Time after time: Flowering phenology and biotic interactions. Trends in Ecology and
Department of Ecology and Evolution, University of Lausanne, CH 1015 Lausanne, Switzerland. Trends in Ecology & Evolution
(Impact Factor: 16.2).
09/2007; 22(8):432-9. DOI: 10.1016/j.tree.2007.05.006
The role of biotic interactions in shaping plant flowering phenology has long been controversial; plastic responses to the abiotic environment, limited precision of biological clocks and inconsistency of selection pressures have generally been emphasized to explain phenological variation. However, part of this variation is heritable and selection analyses show that biotic interactions can modulate selection on flowering phenology. Our review of the literature indicates that pollinators tend to favour peak or earlier flowering, whereas pre-dispersal seed predators tend to favour off-peak or later flowering. However, effects strongly vary among study systems. To understand such variation, future studies should address the impact of mutualist and antagonist dispersal ability, ecological specialization, and habitat and plant population characteristics. Here, we outline future directions to study how such interactions shape flowering phenology.
Available from: Steven Joseph Franks
- "One such trait in plant populations is the timing of first flowering. Flowering time is a key life-history trait that influences mating opportunities, reproductive fitness, gene flow and evolution (Elzinga et al., 2007; Franks, 2015; Primack, 1985). With changing climatic conditions, there have been widespread shifts to earlier flowering (Miller-Rushing & Primack, 2008; Parmesan & Yohe, 2003), with important implications for population and evolutionary dynamics. "
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ABSTRACT: Understanding the genetic basis of natural phenotypic variation is of great importance, particularly since selection can act on this variation to cause evolution. We examined expression and allelic variation in candidate flowering time loci in
plants derived from a natural population and showing a broad range in the timing of first flowering. The loci of interest were orthologs of the Arabidopsis genes
, respectively), which in Arabidopsis play a central role in the flowering time regulatory network, with
promoting flowering. In
, there are four copies of
and three of
. Plants were grown in controlled conditions in the lab. Comparisons were made between plants that flowered the earliest and latest, with the difference in average flowering time between these groups ∼30 days. As expected, we found that total expression of
paralogs was significantly greater in early than in late flowering plants. Paralog-specific primers showed that expression was greater in early flowering plants in the
, although the difference was not significant in
. Thus expression of at least 2 of the 3
orthologs is consistent with their predicted role in flowering time in this natural population. Sequences of the promoter regions of the
orthologs were variable, but there was no association between allelic variation at these loci and flowering time variation. For the
orthologs, expression varied over time, but did not differ between the early and late flowering plants. The coding regions, promoter regions and introns of these genes were generally invariant. Thus the
orthologs do not appear to influence flowering time in this population. Overall, the results suggest that even for a trait like flowering time that is controlled by a very well described genetic regulatory network, understanding the underlying genetic basis of natural variation in such a quantitative trait is challenging.
Available from: Susan J. Mazer
- "Shifts in the timing of phenophases are a well-documented response to climate change (Menzel et al., 2006; Parmesan, 2006), and these shifts can have profound and immediate effects on the interactions of species (Visser & Both, 2005; Both et al., 2006; Ozgul et al., 2010; McKinney et al., 2012), as well as longer term effects on the abundance and distribution of species (Moller et al., 2008; Chuine, 2010; Miller- Rushing et al., 2010; Willis et al., 2010; Cleland et al., 2012), and on ecosystem function and services (Richardson et al., 2010). For flowering plants, the timing of reproductive phenophases is particularly important, as it can influence the strength of mutualistic or antagonistic interactions between plants and their pollinators , seed dispersers, herbivores and seed predators (Elzinga et al., 2007; Yang & Rudolf, 2010; Forrest, 2015; Rafferty et al., 2015). "
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ABSTRACT: For most species, a precise understanding of how climatic parameters determine the timing of seasonal life cycle stages is constrained by limited long-term data. Further, most long-term studies of plant phenology that have examined relationships between phenological timing and climate have been local in scale or have focused on single climatic parameters. Herbarium specimens, however, can expand the temporal and spatial coverage of phenological datasets. Using Trillium ovatum specimens collected over > 100 yr across its native range, we analyzed how seasonal climatic conditions (mean minimum temperature (Tmin ), mean maximum temperature and total precipitation (PPT)) affect flowering phenology. We then examined long-term changes in climatic conditions and in the timing of flowering across T. ovatum's range. Warmer Tmin advanced flowering, whereas higher PPT delayed flowering. However, Tmin and PPT were shown to interact: the advancing effect of warmer Tmin was strongest where PPT was highest, and the delaying effect of higher PPT was strongest where Tmin was coldest. The direction of temporal change in climatic parameters and in the timing of flowering was dependent on geographic location. Tmin , for example, decreased across the observation period in coastal regions, but increased in inland areas. Our results highlight the complex effects of climate and geographic location on phenology.
Available from: Sophia Rhizopoulou
- "Flowers are among the most spectacular products of nature. Blossoming of plants is regulated by mechanisms that act to ensure that flower emergence occurs in suitable environmental conditions (Elzinga et al. 2007; Tooke and Battey 2010). Major importance has been given to floral advertisement, which is related to multifunctional traits; for example, a three-dimensional cuticular relief, observed on petal surfaces, protects the floral tissues against physical, chemical and biological attack, it influences optical properties, it reduces the absorbance of UV radiation that reaches the cells and forms microsculptures (Kevan and Lane 1985; Jacobs, Koper, and Ursem 2007; Whitney and Glover 2007; Domínguez, Heredia-Guerrero, and Heredia 2011; Javelle et al. 2011; Glover et al. 2013). "
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ABSTRACT: The present study revealed that adaxial and abaxial petal epidermises of the blue-flowered Lysimachia arvensis consist of elongated, multi-micro-papillate cells, which may aid the rapid petal expansion. The epidermal cells are covered by a wrinkled relief, which is further ornamented by submicron features that increase in size the surface area of lobes; this may be a well-adapted mechanism of the small-sized flowers of L. arvensis with the short life span. The sculpturally increased surface area of adaxial epidermal cells of petals is expected to contribute to optical and adhesive properties, and wettability of the floral tissues. The adaxial and the abaxial petal surfaces of L. arvensis possess submicron cuticular folds, smaller than the sub-wavelength visible spectrum, which reflect radiation of shorter rather than longer wavelengths, whereas intense absorption was detected in the red spectral region. Also, three-celled capitate trichomes with a pigmented spherical head, which are densely distributed at the corolla margins of L. arvensis, may be involved in adhesive, defensive and functional properties of the floral tissues.
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