Pollen dispersal and gene flow by pollen in Araucaria angustifolia

2003 ◽  
Vol 51 (3) ◽  
pp. 309 ◽  
Author(s):  
V. A. Sousa ◽  
H. H. Hattemer
Keyword(s):  
Gene Flow ◽  
Pollen Dispersal ◽  
Pollen Grains ◽  
Physical Characteristics ◽  
Araucaria Angustifolia ◽  
Effective Population ◽  
Pollen Dispersion ◽  
Biological Studies ◽  
Seed Dispersion ◽  
Dispersion Patterns

Araucaria angustifolia (Bert.) O.Ktze. is an economically important tree in southern Brazil. Indiscriminate exploitation is threatening this species with extinction. Conservation programs are urgently needed to save the remaining forest, and such programs must be guided by biological studies that genetically characterise the remaining populations. Pollen and seed dispersion patterns determine the distance of gene flow and directly influence genetic structure and effective population size. A. angustifolia is a wind-pollinated dioecious tree. For pollen-dispersal airflow, physical characteristics of pollen grain, such as size and shape, must be considered. The aim of this work was to determine the homogeneity of effective pollen clouds as well as to infer the physical characteristics of pollen. The homogeneity of pollen clouds of A. angustifolia was assessed for 70 trees of natural population in Brazil. Analysis of genetic variability and differentiation of the effective pollen clouds detected high diversity at the MDH-B and 6-PGDH-B loci. Heterogeneity G-tests indicated pollen pool heterogeneity in four of seven examined loci (GOT-B, PGM-A, SKDH-B and 6-PGDH-B). The pollen grains measured 61.50 μm. The floating rate ranged from 12.02 to 18.98 cm s–1. The physical characteristics of the pollen suggest that pollen dispersion is likely to be limited.

scholarly journals Hawkmoth Pollination Facilitates Long-distance Pollen Dispersal and Reduces Isolation Across a Gradient of Land-use Change

2019 ◽  
Vol 104 (3) ◽  
pp. 495-511 ◽  
Author(s):  
Krissa A. Skogen ◽  
Rick P. Overson ◽  
Evan T. Hilpman ◽  
Jeremie B. Fant
Keyword(s):  
Land Use ◽  
Gene Flow ◽  
Habitat Fragmentation ◽  
Land Use Change ◽  
Pollen Dispersal ◽  
Suitable Habitat ◽  
Long Distance Dispersal ◽  
Effective Population ◽  
Long Distance ◽  
Genetic Diversity And Structure

Land-use change is among the top drivers of global biodiversity loss, which impacts the arrangement and distribution of suitable habitat for species. Population-level effects include increased isolation, decreased population size, and changes to mutualistic and antagonistic interactions. However, the extent to which species are impacted is determined by life history characteristics including dispersal. In plants, mating dynamics can be changed in ways that can negatively impact population persistence if dispersal of pollen and/or seed is disrupted. Long-distance dispersal has the potential to buffer species from the negative impacts of land-use change. Biotic vectors of long-distance dispersal have been less frequently studied, though specific taxa are known to travel great distances. Here, we describe population genetic diversity and structure in a sphingophilous species that is experiencing habitat fragmentation through land-use change, Oenothera harringtonii W. L. Wagner, Stockh. & W. M. Klein (Onagraceae). We use 12 nuclear and four plastid microsatellite markers and show that pollen dispersal by hawkmoths drives high gene flow and low population differentiation despite a range-wide gradient of land-use change and habitat fragmentation. By separating the contributions of pollen and seed dispersal to gene flow, we show that most of the genetic parameters are driven by hawkmoth-facilitated long-distance pollen dispersal, but populations with small, effective population sizes experience higher levels of relatedness and inbreeding. We discuss considerations for conservation efforts for this and other species that are pollinated by long-distance dispersers.

scholarly journals Camelina (Camelina sativa L. Crantz) Crop Performance, Insect Pollinators, and Pollen Dispersal in the Northeastern US

2019 ◽  
Author(s):  
Richard Rizzitello ◽  
Chuan-Jie Zhang ◽  
Carol Auer
Keyword(s):  
Gene Flow ◽  
Honey Bees ◽  
Pollen Dispersal ◽  
Camelina Sativa ◽  
Genetically Engineered ◽  
Oilseed Crop ◽  
Crop Failure ◽  
Long Distance ◽  
Insect Visitation ◽  
Pollinating Insects

