1. |
- Abreha, Kibrom Berhe, et al.
(author)
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Article leaf apoplast of field-grown potato analyzed by quantitative proteomics and activity-based protein profiling
- 2021
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In: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 22:21
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Journal article (peer-reviewed)abstract
- Multiple biotic and abiotic stresses challenge plants growing in agricultural fields. Most molecular studies have aimed to understand plant responses to challenges under controlled conditions. However, studies on field-grown plants are scarce, limiting application of the findings in agricultural conditions. In this study, we investigated the composition of apoplastic proteomes of potato cultivar Bintje grown under field conditions, i.e., two field sites in June–August across two years and fungicide treated and untreated, using quantitative proteomics, as well as its activity using activity-based protein profiling (ABPP). Samples were clustered and some proteins showed significant intensity and activity differences, based on their field site and sampling time (June–August), indicating differential regulation of certain proteins in response to environmental or developmental factors. Peroxidases, class II chitinases, pectinesterases, and osmotins were among the proteins more abundant later in the growing season (July–August) as compared to early in the season (June). We did not detect significant differences between fungicide Shirlan treated and untreated field samples in two growing seasons. Using ABPP, we showed differential activity of serine hydrolases and β-glycosidases under greenhouse and field conditions and across a growing season. Furthermore, the activity of serine hydrolases and β-glycosidases, including proteins related to biotic stress tolerance, decreased as the season progressed. The generated proteomics data would facilitate further studies aiming at understanding mechanisms of molecular plant physiology in agricultural fields and help applying effective strategies to mitigate biotic and abiotic stresses.
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2. |
- Abreha, Kibrom Berhe, et al.
(author)
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Late Blight Resistance Screening of Major Wild Swedish Solanum Species: S. dulcamara, S. nigrum, and S. physalifolium
- 2018
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In: Phytopathology. - 0031-949X .- 1943-7684. ; 108, s. 847-857
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Journal article (peer-reviewed)abstract
- To understand the contribution of wild Solanum species to the epidemiology of potato late blight in Sweden, we characterized the resistance of the three putative alternative hosts: S. physalifolium, S. nigrum, and S. dulcamara to Phytophthora infestans, the causal agent of late blight. The pathogen sporulated in all 10 investigated S. physalifolium genotypes, suggesting susceptibility (S phenotype). Field-grown S. physalifolium was naturally infected but could regrow, though highly infected genotypes were smaller at the end of the season. In 75 S. nigrum genotypes, there were no symptoms (R phenotype) or a lesion restricted to the point of inoculation (RN phenotype), indicating resistance. In 164 S. dulcamara genotypes, most resistance variability was found within sibling groups. In addition to the three resistance phenotypes (R, RN, and S), in S. dulcamara a fourth new resistance phenotype (SL) was identified with lesions larger than the point of inoculation but without visible sporulation of the pathogen. Quantitative PCR confirmed P. infestans growth difference in RN, SL, and S phenotypes. Thus, in Sweden S. physalifolium is susceptible and could be a player in epidemiology. A limited role of S. dulcamara leaves in the epidemiology of late blight was suggested, since no major symptoms have been found in the field.
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3. |
- Alexandersson, Erik, et al.
(author)
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Plant Resistance Inducers against Pathogens in Solanaceae Species-From Molecular Mechanisms to Field Application
- 2016
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In: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 17
-
Research review (peer-reviewed)abstract
- This review provides a current summary of plant resistance inducers (PRIs) that have been successfully used in the Solanaceae plant family to protect against pathogens by activating the plant's own defence. Solanaceous species include many important crops such as potato and tomato. We also present findings regarding the molecular processes after application of PRIs, even if the number of such studies still remains limited in this plant family. In general, there is a lack of patterns regarding the efficiency of induced resistance (IR) both between and within solanaceous species. In many cases, a hypersensitivity-like reaction needs to form in order for the PRI to be efficient. "-Omics" studies have already given insight in the complexity of responses, and can explain some of the differences seen in efficacy of PRIs between and within species as well as towards different pathogens. Finally, examples of field applications of PRIs for solanaceous crops are presented and discussed. We predict that PRIs will play a role in future plant protection strategies in Solanaceae crops if they are combined with other means of disease control in different spatial and temporal combinations.
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4. |
- Andersen, Christian B., et al.
(author)
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Pythium oligandrum induces growth promotion in starch potato without significantly altering the rhizosphere microbiome
- 2024
-
In: Applied Soil Ecology. - 0929-1393. ; 199
-
Journal article (peer-reviewed)abstract
- Plant health promoting organisms, including microbial biological control agents, are of increasing importance for the development of more sustainable agriculture. To understand the function of these microbes as biological control agents under field conditions and their overall impact on soil and plant health, we need to learn more about the impact of plant beneficial microbes on the rhizosphere microbiome of crops such as potato. The plant beneficial oomycete Pythium oligandrum has previously been reported both as a biocontrol agent and as a plant growth promoter, or biostimulant, in several crop species. To investigate the potential of P. oligandrum as a biostimulant in potato, we performed a series of controlled-environment bioassays in three cultivars. We showed that biostimulation of potato by P. oligandrum is plant genotype-specific. We confirmed the biostimulation by P. oligandrum in the starch potato cultivar Kuras under field conditions. We further investigated the effects of P. oligandrum on the potato rhizosphere microbiome, sampling individual potato plants at three time points over the growing season (representing the vegetative growth phase, flowering, and the onset of senescence). Metabarcoding using ITS and 16S amplicon sequencing revealed no significant overall effect of P. oligandrum application on the bacterial and fungal rhizosphere communities. However, some genera were significantly differentially abundant after P. oligandrum application, including some classified as plant-beneficial microbes. We conclude that P. oligandrum has a cultivar-dependent growth-promoting effect in potato and only minor effects on the rhizosphere microbiome.
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5. |
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6. |
- Andersson, Martin N, et al.
(author)
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Characterization of olfactory sensory neurons in the white clover seed weevil, Apion fulvipes (Coleoptera: Apionidae).
- 2012
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In: Journal of Insect Physiology. - : Elsevier BV. - 1879-1611 .- 0022-1910. ; 58:10, s. 1325-1333
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Journal article (peer-reviewed)abstract
- Seed-eating Apion weevils (Coleoptera: Apionidae) cause large economic losses in white and red clover seed production across Europe. Monitoring and control of clover weevils would be facilitated by semiochemical-based methods. Until now, however, nothing was known about physiological or behavioral responses to semiochemicals in this insect group. Here we analyzed the antenna of the white clover (Trifolium repens L.) specialist Apion fulvipes Geoffroy with scanning electron microscopy, and used single sensillum recordings with a set of 28 host compounds to characterize 18 classes of olfactory sensory neurons (OSNs). Nine of the OSN classes responded strongly to synthetic compounds with high abundance in clover leaves, flowers, or buds. Eight classes responded only weakly to the synthetic stimuli, whereas one collective class responded exclusively to volatiles released from a crushed clover leaf. The OSNs showed a remarkable degree of specificity, responding to only one or a few chemically related compounds. In addition, we recorded a marked difference in the temporal dynamics of responses between different neurons, compounds, and doses. The identified physiologically active compounds will be screened for behavioral activity, with the ultimate goal to develop an odor-based control strategy for this pest.
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7. |
- Bedhomme, Stephanie, et al.
(author)
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How does breeding system variation modulate sexual antagonism?
- 2009
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In: Biology letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 5:5, s. 717-720
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Journal article (other academic/artistic)abstract
- The study of sexually antagonistic (SA) traits remains largely limited to dioecious (separate sex), mobile animals. However, the occurrence of sexual conflict is restricted neither by breeding system (the mode of sexual reproduction, e. g. dioecy or hermaphroditism) nor by sessility. Here, we synthesize how variation in breeding system can affect the evolution and expression of intra- and inter-locus sexual conflicts in plants and animals. We predict that, in hermaphrodites, SA traits will (i) display lower levels of polymorphism; (ii) respond more quickly to selection; and (iii) involve unique forms of interlocus conflict over sex allocation, mating roles and selfing rates. Explicit modelling and empirical tests in a broader range of breeding systems are necessary to obtain a general understanding of the evolution of SA traits.
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8. |
- Carrasco, David, et al.
