Julia Sanchez Vilas
Cardiff University, Organisms and Environment, Faculty Member
Research Interests:
Research Interests:
Research Interests:
Males and females of dioecious plant species often show different responses to competition with individuals of the same or opposite gender, but almost no data are available on the outcome of competition with members of other species.... more
Males and females of dioecious plant species often show different responses to competition with individuals of the same or opposite gender, but almost no data are available on the outcome of competition with members of other species. Here, we show that male and female individuals of the wind‐pollinated herb Mercurialis annua are sexually dimorphic in both their intraspecific and interspecific competitive abilities. In a controlled experiment, we found that both sexes of M. annua were negatively affected by interspecific competition, but the sensitivity of males and females depended on the identity of their competitor species, with females tending to suppress the aboveground growth of competitor species more than males. Further, we found that intrasexual and intersexual competition affected the aboveground growth of males but not that of females: only males showed a significant reduction in growth when growing with conspecific competitors (male or female). We discuss our results with reference to related studies that suggest that males and females of M. annua have different resource requirements for reproduction, which in turn affect their competitive abilities.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Plants are notoriously variable in gender, ranging in sex allocation from purely male through hermaphrodite to purely female. This variation can have both a genetic and an adaptive plastic component. In gynodioecious species, where... more
Plants are notoriously variable in gender, ranging in sex allocation from purely male through hermaphrodite to purely female. This variation can have both a genetic and an adaptive plastic component. In gynodioecious species, where females co-occur with hermaphrodites, hermaphrodites tend to shift their allocation towards greater maleness when growing under low-resource conditions, either as a result of hermaphrodites shifting away from an expensive female function, or because of enhanced siring advantages in the presence of females. Similarly, in the androdioecious plant Mercurialis annua, where hermaphrodites co-exist with males, hermaphrodites also tend to enhance their relative male allocation under low-resource conditions. Here, we ask whether this response differs between hermaphrodites that have been evolving in the presence of males, in a situation analogous to that supposed for gynodioecious populations, vs. those that have been evolving in their absence. We grew hermaphrodites of M. annua from populations in which males were either present or absent under different levels of nutrient availability and compared their reaction norms. We found that, overall, hermaphrodites from populations with males tended to be more female than those from populations lacking males. Importantly, hermaphrodites' investment in pollen and seed production was more plastic when they came from populations with males than without them, reducing their pollen production at low resource availability and increasing their seed production at high resource availability. These results are consistent with the hypothesis that plasticity in sex allocation is enhanced in hermaphrodites that have likely been exposed to variation in mating opportunities due to fluctuations in the frequency of co-occurring males.
Research Interests:
Himalayan balsam (Impatiens glandulifera) is a highly invasive annual herb that has spread rapidly throughout the UK. This species has allelopathic potential – chemicals released into the soil that can reduce seed germination and growth... more
Himalayan balsam (Impatiens glandulifera) is a highly invasive annual herb that has spread rapidly throughout the UK. This species has allelopathic potential – chemicals released into the soil that can reduce seed germination and growth of neighbouring plants. Allelopathy and resource competition are key contributors to the success of this species; however, little is still known about the effects of litter of I. glandulifera on native species. This is important because in the invaded range, I. glandulifera frequently grows in monotypic stands that die back in autumn leaving large amounts of litter. Here, we aim to investigate the effects that seedlings and residues (above-ground plant matter) of I. glandulifera have on the chlorophyll content and growth of co-occurring native species, namely, Trifolium pratense, Linum grandiflora, and Silene dioica. We found reduced chlorophyll content and growth (measured as above-ground dry mass) in the three native species studied in response to ...
