The Experts below are selected from a list of 1722 Experts worldwide ranked by ideXlab platform
Marc T. J. Johnson - One of the best experts on this subject based on the ideXlab platform.
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Fitness consequences of occasional outcrossing in a functionally asexual plant (Oenothera biennis).
Ecology, 2018Co-Authors: John L. Maron, Marc T. J. Johnson, Amy P. Hastings, Anurag A. AgrawalAbstract:Many clonal organisms occasionally outcross, but the long-term consequences of such infrequent events are often unknown. During five years, representing three to five plant generations, we followed 16 experimental field populations of the forb, Oenothera biennis, originally planted with the same 18 original genotypes. Oenothera biennis usually self fertilizes, which, due to its genetic system (permanent translocation heterozygosity), results in seeds that are clones of the maternal plant. However, rare outcrossing produces genetically novel offspring (but without recombination or increased heterozygosity). We sought to understand whether novel genotypes produced through natural outcrossing had greater fecundity or different multigenerational dynamics compared to our original genotypes. We further assessed whether any differences in fitness or abundances through time between original and novel genotypes were exaggerated in the presence vs. absence of insect herbivores. Over the course of the experiment, we genotyped >12,500 plants using microsatellite DNA markers to identify and track the frequency of specific genotypes and estimated fecundity on a subset (>3,000) of plants. The effective outcrossing rate was 7.3% in the first year and ultimately 50% of the plants were of outcrossed origin by the final year of the experiment. Lifetime fruit production per plant was on average 32% higher across all novel genotypes produced via outcrossing compared to the original genotypes, and this fecundity advantage was significantly enhanced in populations lacking herbivores. Among 43 novel genotypes that were abundant enough to phenotype with replication, plants produced nearly 30% more fruits than the average of their specific two parental genotypes, and marginally more fruits (8%) than their most fecund parent. Mean per capita fecundity of novel genotypes predicted their relative frequencies at the end of the experiment. Novel genotypes increased more dramatically in herbivore-present compared to suppressed populations (45% vs. 27% of all plants), countering the increased competition from dandelions (Taraxacum officinale) that resulted from herbivore suppression. Increased interspecific competition likely also lead to the lower realized fitness of novel vs. original genotypes in herbivore-suppressed populations. These results demonstrate that rare outcrossing and the generation of novel genotypes can create high-fecundity progeny, with the biotic environment influencing the dynamical outcome of such advantages.
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Appendix B. Study site information including plot measures of evolutionary change in Oenothera biennis populations, soil characteristics, and plant species composition, and a photograph of the ecosystem assays.
2016Co-Authors: Connor R. Fitzpatrick, Anurag A. Agrawal, Nathan Basiliko, Amy P. Hastings, Marney E. Isaac, Michael Preston, Marc T. J. JohnsonAbstract:Study site information including plot measures of evolutionary change in Oenothera biennis populations, soil characteristics, and plant species composition, and a photograph of the ecosystem assays
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Tolerance to deer herbivory and resistance to insect herbivores in the common evening primrose (Oenothera biennis).
Journal of evolutionary biology, 2015Co-Authors: Adriana Puentes, Marc T. J. JohnsonAbstract:The evolution of plant defence in response to herbivory will depend on the fitness effects of damage, availability of genetic variation and potential ecological and genetic constraints on defence. Here, we examine the potential for evolution of tolerance to deer herbivory in Oenothera biennis while simultaneously considering resistance to natural insect herbivores. We examined (i) the effects of deer damage on fitness, (ii) the presence of genetic variation in tolerance and resistance, (iii) selection on tolerance, (iv) genetic correlations with resistance that could constrain evolution of tolerance and (v) plant traits that might predict defence. In a field experiment, we simulated deer damage occurring early and late in the season, recorded arthropod abundances, flowering phenology and measured growth rate and lifetime reproduction. Our study showed that deer herbivory has a negative effect on fitness, with effects being more pronounced for late-season damage. Selection acted to increase tolerance to deer damage, yet there was low and nonsignificant genetic variation in this trait. In contrast, there was substantial genetic variation in resistance to insect herbivores. Resistance was genetically uncorrelated with tolerance, whereas positive genetic correlations in resistance to insect herbivores suggest there exists diffuse selection on resistance traits. In addition, growth rate and flowering time did not predict variation in tolerance, but flowering phenology was genetically correlated with resistance. Our results suggest that deer damage has the potential to exert selection because browsing reduces plant fitness, but limited standing genetic variation in tolerance is expected to constrain adaptive evolution in O. biennis.