AbstractCamelina sativa (camelina) is an oilseed crop in the Brassicaceae that has been genetically engineered for the production of biofuels, dietary supplements, and other industrial compounds. Cultivation in North America is both recent and limited, so there are gaps in knowledge regarding yield, weed competition, and pollen-mediated gene flow. For these experiments, camelina ‘SO-40’ was grown for three years without weed control. Spring-sown camelina was harvested at 80-88 days with ∼1200 growing degree days (GDD) with yields of 425-508 kg/hectare. Camelina yields were the same with or without weeds, showing competitive ability in low-management conditions. Crop failure in 2015 was associated with delayed rainfall and above-average temperatures after seeding. Camelina flowers attracted pollinating insects from the Hymenoptera, Diptera, Lepidoptera, and Coleoptera. Hymenoptera included honey bees (Apis melifera), mining bees (Andrenidae), sweat bees (Halictidae), bumble bees (Bombus spp.) and leaf cutter bees (Megachilidae). Insect visitation on camelina flowers was associated with modest increases in seed yield. Honey bees comprised 28-33% of all pollinators and were shown to carry camelina pollen on their legs. Air sampling showed that wind-blown pollen was present at low concentrations at 9 m beyond the edges of the field. These experiments demonstrated for the first time that camelina pollen dispersal could occur through honey bees or wind, although bee activity would likely be more significant for long-distance gene flow.

scholarly journals Molecular markers applying in forest trees gene pool conservation

2009 ◽  
pp. 101-113
Author(s):  
Jelena Milovanovic ◽  
Mirjana Sijacic-Nikolic
Keyword(s):  
Population Genetics ◽  
Molecular Markers ◽  
Gene Flow ◽  
Gene Pool ◽  
Statistical Power ◽  
Forest Trees ◽  
Effective Population ◽  
Migration Patterns ◽  
Geographic Diversity ◽  
Marker Loci

Many studies performed during the last years demonstrated the usefulness of neutral molecular markers in the field of conservation and population genetics of forest trees, in particular to understand the importance of migration patterns in shaping current genetic and geographic diversity and to measure important parameters such as effective population size, gene flow and past bottleneck. During the next years, a large amount of data at marker loci or at sequence level is expected to be collected, and to become excellent statistical power for the assessment of biological and evolutionary value.

Living with Other Flowers: Competition and Pollination Ecology

2011 ◽  
Author(s):  
Pat Willmer
Keyword(s):  
Gene Flow ◽  
Seed Dispersal ◽  
Female Choice ◽  
Intraspecific Competition ◽  
Pollen Dispersal ◽  
Male Competition ◽  
Pollination Ecology ◽  
Potential Outcomes ◽  
Selective Force ◽  
Genetic Level

This chapter examines competition in the context of pollination ecology. Competition is typically treated from the perspective of the plants, but it is also likely to occur among and between the pollinators. Furthermore, competition can occur at various levels—as a structuring factor in communities, as a selective force on an individual plant’s phenology, morphology, or rewards, and at a genetic level structuring competition for pollens between males, and female choice between possible mates. The chapter first considers several types of of competition in pollination ecology, potential outcomes of competition, and competition between pollinators before discussing how selection reduces intraspecific competition among plants and competition among pollinators. It also explores paternity, maternity, and gene flow in coflowering communities, focusing in particular on male competition and female choice, along with gene flow via pollen dispersal and seed dispersal.

Staying close: short local dispersal distances on a managed forest of two Patagonian Nothofagus species

2020 ◽  
Vol 93 (5) ◽  
pp. 652-661 ◽  
Author(s):  
Georgina Sola ◽  
Verónica El Mujtar ◽  
Leonardo Gallo ◽  
Giovanni G Vendramin ◽  
Paula Marchelli
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Spatial Genetic Structure ◽  
Pollen Dispersal ◽  
Dispersal Distance ◽  
Restricted Gene Flow ◽  
Fine Scale ◽  
Gene Dispersal ◽  
Mature Trees ◽  
The Impact

Abstract Understanding the impact of management on the dispersal potential of forest tree species is pivotal in the context of global change, given the implications of gene flow on species evolution. We aimed to determine the effect of logging on gene flow distances in two Nothofagus species from temperate Patagonian forests having high ecological relevance and wood quality. Therefore, a total of 778 individuals (mature trees and saplings) of Nothofagus alpina and N. obliqua, from a single plot managed 20 years ago (2.85 hectares), were mapped and genotyped at polymorphic nuclear microsatellite loci. Historical estimates of gene dispersal distance (based on fine-scale spatial genetic structure) and contemporary estimates of seed and pollen dispersal (based on spatially explicit mating models) were obtained. The results indicated restricted gene flow (gene distance ≤ 45 m, both pollen and seed), no selfing and significant seed and pollen immigration from trees located outside the studied plot but in the close surrounding area. The size of trees (diameter at breast height and height) was significantly associated with female and/or male fertility. The significant fine-scale spatial genetic structure was consistent with the restricted seed and pollen dispersal. Moreover, both estimates of gene dispersal (historical and contemporary) gave congruent results. This suggests that the recent history of logging within the study area has not significantly influenced on patterns of gene flow, which can be explained by the silviculture applied to the stand. The residual tree density maintained species composition, and the homogeneous spatial distribution of trees allowed the maintenance of gene dispersal. The short dispersal distance estimated for these two species has several implications both for understanding the evolution of the species and for defining management, conservation and restoration actions. Future replication of this study in other Nothofagus Patagonian forests would be helpful to validate our conclusions.