Research Interests:
Complete datase
Research Interests:
1. Plants vary widely in the extent to which they defend themselves against herbivores. Because the resources available to plants are often site-specific, variation among sites dictates investment into defence, and may reveal a... more
1. Plants vary widely in the extent to which they defend themselves against herbivores. Because the resources available to plants are often site-specific, variation among sites dictates investment into defence, and may reveal a growth-defence trade-off. Moreover, plants that have evolved different life-history strategies in different environments may situate themselves on this trade-off curve differently. For instance, plants that flower later have a longer vegetative lifespan, and may accordingly defend themselves differently than those that flower earlier. 2. Here, we tested whether late-flowering plants, with a longer vegetative lifespan, invest more in defence than early-flowering plants, using recombinant genotypes of the annual herb Cardamine hirsuta that differ in flowering time as a result of differences in the activity of the major floral repressor Flowering Locus C (FLC). 3. We found that variation at FLC was mainly responsible for regulating flowering time and allocation to reproduction, but this partially depended on where the plants grew. We also found that variation at FLC mediated plant allocation to defence, with late-flowering plants producing higher levels of total glucosinolates and stress-related phytohormones. Nonetheless, plant growth and the qualitative values of plant defence and plant resistance against specialist herbivores were mainly independent from FLC. 4. Synthesis - Our results highlight pleiotropic effects associated with flowering-time genes that might influence plant defence and plant-herbivore interactions
Research Interests:
Himalayan balsam (Impatiens glandulifera) is a highly invasive annual herb that has become extremely prevalent in riparian zones across the UK. The competitive ability of I. glandulifera, both in terms of resource exploitation and... more
Himalayan balsam (Impatiens glandulifera) is a highly invasive annual herb that has become extremely prevalent in riparian zones across the UK. The competitive ability of I. glandulifera, both in terms of resource exploitation and allelopathy (i.e., the release of biochemicals that may be toxic to neighbouring plants), is considered a key determinant of its success. Little is known, however, about the effects of the resident community on the establishment and growth of I. glandulifera. Here, we aim to increase our understanding of the competitive ability of this highly invasive plant by investigating the effects of soil conditioning on the performance of four co-occurring native species (Tanacetum vulgare, Urtica dioica, Chelidonium majus and Arabidopsis thaliana). In addition, we also aim to investigate the effect that the pre-existing species composition have on the performance of I. glandulifera seedlings by establishing artificial communities (monocultures and mixtures of four U...
Research Interests:
Research Interests:
Research Interests:
Plant Ecology, Plant Biology, Biology, Ecology, Sexual dimorphism, and 3 moreHerb, Herbivore, and Spinacia
Increased phenotypic plasticity for a number of plant traits has been suggested as a possible reason for the success and spread of polyploids. One such trait is a plant’s sex allocation (or gender), which influences its reproductive... more
Increased phenotypic plasticity for a number of plant traits has been suggested as a possible reason for the success and spread of polyploids. One such trait is a plant’s sex allocation (or gender), which influences its reproductive success directly as a function of the potentially heterogeneous mating prospects in the population. However, it is unknown how polyploidy per se might affect plasticity in a plant’s sex allocation. Although there have been numerous comparisons between diploid and (usually) tetraploid taxa, we know very little about how elevated ploidy above the diploid level might affect plasticity. Here, we ask whether different ploidy levels > 2x express different plasticity in the ruderal plant Mercurialis annua. We grew tetraploid and hexaploid hermaphrodites under different levels of nutrient availability and compared their reaction norms for growth (above-ground biomass, SLA) and reproductive traits (reproductive effort, phenotypic gender). Overall, we found tha...
Research Interests:
Research Interests:
Research Interests:
The males and females of many dioecious plant species differ from one another in important life-history traits, such as their size. If male and female reproductive functions draw on different resources, for example, one should expect... more
The males and females of many dioecious plant species differ from one another in important life-history traits, such as their size. If male and female reproductive functions draw on different resources, for example, one should expect males and females to display different allocation strategies as they grow. Importantly, these strategies may differ not only between the two sexes, but also between plants of different age and therefore size. Results are presented from an experiment that asks whether males and females of Mercurialis annua, an annual plant with indeterminate growth, differ over time in their allocation of two potentially limiting resources (carbon and nitrogen) to vegetative (below- and above-ground) and reproductive tissues. Comparisons were made of the temporal patterns of biomass allocation to shoots, roots and reproduction and the nitrogen content in the leaves between the sexes of M. annua by harvesting plants of each sex after growth over different periods of time....
Research Interests:
Research Interests:
Many species expanded their geographic ranges from core “refugium” populations when the global climate warmed after the Pleistocene. The bottlenecks that occur during such range expansions diminish genetic variation in marginal... more
Many species expanded their geographic ranges from core “refugium” populations when the global climate warmed after the Pleistocene. The bottlenecks that occur during such range expansions diminish genetic variation in marginal populations, rendering them less responsive to selection. Here, we show that range expansion also strongly depletes inbreeding depression. We compared inbreeding depression among 20 populations across the expanded range of a common European plant, and found that marginal populations had greatly reduced inbreeding depression. Similar patterns were also revealed by multilocus computer simulations. Low inbreeding depression is predicted to ease conditions for the evolution of self-fertilization, and selfing is known to be particularly frequent in marginal populations. Therefore, our findings expose a remarkable aspect of evolution at range margins, where a history of expansion can reverse the direction of selection on the mating system, providing a parsimonious ...