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Latitudinal gradients in herbivory on Oenothera biennis vary according to herbivore guild and specialization
Ecology, 2014Co-Authors: Daniel N. Anstett, Ilona Naujokaitis-lewis, Marc T. J. JohnsonAbstract:The latitudinal herbivory-defense hypothesis (LHDH) posits that herbivory and plant defenses increase toward lower latitudes. Recent studies provide contradictory evidence and suggest alternative explanations for biogeographic patterns in plant–herbivore interactions. Here we test the LHDH by sampling herbivory from multiple generalist and specialist insect herbivores over the entire latitudinal native range of the plant species Oenothera biennis L. (Onagraceae). We sampled 79 populations on a 16° north-south gradient from Ontario and Maine to Alabama and Florida. From each population, we quantified herbivory across feeding guilds by considering leaf herbivory caused by generalist insects, damage by a specialist stem-boring beetle, and flower/seed herbivory by three Lepidoptera that specialize on Oenothera. We also related environmental and population density variables to herbivory. Our results show that latitudinal patterns vary dramatically among herbivore species. While generalist leaf herbivory showed no latitudinal pattern, stem borer damage increased with decreasing latitude. By contrast, the specialist flower/seed herbivores all caused less damage at lower latitudes. Temperature explained slightly more variation in herbivory than latitude, while precipitation and population density were less important. Overall, we show that every pattern of herbivory (positive, negative and no relationship) is possible across a latitudinal gradient, and this variation depends on the insects' degree of specialization and feeding guild.
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The contribution of evening primrose (Oenothera biennis) to a modern synthesis of evolutionary ecology
Population Ecology, 2011Co-Authors: Marc T. J. JohnsonAbstract:In this review, I consider the contribution that common evening primrose ( Oenothera biennis ) has made towards integrating the ecology, evolution and genetics of species interactions. Oenothera biennis was among the earliest plant models in genetics and cytogenetics and it played an important role in the modern synthesis of evolutionary biology. More recently, population and ecological genetics approaches have provided insight into the patterns of genetic variation within and between populations, and how a combination of abiotic and biotic factors maintain and select on heritable variation within O. biennis populations. From an ecological perspective, field experiments show that genetic variation and evolution within populations can have cascading effects throughout communities. Plant genotype affects the preference and performance of individual arthropod populations, as well as the composition, biomass, total abundance and diversity of arthropod species on plants. A combination of experiments and simulation models show that natural selection on specific plant traits can drive rapid ecological changes in these same community variables. At the patch level, increasing genotypic diversity leads to a greater abundance and diversity of omnivorous and predaceous arthropods, which is also associated with increased biomass and fecundity of plants in genetically diverse patches. Finally, in questioning whether a community genetics perspective is needed in biology, I review several multifactorial experiments which show that plant genotype often explains as much variation in community variables as other ecological factors typically identified as most important in ecology. As a whole, research in the O. biennis system has contributed to a more complete understanding of the dynamic interplay between ecology, evolution and genetics.
Slawomir Majewski - One of the best experts on this subject based on the ideXlab platform.
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the effect of enzymatic hydrolysis on the biological properties of Oenothera biennis borago officinalis and nigella sativa seedcake by products from oil pressing
International Journal of Food Science and Technology, 2014Co-Authors: Anna Ratzłyko, Jacek Arct, Anna Herman, Katarzyna Pytkowska, Slawomir MajewskiAbstract:Summary The biological properties of ethanolic (50%, v/v) extracts from Oenothera biennis, Borago officinalis, Nigella sativa seedcake before and after enzymatic hydrolysis by alpha-amylase (EC 3.2.1.1) from Aspergillus oryzae, beta-glucosidase (EC 3.2.1.21) and beta-glucanase (EC 3.2.1.6) from Aspergillus niger combinations in a ratio of 1:1:1 were investigated. Total phenolic, flavonoid and reducing sugar content for O. biennis extract after enzymatic hydrolysis was, respectively, 0.5, 1.5 and 2 times higher in comparison with nonhydrolysed extract. Iron-chelating and radical-scavenging activity of O. biennis seedcake extract after hydrolysis (IC50 = 0.076 mg mL−1 and IC50 = 0.050 mg mL−1) was at a similar level as that nonhydrolyeed (IC50 = 0.070 mg mL−1 and IC50 = 0.065 mg mL−1). The antioxidant activity was two times higher after hydrolysis than before enzymatic hydrolysis of O. biennis seedcake extract. Also strong elastase inhibition activity has been shown to O. biennis seedcake extract before (IC50 = 0.095 mg mL−1) and after enzymatic hydrolysis (IC50 = 0.07 mg mL−1), respectively. Oenothera biennis and B. officinalis seedcake extracts before and after hydrolysis have stronger antibacterial activity against Pseudomonas aeruginosa strain in comparison with N. sativa seedcake.
