scholarly journals Experimental evidence that belowground competition can influence the evolution of root traits in two closely related morning glory species

2019 ◽  
Author(s):  
Sara M. Colom ◽  
Regina S. Baucom
Keyword(s):  
Critical Role ◽  
Natural Populations ◽  
Root Traits ◽  
The United States ◽  
Morning Glory ◽  
Competitive Interactions ◽  
Plant Interactions ◽  
Belowground Competition ◽  
Ipomoea Purpurea ◽  
Root Angle

AbstractAlthough root traits play a critical role in mediating plant-plant interactions and resource acquisition from the soil environment, research examining if and how belowground competition can influence the evolution of root traits remains largely unexplored. Here we examine the potential that root traits may evolve as a target of selection from interspecific competition using Ipomoea purpurea and I. hederacea, two closely related morning glory species that commonly co-occur in the United States. We show that belowground competitive interactions between the two species can alter the pattern of selection on root traits in each species. Specifically, competition with I. purpurea changes the pattern of selection on root angle in I. hederacea, and competitive interactions with I. hederacea changes the pattern of selection on root size in I. purpurea. However, we did not uncover evidence that intraspecific competition altered the pattern of selection on any root traits within I. hederacea. Overall, our results suggest that belowground competition between closely related species can influence the phenotypic evolution of root traits in natural populations. Our findings provide a microevolutionary perspective of how competitive belowground interactions may impact plant fitness, potentially leading to patterns of plant community structure.

scholarly journals Belowground competition favors character convergence but not character displacement in root traits

2020 ◽  
Author(s):  
Sara M Colom ◽  
Regina S Baucom
Keyword(s):  
Root Traits ◽  
Character Displacement ◽  
Morning Glory ◽  
List Type ◽  
Belowground Competition ◽  
Maternal Line ◽  
Ipomoea Purpurea ◽  
Local Environments ◽  
The Common ◽  
Species Ecology

SummaryCharacter displacement can play a major role in species ecology and evolution, however, research testing whether character displacement can influence the evolution of root traits in plant systems remains scarce in the literature. Here we investigated the potential that character displacement may influence the evolution of root traits using two closely related morning glory species, Ipomoea purpurea and I. hederacea.We performed a field experiment where we grew the common morning glory, I. purpurea, in the presence and absence of competition from I. hederacea and examined the potential that the process of character displacement could influence the evolution of root traits.We found maternal line variation in root phenotypes and evidence that belowground competition acts as an agent of selection on these traits. Our test of character displacement, however, showed evidence of character convergence on our measure of root architecture rather than displacement. These results suggest that plants may be constrained by their local environments to express a phenotype that enhances fitness. Therefore, the conditions of the competitive environment experienced by a plant may influence the potential for character convergence or displacement to influence the evolution of root traits.

scholarly journals Biomass explains the intensity of facilitative – not competitive – interactions: three intraspecific tests with annuals

Web Ecology ◽  
2012 ◽  
Vol 12 (1) ◽  
pp. 49-55 ◽  
Author(s):  
C. Ariza ◽  
K. Tielbörger
Keyword(s):  
Size Dependence ◽  
Resource Competition ◽  
Theoretical Models ◽  
Plant Size ◽  
Competitive Interactions ◽  
Positive Interactions ◽  
Plant Interactions ◽  
Belowground Competition ◽  
Size Dependent ◽  
Negative Effect

Abstract. Despite efforts to discern the role of plant size in resource competition, the circumstances under which size-dependent plant-plant interactions occur are still unclear. The traditional assumption is that competition intensifies with increasing neighbour size. However, recent studies suggest that the size (biomass) dependence of competitive interactions is strongest at very low biomass levels and becomes negligible after a certain threshold neighbour biomass has been reached. We searched for the generality of such patterns for three common annual plant species in Israel. We monitored target and neighbour biomass along their entire lifecycle using an even-aged, intraspecific and intrapopulation competition screenhouse experiment under water-limited conditions. For all focal species, neighbour presence had a net negative effect on vegetative biomass at harvest. However, this was not explained by increasing neighbour biomass over time, as a consistent pattern of size-dependent facilitative, rather than competitive, interactions was observed at all life stages. We explain these observations in terms of co-occurring aboveground facilitation and dominant belowground competition for water. Since our findings are the first of their kind and contradict theoretical predictions of biomass dependence of net negative interactions, we advocate further experiments addressing size dependence in interactions among plants. In particular, theoretical models addressing size dependence of positive interactions must be developed.