Research Interests:
Research Interests:
Males and females of dioecious plant species often show different responses to competition with individuals of the same or opposite gender, but almost no data are available on the outcome of competition with members of other species.... more
Males and females of dioecious plant species often show different responses to competition with individuals of the same or opposite gender, but almost no data are available on the outcome of competition with members of other species. Here, we show that male and female individuals of the wind‐pollinated herb Mercurialis annua are sexually dimorphic in both their intraspecific and interspecific competitive abilities. In a controlled experiment, we found that both sexes of M. annua were negatively affected by interspecific competition, but the sensitivity of males and females depended on the identity of their competitor species, with females tending to suppress the aboveground growth of competitor species more than males. Further, we found that intrasexual and intersexual competition affected the aboveground growth of males but not that of females: only males showed a significant reduction in growth when growing with conspecific competitors (male or female). We discuss our results with...
Research Interests:
Honckenya peploides is a subdioecious dune plant that reproduces both sexually and by clonal growth. In northwest Spain this species was found to exhibit an extreme spatial segregation of the sexes, and our objective was to investigate... more
Honckenya peploides is a subdioecious dune plant that reproduces both sexually and by clonal growth. In northwest Spain this species was found to exhibit an extreme spatial segregation of the sexes, and our objective was to investigate genetic variation in unisexual clumps. Genetic variation was studied in six unisexual clumps of H. peploides, three of them exclusively composed of males and three exclusively female. In total, 193 samples were analysed using isozyme analysis and 80 samples were analysed using two AFLP primer combinations. Both techniques revealed considerably high genetic diversity (average proportion of distinguishable genotypes: 0.22 for isozymes and 0.36 for AFLP; average Simpson’s D: 0.65 for isozymes and 0.68 for AFLP). Our results show that, in spite of clonal growth, each unisexual clump consists of different genotypes. Genetic diversity within clumps is similar for both sexual morphs. Reasons for unisexuality of the clumps are discussed.
Research Interests:
The gender of dimorphic plant species is often affected by ecophysiological variables. Differences have been interpreted as a response of the sexes to meet specific resource demands associated with reproduction. This study investigated... more
The gender of dimorphic plant species is often affected by ecophysiological variables. Differences have been interpreted as a response of the sexes to meet specific resource demands associated with reproduction. This study investigated whether sex‐specific variations in ecophysiological traits in response to water availability determine the performance of each sex in different habitats, and therefore promote extreme spatial segregation of the sexes in the subdioecious plant, Honckenya peploides. Twenty‐seven plants of each sex were individually potted in dune sand and assigned randomly to one of three water treatments. Well‐watered plants were watered daily to field capacity, whereas plants in the moderate and high‐water stress treatments received 40% and 20%, respectively, of the water given to well‐watered plants. Photochemical efficiency, leaf spectral properties and components of relative growth rate (leaf area ratio and net assimilation rate) were measured. Photochemical effici...
Research Interests:
Males and females of dioecious plants often differ in morphological, physiological and life‐history traits, probably as a result of their different requirements for reproduction. We found that the growth and reproductive effort of... more
Males and females of dioecious plants often differ in morphological, physiological and life‐history traits, probably as a result of their different requirements for reproduction. We found that the growth and reproductive effort of individuals of the dioecious herb Mercurialis annua depended on whether males or females had been growing in the soil previously. This suggests that males and females of M. annua differentially modify the soil in which they are growing. Our study indicates that sexual dimorphism in dioecious plants can give rise to increased environmental heterogeneity as a consequence of sex‐specific niche modification.
Research Interests:
... Maintains Invariant Scaling Relations in Biomass Allocation. Julia Sanchez-Vilas, Ruben Retuerto International Journal of Plant Sciences 168:77, 973-983, University of Chicago Press, PO Box 37005 Chicago IL 60637 USA,, 2007. ...
Research Interests:
Sex dimorphic plants often show sex‐specific differences in growth and biomass allocation. These differences have been explained as a consequence of the different reproductive functions performed by the sexes. Such differences may... more
Sex dimorphic plants often show sex‐specific differences in growth and biomass allocation. These differences have been explained as a consequence of the different reproductive functions performed by the sexes. Such differences may determine the performance of each sex in different habitats and therefore might explain the spatial segregation of the sexes described in many dimorphic plants. We examined the growth, reproductive and physiological responses of the sexes of the subdioecious plant Honckenya peploides to two levels each of salt spray and nutrients, which are assumed to be important selective forces in coastal environments. We found sex‐related differences in H. peploides. In particular, females allocated proportionally more dry mass to reproduction and grew less and more slowly than males regardless of salt spray and nutrient conditions, which is interpreted as a trade‐off between reproductive and vegetative growth. Regarding physiological response, nutrients significantly ...
Research Interests:
Research Interests:
... Julia Sánchez-Vilas a , E-mail The Corresponding Author and Rubén Retuerto Corresponding Author Contact Information , a , E-mail The ... sex ([Lloyd and Web, 1977], [Dawson and Bliss, 1989], [Dawson and Ehleringer, 1993], [Gehring and... more
... