Evolution of the Mating System in a Partially Self‐Incompatible Species: Reproductive Assurance and Pollen Limitation in Populations That Differ in the Timing of Self‐Compatibility

2009 ◽  
Vol 170 (7) ◽  
pp. 885-893 ◽  
Author(s):  
Jennifer J. Weber ◽  
Carol Goodwillie
2015 ◽  
Vol 63 (5) ◽  
pp. 387 ◽  
Author(s):  
Marta Correia ◽  
Sílvia Castro ◽  
Susana Rodríguez-Echeverría

The reproductive biology of exotic species affects their capacity to become naturalised and invasive in non-native areas. Selfing is a common trait in many invasive plants probably because it provides reproductive assurance under low availability of pollination vectors and sexual partners. Nonetheless, the predominantly self-incompatible Australian Acacia species are among the most aggressive plants worldwide. To address whether there have been changes in selfing ability and natural reproductive success of A. longifolia during invasion, we compared one population in the invaded area (Portugal) with one population in the native range (Australia). We specifically assessed floral traits, fruit set and offspring traits for selfing and open-pollination treatments. Within each pollination treatment, no differences were found between areas, suggesting that the level of self-compatibility has not changed during invasion. However, the number of aborted seeds and seed size were significantly different between pollination treatments in Australia but not in Portugal. There were significant differences in the number of seeds per pod and in seed weight between ranges. A lower number of aborted seeds, a higher number of fully developed seeds and a greater seed size were found in the invaded area for both pollination treatments. In spite of the low selfing ability of A. longifolia in the invaded area, there was an increase in the quantity and size of the seeds produced in the new region, even for self-pollinated fruits, which might contribute to A. longifolia invasiveness.


2007 ◽  
Vol 21 (2) ◽  
pp. 325-333 ◽  
Author(s):  
Claudia Maria Jacobi ◽  
Mário César Laboissiérè del Sarto

The pollinators and breeding system of two species of Vellozia (Velloziaceae) from high-altitude quartzitic grasslands in SE Brazil were studied. Vellozia leptopetala is shrubby and grows solely on rocky outcrops, V. epidendroides is herbaceous and grows on stony soils. Both bear solitary, hermaphrodite flowers, and have massive, short-lasting annual blooms. We evaluated the level of self-compatibility and need for pollinators of 50 plants of each species and 20-60 flowers per treatment: hand self- and cross-pollination, spontaneous pollination, agamospermy and control. The behavior of floral visitors on flowers and within plants was recorded. Both species are mostly self-incompatible, but produce a small number of seeds by self-fertilization. The pollen-ovule ratio suggests facultative xenogamy. They were visited primarily by bees, of which the most important pollinators were two leaf-cutting bees (Megachile spp.). Vellozia leptopetala was also pollinated by a territorial hummingbird. Low natural seed production compared to cross-pollination seed numbers suggests that pollen limitation is the main cause of low seed set. This was attributed to the combined effect of five mechanisms: selfing prior to anthesis, enhanced geitonogamy as a result of large floral displays, low number of visits per flower for the same reason, pollen theft by many insect species, and, in V. leptopetala, delivery of mixed pollen loads on the stigma as a consequence of hummingbird promiscuity.


2014 ◽  
Vol 369 (1648) ◽  
pp. 20130344 ◽  
Author(s):  
Spencer C. H. Barrett ◽  
Ramesh Arunkumar ◽  
Stephen I. Wright

The evolution of self-fertilization from outcrossing has occurred on numerous occasions in flowering plants. This shift in mating system profoundly influences the morphology, ecology, genetics and evolution of selfing lineages. As a result, there has been sustained interest in understanding the mechanisms driving the evolution of selfing and its environmental context. Recently, patterns of molecular variation have been used to make inferences about the selective mechanisms associated with mating system transitions. However, these inferences can be complicated by the action of linked selection following the transition. Here, using multilocus simulations and comparative molecular data from related selfers and outcrossers, we demonstrate that there is little evidence for strong bottlenecks associated with initial transitions to selfing, and our simulation results cast doubt on whether it is possible to infer the role of bottlenecks associated with reproductive assurance in the evolution of selfing. They indicate that the effects of background selection on the loss of diversity and efficacy of selection occur rapidly following the shift to high selfing. Future comparative studies that integrate explicit ecological and genomic details are necessary for quantifying the independent and joint effects of selection and demography on transitions to selfing and the loss of genetic diversity.


