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Aguilar-García SA, Figueroa-Castro DM, Valverde PL, Vite F. Effect of flower orientation on the male and female traits of Myrtillocactus geometrizans (Cactaceae). PLANT BIOLOGY (STUTTGART, GERMANY) 2018; 20:531-536. [PMID: 29450960 DOI: 10.1111/plb.12713] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 02/12/2018] [Indexed: 06/08/2023]
Abstract
Intra-individual variation in the production and size of reproductive traits has been documented in columnar cacti, being higher in equator-facing flowers. Such variation is attributed to the high amount of PAR intercepted by stems oriented towards the equator. Most studies focused on this phenomenon have documented the existence of intra-individual variation on traits associated with the female function; however, its impact on traits associated with the male function has been neglected. We tested the hypothesis that equator-facing flowers of Myrtillocactus geometrizans exhibit higher values on traits associated with both male and female functions than flowers facing against it. Number and size of anthers and ovaries, pollen:ovule ratio and number and quality of pollen grains (diameter, germinability, viability and pollen tube length) were estimated from reproductive structures facing north and south, and compared with t-tests between orientations. Number of anthers per flower, number of pollen grains per anther and per floral bud; pollen size, viability and germinability; pollen tube length; ovary length and pollen:ovule ratio were significantly higher in reproductive structures oriented towards the south (i.e. equator). These findings suggest that intra-individual variation in floral traits of M. geometrizans might be associated with different availability of resources in branches with contrasting orientation. Our results provide new evidence of the existence of a response to an orientation-dependent extrinsic gradient. To our knowledge, this is the first study documenting the existence of intra-individual variation on pollen quality and P:O ratio in Cactaceae species.
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Affiliation(s)
- S A Aguilar-García
- Departamento de Biología, Universidad Autónoma Metropolitana-Iztapalapa, Ciudad de México, México
| | - D M Figueroa-Castro
- Facultad de Ciencias Biológicas, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Puebla, México
| | - P L Valverde
- Departamento de Biología, Universidad Autónoma Metropolitana-Iztapalapa, Ciudad de México, México
| | - F Vite
- Departamento de Biología, Universidad Autónoma Metropolitana-Iztapalapa, Ciudad de México, México
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Mazer SJ, Delesalle VA, Neal PR. RESPONSES OF FLORAL TRAITS TO SELECTION ON PRIMARY SEXUAL INVESTMENT IN SPERGULARIA MARINA: THE BATTLE BETWEEN THE SEXES. Evolution 2017; 53:717-731. [PMID: 28565623 DOI: 10.1111/j.1558-5646.1999.tb05366.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/1998] [Accepted: 12/16/1998] [Indexed: 11/28/2022]
Abstract
Two widespread assumptions underlie theoretical models of the evolution of sex allocation in hermaphroditic species: (1) resource allocations to male and female function are heritable; and (2) there is an intrinsic, genetically based negative correlation between male and female reproductive function. These assumptions have not been adequately tested in wild species, although a few studies have detected either genetic variation in pollen and ovule production per flower or evidence of trade-offs between male and female investment at the whole plant level. It may also be argued, however, that in highly autogamous, perfect-flowered plant taxa that exhibit genetic variation in gamete production, strong stabilizing selection for an efficient pollen:ovule ratio should result in a positive correlation among genotypes with respect to mean ovule and mean pollen production per flower. Here we report the results of a three-generation artificial selection experiment conducted on a greenhouse population of the autogamous annual plant Spergularia marina. Starting with a base population of 1200 individuals, we conducted intense mass selection for two generations, creating four selected lines (high and low ovule production per flower; high and low anther production per flower) and a control line. By examining the direct and correlated responses of several floral traits to selection on gamete production per flower, we evaluated the expectations that primary sexual investment would exhibit heritable variation and that resource-sharing, variation in resource-garnering ability, or developmental constraints mold the genetic correlations expressed among floral organs. The observed direct and correlated responses to selection on male and female gamete production revealed significant heritabilities of both ovule and anther production per flower and a significant negative genetic correlation between them. When plants were selected for increased ovules per flower over two generations, ovule production increased and anther production declined relative to the control line. Among plants selected for decreased anthers per flower, we observed a decline in anther production and an increase in ovule production relative to the control line. In contrast, the lines selected for low ovules per flower and for high anthers per flower exhibited no evidence for significant genetic correlations between male and female primary investment. Correlated responses to selection also indicate a genetically based negative correlation between the production of normal versus developmentally abnormal anthers (staminoid organs); a positive correlation between the production of ovules versus staminoid organs; and a positive correlation between the production of anthers and petals. The negative relationship between male versus female primary investment supports classical sex allocation theory, although the asymmetrical correlated responses to selection indicate that this relationship is not always expressed.