(author)
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Characterization of olfactory sensory neurons in the red clover seed weevil, Protapion trifolii (Coleoptera : Brentidae) and comparison to the closely related species P. fulvipes
- 2019
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In: Journal of Insect Physiology. - : Elsevier BV. - 0022-1910 .- 1879-1611. ; 119
-
Journal article (peer-reviewed)abstract
- Protapion trifolii and P. fulvipes (Coleoptera: Brentidae) are major pests in European clover seed production. Previous studies have reported a high host plant fidelity of these weevils for red and white clover species, respectively, driven by host plant olfactory cues. Given the specific host preferences observed in these weevils, we aimed to elucidate to which extent such selectivity is reflected in their peripheral olfactory systems. Using an electrophysiological approach, we performed the first functional characterisation of olfactory sensory neurons (OSNs) in P. trifolii to a panel of volatile compounds emitted by red clover plants, and compared the results with the reported OSN types of P. fulvipes. Nineteen OSN classes were characterized in P. trifolii, with the majority of these neurons responding strongly to common volatiles released by the host plant. Based on response profiles, eight of these OSN classes have clear matches to OSN classes in P. fulvipes. The OSN colocalisation patterns and antennal frequency of these classes are similar in the two species. Additionally, the responses of these OSNs are generally highly conserved in the two species, with clear response shifts only revealed for two of the OSN classes. These response shifts in combination with additional response dissimilarities for compounds that vary in abundance between red and white clover plants may underlie the species-specific host preferences. Further behavioural and field experiments should focus on these differentially detected compounds to elucidate their potential role in host selection and use in semiochemical-based control of these pests.
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9. |
- D'Hertefeldt, Tina, et al.
(author)
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Escaped oilseed rape : Occurrence in the agricultural landscape and potential pollen-mediated gene flow from crop oilseed rape
- 2021
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In: Journal of Pollination Ecology. - Cambridge, ON : International Commission for Plant Pollinator Relations. - 1920-7603. ; 28, s. 127-137
-
Journal article (peer-reviewed)abstract
- To assess the role of feral oilseed rape (OSR) plants as resources for pollinators and avenues for gene flow, we compared occurrence of feral populations in standardized agricultural landscapes, using a landscape ecological approach. The occurrence of feral and volunteer populations was investigated in relation to differences in road length and width, number of OSR fields, and landscape scale. The potential for pollen-mediated gene flow from crop to feral oilseed rape was investigated with fluorescent dye in a field experiment. Moreover, greenhouse estimates of pollen germination rate and pollen tube growth rate were performed to get an indication of siring success in crop and feral plants. Escaped OSR occurred in 14 out of the 16 investigated landscapes, and feral populations were more common alongside large roads than small roads in large-scale landscapes. The number of plants in a habitat ranged from 1-160 individuals, with 1-19 habitats per landscape. In the field experiment with fluorescent dye, no transfer of dye was detected during early flowering in May. At the end of the flowering period in June, transfer of dye was found in 71.4% of the feral plants, showing that significant transfer, most likely by pollinators, occurred from the field to the feral plants. There was no difference in pollen germination rate between crop and feral plants. Pollen tube growth rate was significantly higher in feral oilseed rape than in the crop (P < 0.001). Our results contribute to increased understanding of i) the utilization of feral populations by pollinators in an intensively farmed agricultural landscape, and ii) crop-feral gene flow within OSR.
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10. |
- Hederström, Veronica, et al.
(author)
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Dispersal and spatiotemporal distribution of Protapion fulvipes in white clover fields : implications for pest management
- 2022
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In: Journal of Pest Science. - : Springer Science and Business Media LLC. - 1612-4758 .- 1612-4766. ; 95:2, s. 917-930
-
Journal article (peer-reviewed)abstract
- Yield loss caused by insect pests remains a substantial problem in agriculture. Chemical control, with potential negative effects on non-target organisms, is still the main tool for pest management. For pest species with limited dispersal capacity, rotation of the crop in time and space has potential as an alternative management measure. This is particularly important in organic farming, where most agrochemicals are prohibited, but also relevant as a complementary pest management strategy in conventional agriculture. Clover is an important crop used for animal feed and as green manure; however, seed-eating weevils can severely limit the seed yield. We hypothesized that the previous year’s clover seed fields constitute the major sources of weevil pests. Consequently, a greater distance to, and a smaller pest load from, this source should reduce the number of weevils colonizing the new seed fields. To map population dynamics and dispersal range of Protapion fulvipes, an economically important seed weevil specialized on white clover, we conducted field studies over four years in 45 white clover seed fields. We found that P. fulvipes overwinters close to its source field and disperses to new fields in early spring the following year. Pest abundance increased with pest load in the previous year’s seed field, but decreased by 68% per km distance to the previous year’s field. Thus, separation of seed production fields between years by 2–3 km would create a spatiotemporal pest management tool to reduce the pest infestation below the estimated economic injury level.
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11. |
- Hederström, Veronica, et al.
(author)
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Do plant ploidy and pollinator tongue length interact to cause low seed yield in red clover?
- 2021
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In: Ecosphere. - : Wiley. - 2150-8925. ; 12:3
-
Journal article (peer-reviewed)abstract
- The loss of long-tongued pollinator species and dominance of a few short-tongued generalist species, related to agricultural intensification in recent decades, may have consequences for the quality, quantity, and stability of yields in insect-pollinated crops. Interestingly, the changes in pollinator community coincide with an increase in poor and variable seed yield in red clover, an important crop for green manure and forage production. However, to date we lack a holistic understanding of the factors that drive seed yield in red clover crops. To remedy this, we related plant and pollinator traits to pollinator visitation, behavior, and pollination efficiency in four diploid and five tetraploid red clover cultivars during three years in a common garden setting. Tetraploid cultivars produced 52% fewer seeds and 41% lower seed weight per flower head compared with diploid cultivars. They also had fewer flower heads per plant, larger florets, and lower pollen viability than diploids. Pollinator species with shorter tongues visited diploid cultivars more frequently than tetraploid cultivars. Pollinator species with longer tongues deposited more pollen and showed higher pollination efficiency in terms of seeds produced after single visits. Our results suggest that while both diploid and tetraploid red clover cultivars benefit from the presence of longer-tongued pollinator species, seed yield in tetraploid cultivars may be more sensitive to the loss of these bumble bee species in intensively cultivated agricultural landscapes.
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12. |
- Hederström, Veronica, et al.
(author)
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White clover pollinators and seed set in relation to local management and landscape context
- 2024
-
In: Agriculture, Ecosystems and Environment. - 0167-8809. ; 365
-
Journal article (peer-reviewed)abstract
- Bees are declining, which is worrisome since they both have intrinsic conservation value and play a major role as pollinators in both natural and managed ecosystems. Land use change and lack of suitable habitats are often suggested as driving forces of bee decline. To propose mitigation measures to halt bee decline, it is important to understand how land use relates to bee abundance and diversity, and to explore consequences for their provision of pollination services. White clover, Trifolium repens, is an outcrossing mass-flowering crop, which could serve as an abundant, although ephemeral, food resource for bees. We investigated how the bee community in 39 fields of white clover grown for seed, related to local field management (organic, conventional without insecticides and conventional with insecticides) and landscape context (proportion semi-natural land), and how this pollinator community related to white clover seed set. The honey bee, Apis mellifera, was the most commonly observed bee species, and two generalist bumble bee species, Bombus terrestris and B. lapidarius, were the subsequently most common. We observed fewer non-Apis bees, and a lower bee species richness in organic white clover seed fields compared to conventional fields independent of insecticide treatment. Bee species richness in both conventional and organic fields were positively related to the proportion of semi-natural land in the landscape, likely because of a larger species pool in such landscapes. Initial seed set in immature inflorescences was positively related to bee abundance, whereas final seed set in mature inflorescences was unrelated to bee abundance, possibly as a consequence of seed-eating weevils consuming a large proportion of the seeds. We conclude that both bee visitation and seed set in white clover benefit from conventional management and that landscapes rich in semi-natural habitats will make future crop production more resilient. The observed positive relationship between bee abundance and initial seed set suggests that if we can mitigate pest impacts and increase bee abundance in clover seed fields, the final seed yield can be increased. Thus, bee decline should be considered and mitigated both to maintain biodiversity in general and for crop seed production specifically.
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13. |
- Hersh, Evan, et al.
(author)
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Sexual antagonism in the pistil varies among populations of a hermaphroditic mixed-mating plant.
- 2015
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In: Journal of evolutionary biology. - : Wiley. - 1420-9101 .- 1010-061X. ; 28:7, s. 1321-1334
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Journal article (peer-reviewed)abstract
- Sexual conflicts and their evolutionary outcomes may be influenced by population-specific features such as mating system and ecological context; however, very few studies have investigated the link between sexual conflict and mating system. The self-compatible, mixed-mating hermaphrodite Collinsia heterophylla (Plantaginaceae) is thought to exhibit a sexual conflict over timing of stigma receptivity. This conflict involves 1) delayed stigma receptivity, which intensifies pollen competition, and 2) early fertilization forced by pollen, which reduces seed set. We investigated the potential for the conflict to occur under field conditions and performed greenhouse crosses within eight populations to assess its consistency across populations. Flowers were visited, and produced seeds after pollination, at all developmental stages, suggesting that the conflict can be of significance under natural conditions. In the greenhouse, early pollination imposed costs in all populations. Overall, the timing of first seed set was most strongly affected by the maternal parent, denoting stronger female than male ability to influence onset of stigma receptivity. Crosses also revealed a negative relationship between donor- and recipient-related onset of receptivity within individuals, a novel result hinting at trade-offs in sex-allocation or a history of antagonistic selection. Neither timing of stigma receptivity, timing of first seed set, nor pollen competitive ability covaried with population outcrossing rate. In conclusion, these results indicate that sexually antagonistic selection may be present in varying degrees in different populations of C. heterophylla, but this variation does not appear to be directly related to mating system variation. This article is protected by copyright. All rights reserved.
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14. |
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15. |
- Iciar, Frades, et al.
(author)
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A novel workflow correlating RNA-seq data to Phythophthora infestans resistance levels in wild Solanum species and potato clones
- 2015
-
In: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 6
-
Journal article (peer-reviewed)abstract
- Comparative transcriptomics between species can provide valuable understanding of plant-pathogen interactions. Here, we focus on wild Solarium species and potato clones with varying degree of resistance against Phytophthora infestans, which causes the devastating late blight disease in potato. The transcriptomes of three wild Solanurn species native to Southern Sweden, Solarium dulcamara, Solanum nigrum, and Solanurn physalifolium were compared to three potato clones, Desiree (cv.), SW93-1015 and Sarpo Mira. Desiree and S. physalifolium are susceptible to P. infestans whereas the other four have different degrees of resistance. By building transcript families based on de novo assembled RNA-seq across species and clones and correlating these to resistance phenotypes, we created a novel workflow to identify families with expanded or depleted number of transcripts in relation to the P. infestans resistance level. Analysis was facilitated by inferring functional annotations based on the family structure and semantic clustering. More transcript families were expanded in the resistant clones and species and the enriched functions of these were associated to expected gene ontology (GO) terms for resistance mechanisms such as hypersensitive response, host programmed cell death and endopeptidase activity. However, a number of unexpected functions and transcripts were also identified, for example transmembrane transport and protein acylation expanded in the susceptible group and a cluster of Zinc knuckle family proteins expanded in the resistant group. Over 400 expressed putative resistance (R)genes were identified and resistant clones Sarpo Mira and 5W93-1015 had ca 25% more expressed putative R-genes than susceptible cultivar Desiree. However, no differences in numbers of susceptibility (S)gene homologs were seen between species and clones. In addition, we identified P infestans transcripts including effectors in the early stages of P. infestans-Solanum interactions.
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16. |
- Karlsson Green, Kristina, et al.
(author)
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Långliggande fältförsök för rot och knölväxter – behov och möjligheter identifierade genom intervjuer
- 2021
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Reports (other academic/artistic)abstract
- I den här rapporten presenteras en utredning om behov och möjligheter för långliggande fältförsök för rot- och knölgrödor. Utredningen baseras huvudsakligen på intervjuer med representanter från universitet, näring, rådgivning och finansiärer, och även på en mindre uppföljande enkät till de intervjuade. Intervjuerna visar på att det finns ett brett intresse av långliggande fältförsök med frågeställningar som explicit rör rot- och knölgrödor. Frågeställningar som anses särskilt viktiga rör markbearbetning, växtskydd och växtföljd men även andra aspekter föreslås. Det finns ett intresse av att samarbeta om den här typen av försök men för många aktörer är det viktigt att man då kan få ut även kortsiktigare resultat och att dessa ska vara användbara för organisationen. Den främsta utmaningen kan vara att säkra långsiktig finansiering men även experimentdesign och organisation runt försöken är viktiga att beakta för att de ska ha ett långsiktigt värde.
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17. |
- Karlsson Green, Kristina, et al.
(author)
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Making sense of Integrated Pest Management (IPM) in the light of evolution
- 2020
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In: Evolutionary applications. - : Wiley. - 1752-4571. ; 13, s. 1791-1805
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Journal article (peer-reviewed)abstract
- Integrated Pest Management (IPM) is a holistic approach to combat pests (including herbivores, pathogens, and weeds) using a combination of preventive and curative actions, and only applying synthetic pesticides when there is an urgent need. Just as the recent recognition that an evolutionary perspective is useful in medicine to understand and predict interactions between hosts, diseases, and medical treatments, we argue that it is crucial to integrate an evolutionary framework in IPM to develop efficient and reliable crop protection strategies that do not lead to resistance development in herbivores, pathogens, and weeds. Such a framework would not only delay resistance evolution in pests, but also optimize each element of the management and increase the synergies between them. Here, we outline key areas within IPM that would especially benefit from a thorough evolutionary understanding. In addition, we discuss the difficulties and advantages of enhancing communication among research communities rooted in different biological disciplines and between researchers and society. Furthermore, we present suggestions that could advance implementation of evolutionary principles in IPM and thus contribute to the development of sustainable agriculture that is resilient to current and emerging pests.
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18. |
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19. |
- Lankinen, Åsa, et al.
(author)
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Allocation to pollen competitive ability versus seed production in Viola tricoloras an effect of plant size, soil nutrients and presence of a root competitor
- 2012
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In: Oikos. - : John Wiley & Sons. - 0030-1299 .- 1600-0706. ; 122:5, s. 779-789
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Journal article (peer-reviewed)abstract
- In hermaphroditic plants, the effect of a social environment on sex allocation has not been studied to our knowledge, while in hermaphroditic animals such effects are known to be common. In recent years, studies on root competition beyond the effects of nutrients have shown that plants can respond to their conspecific root competitors (social environment), making it interesting to ask if these effects could also influence sex allocation in addition to more commonly studied factors, such as plant size or resources. In this study on hermaphroditic Viola tricolor, we investigated how plant size, soil nutrients and presence of a root competitor influenced allocation to pollen competitive ability versus seed production, i.e. male and female reproductive functions. We allowed plants to grow in pairs with partly intermingled or separate roots in the same amount of soil. In additional treatments with intermingled roots (as part of the same experiment) one of the two competitors was given combinations of nitrogen (N), phosphorous (P) and micro nutrients. We found that pollen performance but not seed production increased when plants were in contact in the soil. Additionally, pollen performance was negatively correlated to plant size across fertilisation treatments. For seed production, the opposite relation to plant size was seen, indicating that large, fertilized plants invest relatively more in the female function. In conclusion, in violets, sex allocation appears to be size-dependent and influenced by both the presence of a root competitor and by nutrients. These results suggest that social environment can influence sex allocation in plants as well as in animals, indicating that such effects are important to consider in sex allocation studies across taxa.
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20. |
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21. |
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22. |
- Lankinen, Åsa, et al.
(author)
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Can Sexual Selection Cause Divergence in Mating System-Related Floral Traits?
