Determining whether seed production is pollen limited has been an area of intensive empirical study over the last two decades. Yet current evidence does not allow satisfactory assessment causes or consequences limitation. Here, we critically evaluate existing theory and issues concerning Our main conclusion that a change in approach needed to determine limitation reflects random fluctuations around pollen–resource equilibrium, adaptation stochastic pollination environments, chronic syndrome...

▪ Abstract Quantifying the extent to which seed production is limited by availability of pollen has been an area intensive empirical study over past few decades. Whereas theory predicts that augmentation should not increase production, numerous studies report significant and strong limitation. Here, we use a variety approaches examine correlates limitation in effort understand its occurrence importance plant evolutionary ecology. In particular, role recent ecological perturbations...

Hermaphroditic individuals can produce both selfed and outcrossed progeny, termed mixed mating. General theory predicts that mixed-mating populations should evolve quickly toward high rates of selfing, driven by rapid purging genetic load loss inbreeding depression (ID), but the substantial number species observed in nature calls this prediction into question. Lower average ID reported for selfing than outcrossing is consistent with suggests taxa evolutionary transition will have...

Reduced allocation to structures for pollinator attraction is predicted in selfing species. We explored the association between outcrossing and floral display a broad sample of angiosperms. used demonstrated relationship test bias against species rate distribution, shape which has relevance stability mixed mating. Relationships rate, flower size, number display, measured as product size number, were examined using phylogenetically independent contrasts. The distribution displays among...

Although certain acquired nongenetic (i.e., epigenetic) traits are known to be heritable in plants, little is currently about whether environmental parameters can induce adaptive epigenetic responses plants and such effects persist through generations. We used an experimental design based on classical genetics principles assess respond the conditions of their ancestors manner. An extensive examination genetically identical Arabidopsis thaliana (L.) Heynh lines exposed mild heat (30 °C) or...

Using both multivariate and univariate regression techniques, I measured selection acting through female reproductive success in two hermaphroditic species with precise pollen placement but different pollinators: hummingbird-pollinated Lobelia cardinalis bumblebee-pollinated L. siphilitica. Six traits were analyzed populations of one population siphilitica: flower number, mean number flowers open per day, inflorescence height, days flower, median-flower date nectar-stigma distance. In...

Inbreeding depression, or the decreased fitness of progeny derived from self‐fertilization as compared to outcrossing, is thought be most general factor affecting evolution in plants. Nevertheless, data on inbreeding depression characters are almost nonexistent for perennials observed their natural environments. In this study I measured both survival and fertility two sympatric, short‐lived, perennial herbs: hummingbird‐pollinated Lobelia cardinalis (two populations) bumblebee‐pollinated L....

Abstract Latitudinal gradients in biotic interactions have been suggested as causes of global patterns biodiversity and phenotypic variation. Plant biologists long speculated that outcrossing mating systems are more common at low than high latitudes owing to a greater predictability plant–pollinator the tropics; however, these ideas not previously tested. Here, we present first biogeographic analysis plant based on 624 published studies from 492 taxa. We found weak decline rate towards...

We carried out phenotypic selection analyses to assess the relative importance of several floral traits, as well microhabitat, in determining both male and female pollination success a nonrewarding orchid (Cypripedium acaule Ait.) two Nova Scotia populations. Fruit production these one-flowered, cosexual plants was strongly pollen limited within season: 100% individuals set fruit following hand-pollination, but only 5% 13% did so under natural circumstances Male reproductive were highly...

Seed germination constitutes an important event in the life cycle of plants. Two related seed traits affect fitness: size and timing germination. In three sets experiments, we (1) partition sources seed-size variance Lobelia inflata into components attributable to fruit size, relative position, parental identity; (2) examine influence pregermination conditions on time germination; (3) assess fitness consequences under seminatural, harsh conditions. Seed-size is both identity position within...

Theories about the evolution of sex and effects inbreeding depend on knowledge mutation rate dominance level deleterious alleles affecting total fitness. In two species largely self-fertilizing annual plants, minimal estimates such rates were found to be 0.24 0.87 per sporophyte genome generation, but confidence intervals exceeded 1.0 in each four populations. Dominance levels near zero one intermediate (0.28 0.35) other. These results suggest that detrimental are a result new partially...