scholarly journals Fitness costs of herbicide resistance across natural populations of the common morning glory,Ipomoea purpurea

2015 ◽  
Author(s):  
Megan L. van Etten ◽  
Adam Kuester ◽  
Shu-Mei Chang ◽  
Regina S Baucom
Keyword(s):  
Life History ◽  
Herbicide Resistance ◽  
Natural Populations ◽  
Cumulative Effect ◽  
Morning Glory ◽  
Visual Exploration ◽  
Fitness Costs ◽  
Ipomoea Purpurea ◽  
Life Cycle Stages ◽  
Trade Offs

AbstractAlthough fitness costs associated with plant defensive traits are widely expected, they are not universally detected, calling into question their generality. Here we examine the potential for life history trade-offs associated with herbicide resistance by examining seed germination, root growth, and above-ground growth across 43 naturally occurring populations ofIpomoea purpureathat vary in their resistance to RoundUp®, the most commonly used herbicide worldwide. We find evidence for life history trade-offs associated with all three traits; highly resistant populations had lower germination rates, shorter roots and smaller above-ground size. A visual exploration of the data indicated that the type of trade-off may differ among populations. Our results demonstrate that costs of adaptation may be present at stages other than simply the production of progeny in this agricultural weed. Additionally, the cumulative effect of costs at multiple life cycle stages can result in severe consequences to fitness when adapting to novel environments.

scholarly journals Fitness costs of herbicide resistance across natural populations of the common morning glory, Ipomoea purpurea

Evolution ◽  
2016 ◽  
Vol 70 (10) ◽  
pp. 2199-2210 ◽  
Author(s):  
Megan L. Van Etten ◽  
Adam Kuester ◽  
Shu-Mei Chang ◽  
Regina S. Baucom
Keyword(s):  
Herbicide Resistance ◽  
Natural Populations ◽  
Morning Glory ◽  
Fitness Costs ◽  
Ipomoea Purpurea ◽  
The Common

scholarly journals First Report of Sweet potato leaf curl Georgia virus Infecting Tall Morning Glory (Ipomoea purpurea) in China

Plant Disease ◽  
2014 ◽  
Vol 98 (11) ◽  
pp. 1588-1588
Author(s):  
S. B. Zhang ◽  
Z. G. Du ◽  
Z. Wang ◽  
Y. F. Tang ◽  
X. M. She ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Rolling Circle Amplification ◽  
The United States ◽  
Morning Glory ◽  
Central China ◽  
Potato Leaf ◽  
First Report ◽  
Ipomoea Purpurea ◽  
Sequence Identity ◽  
Leaf Curl

