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American Journal of Botany

Hervé Sauquet, Sean W Graham
No abstract text is available yet for this article.
December 5, 2016: American Journal of Botany
Polina V Karpunina, Alexei A Oskolski, Maxim S Nuraliev, Porter P Lowry, Galina V Degtjareva, Tahir H Samigullin, Carmen M Valiejo-Roman, Dmitry D Sokoloff
PREMISE OF THE STUDY: Revealing the relative roles of gradual and abrupt transformations of morphological characters is an important topic of evolutionary biology. Gynoecia apparently consisting of one carpel have evolved from pluricarpellate syncarpous gynoecia in several angiosperm clades. The process of reduction can involve intermediate stages, with one fertile and one or more sterile carpels (pseudomonomery). The possible origin of monomery directly via an abrupt change of gynoecium merism has been a matter of dispute...
December 5, 2016: American Journal of Botany
Miriam J Bienau, R Lutz Eckstein, Annette Otte, Walter Durka
PREMISE OF THE STUDY: Vegetative reproduction and spread through clonal growth plays an important role in arctic-alpine ecosystems with short cool growing seasons. Local variation in winter snow accumulation leads to discrete habitat types that may provide divergent conditions for sexual and vegetative reproduction. Therefore, we studied variation in clonal structure of a dominant, evergreen, dwarf shrub (Empetrum nigrum s.l. with the two taxa E. nigrum L. s.s. and E. hermaphroditum Hagerup) along a snow cover gradient and compared clonal diversity and spatial genetic structure between habitats...
December 5, 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
Simon C Groen, Michael D Purugganan
No abstract text is available yet for this article.
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
Ricky S Kong, Hugh A L Henry
PREMISE OF THE STUDY: Both freezing and drought cause cellular dehydration, and they elicit similar increases in protective compounds, which suggests that these stresses could potentially interact. We examined whether the physiological changes that occur in response to freezing in the fall and spring could affect subsequent survival and growth after summer drought. METHODS: We froze Poa pratensis tillers in the late fall, early spring, or late spring at 0, -5, or -10°C for 3 d and then subjected them to no drought (-0...
November 1, 2016: American Journal of Botany
Robin L Chazdon, Lars Laestadius
No abstract text is available yet for this article.
November 1, 2016: American Journal of Botany
Krissa A Skogen, Tania Jogesh, Evan T Hilpman, Sadie L Todd, Matthew K Rhodes, Shannon M Still, Jeremie B Fant
PREMISE OF THE STUDY: Land-use change is cited as a primary driver of global biodiversity loss, with myriad consequences for species, populations, and ecosystems. However, few studies have examined its impact on species interactions, particularly pollination. Furthermore, when the effects of land-use change on pollination have been studied, the focus has largely been on species pollinated by diurnal pollinators, namely, bees and butterflies. Here, we focus on Oenothera harringtonii, a night-flowering, disturbance-adapted species that has experienced a range-wide gradient of land-use change...
November 1, 2016: American Journal of Botany
Paul Bayman, Ana T Mosquera-Espinosa, Carla M Saladini-Aponte, Nilbeth C Hurtado-Guevara, Naida L Viera-Ruiz
PREMISE OF THE STUDY: Oeceoclades maculata is a naturalized, invasive, terrestrial orchid in Puerto Rico and elsewhere in the neotropics. We asked whether its success might be partly explained by its mycorrhizal associations, hypothesizing a relationship with many fungal partners or with one widely distributed partner. METHODS: Oeceoclades maculata roots were collected throughout Puerto Rico, and the degree of mycorrhizal colonization was measured. For identification of fungi, the ITS region was sequenced from pure cultures and directly from roots...
October 26, 2016: American Journal of Botany
Toshiaki Kondo, Sen Nishimura, Naoki Tani, Kevin Kit Siong Ng, Soon Leong Lee, Norwati Muhammad, Toshinori Okuda, Yoshihiko Tsumura, Yuji Isagi
PREMISE OF THE STUDY: In tropical rainforests of Southeast Asia, a highly fecund thrips (Thrips spp.) responds rapidly to the mass flowering at multiple-year intervals characteristic of certain species such as the canopy tree studied here, Shorea acuminata, by feeding on flower resources. However, past DNA analyses of pollen adherent to thrips bodies revealed that the thrips promoted a very high level of self-pollination. Here, we identified the pollinator that contributes to cross-pollination and discuss ways that the pollination system has adapted to mass flowering...
October 20, 2016: American Journal of Botany
Jeremy B Yoder
Decades of research on the evolution of mutualism has generated a wealth of possible ways whereby mutually beneficial interactions between species persist in spite of the apparent advantages to individuals that accept the benefits of mutualism without reciprocating - but identifying how any particular empirical system is stabilized against cheating remains challenging. Different hypothesized models of mutualism stability predict different forms of coevolutionary selection, and emerging high-throughput sequencing methods allow examination of the selective histories of mutualism genes and, thereby, the form of selection acting on those genes...
October 18, 2016: American Journal of Botany
Jeff J Doyle
No abstract text is available yet for this article.
October 18, 2016: American Journal of Botany
Luis Abdala-Roberts, Johnattan Hernández-Cumplido, Luis Chel-Guerrero, David Betancur-Ancona, Betty Benrey, Xoaquín Moreira
PREMISE OF STUDY: Although there is increasing recognition of the effects of plant intraspecific diversity on consumers, the mechanisms by which such effects cascade-up to higher trophic levels remain elusive. METHODS: We evaluated the effects of plant (lima bean, Phaseolus lunatus) intraspecific diversity on a suite of insect herbivores (leaf-chewers, aphids, and seed-eating beetles) and their third trophic-level associates (parasitoids and aphid-tending ants)...
October 18, 2016: American Journal of Botany
Marta R Pereira, Cristian S Dambros, Charles E Zartman
PREMISE OF THE STUDY: Resource allocation is difficult to characterize in plants because of the challenges of quantifying gametes and propagules. We surveyed six sympatric, unisexual species in the family Calymperaceae (Bryophyta) to test for trade-offs in prezygotic sexual and asexual expression and density-dependent survivorship of female gametangia. METHODS: We tallied gametangial and asexual propagule output for 1820 shoots from 17 populations of six species at monthly intervals during one year (2010-2011) in a central Amazonian forest...
October 7, 2016: American Journal of Botany
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