Floral Correlates and Fitness Consequences of Mating-System Variation in Turnera ulmifolia

Belaoussoff, Svenja; Shore, Joel S.

doi:10.2307/2410278

Cited by 68 publications

(80 citation statements)

References 40 publications

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“…Several authors have demonstrated that pollinator-mediated selection might play an important role in floral trait evolution in animal-pollinated species (Stanton et al,1986 ;Galen, 1989 ;Robertson & Wyatt, 1990). In this context there has been much interest in the adaptive significance of variation in stigma position, owing to the effect of this trait on pollen receipt and maternal fecundity (Campbell et al, 1994 ;Belaoussoff & Shore, 1995 ;Armbruster, 1996).…”

Section: mentioning

confidence: 99%

Morph‐specific patterns of variation in stigma height in natural populations of distylous Jasminum fruticans

Thompson

Dommée

2000

New Phytologist

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The purpose of this study was to describe morph-specific patterns of stigma-anther separation and style curling in the distylous Jasminum fruticans. We also examined whether variation in floral traits is correlated with variation in seed production. Stigma-anther separation is more variable in short-styled plants than in long-styled plants. In all populations studied, some plants bear flowers that lack any stigma-anther separation. These plants have the pollen characteristics (size and number) and compatibility relations of short-styled plants. Comparison with other distylous species illustrates that the variability of stigma-anther separation in short-styled plants is a novel finding for a distylous species. Long-styled plants have greater stigma-anther separation than short-styled plants, styles are often curled and protrude from the corolla, and anthers are placed well within the corolla tube. The frequency of long-styled plants with curled styles and the mean degree of style curling were significantly correlated with style length. Short-styled plants have larger corollas than long-styled plants and never have curled styles. Morph ratios are always 50 : 50 in natural populations. Mean values of each floral trait in the two morphs were significantly correlated among populations. There were no consistent differences in fecundity of the two morphs nor any correlation between floral traits and seed set for each morph in natural populations. We discuss the potential causes and significance of the two morph-specific patterns we describe ; reduced stigma-anther separation in short-styled plants and the presence of curled styles in long-styled plants.

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Section: mentioning

confidence: 99%

Morph‐specific patterns of variation in stigma height in natural populations of distylous Jasminum fruticans

Thompson

Dommée

2000

New Phytologist

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“…Such studies have shown among-population correlations between the average amount of herkogamy and outcrossing rates (Rick et al, 1977;Holtsford and Ellstrand, 1992;Belaoussoff and Shore, 1995). Less known is the extent of within-population variation in outcrossing rates and the factors influencing such variation, even though this is one of the primary levels at which natural selection acts.…”

Section: Introductionmentioning

confidence: 99%

Effect of variation in herkogamy on outcrossing within a population of Gilia achilleifolia

2005

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The diverse features of floral morphology are often thought to be well-designed mechanisms to manipulate plant mating systems. We evaluated the effectiveness of one such mechanism, anther-stigma separation (herkogamy), in controlling variation in the level of outcrossing among plants in a population of Gilia achilleifolia. Variation in outcrossing rates within populations has the potential to influence the coevolution between inbreeding depression and mating system. Using four polymorphic allozymes, we compared the outcrossing-rate estimates of two groups of individuals under natural conditions: one group with low herkogamy and another with high herkogamy. The high herkogamy group had a higher outcrossing rate (0.572) than the low herkogamy group (0.335). This suggests that the withinpopulation variation in outcrossing rate could potentially cause the previously observed association between herkogamy and inbreeding depression (Takebayashi and Delph, 2000). A previous study of floral traits among G. achilleifolia populations failed to detect a relationship between herkogamy and outcrossing rate, demonstrating that the functionality of traits may be obscured in amongpopulation studies as a consequence of uncontrolled environmental variation. Additionally, the effect of herkogamy on outcrossing rate in delayed selfers such as G. achilleifolia may be particularly prominent when pollinator availability is low. Our population-level estimate of outcrossing rate (0.444) was somewhat lower than an estimate from the same population, 15 years prior to our study (0.75), suggesting that pollinator availability may fluctuate among years. Both within-year and among-year variation in the outcrossing rate may have a strong influence on matingsystem evolution.

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“…The majority of hermaphroditic autopolyploid species have mixed mating systems with intermediate or high outcrossing rates (MacDonald and Lieffers, 1991;Husband and Schemske, 1997;Petit et al, 1997;Inoue et al, 1998; but see Murawski et al, 1994). In contrast, selfing is more prevalent in allopolyploids (Belaoussoff and Shore, 1995;Johnston and Schoen, 1996;Cook and Soltis, 1999).…”

Section: Introductionmentioning

confidence: 99%

Outcrossing rate and inbreeding depression in the herbaceous autotetraploid, Campanula americana

2003

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Polyploidy in angiosperms is frequently associated with an increase in self-compatibility. Self-fertilization can enhance polyploid establishment, and theory predicts reduced inbreeding depression in polyploids relative to diploids. Therefore, we may expect mating systems that promote selffertilization or mixed-mating in polyploid species. However, few studies have measured polyploid mating systems and inbreeding depression. We report the outcrossing rate and inbreeding depression for Campanula americana, a selfcompatible protandrous herb. Allozyme genotypes suggest that C. americana is an autotetraploid with tetrasomic inheritance. We found that the multilocus outcrossing rate, t m ¼ 0.938, did not differ from unity. This result was unexpected since previous work demonstrated that pollinators frequently move from male-to female-phase flowers on the same plant, that is, geitonogamy. Self and outcross pollinations were conducted for three populations. Offspring were germinated in controlled conditions and grown to maturity in pots in nature. Inbreeding depression was not significant for most seed and germination characters. However, all later life traits except flowering date differed between inbred and outcrossed individuals resulting in a 26% reduction in cumulative fitness for inbred plants. Limited early-and moderate later-life inbreeding depression suggest that it is buffered by the higher levels of heterozygosity found in an autotetraploid. C. americana appears to have a flexible mating system where within flower protandry and/or cryptic self-incompatibility result in a high outcrossing rate when pollinators are abundant, but self-compatibility and limited inbreeding depression maintain reproductive success when mates are limited.

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Floral Correlates and Fitness Consequences of Mating-System Variation in Turnera ulmifolia

Cited by 68 publications

References 40 publications

Morph‐specific patterns of variation in stigma height in natural populations of distylous Jasminum fruticans

Morph‐specific patterns of variation in stigma height in natural populations of distylous Jasminum fruticans

Effect of variation in herkogamy on outcrossing within a population of Gilia achilleifolia

Outcrossing rate and inbreeding depression in the herbaceous autotetraploid, Campanula americana

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