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Affiliation(s)
- Susan J Mazer
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California, 93106
| | | | - Paul R Neal
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California, 93106
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Selective pressure along a latitudinal gradient affects subindividual variation in plants. PLoS One 2013; 8:e74356. [PMID: 24069297 PMCID: PMC3778006 DOI: 10.1371/journal.pone.0074356] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 07/31/2013] [Indexed: 11/19/2022] Open
Abstract
Individual plants produce repeated structures such as leaves, flowers or fruits, which, although belonging to the same genotype, are not phenotypically identical. Such subindividual variation reflects the potential of individual genotypes to vary with micro-environmental conditions. Furthermore, variation in organ traits imposes costs to foraging animals such as time, energy and increased predation risk. Therefore, animals that interact with plants may respond to this variation and affect plant fitness. Thus, phenotypic variation within an individual plant could be, in part, an adaptive trait. Here we investigated this idea and we found that subindividual variation of fruit size of Crataegus monogyna, in different populations throughout the latitudinal gradient in Europe, was explained at some extent by the selective pressures exerted by seed-dispersing birds. These findings support the hypothesis that within-individual variation in plants is an adaptive trait selected by interacting animals which may have important implications for plant evolution.
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Andersson S. Experimental demonstration of floral allocation costs in Crepis tectorum. ACTA ACUST UNITED AC 2006. [DOI: 10.1139/b06-041] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Information on floral resource costs is fundamental for understanding how selection operates on floral morphology. In this study, I explored the cost of maturing flowers in a self-incompatible population of the ligulate composite Crepis tectorum L. by experimentally manipulating floral investment and then monitoring the response in reproductive effort. Plants on which the heads were removed during the initial stage of ligule expansion had a higher reproductive effort than plants whose heads were removed immediately after flower maturation, and the latter plants had a higher reproductive effort than plants on which all flowers were permitted to set fruit. Judging from biomass estimates and the magnitude of the observed tradeoffs, the amount of resources allocated to maturing flowers was about half as great as the amount of resources devoted to fruit maturation. These and other results suggest that floral tradeoffs may exert negative selection on floral size variables.
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Affiliation(s)
- Stefan Andersson
- Plant Ecology and Systematics, Department of Ecology, University of Lund, Sölvegatan 37, S-223 62 Lund, Sweden
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Ashman TL, Majetic CJ. Genetic constraints on floral evolution: a review and evaluation of patterns. Heredity (Edinb) 2006; 96:343-52. [PMID: 16598191 DOI: 10.1038/sj.hdy.6800815] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The characteristics of flowers influence most aspects of angiosperm reproduction, including the agents of pollination and patterns of mating. Thus, a clear view of the forces that mediate floral phenotypic evolution is central to understanding angiosperm diversity. Here, we inform on the capacity for floral phenotype to respond to selection by reviewing published data on heritabilities and genetic correlations for several classes of floral traits (primary sexual, attraction, mating system) in hermaphroditic plants. We find significant heritability for all floral traits but also variation among them, as well as a tendency for heritability to vary with mating system, but not life history. We additionally test predictions stemming from life history theory (eg, negative covariation between male-female traits and flower size-flower number), and ideas concerning the extent and pattern of genetic integration between flowers and leaves, and between the sexes of dioecious and gynodioecious species. We find mixed evidence for life history tradeoffs. We find strong support for floral integration and its relation with floral morphology (actinomorphy vs zygomorphy) and for a decoupling of floral and vegetative traits, but no evidence that modular integration varies with floral morphology. Lastly, we find mixed evidence for a relationship between the level of sexual dimorphism in attraction traits and the between-sex correlation in gender dimorphic plants.
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Affiliation(s)
- T-L Ashman
- 1Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Ave and Ruskin, Pittsburgh, PA 15260, USA.
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Lamborn E, Cresswell JE, Macnair MR. The potential for adaptive evolution of pollen grain size in Mimulus guttatus. THE NEW PHYTOLOGIST 2005; 167:289-96. [PMID: 15948850 DOI: 10.1111/j.1469-8137.2005.01403.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We tested whether pollen grain size (PGS) shows heritable variation in three independent populations of Mimulus guttatus by imposing artificial selection for this character. In addition, we looked for correlated responses to selection in a range of 15 other floral characters. Heritable variation in PGS was found in all three populations, with heritabilities of between 19 and 40% (average 30%). After three generations, upward and downward lines differed on average by 30% in pollen volume. No consistent patterns of correlated response were found in other characters, indicating that PGS can respond to selective forces acting on PGS alone. Possible selection mechanisms on PGS in this species could include intermale selection, if large pollen grains produce more competitive gametophytes; or optimization of patterns of resource allocation, if local mate competition varies.
