentapetalous angiosperms placed in a phylogenetic framework, the goal being to find if the different patterns of floral organ initiation are connected with particular patterns of zygomorphy...
December 15, 2017: American Journal of Botany
Juan M Losada, Jose I Hormaza, Jorge Lora
PREMISE OF THE STUDY: The pawpaw, Asimina triloba , is an underutilized fruit crop native to North America that belongs to the mainly tropical, early-divergent family Annonaceae. Asimina is the only genus within the Annonaceae with species adapted to cold climates. A thorough analysis of its reproductive biology, specifically pollen-pistil interaction during the progamic phase, is essential to understand both its adaptation to cold climates and how to optimize its fertilization and fruit set...
December 2017: American Journal of Botany
Charlotte Prieu, Hervé Sauquet, Pierre-Henri Gouyon, Béatrice Albert
PREMISE OF THE STUDY: Apertures in pollen grains are key structures of the wall, involved in pollen tube germination and exchanges with the environment. Aperture types in angiosperms are diverse, but pollen with one and three apertures (including monosulcate and tricolpate, respectively) are the two most common types. Here, we investigate the phylogenetic distribution in angiosperms of pollen with many round, scattered apertures called pantoporate pollen. METHODS: We constructed a morphological data set with species producing pantoporate pollen and representative angiosperm species with other pollen types, sampled from every angiosperm order, with a total of 1260 species distributed in 330 families...
December 2017: American Journal of Botany
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