David M Reid - One of the best experts on this subject based on the ideXlab platform.
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single and combined effects of temperature and red far red light ratio on evening primrose Oenothera biennis
Botany, 2015Co-Authors: Mirwais M Qaderi, Victoria J Godin, David M ReidAbstract:Few studies have considered the interactive effects of temperature and red:far-red light ratio (R:FR) on plants. We studied the effects of these two factors on evening primrose (Oenothera biennis L...
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Single and combined effects of temperature and red:far-red light ratio on evening primrose (Oenothera biennis).
Botany, 2015Co-Authors: Mirwais M Qaderi, Victoria J Godin, David M ReidAbstract:Few studies have considered the interactive effects of temperature and red:far-red light ratio (R:FR) on plants. We studied the effects of these two factors on evening primrose (Oenothera biennis L.). Plants were grown under two temperature regimes (22 °C day – 18 °C night and 28 °C day – 24 °C night) and two R:FR light ratios (low, simulated shade FR enrichment and normal, simulated natural sunlight) in controlled-environment chambers and their growth and physiological characteristics were measured. Among the 23 parameters, 20 were affected by temperature, 21 were affected by light quality, and 16 were affected by their interactions. Higher temperatures increased stem height, photosynthetic pigments, and ethylene, but decreased gas exchange and, in turn, plant biomass. Low R:FR increased stem height, transpiration, stomatal conductance, and ethylene, but decreased photosynthetic pigments, water-use efficiency, and photosynthesis and, in turn, plant biomass. Distinct parallel patterns were found for the c...
Katarzyna Pytkowska - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of antioxidant and antimicrobial activities of Oenothera biennis, Borago officinalis, and Nigella sativa seedcake extracts
Food Science and Biotechnology, 2014Co-Authors: Anna Ratz-Łyko, Jacek Arct, Anna Herman, Katarzyna PytkowskaAbstract:The antioxidant and antimicrobial activities of Oenothera biennis, Borago officinalis, and Nigella sativa seedcake extracts were determined. Seedcakes were subjected to extraction using 50% ethanol (v/v) during 48 h at a solvent temperature of 50°C. The total polyphenol and flavonoid contents were assayed using UV spectrophotometry and the antioxidant activities were determined using DPPH and ABTS testing methods. Extracts were also analyzed for polyphenol content using HPLC. In vitro antimicrobial activities were evaluated using the disc diffusion method and resazurin testing. The ranking of the polyphenol contents and the antioxidant activities of examined seedcake extracts was O. bienis>B.officinalis>N. sativa. The highest antimicrobial activity in both tests was for N. sativa seedcake extracts against Pseudomonas aeruginosa (MIC=300 mg/mL), Escherichia coli (MIC=300 mg/mL), and Staphylococcus aureus (MIC=700 mg/mL).