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Affiliation(s)
- Ellen Lamborn
- School of Biological and Chemical Sciences, Hatherly Laboratories, University of Exeter, Prince of Wales Road, Exeter, Devon EX4 4PS, UK
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Parachnowitsch AL, Elle E. Variation in sex allocation and male-female trade-offs in six populations of Collinsia parviflora (Scrophulariaceae s.l.). AMERICAN JOURNAL OF BOTANY 2004; 91:1200-1207. [PMID: 21653477 DOI: 10.3732/ajb.91.8.1200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Assumed trade-offs between male and female functions in hermaphroditic flowers have been difficult to demonstrate. Collinsia parviflora (Scrophulariaceae) is a winter annual that exhibits significant among-population variation in corolla size in British Columbia, Canada. We asked whether reduction in secondary male allocation (i.e., the attractive corolla), a preliminary indicator of mating system, was matched by a reduction in primary male allocation (i.e., pollen production), and whether there were allocation trade-offs between male and female function both within and among six study populations. Larger-flowered populations allocated more to male function (androecium and corolla biomass), and because populations did not vary in female biomass allocation (gynoecium and calyx), population differences were not due to simple allometric scaling. Populations also differed in per-flower gamete production (pollen and ovules). We found male-female trade-offs within populations between androecium and gynoecium mass and between corolla and calyx mass. Among populations, there was a marginal trade-off between pollen and ovule production and a significant within-male trade-off between pollen grain size and number. Trade-offs between the sexes were primarily apparent when we controlled for flower size in the analysis. Variation among populations in sex allocation may reflect different optima related to the mating system.
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Affiliation(s)
- Amy L Parachnowitsch
- Department of Biological Sciences and Behavioural Ecology Research Group, 8888 University Drive, Simon Fraser University, Burnaby, British Columbia V5A 1S6 Canada
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Mazer SJ, Lowry DE, Hansen T. Effects of nutrient availability on primary sexual traits and their response to selection in Spergularia marina (Caryophyllaceae). J Evol Biol 2003; 16:767-78. [PMID: 14632239 DOI: 10.1046/j.1420-9101.2003.00555.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- S J Mazer
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA.
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Andersson S. Sex-allocation trade-offs in Nigella sativa (Ranunculaceae) examined with flower manipulation experiments. Evol Ecol 2003. [DOI: 10.1023/a:1023028211164] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Kelly JK, Arathi HS. Inbreeding and the genetic variance in floral traits of Mimulus guttatus. Heredity (Edinb) 2003; 90:77-83. [PMID: 12522429 DOI: 10.1038/sj.hdy.6800181] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The additive genetic variance, V(A), is frequently used as a measure of evolutionary potential in natural plant populations. Many plants inbreed to some extent; a notable observation given that random mating is essential to the model that predicts evolutionary change from V(A). With inbreeding, V(A) is not the only relevant component of genetic variation. Several nonadditive components emerge from the combined effects of inbreeding and genetic dominance. An important empirical question is whether these components are quantitatively significant. We use maximum likelihood estimation to extract estimates for V(A) and the nonadditive 'inbreeding components' from an experimental study of the wildflower Mimulus guttatus. The inbreeding components contribute significantly to four of five floral traits, including several measures of flower size and stigma-anther separation. These results indicate that inbreeding will substantially alter the evolutionary response to natural selection on floral characters.
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Affiliation(s)
- J K Kelly
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, 660045-7534, USA.
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Locher R, Baur B. Nutritional stress changes sex-specific reproductive allocation in the simultaneously hermaphroditic land snail Arianta arbustorum. Funct Ecol 2002. [DOI: 10.1046/j.1365-2435.2002.00657.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Locher, Baur. Mating frequency and resource allocation to male and female function in the simultaneous hermaphrodite land snail Arianta arbustorum. J Evol Biol 2000. [DOI: 10.1046/j.1420-9101.2000.00206.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Ashman. Determinants of sex allocation in a gynodioecious wild strawberry: implications for the evolution of dioecy and sexual dimorphism. J Evol Biol 1999. [DOI: 10.1046/j.1420-9101.1999.00059.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Mazer SJ, Delesalle VA. Contrasting variation within and covariation between gender-related traits in autogamous versus outcrossing species: Alternative evolutionary predictions. Evol Ecol 1998. [DOI: 10.1023/a:1006568704381] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Andersson S. Floral reduction in Crepis tectorum (Asteraceae): tradeoffs and dominance relationships. Biol J Linn Soc Lond 1996. [DOI: 10.1111/j.1095-8312.1996.tb01696.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Robertson AW, Diaz A, Macnair MR. The quantitative genetics of floral characters in Mimulus guttatus. Heredity (Edinb) 1994. [DOI: 10.1038/hdy.1994.40] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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