| 434021. |
- Lankinen, Åsa, et al.
(författare)
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Effects of soil resources on expression of a sexual conflict over timing of stigma receptivity in a mixed-mating plant
- 2017
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 126, s. 692-702
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Tidskriftsartikel (refereegranskat)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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| 434022. |
- Lankinen, Åsa, et al.
(författare)
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Enhancing Pollen Competition By Delaying Stigma Receptivity: Pollen Deposition Schedules Affect Siring Ability, Paternal Diversity, And Seed Production In Collinsia Heterophylla (Plantaginaceae)
- 2011
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Ingår i: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 98:7, s. 1191-1200
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Tidskriftsartikel (refereegranskat)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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| 434023. |
- Lankinen, Åsa, et al.
(författare)
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Evolution of pistil length as a choice mechanism for pollen quality
- 2001
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Ingår i: Oikos. - : Wiley. - 1600-0706 .- 0030-1299. ; 92:1, s. 81-90
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Tidskriftsartikel (refereegranskat)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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| 434024. |
- Lankinen, Åsa, et al.
(författare)
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Geographic variation in floral traits is associated with environmental and genetic differences among populations of the mixed mating species Collinsia heterophylla (Plantaginaceae)
- 2017
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Ingår i: Botany. - : Canadian Science Publishing. - 1916-2804 .- 1916-2790. ; 95:2, s. 121-128
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Tidskriftsartikel (refereegranskat)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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| 434025. |
- Lankinen, Åsa
(författare)
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In vitro pollen competitive ability in Viola tricolor: temperature and pollen donor effects
- 2001
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 1432-1939 .- 0029-8549. ; 128:4, s. 492-498
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Tidskriftsartikel (refereegranskat)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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| 434026. |
- Lankinen, Åsa, et al.
(författare)
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Nongenetic Inheritance of Induced Resistance in a Wild Annual Plant
- 2016
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Ingår i: Phytopathology. - 0031-949X .- 1943-7684. ; 106, s. 877-883
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Tidskriftsartikel (refereegranskat)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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| 434027. |
- Lankinen, Åsa, et al.
(författare)
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Plant immunity in natural populations and agricultural fields: Low presence of pathogenesis-related proteins in Solanum leaves
- 2018
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13
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Tidskriftsartikel (refereegranskat)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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| 434028. |
- Lankinen, Åsa, et al.
(författare)
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Pollen competition reduces inbreeding depression in Collinsia heterophylla (Plantaginaceae)
- 2007
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Ingår i: Journal of evolutionary biology. - : Wiley. - 1420-9101 .- 1010-061X. ; 20:2, s. 737-749
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Tidskriftsartikel (refereegranskat)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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| 434029. |
- Lankinen, Åsa, et al.
(författare)
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Pollen competitive ability: the effect of proportion in two-donor crosses
- 2002
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Ingår i: Evolutionary Ecology Research. - 1522-0613. ; 4:5, s. 687-700
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Tidskriftsartikel (refereegranskat)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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| 434030. |
- Lankinen, Åsa, et al.
(författare)
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Pollen donor identity affects timing of stigma receptivity in Collinsia heterophylla (Plantaginaceae): a sexual conflict during pollen competition?
- 2007
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Ingår i: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 170, s. 854-863
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Tidskriftsartikel (refereegranskat)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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