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the effect of enzymatic hydrolysis on the biological properties of Oenothera biennis borago officinalis and nigella sativa seedcake by products from oil pressing
International Journal of Food Science and Technology, 2014Co-Authors: Anna Ratzłyko, Jacek Arct, Anna Herman, Katarzyna Pytkowska, Slawomir MajewskiAbstract:Summary The biological properties of ethanolic (50%, v/v) extracts from Oenothera biennis, Borago officinalis, Nigella sativa seedcake before and after enzymatic hydrolysis by alpha-amylase (EC 3.2.1.1) from Aspergillus oryzae, beta-glucosidase (EC 3.2.1.21) and beta-glucanase (EC 3.2.1.6) from Aspergillus niger combinations in a ratio of 1:1:1 were investigated. Total phenolic, flavonoid and reducing sugar content for O. biennis extract after enzymatic hydrolysis was, respectively, 0.5, 1.5 and 2 times higher in comparison with nonhydrolysed extract. Iron-chelating and radical-scavenging activity of O. biennis seedcake extract after hydrolysis (IC50 = 0.076 mg mL−1 and IC50 = 0.050 mg mL−1) was at a similar level as that nonhydrolyeed (IC50 = 0.070 mg mL−1 and IC50 = 0.065 mg mL−1). The antioxidant activity was two times higher after hydrolysis than before enzymatic hydrolysis of O. biennis seedcake extract. Also strong elastase inhibition activity has been shown to O. biennis seedcake extract before (IC50 = 0.095 mg mL−1) and after enzymatic hydrolysis (IC50 = 0.07 mg mL−1), respectively. Oenothera biennis and B. officinalis seedcake extracts before and after hydrolysis have stronger antibacterial activity against Pseudomonas aeruginosa strain in comparison with N. sativa seedcake.
Anna Herman - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of antioxidant and antimicrobial activities of Oenothera biennis, Borago officinalis, and Nigella sativa seedcake extracts
Food Science and Biotechnology, 2014Co-Authors: Anna Ratz-Łyko, Jacek Arct, Anna Herman, Katarzyna PytkowskaAbstract:The antioxidant and antimicrobial activities of Oenothera biennis, Borago officinalis, and Nigella sativa seedcake extracts were determined. Seedcakes were subjected to extraction using 50% ethanol (v/v) during 48 h at a solvent temperature of 50°C. The total polyphenol and flavonoid contents were assayed using UV spectrophotometry and the antioxidant activities were determined using DPPH and ABTS testing methods. Extracts were also analyzed for polyphenol content using HPLC. In vitro antimicrobial activities were evaluated using the disc diffusion method and resazurin testing. The ranking of the polyphenol contents and the antioxidant activities of examined seedcake extracts was O. bienis>B.officinalis>N. sativa. The highest antimicrobial activity in both tests was for N. sativa seedcake extracts against Pseudomonas aeruginosa (MIC=300 mg/mL), Escherichia coli (MIC=300 mg/mL), and Staphylococcus aureus (MIC=700 mg/mL).
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the effect of enzymatic hydrolysis on the biological properties of Oenothera biennis borago officinalis and nigella sativa seedcake by products from oil pressing
International Journal of Food Science and Technology, 2014Co-Authors: Anna Ratzłyko, Jacek Arct, Anna Herman, Katarzyna Pytkowska, Slawomir MajewskiAbstract:Summary The biological properties of ethanolic (50%, v/v) extracts from Oenothera biennis, Borago officinalis, Nigella sativa seedcake before and after enzymatic hydrolysis by alpha-amylase (EC 3.2.1.1) from Aspergillus oryzae, beta-glucosidase (EC 3.2.1.21) and beta-glucanase (EC 3.2.1.6) from Aspergillus niger combinations in a ratio of 1:1:1 were investigated. Total phenolic, flavonoid and reducing sugar content for O. biennis extract after enzymatic hydrolysis was, respectively, 0.5, 1.5 and 2 times higher in comparison with nonhydrolysed extract. Iron-chelating and radical-scavenging activity of O. biennis seedcake extract after hydrolysis (IC50 = 0.076 mg mL−1 and IC50 = 0.050 mg mL−1) was at a similar level as that nonhydrolyeed (IC50 = 0.070 mg mL−1 and IC50 = 0.065 mg mL−1). The antioxidant activity was two times higher after hydrolysis than before enzymatic hydrolysis of O. biennis seedcake extract. Also strong elastase inhibition activity has been shown to O. biennis seedcake extract before (IC50 = 0.095 mg mL−1) and after enzymatic hydrolysis (IC50 = 0.07 mg mL−1), respectively. Oenothera biennis and B. officinalis seedcake extracts before and after hydrolysis have stronger antibacterial activity against Pseudomonas aeruginosa strain in comparison with N. sativa seedcake.