In September 2013, tall morning glory (Ipomoea purpurea) plants showing vein yellowing and leaf curl symptoms typical of a begomovirus infection were observed in Jingzhou, Hubei Province, China. Total nucleic acids were extracted from a symptomatic plant using cetyltrimethylammonium bromide (CTAB). Rolling circle amplification (RCA) was conducted using TempliPhi kit (GE Healthcare) to recover the genome of a putative begomovirus. Digestion of the RCA product with PstI yielded a ~2.8 kbp DNA fragment suggestive of a monomerized begomoviral genome. The fragment was cloned and sequenced and the sequence was deposited in GenBank under accession no. KF769447. SDTv1.0 (species demarcation tool) analysis revealed that the putative begomovirus showed 98.5 and 92.0% nucleotide sequence identity with Sweet potato leaf curl Georgia virus (SPLCGV)-[China:Hebei:2011] (GenBank Accession No. JX448368) and SPLCGV-[US:Geo:16] (AF326775), respectively. The virus contained six ORFs, which encoded proteins showing 96.5 to 100% and 90.6 to 95.6% amino acid sequence identity with their counterparts of SPLCGV-[China:Hebei:2011] and SPLCGV-[US:Geo:16], respectively. Thus, the virus should be considered as an isolate of SPLCGV-[China:Hebei:2011]. Tall glory morning in a nearby field (which covers an area of 3 square kilometers) was surveyed and 70 to 100% of plants were found showing symptoms reminiscent of begomoviral infection. Total nucleic acid was extracted from 13 randomly selected (10 symptomatic and 3 healthy) plants and used as templates for PCR with a pair of specific primers (5′-CGCAGCCTTTCCACACTATC-3′/5′-AAAACAGTTTGGGCTCGGTC-3′) designed according to the sequence described above. Positive results were obtained for all of the symptomatic, but none of the healthy-looking tall morning glory plants. SPLCGV (genus Begomovirus, family Geminiviridae) was reported to infect sweet potato (I. batatas) in the United States (4), India (2), and China (3). To our knowledge, this is the first report of SPLCGV infecting tall morning glory in China. Also, it is the first report of a geminivirus in Hubei, a province of central China. Whereas the finding of SPLCGV in sweet potato (3) may be a result of vegetative propagation of this crop, the detection of SPLCGV in tall morning glory, an annual plant, raises the possibility that this virus is transmissible and is spreading in China. References: (1) B. Muhire et al. Arch. Virol. 158:1411, 2013. (2) G. Prasanth and V. Hegde. Plant Dis. 92:311, 2008. (3) Y. Qin et al. Plant Dis. 97:1388, 2013. (4) R. A. Valverde and D. L. Gutierrez. Rev. Mex. Fitopatol. 21:128, 2003.

Bilingual and Monolingual Students' Perceptions of the CSD Major: A Qualitative Study

2015 ◽  
Vol 18 (1) ◽  
pp. 16-31 ◽  
Author(s):  
Flora Keshishian ◽  
Rebecca Wiseheart
Keyword(s):  
Qualitative Study ◽  
Undergraduate Students ◽  
Critical Role ◽  
School Setting ◽  
The United States ◽  
Bilingual Students ◽  
Speech Language Pathology ◽  
Diverse Environment ◽  
Language Pathology ◽  
Areas Of Interest

There is a growing demand for bilingual services in speech-language pathology and audiology. To meet this growing demand, and given their critical role in the recruitment of more bilingual professionals, higher education institutions need to know more about bilingual students' impression of Communication Sciences and Disorders (CSD) as a major. The purpose of this qualitative study was to investigate bilingual and monolingual undergraduate students' perceptions of the CSD major. One hundred and twenty-two students from a large university located in a highly multicultural metropolitan area responded to four open-ended questions aimed at discovering students' major areas of interest (and disinterest) as well as their motivations for pursuing a degree in CSD. Consistent with similar reports conducted outside the United States, students from this culturally diverse environment indicated choosing the major for altruistic reasons. A large percentage of participants were motivated by a desire to work with children, but not in a school setting. Although 42% of the participants were bilingual, few indicated an interest in taking an additional course in bilingual studies. Implications of these findings as well as practical suggestions for the recruitment of bilingual students are discussed.

Building America

2019 ◽  
Author(s):  
Jean H. Baker
Keyword(s):  
United States ◽  
Early Republic ◽  
Critical Role ◽  
Water System ◽  
The United States ◽  
Primary Sources ◽  
Early American ◽  
Transatlantic Exchange ◽  
The Us ◽  
Private Homes

Building America: The Life of Benjamin Henry Latrobe is a biography of America’s first professionally trained architect and engineer. Born in 1764, Latrobe was raised in Moravian communities in England and Germany. His parents expected him to follow his father and brother into the ministry, but he rebelled against the church. Moved to London, he studied architecture and engineering. In 1795 he emigrated to the United States and became part of the period’s Transatlantic Exchange. Latrobe soon was famous for his neoclassical architecture, designing important buildings, including the US Capitol and Baltimore Basilica as well as private homes. Carpenters and millwrights who built structures more cheaply and less permanently than Latrobe challenged his efforts to establish architecture as a profession. Rarely during his twenty-five years in the United States was he financially secure, and when he was, he speculated on risky ventures that lost money. He declared bankruptcy in 1817 and moved to New Orleans, the sixth American city that he lived in, hoping to recoup his finances by installing a municipal water system. He died there of yellow fever in 1820. The themes that emerge in this biography are the critical role Latrobe played in the culture of the early republic through his buildings and his genius in neoclassical design. Like the nation’s political founders, Latrobe was committed to creating an exceptional nation, expressed in his case by buildings and internal improvements. Additionally, given the extensive primary sources available for this biography, an examination of his life reveals early American attitudes toward class, family, and religion.