- 2019
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In: International journal of plant sciences. - : University of Chicago Press. - 1058-5893 .- 1537-5315. ; 180, s. 996-1003
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Journal article (peer-reviewed)abstract
- Premise of research. The wide diversity of floral traits seen among plants is shaped by neutral and selective evolutionary processes. In outcrossing species, sexual selection from competing pollen donors is expected to be important for shaping mating system-related traits, but empirical evidence is scarce. In a previous evaluation of experimental evolution lines crossed with either one or two pollen donors (monogamous, M, or polyandrous, P, lines) at early floral stages in mixed-mating Collinsia heterophylla (Plantaginaceae), P evolved enhanced pollen competitive ability and reduced maternal seed set compared with M, in accordance with the sexually antagonistic evolution of pollen. Here, we asked whether the presence of sexual selection during pollen competition affects mating system-related floral traits in the same lines. Methodology. We compared flowering start, timing of anther-stigma contact (as an indication of timing of self-pollination), timing of stigma receptivity, and first seed set between M and P and with a source line, S (starting plants). The first three traits are later in outcrossers than in selfers of Collinsia. The last trait was expected to be earlier in P than in M, resulting from sexual selection for early seed siring of pollen. Pivotal results. Artificial polyandry for four generations resulted in later flowering start and later anther-stigma contact in P compared with M, and the latter trait was intermediate in S. Thus, P appeared more "outcrossing" than M. Timing of stigma receptivity did not differ between lines. First seed set was earlier in P than in M, as expected from sexual selection. Conclusions. Our results from the C. heterophylla experimental evolution lines suggest that a component of sexual selection during outcross pollination could enhance the patterns of floral divergence commonly found between outcrossers and selfers.
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23. |
- Lankinen, Åsa, et al.
(author)
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Challenges and opportunities for increasing the use of low-risk plant protection products in sustainable production. A review
- 2024
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In: Agronomy for Sustainable Development. - : Springer. - 1774-0746 .- 1773-0155. ; 44:2
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Research review (peer-reviewed)abstract
- Plant production systems worldwide are struggling to meet the diverse and increasing needs of humankind while also facing challenges such as climate change and biodiversity loss. This, combined with the desirable transition from the use of conventional pesticides to more sustainable plant protection solutions, has led to an urgent, and increasing, need for low-risk plant protection products (PPPs) to be developed, applied, and integrated into management practices across all types of plant production systems. Despite a high demand from end users and consumers together with joint political goals at the EU level to replace conventional pesticides, the number of low-risk PPPs on the European market remains low, in comparison to synthetic agrochemicals. In this review, we summarize knowledge about the policy, technical, and administrative issues hampering the process of bringing new low-risk PPPs to the European market. We present an overview of the challenges in using the low-risk PPPs that are currently available within the EU agricultural, horticultural, and forestry sectors. We describe the variation in modes of action and the limitations associated with different application techniques and give concrete examples of problems and solutions from Swedish plant production sectors, in contrast to global perspectives as demonstrated by examples from African agriculture. Finally, we conclude that trans-sectoral, multi-actor approaches are required and provide suggestions on how to address the remaining knowledge gaps related to efficiency, application, and economics of low-risk PPP use in Integrated Pest Management (IPM) solutions for plant protection to improve future food security in Europe.
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24. |
- Lankinen, Åsa, et al.
(author)
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Conflicting selection pressures on reproductive functions and speciation in plants.
- 2009
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In: Evolutionary Ecology. - : Springer Science and Business Media LLC. - 0269-7653 .- 1573-8477. ; 23:1, s. 147-157
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Conference paper (peer-reviewed)abstract
- Recent developments in the field of genetic divergence and speciation focus more on diversifying processes than on geographic mode of speciation (i.e. allopatric versus sympatric). Some of these new theories concern speciation driven by conflicts between the sexes. Even though it is well known that the two reproductive functions in plants can have different selective optima, sexual selection in plants is by many assumed to be weak or non-existent. Here we outline potential sexual conflicts in plants and discuss how selection pressures generated by such conflicts may influence genetic divergence. There is opportunity for conflicting selection pressures between individuals, such as manipulative pollen traits that enhance male reproductive success at the expense of the female reproductive function. Within individual plants, fitness of the male function (pollen export) and fitness of the female function (pollen import) may be optimised by different traits, leading to conflicting selection pressures in relation to pollen transfer. This may affect selection for floral specialisation versus floral generalisation in animal-pollinated species. We believe that selection pressures generated by sexual conflict need to be appreciated in order to fully understand microevolutionary processes which may lead to genetic divergence and speciation in plants.
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25. |
- Lankinen, Åsa, et al.
(author)
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Delayed stigma receptivity in Collinsia heterophylla (Plantaginaceae): Genetic variation and adaptive significance in relation to pollen competition, delayed self-pollination and mating-system evolution
- 2007
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In: American Journal of Botany. - 0002-9122. ; 94:7, s. 1183-1192
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Journal article (peer-reviewed)abstract
- To increase our knowledge about mating-system evolution, we need to understand the relationship between specific floral traits and mating system. Species of Collinsia (Plantaginaceae) vary extensively in mating system; this variation is associated with variation in floral morphology and development and with the timing of self-pollination. Counterintuitively, large-flowered, more outcrossing species tend to have delayed stigma receptivity, reducing the amount of time that the stigma is receptive to cross-pollination before autonomous self-pollination. To understand how the timing of stigma receptivity is related to mating-system evolution, we studied in detail the timing of both stigma receptivity and self-pollination (anther-stigma contact) in two greenhouse-grown populations of large-flowered Collinsia heterophylla. Crosses on emasculated flowers at different stages of floral development always produced seeds, suggesting that cross-fertilization can be effected by pollen arriving prior to physiological receptivity. Phenotypic and genetic variation within populations in the timing of stigma receptivity and antherstigma contact was substantial, although slightly less for the contact. Despite strong interspecific and interpopulation correlations, we did not find an among-genet phenotypic correlation between the traits. This indicates that each trait may respond independently to selection, and the trait association may be the result of correlational selection.
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26. |
- Lankinen, Åsa, et al.
(author)
-
Differential selection on pollen and pistil traits in relation to pollen competition in the context of a sexual conflict over timing of stigma receptivity
- 2016
-
In: AoB Plants. - : Oxford University Press (OUP). - 2041-2851. ; 8
-
Journal article (peer-reviewed)abstract
- Sexual conflict and its evolutionary consequences are understudied in plants, but the theory of sexual conflict may help explain how selection generates and maintains variability. Here, we investigated selection on pollen and pistil traits when pollen arrives sequentially to partially receptive pistils in relation to pollen competition and a sexual conflict over timing of stigma receptivity in the mixed-mating annual Collinsia heterophylla (Plantaginaceae). In this species the conflict is generated by early fertilizing pollen that reduces seed production, which is counteracted by delaying receptivity in the recipient. We performed sequential two-donor pollinations at early floral developmental stages involving two pollen deposition schedules (with or without a time lag of 1 day), using only outcross or self and outcross pollen. We investigated pollen and pistil traits in relation to siring success (male fitness) and seed production (female fitness). In contrast to previous findings in receptive pistils in C. heterophylla and in other species, last arriving pollen donors showed highest siring success in partially receptive pistils. The last male advantage was weaker when self pollen was the first arriving donor. Two measures of germination rate (early and late) and pollen tube growth rate of first arriving donors were important for siring success in crosses with a time lag, while only late germination rate had an effect in contemporary crosses. Curiously, late stigma receptivity was negatively related to seed production in our contemporary crosses, which was opposite to expectation. Our results in combination with previous studies suggest that pollen and pistil traits in C. heterophylla are differentially advantageous depending on stage of floral development and varying pollen deposition schedules. Variation in success of these traits over floral development time may result from sexually antagonistic selection.
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27. |
- Lankinen, Åsa, et al.
(author)
-
Effect of root contact on pollen competitive ability in a hermaphroditic winter-annual herb
- 2016
-
In: Evolutionary Ecology. - : Springer Science and Business Media LLC. - 0269-7653 .- 1573-8477. ; 30:4, s. 739-754
-
Journal article (peer-reviewed)abstract
- Presence of a root neighbor can induce changes in root allocation and pollen traits, but only a limited number of studies have investigated such effects on pollen. To learn more about effects of root contact on pollen competitive ability, we studied plants of the hermaphroditic winter-annual Collinsia heterophylla, native to California. We cultivated plants in two-pot treatments with roots kept either separate or intermingled with the same amount of resources. Pollen-tube growth rate, as an indication of pollen competitive ability, was affected by root treatment but the response varied among competing plant families. The response to root-treatment was not an effect of differential resource uptake of the two competitors. Root biomass was significantly higher when roots were intermingled compared to separate. This finding adds to the number of species with a strategic root response in the presence of competitors, but could also be a consequence of a larger rooting volume. Allocation to pollen performance versus roots in the presence of a competitor was lower in small plants and higher in large plants, potentially implying high costs of producing competitive pollen. We conclude that our study demonstrated that pollen tube growth rate is highly sensitive to the root environment in C. heterophylla.
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28. |
- Lankinen, Åsa
(author)
-
Effects of soil pH and phosphorus on in vitro pollen competitive ability and sporophytic traits in clones of Viola tricolor
- 2000
-
In: International Journal of Plant Sciences. - 1058-5893. ; 161:6, s. 885-893
-
Journal article (peer-reviewed)abstract
- Greenhouse-grown clones of Viola tricolor were used to evaluate the importance of genetic effects on in vit ro pollen tube growth rate in relation to the influence of two environmental soil factors-pH and phosphorus content. After 1 mo in different soil treatments, individual pollen tube growth rate was affected by a genotype by phosphorus interaction, while it was unaffected by either main effects. Though individuals differed in their response to phosphorus availability, the rank order of pollen donors remained consistent between treatments; i.e., the pollen donors with the highest pollen tube growth rate were the same in all soil conditions. Sporophytic traits were also affected by a genotype by phosphorus interaction. The response of pollen growth and sporophytic traits to soil phosphorus content were correlated within individuals in the high pH treatments. These results, in combination with a high value of clonal repeatability of pollen tube growth rate, indicate that pollen competitive ability has a genetic basis in this species. One prerequisite for this trait to have evolutionary effects on male fitness is thus fulfilled. Furthermore, if the response to phosphorus among pollen donors is more pronounced under natural conditions, variation in this environmental factor within populations has the potential to maintain some genetic Variation in pollen tube growth rate even if this trait is constantly selected.
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29. |
- Lankinen, Åsa, et al.
(author)
-
Effects of soil resources on expression of a sexual conflict over timing of stigma receptivity in a mixed-mating plant
- 2017
-
In: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 126, s. 692-702
-
Journal article (peer-reviewed)abstract
- While environmental factors strongly influence plant growth and reproduction, less is known about environmental effects on sexual selection and sexual conflict. In this study on mixed-mating Collinsia heterophylla we investigated whether soil resource environment affected traits associated with sexual conflict. In C. heterophylla a sexual conflict over timing of stigma receptivity occurs. Early stigma receptivity benefits pollen parents by securing paternity while late stigma receptivity benefits female fitness in terms of increased seed production. We performed hand-pollinations combining recipients and donors grown either in high or low resource environments and asked whether these treatments influenced sexual conflict traits - recipient- and donor-based influence on timing of stigma receptivity - and conflict costs related to reduced early seed production. We also asked whether resource environment affected eight traits related to general fitness and mating system. Sexual conflict-associated traits - timing of stigma receptivity and seed production -were generally unaffected by resource environment. While no universal effect of resources was detected, we did observe donor-specific responses to environment, suggesting that environment can nonetheless contribute to variation in timing of stigma receptivity. Recipients grown under low resources showed pronounced differences among donors for number of seeds per capsule, indicating that recipients favour some donors over others under resource-low conditions. Moreover, high resources increased number of flowers but reduced pollen germination rate, while other traits were unaffected, indicating variation in the response to resource environment for fitness-and mating system-traits. Our results suggest that even though soil resource environment had a low impact on the sexual conflict traits and related costs in C. heterophylla, it generated variability in pollen donor-influence on this trait and in recipient sorting among donors. Thus, it is possible that both sexual conflict and sexual selection is affected by environmental factors not only in animals but also in plants.
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30. |
- Lankinen, Åsa, et al.
(author)
-
Enhancing Pollen Competition By Delaying Stigma Receptivity: Pollen Deposition Schedules Affect Siring Ability, Paternal Diversity, And Seed Production In Collinsia Heterophylla (Plantaginaceae)
- 2011
-
In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 98:7, s. 1191-1200
-
Journal article (peer-reviewed)abstract
- Premise of the study: Even though pollen deposition schedules may have profound effects on the evolutionary outcome of pollen competition, few studies have investigated such effects in relation to pistil traits such as delayed stigma receptivity that enhance pollen competition. In Collinsia heterophylla, a largely outcrossing species with delayed stigma receptivity, we performed a series of controlled crosses involving several donors to understand how timing of pollen deposition influences siring ability, paternal diversity, and offspring fitness. Methods: Pollen was applied to fully receptive stigmas either as mixtures or consecutively with or without a time lag to mimic cases with early or delayed stigma receptivity. We used a genetic marker to assess offspring paternity. Key results: As expected, siring ability was affected by application order in crosses without a time lag, providing a first-donor advantage for pollen arriving on unreceptive stigmas. However, because pollen donor identity influenced siring ability, delaying stigma receptivity may still favor pollen of high competitive ability. In crosses on fully receptive pistils with a time lag of 24 h, a surprisingly high proportion of seeds (12-47%) were sired by pollen applied last. A novel finding was that pollen applied only once (as a mixture), mimicking delayed stigma receptivity, led to higher paternal diversity within progeny families, which was associated with increased seed production. Conclusions: Our results suggest fitness advantages of enhancing pollen competition by delaying stigma receptivity in C. heterophylla, particularly in relation to increased paternal diversity.
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31. |
- Lankinen, Åsa, et al.
(author)
-
Evolution of pistil length as a choice mechanism for pollen quality
- 2001
-
In: Oikos. - : Wiley. - 1600-0706 .- 0030-1299. ; 92:1, s. 81-90
-
Journal article (peer-reviewed)abstract
- During the fertilisation process in plants, pollen tube growth rate may be selected as a trait important in male to male competition. Since female morphology provides the necessary selective arena for such competition. we investigate if sexual selection theory can be used to explain the evolution of pistil length as a female choice mechanism. This choice is performed by direct interference with male to male competition. Furthermore, the sessile nature of plants limits the number of mates a female can choose between, which could limit the benefit a female can gain from distinguishing between donors. To mirror these circumstances, we model a situation when there are only two competitors at a time. Using a game theoretical approach we show that if pollen tube growth rate can be used as an indication of heritable quality, pistil length can be selected in response to variation of this trait. We further find that length of the pistil affects selection of pollen tube growth rate. Thus female preference and male competitive ability co-evolve, but this does not necessarily lead to a positive relationship between the two. Under certain circumstances we find a negative relation instead. Given realistic differences in male quality, the model indicates that there is a potential for evolution of female morphology as a choice mechanism for pollen quality.
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32. |
- Lankinen, Åsa, et al.