scholarly journals Genic differentiation and origin of Robertsonian populations of the house mouse (Mus musculus domesticus Rutty)

1989 ◽  
Vol 53 (1) ◽  
pp. 29-44 ◽  
Author(s):  
Janice Britton-Davidian ◽  
Joseph H. Nadeau ◽  
Henri Croset ◽  
Louis Thaler
Keyword(s):  
Gene Flow ◽  
House Mouse ◽  
Mus Musculus ◽  
Western Europe ◽  
Chromosomal Rearrangements ◽  
Nuclear Gene ◽  
Electrophoretic Analysis ◽  
Mus Musculus Domesticus ◽  
Effective Population ◽  
Chromosomal Races

SummaryThis paper examines the relation between chromosomal and nuclear-gene divergence in 28 wild populations of the house mouse semi-species, Mus musculus domesticus, in Western Europe and North Africa. Besides describing the karyotypes of 15 of these populations and comparing them to those of 13 populations for which such information was already known, it reports the results of an electrophoretic survey of proteins encoded by 34 nuclear loci in all 28 populations. Karyotypic variation in this taxon involves only centric (or Robertsonian) fusions which often differ in arm combination and number between chromosomal races. The electrophoretic analysis showed that the amount of genic variation within Robertsonian (Rb) populations was similar to that for all-acrocentric populations, i.e. bearing the standard karyotype. Moreover, divergence between the two types of populations was extremely low. These results imply that centric fusions in mice have not modified either the level or the nature of genic variability. The genetic similarity between Rb and all-acrocentric populations is not attributed to the persistence of gene flow, since multiple fusions cause marked reproductive isolation. Rather, we attribute this extreme similarity to the very recent origin of chromosomal races in Europe. Furthermore, genic diversity measures suggest that geographically separated Rb populations have in situ and independent origins. Thus, Rb translocations are probably not unique events, but originated repeatedly. Two models are presented to explain how the rapid fixation of a series of chromosomal rearrangements can occur in a population without lowering variability in the nuclear genes. The first model assumes that chromosomal mutation rates are between 10−3 and 10−4 and that populations underwent a series of transient bottlenecks in which the effective population size did not fall below 35. In the second model, genic variability is restored following severe bottlenecks, through gene flow and recombination.

scholarly journals Voter Model and Biased Voter Model in Heterogeneous Environments

2007 ◽  
Vol 44 (03) ◽  
pp. 770-787
Author(s):  
N. Lanchier ◽  
C. Neuhauser
Keyword(s):  
Gene Flow ◽  
Pollen Dispersal ◽  
Transgenic Crops ◽  
Wild Relatives ◽  
Voter Model ◽  
Wild Plants ◽  
Transgenic Crop ◽  
Heterogeneous Environments ◽  
Wild Type ◽  
Type Gene

With the rapid adoption of transgenic crops, gene flow from transgenic crops to wild relatives through pollen dispersal is of significant concern and warrants both empirical and theoretical studies to assess the risk of introduction of transgenes into wild populations. We propose to use the (biased) voter model in a heterogeneous environment to investigate the effects of recurrent gene flow from transgenic crop to wild relatives. The model is defined on the d-dimensional integer lattice that is divided into two parts, Δ and Z d \ Δ. Individuals carrying the transgene and individuals carrying the wild type gene compete according to the evolution rules of a (biased) voter model on Z d \ Δ, while the process is conditioned to have only individuals carrying the transgene on Δ. Our main findings suggest that unless transgenes confer increased fitness in wild relatives, introgression of transgenes into populations of wild plants is slow and may even be reversible without intervention. Our study also addresses the effects of different spatial planting patterns of transgenic crops on the rate of introgression.