Glyphosate induces transient male sterility in Ipomoea purpurea

Botany ◽  
2008 ◽  
Vol 86 (6) ◽  
pp. 587-594 ◽  
Author(s):  
Regina S. Baucom ◽  
Rodney Mauricio ◽  
Shu-Mei Chang
Keyword(s):  
Male Sterility ◽  
Lethal Dose ◽  
Female Fertility ◽  
Morning Glory ◽  
Response To Treatment ◽  
Mixed Mating ◽  
Mixed Mating System ◽  
Ipomoea Purpurea ◽  
Female Function ◽  
Common Effect

Plant death is the most common effect resulting from the application of glyphosate, the active ingredient in the herbicide Roundup®. Individual seedlings of the morning glory, Ipomoea purpurea L. Roth, however, have been shown to exhibit tolerance to glyphosate, surviving after what should have been a lethal dose. Those that grow and reach reproductive maturity often exhibit deformed anthers within what appear to be normally developed flowers. Ipomoea purpurea has a mixed mating system and normally has hermaphroditic flowers that are capable of both selfing and outcrossing. The deformed anthers do not produce pollen, essentially converting a hermaphroditic flower to a female. Here we describe this morphological change and investigate the reproductive consequences of anther deformation. First, there is phenotypic variation for the propensity of an individual to exhibit male sterility through deformed anthers in response to treatment, but a series of field and greenhouse studies suggest that this variation is not genetic. The male sterility is also transient; within an individual, the frequency of flowers with deformed anthers declines over time. Although flowers with deformed anthers do not produce pollen, we observed mixed effects on female function of such flowers. In the greenhouse, flowers with deformed anthers that were hand-pollinated produced as many seeds as flowers with normal anthers, suggesting no effect on female fertility. In the field, however, plants with a higher proportion of anther deformation set significantly fewer seeds than those untreated, suggesting either reduced female fertility, or a reproductive penalty in flowers with deformed anthers due to the inability to self pollinate. Thus, the presence of this trait could alter the selfing to outcrossing ratio in populations that are sprayed with the herbicide. Individuals that exhibited a higher proportion of anther deformation also produce fewer total flowers than untreated plants, suggesting that anther deformation is part of a suite of responses to damage by glyphosate.

Confronting Soviet Power: U.S. Policy during the Early Cold War

2012 ◽  
Vol 36 (4) ◽  
pp. 151-188 ◽  
Author(s):  
Paul C. Avey
Keyword(s):  
United States ◽  
Cold War ◽  
Soviet Union ◽  
Critical Role ◽  
Balance Of Power ◽  
The United States ◽  
Soviet Power ◽  
The Soviet Union ◽  
Foreign Policies ◽  
Distribution Of Power

Many self-identified realist, liberal, and constructivist scholars contend that ideology played a critical role in generating and shaping the United States' decision to confront the Soviet Union in the early Cold War. A close look at the history reveals that these ideological arguments fail to explain key aspects of U.S. policy. Contrary to ideological explanations, the United States initially sought to cooperate with the Soviet Union, did not initially pressure communist groups outside the Soviet orbit, and later sought to engage communist groups that promised to undermine Soviet power. The U.S. decision to confront the Soviets stemmed instead from the distribution of power. U.S. policy shifted toward a confrontational approach as the balance of power in Eurasia tilted in favor of the Soviet Union. In addition, U.S. leaders tended to think and act in a manner consistent with balance of power logic. The primacy of power over ideology in U.S. policymaking—given the strong liberal tradition in the United States and the large differences between U.S. and Soviet ideology—suggests that relative power concerns are the most important factors in generating and shaping confrontational foreign policies.

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