A survey of restriction site variation in the chloroplast genome annual plant genus Amsinckia, together with estimation outcrossing rates, was conducted to analyze evolutionary history mating system. Species, and some cases populations within species, differ markedly their Five taxa are distylous predominantly outcrossing, or show mixed systems, while remaining homostylous self-fertilizing. Reconstruction molecular phylogeny group places different at four separate branch tips. When distyly...

Journal Article ON THE MEASUREMENT OF INBREEDING DEPRESSION Get access Mark O. Johnston, Johnston Department of Biology McGill University 1205 Avenue Docteur Penfield Montreal Quebec H3A 1B1 Canada Search for other works by this author on: Oxford Academic Google Scholar Daniel J. Schoen Evolution, Volume 48, Issue 5, 1 October 1994, Pages 1735–1741, https://doi.org/10.1111/j.1558-5646.1994.tb02209.x Published: 01 1994 history Received: 14 July 1993 Accepted: 10 January

Abstract .Environmental variation that is not predictably related to cues expected drive the evolution of bet-hedging strategies. The high variance observed in timing seed germination has led it being most cited diversification strategy theoretical literature. Despite this focus, virtually nothing known about mechanisms responsible for generation individual-level diversification. Here we report analyses sources within seasons, fraction over two generations and three sequential genetic...

The number of ovules per flower varies over several orders magnitude among angiosperms. Here we consider evidence that stochastic uncertainty in pollen receipt and ovule fertilization has been a selective factor the evolution flower. We hypothesize variation floral mating success creates an advantage to producing many because plant will often gain more fitness from occasional abundant seed production randomly successful flowers than it loses resource commitment less flowers. Greater...

The relation between inbreeding depression and rate of self-fertilization was studied in nine natural populations the annual genus Amsinckia. study included two clades (phylogenetic lineages) which small-flowered, homostylous or species are believed to have evolved from large-flowered, heterostylous, self-compatible ones. In one lineage small-flowered is tetraploid with disomic inheritance. Rates were 25% 55% four heterostylous populations; 72% a large-flowered but population; greater than...

Environmental variation that is not predictably related to cues expected drive the evolution of bet-hedging strategies. The high variance observed in timing seed germination has led it being most cited diversification strategy theoretical literature. Despite this focus, virtually nothing known about mechanisms responsible for generation individual-level diversification. Here we report analyses sources within seasons, fraction over two generations and three sequential genetic correlation...

In temporally varying environments selection will often act, at the expense of expected fitness in any given generation, so as to maximize geometric mean across a number generations (Gillespie 1977). Such bet hedging (Slatkin 1974) may occur two ways (Seger and Brockmann 1987). conservative genotype minimizes risk very low bout by producing narrowly unimodal distribution safe trait values. contrast, practising diversification spreads traits with increased variance (see Philippi Seger 1989...

Classical models studying the evolution of self-fertilization in plants conclude that only complete selfing and outcrossing are evolutionarily stable. In contrast with this prediction, 42% seed-plant species reported to have rates between 0.2 0.8. We propose many previous fail predict intermediate because they do not allow for functional relationships among three components reproductive fitness: self-fertilized ovules, outcrossed ovules sired by successful pollen export. Because optimal...

Herbarium specimens are increasingly used in phenological studies. However, natural history collections can have biases that influence the analysis of events. Arctic environments, where remoteness and cold climate govern collection logistics, may give rise to unique or pronounced biases.We assessed presence time, space, events, collectors, taxonomy, plant traits across Nunavut using herbarium accessioned at National Canada (CAN).We found periods high low corresponded societal institutional...

Age and size at reproduction are important components of fitness, variable both within among angiosperm species. The fitness consequences such life-history variation most readily studied in organisms that reproduce only once their lifetime. timing the onset (bolting) monocarpic perennial, Lobelia inflata, occurs over a range dates season, may be postponed to later year. Empirical relationships traits, derived from 950 wild-growing experimentally manipulated plants field, used model an...

Although there is substantial evidence that, in animals, male-inherited neutral DNA evolves at a higher rate than female-inherited DNA, the relative evolutionary of male- versus has not been investigated plants. We compared substitution rates sites maternally and paternally inherited organellar gymnosperms. The analysis provided support for presence both mitochondrial chloroplastidial when organelle was maternally. These results suggest with eggs, sperm tend to carry greater number mutations...