1998 ◽  
Vol 46 (4) ◽  
pp. 465 ◽  
Author(s):  
Luise Hermanutz ◽  
David Innes ◽  
Andrew Denham ◽  
Robert Whelan

Members of the family Proteaceae have extremely low mature fruit : flower (FR : FL) ratios (range 0.001–0.163) compared with other temperate, hermaphroditic, woody perennials. Sutherland’s (1986) survey of FR : FL ratios indicated that compatibility was an important factor explaining levels of fruit set. The role of compatibility in regulating FR : FL ratios was tested in five closely related species of Grevillea (Proteaceae). Species-specific compatibility was compared using the self-compatibility index (SI = ratio of selfed fruit set to crossed fruit set) calculated at fruit initiation to minimise the confounding effect of other post-fertilisation fruit losses, such as inbreeding depression and pre-dispersal predation. Fruit : flower ratios at initiation ranged from 0.041–0.249, and at maturity 0.015–0.096. Grevillea species showed highly variable breeding systems: G. linearifolia was self-incompatible (SI = 0.003), G. sphacelata, G. mucronulata, and G. oleoides were partially self-compatible (SI = 0.07–0.28) and G. longifolia was self-compatible (SI = 0.61). Intrapopulation variability in the level of self-incompatibility was high in all species but G. linearifolia. The correlation between SI and FR: FL ratios was non-significant, indicating that compatibility has a minimal effect on fruit set in the Grevillea species studied, and that these data, together with other data on proteaceous species do not support trends observed in Sutherland’s survey. Low FR : FL ratios resulted from of a combination of pollen limitation, and high levels of flower and fruit predation.


2011 ◽  
Vol 172 (7) ◽  
pp. 862-869 ◽  
Author(s):  
Loren P. Albert ◽  
Lesley G. Campbell ◽  
Kenneth D. Whitney

Author(s):  
Peter J Quakenbush

An investigation into the reproductive biology of Medinilla multiflora Merr. (Melastomataceae) from Mt Makiling, Luzon, is presented. This includes a morphological and distributional examination of the population on the mountain, the documentation of reproductive phenological patterns, a study of the mating system and observations of biotic interactions. Measurements were made of trait variability, reproductive phenology was characterised from field and herbarium observations, stigmatic receptivity was tested by counting pollen germination, insect exclusion and hand-pollination experiments helped determine the mating system and field observations recorded the identity and behaviour of floral visitors. Significant reproductive morphological differences were found between described populations. This identified a need for the recognition of this diversity and further delimitation of the Medinilla multiflora species complex. Although Medinilla multiflora produced flowers and fruit year-round, the population also exhibited cycles of increased reproduction most likely initiated by seasonal low temperatures. Medinilla multiflora was found to require pollination but not cross-pollination. Two major peaks in stigmatic receptivity occurred throughout the day and the majority of pollen was found to be viable. Generalist bees proved to be the primary pollinators of the study population and were most active in the morning depending on weather conditions. Generalist pollinators and self-compatibility are advantageous traits for establishment and persistence in isolated mountain habitats; however, losses of this habitat due to climate change could have profound consequences for the future success of Medinilla multiflora.


2020 ◽  
Vol 99 (1) ◽  
pp. 80-91
Author(s):  
Víctor Parra-Tabla ◽  
Conchita Alonso

Background: Self-compatibility is common on endemic plant species, but pollen limitation and self-pollination could be risk factors. Study species: The endemic Cienfuegosia yucatanensis (Malvaceae), whose distribution is mainly restricted to the north coast of the peninsula of Yucatán, México. Questions: a) Are flowers of C. yucatanensis autonomous for pollination? b) Are C. yucatanensis fruit or seed-set limited by pollen deposition? and, c) Is there evidence of early inbreeding depression in C. yucatanensis? Study sites and dates: Two sites in the north of the peninsula of Yucatán in a seasonally dry scrubland, in the rainy season of 2013 and 2014. Methods: Number of flowers and fruits were weekly recorded. Flowers were collected to count the number of conspecific pollen load and the number of pollen tubes. Autonomous pollination and pollen limitation were evaluated with a hand-pollination experiment. Inbreeding depression on fruit and seed production, and seed weight was evaluated. Results: Flower and fruit production occur simultaneously and last from August to October. Conspecific pollen deposition on stigmas occurred through the whole flowering season and a maximum of pollen tubes was observed in August. Autonomous pollination treatment lead to similar fruit and seed production than cross-pollination, but open pollination produced significantly more seeds. No significant differences among self- and cross-pollination treatments on fruit and seed production or seed weight, were found.  Conclusions: Our results suggest that self-compatibility combined with a relatively efficient autonomous pollination, are suitable mechanisms for the reproductive assurance in C. yucatanensis, with no apparent effects of early inbreeding depression.


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