(author)
-
Fokusprojekt Lågriskmedel i växtskyddet
- 2019
-
Reports (pop. science, debate, etc.)abstract
- Fokusgruppens syfte har varit att definiera kunskapsluckor avseende den praktiska användningen och implementeringen av alternativa medel med låg risk för bekämpning av skadegörare och sjukdomar inom jordbruk, trädgårdsodling och skogsbruk. Vi har utgått från en bred definition av medel med låg risk, som har omfattat både allmänkemikalier och växtskyddsmedel med låg risk (enligt gällande EU-lagstiftning). Trots att det idag finns ett ökat behov av alternativa verktyg inom växtskyddet och politiska mål om minimerad användning av kemiska medel, så är användningen av alternativa bekämpningsmedel i fältodlade grödor mycket begränsad. • En viktig faktor som styr och begränsar tillgängligheten av alternativa medel är EU-lagstiftningen för godkännande av dessa medel. För att kunna registrera ett medel behövs en investering från det företag som ansöker om godkännande, vilket kan vara en anledning till att medel inte blir tillgängliga på marknaden. En annan lagteknisk begränsning är ogynnsamma skatteregler för dessa medel. • Från ett användarperspektiv är bristande kunskap om hur effektiva dessa medel är, hur man bäst applicerar dem samt hur de kan integreras i befintliga växtskyddsstrategier en bidragande orsak till att de inte används fullt ut. • Rådgivningen pekar också på en otydlighet om vilka medel som får användas speciellt i ekologisk produktion och att användningen missgynnas av höga priser i kombination med en osäkerhet om hur effektiva dessa medel är. • I Jordbruksverkets rapport ”Hinder för ökad användning av alternativa bekämpningsmedel” (SJV, Rapport 2019:3), som medlemmar av fokusgruppen har varit med att skriva, är ett av förslagen en utökad rådgivningsverksamhet. Detta eftersom informationsinsatser och aktiv rådgivning kan påverka hur snabbt odlare accepterar och börjar använda ett växtskyddsmedel, speciellt om det har nya egenskaper (och en ny verkningsmekanism). Forskning visar att en ny åtgärd/metod inte bara ska Sammanfattning och slutsatser 5 passa in i befintliga verksamheter utan också passa med attityd och värderingar hos användaren. • Från ett forskningsperspektiv kan vi se ett klart behov av tillämpningsnära forskning framför allt för att få en ökad kunskap om hur alternativa bekämpningsmedel kan integreras i befintliga växtskyddsstrategier. En utmaning är den begränsade mängd forskningsmedel som finns att söka för denna typ av forskning. • Forskningen är ofta väldigt uppdelad mellan agrikultur, hortikultur och skogsbruk. Här skulle man kunna dra nytta av kunskap inom respektive system eftersom vissa aspekter är generella mellan olika system, åtminstone för vissa grödor/träd. • Från ett internationellt perspektiv kan vi se vinster med ett bättre samarbete med närliggande länder, tex Plant Biologicals Network (PBN) som koordineras från Danmark, men även engagemang inom det vidare EUperspektivet (bla lagar). • Ytterligare en slutsats från fokusgruppens arbete är att växtskyddsforskningen på SLU behöver samordnas bättre, tex genom att knyta samman de kompetenscentrum som finns idag – CBC och CKB – med nya strukturer som skulle kunna fokusera på i) analys av växtskadegörare och ii) lågrisk-metoder och hur dessa kan spela en roll i integrerat växtskydd (IPM). • ygarbeta tillsammans för att få till en bra samverkan och kunskapsutbyte.
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33. |
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34. |
- Lankinen, Åsa, et al.
(author)
-
Geographic variation in floral traits is associated with environmental and genetic differences among populations of the mixed mating species Collinsia heterophylla (Plantaginaceae)
- 2017
-
In: Botany. - : Canadian Science Publishing. - 1916-2804 .- 1916-2790. ; 95:2, s. 121-128
-
Journal article (peer-reviewed)abstract
- Relatively few studies have investigated how geography, environmental factors, and genetics affect floral trait variation. We used mixed-mating Collinsia heterophylla Buist to explore variation in a suite of floral traits related to mating system in populations representing four geographic regions of California, USA, and relate this variation to geography, climatic factors, and local site characteristics. We evaluated the environmental vs. genetic trait variability in the greenhouse. Stage of anther–stigma contact correlated positively with temperature, stage of stigma receptivity was negatively associated with vegetation cover, and flower size differed among populations without any clear relation to environmental factors. Greenhouse data indicated heritability for stage of anther– stigma contact, flower size, and time to flowering, and positive correlations between field and greenhouse for stage of stigma receptivity and flower size; however, stage of anther–stigma contact showed a high degree of environmental influence. Stage of anther–stigma contact covaried positively with stage of stigma receptivity and flower size across maternal families, indicating genetic correlations between traits. In conclusion, phenotypic floral variation within mixed-mating C. heterophylla is mostly determined by a genetic component. Geography, environment, and genetics affect traits differently, suggesting that ecological and evolutionary processes contribute to shaping variability in mating system-related traits.
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35. |
- Lankinen, Åsa
(author)
-
In vitro pollen competitive ability in Viola tricolor: temperature and pollen donor effects
- 2001
-
In: Oecologia. - : Springer Science and Business Media LLC. - 1432-1939 .- 0029-8549. ; 128:4, s. 492-498
-
Journal article (peer-reviewed)abstract
- In this study on Viola tricolor pollen, the competitive ability of 16 pollen donors originating from a wild population was analysed in a set of greenhouse and germination temperatures. The aim was to examine the consistency in donor pollen performance across temperatures and to see whether variation in performance was random or due to individual differences in the plastic response to temperature. Pollen tube growth rate in vitro was investigated in two greenhouse temperatures (on the day pollen was collected) and in four germination temperatures. In addition, pollen tube growth rate was assessed in vivo (in one temperature) to examine the relationship between in vivo and in vitro growth. A temperature difference of 5 K - corresponding to natural variation in time and space detected in the field - affected pollen tube growth rate. For both temperature components, significant pollen donor by temperature interactions were found and rank order of pollen donors changed across treatments. Although pollen competitive ability in violets was strongly influenced by both temperature components, the occurrence of pollen donor by temperature interactions indicates that donor siring ability varies with temperature. This, in turn, may suggest a means to maintain pollen competitive ability despite selection for this trait.
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36. |
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37. |
- Lankinen, Åsa, et al.
(author)
-
Nongenetic Inheritance of Induced Resistance in a Wild Annual Plant
- 2016
-
In: Phytopathology. - 0031-949X .- 1943-7684. ; 106, s. 877-883
-
Journal article (peer-reviewed)abstract
- Nongenetic inheritance (e.g., transgenerational epigenetic effects) has received increasing interest in recent years, particularly in plants. However, most studies have involved a few model species and relatively little is known about wild species in these respects. We investigated transgenerational induced resistance to infection by the devastating oomycete Phytophthora infestans in Solanum physalifolium, a wild relative of cultivated potato. We treated plants with b-aminobutyric acid (BABA), a nontoxic compound acting as an inducing agent, or infected plants with P. infestans. BABA treatment reduced lesion size in detached-leaf assays inoculated by P. infestans in two of three tested genotypes, suggesting that resistance to oomycetes can be induced by BABA within a generation not only in crops or model species but also in wild species directly collected from nature. Both BABA treatment and infection in the parental generation reduced lesions in the subsequent generation in one of two genotypes, indicating a transgenerational influence on resistance that varies among genotypes. We did not detect treatment effects on seed traits, indicating the involvement of a mechanism unrelated to maternal effects. In conclusion, our study provides data on BABA induction and nongenetic inheritance of induced resistance in a wild relative of cultivated potato, implying that this factor might be important in the ecological and agricultural landscape.
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38. |
- Lankinen, Åsa, et al.
(author)
-
Plant immunity in natural populations and agricultural fields: Low presence of pathogenesis-related proteins in Solanum leaves
- 2018
-
In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13
-
Journal article (peer-reviewed)abstract
- Plant immunity has mainly been studied under controlled conditions, limiting our knowledge regarding the regulation of immunity under natural conditions where plants grow in association with multiple microorganisms. Plant pathology theory, based on laboratory data, predicts complex biochemical plant-pathogen interactions leading to coevolution of pathogen infectivity vs. plant recognition of microbes in multiple layers over time. However, plant immunity is currently not evaluated in relation to ecological time-scales and field conditions. Here we report status of immunity in plants without visible disease symptoms in wild populations of nightshades, Solanum dulcamara and Solanum nigrum, and in agricultural fields of potato, Solanum tuberosum. We analysed presence of pathogenesis-related proteins in over 500 asymptomatic leaf samples collected in the field in June, July and August over three years. Pathogenesis-related proteins were present in only one-third of the collected samples, suggesting low activity of the immune system. We could also detect an increase in pathogenesis-related proteins later in the growing season, particularly in S. tuberosum. Our findings, based on pathogenesis-related protein markers, indicate major gaps in our knowledge regarding the status and regulation of plant immunity under field conditions.
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39. |
- Lankinen, Åsa
(author)
-
Pollen Competition as a Target for Sexual Selection in Plants
- 2000
-
Doctoral thesis (other academic/artistic)abstract
- According to the theory of sexual selection, traits can evolve because they confer a mating advantage in competition with members from the same sex. In animals, sexual selection is considered as an important evolutionary force. In this thesis I have investigated the potential for sexual selection in plants. I have concentrated on the phase of reproduction that occurs after pollinators have deposited pollen on the stigma. At this stage, pollen competition can take place between individual pollen donors with the goal to fertilise a high proportion of the ovules. In greenhouse studies of Viola tricolor, pollen tube growth rate of donors was important for siring ability in competitive situations. Other pollen traits, such as pollen germination ability, pollen grain size and the ability to inhibit pollen from other donors was of less significance. Pollen tube growth rate was further heritable, which indicates that this trait can respond to selection. Genotype by environment interactions influenced pollen tube growth rate and sporophytic traits in V. tricolor. A theoretical model where both life phases were affected by genotype by environment interactions, showed that a balance between diversifying selection and pollen flow can maintain variation in pollen competitive ability despite strong selection. Pollen tube growth rate may not only be of importance for male reproductive success, but could also function as a cue for female choice. In V. tricolor, pollen donors with a high pollen tube growth rate showed a superior sporophytic quality, and sired offspring with enhanced fitness. Female traits that increase the probability to be fertilised by highly competitive pollen (e.g. a long pistil) may thus be selected. A theoretical analysis of both male and female interests during pollen competition indicated that pollen tube growth rate and pistil length can co-evolve in response to each other, though the response of both traits is not always positively correlated.
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40. |
- Lankinen, Åsa, et al.
(author)
-
Pollen competition reduces inbreeding depression in Collinsia heterophylla (Plantaginaceae)
- 2007
-
In: Journal of evolutionary biology. - : Wiley. - 1420-9101 .- 1010-061X. ; 20:2, s. 737-749
-
Journal article (peer-reviewed)abstract
- We tested two predictions of the hypothesis that competition between self-pollen may mitigate negative genetic effects of inbreeding in plants: (1) intense competition among self-pollen increases offspring fitness; and (2) pollen competition reduces the measured strength of inbreeding depression. We used Collinsia heterophylla (Plantaginaceae), an annual with a mixed mating system, to perform controlled crosses in which we varied both the size of the pollen load and the source of pollen (self vs. outcross). Fitness of selfed offspring was higher in the high pollen-load treatment. Our second prediction was also upheld: inbreeding depression was, on average, lower when large pollen loads were applied (11%) relative to the low pollen-load treatment (28%). The reduction was significant for two fitness components relatively late in the life-cycle: number of surviving seedlings and pollen-tube growth rate in vitro. These findings suggest that intermittent inbreeding, which leads to self-fertilization in plants with genetic loads, may select for traits that enhance pollen competition.
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41. |
- Lankinen, Åsa, et al.
(author)
-
Pollen competitive ability: the effect of proportion in two-donor crosses
- 2002
-
In: Evolutionary Ecology Research. - 1522-0613. ; 4:5, s. 687-700
-
Journal article (peer-reviewed)abstract
- Pollen competitive ability depends on the innate capacity of a pollen donor to produce pollen that reaches the ovules fast, but could also be a consequence of the ability to interfere with pollen from other donors. In a greenhouse study on Viola tricolor, we examined the relative importance of both of these effects by performing crosses where we varied the pollen load composition of two donors. We found that when a pollen donor had higher in vitro pollen tube growth rate than a competitor, this donor sired proportionally more seeds in most cases. At very low proportions, however, there was no benefit of producing fast growing pollen. We further investigated the potential for pollen interactions by comparing in vitro performance in single- and mixed-donor batches of the same density. Pollen tube growth rate differed between treatments in some donor combinations, indicating that pollen from different donors interact. Only donors with the faster growing pollen tubes in the single samples showed signs of interference in the mixtures. Donors with slower pollen tube growth had an increased growth rate when mixed. Although our results suggest interactions between pollen grains from different donors that might affect siring ability, the intrinsic pollen tube growth rate was more important for siring ability in this species.
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42. |
- Lankinen, Åsa, et al.
(author)
-
Pollen donor identity affects timing of stigma receptivity in Collinsia heterophylla (Plantaginaceae): a sexual conflict during pollen competition?
- 2007
-
In: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 170, s. 854-863
-
Journal article (peer-reviewed)abstract
- Theory predicts that, during pollen competition, selection may favor a pollen trait that increases donor competitive ability at the expense of the female reproductive function. One such pollen trait could be manipulation of the onset of stigma receptivity. We evaluated the potential occurrence of this kind of sexual conflict by testing female control of the timing of stigma receptivity in the self-compatible annual Collinsia heterophylla. By performing one-donor crosses in the greenhouse, we found that differences in both recipients and pollen donors influenced when stigmas became receptive. Because we did not detect an interaction effect, our result suggests that some donors were consistently better than others at germinating pollen and siring seeds earlier. Unexpectedly, self-pollen was able to fertilize seeds earlier during floral development compared with outcross pollen. These results suggest that female control on timing of stigma receptivity is not complete in this species. In addition, fertilizations that occurred early during floral development resulted in fewer seeds than later fertilizations, possibly indicating a cost of lost control over the onset of receptivity. The ability of pollen donors to influence the timing of stigma receptivity might reflect a conflict between the sexual functions in C. heterophylla.
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43. |
- Lankinen, Åsa, et al.
(author)
-
Pollen-tube growth rates in Collinsia heterophylla (Plantaginaceae) : one-donor crosses reveal heritability but no effect on sporophytic-offspring fitness
- 2009
-
In: Annals of Botany. - : Oxford University Press (OUP). - 0305-7364 .- 1095-8290. ; 103:6, s. 941-950
-
Journal article (peer-reviewed)abstract
- Evolutionary change in response to natural selection will occur only if a trait confers a selective advantage and there is heritable variation. Positive connections between pollen traits and fitness have been found, but few studies of heritability have been conducted, and they have yielded conflicting results. To understand better the evolutionary significance of pollen competition and its potential role in sexual selection, the heritability of pollen tube-growth rate and the relationship between this trait and sporophytic offspring fitness were investigated in Collinsia heterophylla. Because the question being asked was if female function benefited from obtaining genetically superior fathers by enhancing pollen competition, one-donor (per flower) crosses were used in order to exclude confounding effects of post-fertilization competition/allocation caused by multiple paternity. Each recipient plant was crossed with an average of five pollen donors. Pollen-tube growth rate and sporophytic traits were measured in both generations. Pollen-tube growth rate in vitro differed among donors, and the differences were correlated with in vivo growth rate averaged over two to four maternal plants. Pollen-tube growth rate showed significant narrow-sense heritability and evolvability in a father-offspring regression. However, this pollen trait did not correlate significantly with sporophytic-offspring fitness. These results suggest that pollen-tube growth rate can respond to selection via male function. The data presented here do not provide any support for the hypothesis that intense pollen competition enhances maternal plant fitness through increased paternity by higher-quality sporophytic fathers, although this advantage cannot be ruled out. These data are, however, consistent with the hypothesis that pollen competition is itself selectively advantageous, through both male and female function, by reducing the genetic load among successful gametophytic fathers (pollen), and reducing inbreeding depression associated with self-pollination in plants with mix-mating systems.
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44. |
- Lankinen, Åsa
(author)
-
Root competition influences pollen competitive ability in Viola tricolor: effects of presence of a competitor beyond resource availability?
- 2008
-
In: Journal of Ecology. - : Wiley. - 1365-2745 .- 0022-0477. ; 96:4, s. 756-765
-
Journal article (peer-reviewed)abstract
- 1. It has recently been suggested that not only nutrients but also presence of a competitor can influence competitive ability in plants, for example, by strategic changes in allocation to roots (a 'tragedy of the commons' effect). Such strategic changes might occur also in pollen, because this has potential to increase siring success during pollen competition in the pistil. 2. I tested the new hypothesis that pollen competitive ability - a trait often strongly affected by resources of the pollen parent - was influenced by presence of a root competitor using glasshouse-grown Viola tricolor in 2 years. Plants of two maternal families were combined in pairs with their roots either separated or intermingled in the same amount of resources. 3. Maternal families varied in response to root competition, with pollen performance increasing in some families, decreasing in others and unchanged in others. An increase did not mirror a decrease in the competing family, suggesting an explanation beyond differential ability to gain resources. The responses to competitive environment were often consistent across three independent competitors. 4. There was a positive correlation between family responses in pollen performance and family responses in plant size to root competitors. Larger plants did not produce better pollen per se, indicating that the change in pollen performance was not a pure side effect of altered plant size. There was no support for a 'tragedy of the commons' effect on root production. With the experimental design used, an effect of rooting volume could not be completely ruled out. 5. The currently unknown mechanism of the below-ground interactions between plants of V. tricolor was strong enough to change relative pollen competitive ability. These interactions might thus promote variation in the outcome of pollen competition. 6. Synthesis. The results of this study indicate the presence of a competitor on pollen competitive ability beyond the effect of nutrients. Even though the underlying mechanism needs to be explored further, the detected link between pollen competition and soil competition suggests a phenomenon well worth investigating. Further studies may lead to increased understanding of the evolutionary consequences of selection operating in response to interactions with neighbours.