Pollen biodiversity – why are pollen grains different despite having the same function? A review

2020 ◽  
Vol 193 (2) ◽  
pp. 141-164 ◽  
Author(s):  
Ettore Pacini ◽  
Gian Gabriele Franchi
Keyword(s):  
Pollen Dispersal ◽  
Pollen Grains ◽  
Reproductive Function ◽  
Female Competition ◽  
Size Number ◽  
Pollen Presentation ◽  
Dispersal Unit ◽  
Number Of Cells ◽  
Physiological Characters ◽  
Female Counterpart

Abstract The main morphological, cytological and physiological characters of ripe pollen are described, compared, analysed and discussed individually, in multiple combinations and in respect to the female counterpart and the biotic and abiotic components of the environment. This is to try to understand the reasons why pollen grains have the same reproductive function, but at dispersal are morphologically and physiologically different in many respects. The considered characters are: one or more types of grain per species; shape and size; number of cells; types of pollen dispersal unit; sporoderm stratification, furrows, colpori and other kinds of apertures; pollen presentation and array; water content percentage; and mature pollen reserves and osmotics. Some of the pollen features are correlated between themselves, some with the female counterpart or male and female competition, and others with the different components of the environment where the species lives, when it flowers and when pollen presentation occurs.

scholarly journals Sporadic Genetic Connectivity among Small Insular Populations of the Rare Geoendemic Plant Caulanthus amplexicaulis var. barbarae (Santa Barbara Jewelflower)

2019 ◽  
Vol 110 (5) ◽  
pp. 587-600
Author(s):  
A Millie Burrell ◽  
Jeffrey H R Goddard ◽  
Paul J Greer ◽  
Ryan J Williams ◽  
Alan E Pepper
Keyword(s):  
Gene Flow ◽  
Genetic Connectivity ◽  
Effective Population ◽  
Evolutionary Potential ◽  
Isolated Populations ◽  
Long Distance ◽  
Population Sizes ◽  
History Of ◽  
Small Set ◽  
Nuclear Microsatellite

Abstract Globally, a small number of plants have adapted to terrestrial outcroppings of serpentine geology, which are characterized by soils with low levels of essential mineral nutrients (N, P, K, Ca, Mo) and toxic levels of heavy metals (Ni, Cr, Co). Paradoxically, many of these plants are restricted to this harsh environment. Caulanthus ampexlicaulis var. barbarae (Brassicaceae) is a rare annual plant that is strictly endemic to a small set of isolated serpentine outcrops in the coastal mountains of central California. The goals of the work presented here were to 1) determine the patterns of genetic connectivity among all known populations of C. ampexlicaulis var. barbarae, and 2) estimate contemporary effective population sizes (Ne), to inform ongoing genomic analyses of the evolutionary history of this taxon, and to provide a foundation upon which to model its future evolutionary potential and long-term viability in a changing environment. Eleven populations of this taxon were sampled, and population-genetic parameters were estimated using 11 nuclear microsatellite markers. Contemporary effective population sizes were estimated using multiple methods and found to be strikingly small (typically Ne < 10). Further, our data showed that a substantial component of genetic connectivity of this taxon is not at equilibrium, and instead showed sporadic gene flow. Several lines of evidence indicate that gene flow between isolated populations is maintained through long-distance seed dispersal (e.g., >1 km), possibly via zoochory.

Effects of Chinese honeybee foraging on oilseed rape gene flow and honey ingredients

2017 ◽  
Vol 155 (10) ◽  
pp. 1623-1632
Author(s):  
F. X. LIU ◽  
C. P. BU ◽  
T. TANG ◽  
G. M. CHEN ◽  
S. K. GU ◽  
...  
Keyword(s):  
Gene Flow ◽  
Oilseed Rape ◽  
Safety Management ◽  
Apis Cerana ◽  
Pollen Grains ◽  
Intermediate Frequency ◽  
Scientific Basis ◽  
Trade Disputes ◽  
Exogenous Genes

SUMMARYHoneybee foraging can transfer exogenous genes from genetically modified (GM) oilseed rape (Brassica napusL.) to closely related plants, which not only induces potential ecological risks but also contaminates non-GM seeds or honey products with GM ingredients. These events may lead to international trade disputes. Chinese honeybees (Apis cerana ceranaFabricius) and a herbicide (glufosinate)-resistant GM strain ofB. napus(Z7B10) were studied to examine the effects of honeybee short-range foraging on oilseed rape gene flow and honey ingredients. Results showed variable frequencies of gene flow between GM and non-GM oilseed rape cultivars, with the highest frequency under nylon net isolation with artificially stocked honeybees, the lowest frequency under nylon net isolation alone, and an intermediate frequency under natural pollination, suggesting the important role of honeybee foraging in gene flow frequency. Additionally, GM pollen grains were found in honey collected from honeybees foraging on both GM and non-GM oilseed rape cultivars. The phosphinothricin acetyltransferase protein was also detected in both unbroken pollen-containing and pollen-free honey by protein testing strips, suggesting that honeybee foraging on GM oilseed rape could lead to contamination with GM ingredients. Overall, the results provide a direct scientific basis for the ecological risk assessment and safety management of GM oilseed rape.

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