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45. |
- Lankinen, Åsa, et al.
(author)
-
Selection on pollen and pistil traits during pollen competition is affected by both sexual conflict and mixed mating in a self-compatible herb.
- 2016
-
In: American Journal of Botany. - : Wiley. - 1537-2197 .- 0002-9122. ; 103:3, s. 541-552
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Journal article (peer-reviewed)abstract
- Although much attention has focused on the diversity of plant mating systems, only a few studies have considered the joint effects of mating system and sexual conflict in plant evolution. In mixed-mating Collinsia heterophylla, a sexual conflict over timing of stigma receptivity is proposed: pollen with a capacity to induce early onset of stigma receptivity secures paternity for early-arriving pollen (at the expense of reduced maternal seed set), whereas late onset of stigma receptivity mitigates the negative effects of early-arriving pollen. Here we investigated whether selection on pollen and pistil traits involved in sexual conflict is affected by the presence of both outcross- and self-pollen (mixed mating) during pollen competition.
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46. |
- Lankinen, Åsa, et al.
(author)
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Sexual conflict over floral receptivity
- 2006
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In: Evolution. - : Wiley. - 1558-5646 .- 0014-3820. ; 60:12, s. 2454-2465
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Journal article (peer-reviewed)abstract
- In flowering plants, the onset and duration of female receptivity vary among species. In several species the receptive structures wilt upon pollination. Here we explore the hypothesis that postpollination wilting may be influenced by pollen and serve as a general means to secure paternity of the pollen donor at the expense of female fitness. Taking a game-theoretical approach, we examine the potential for the evolution of a pollen-borne wilting substance, and for the coevolution of a defense strategy by the recipient plant. The model without defense predicts an evolutionarily stable strategy (ESS) for the production of wilting substance. The ESS value is highest when pollinator visiting rates are intermediate and when the probability that pollen from several donors arrives at the same time is low. This finding has general implications in that it shows that male traits to secure paternity also can evolve in species, such as plants, where mating is not strictly sequential. We further model coevolution of the wilting substance with the timing of stigma receptivity. We assume that pollen-receiving plants can reduce the costs induced by toxic pollen by delaying the onset of stigmatic receptivity. The model predicts a joint ESS, but no female counter-adaptation when the wilting substance is highly toxic. This indicates that toxicity affects the probability that a male manipulative trait stays beneficial (i.e., not countered by female defense) over evolutionary time. We discuss parallels to male induced changes in female receptivity known to occur in animals and the role of harm for the evolution of male manipulative adaptations.
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47. |
- Lankinen, Åsa, et al.
(author)
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Sexually antagonistic evolution caused by male-male competition in the pistil
- 2017
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In: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 71:10, s. 2359-2369
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Journal article (peer-reviewed)abstract
- Although sexual selection and sexual conflict are important evolutionary forces in animals, their significance in plants is uncertain. In hermaphroditic organisms, such as many plants, sexual conflict may occur both between mating partners (interlocus conflict) and between male and female sex roles within an individual (intralocus conflict). We performed experimental evolution, involving lines that were crossed with either one or two pollen donors (monogamous or polyandrous lines), in the hermaphroditic plant (Collinsia heterophylla) where early fertilizations are associated with female fitness costs (reduced seed set). Artificial polyandry for four generations resulted in enhanced pollen performance and increased female fitness costs compared to the monogamous and source (starting material) lines. Female fitness was also reduced in the monogamous line, indicating a possible trade-off between sex roles, resulting from early pollination. We performed a second experiment to investigate a potential harming effect of pollen performance on seed set. We found that high siring success of early arriving pollen competing with later-arriving pollen was associated with high female fitness costs, consistent with an interlocus sexual conflict. Our study provides evidence for the importance of sexual selection in shaping evolution of plant reproductive strategies, but also pinpoints the complexity of sexual conflict in hermaphroditic species.
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48. |
- Lankinen, Åsa, et al.
(author)
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The effect of pollen competition on maintenance of variation in fertilisation ability
- 2001
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In: Oikos. - : Wiley. - 1600-0706 .- 0030-1299. ; 93:3, s. 459-469
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Journal article (peer-reviewed)abstract
- Pollen competition in the pistil does not only give flowering plants the possibility to reduce inbreeding but also provides an opportunity for selection of pollen traits that increase male reproductive success. An objection to the existence of selection on pollen competitive ability is that individual variation should quickly vanish if selection is strong. A balance between selection for local adaptation of sporophytes within sites and pollen flow between sites could maintain variation in pollen competitive ability. A prerequisite is that variation in male competitive ability is condition dependent, i.e., influenced by sporophytic adaptation to a parch. This further means that selection on pollen competitive ability can occur both directly on the gamethophytic level and indirectly on the sporophytic level. Our dynamic model shows that maintenance of variation in male competitive ability is more probable when: differences in pollen competitive ability influence male fitness, i.e., in cases with pollen competition, than when differences in this trait only is a side effect of selection for more viable individuals. Since there is a connection between the gamethophytic and sporophytic life-phases, the incidence of pollen competition between donors should make it more probable that variability also in sporophyte fitness is preserved.
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49. |
- Lankinen, Åsa
(author)
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Upper petal lip colour polymorphism in Collinsia heterophylla (Plantaginaceae): genetic basis within a population and its use as a genetic marker.
- 2009
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In: Journal of Genetics. - : Springer Science and Business Media LLC. - 0022-1333 .- 0973-7731. ; 88:2, s. 205-215
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Journal article (peer-reviewed)abstract
- Understanding the genetics of a polymorphic trait is important to predict its likely evolution. In Collinsia heterophylla, the upper petal lip colour can be either be white or white with a purple band, while the lower petal lip colour is invariably purple. Because the corolla is only partly polymorphic, the polymorphism can not have evolved due to a mutation where a pigment was lost in the entire plant, which is common in other polymorphic species. In a previous study, high frequency of the purple band was found in populations with darker flowers, indicating possible selection for this trait. In this study, I determined inheritance of the colour polymorphism using two populations (one with only white morph and other with both morphs). I conducted experimental crosses within and between floral morphs to determine whether patterns of segregation in offspring conform to single-gene predictions. Data from F1, F2, F3 and backcross progeny are consistent with a genetic model of one major locus with presence of the band being completely dominant, as indicated in earlier studies using distantly related populations. A novel finding in this study was that the two morphs did not show a difference in seed germination frequency or seedling survival. This trait can thus be valuable as a genetic marker. Even though more thorough ecological data are needed to understand the potential selection pressures on upper petal lip colour in C. heterophylla, its simple inheritance may indicate the possibility of fast evolutionary response to selective forces acting on this trait.
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50. |
- Lankinen, Åsa, et al.
(author)
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Using theories of sexual selection and sexual conflict to improve our understanding of plant ecology and evolution
- 2015
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In: AoB PLANTS. - : Oxford University Press (OUP). - 2041-2851. ; 7
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Research review (peer-reviewed)abstract
- Today it is accepted that the theories of sexual selection and sexual conflict are general and can be applied to both animals and plants. However, potentially due to a controversial history, plant studies investigating sexual selection and sexual conflict are relatively rare. Moreover, these theories and concepts are seldom implemented in research fields investigating related aspects of plant ecology and evolution. Even though these theories are complex, and can be difficult to study, we suggest that several fields in plant biology would benefit from incorporating and testing the impact of selection pressures generated by sexual selection and sexual conflict. Here we give examples of three fields where we believe such incorporation would be particularly fruitful, including (i) mechanisms of pollen-pistil interactions, (ii) mating-system evolution in hermaphrodites and (iii) plant immune responses to pests and pathogens.
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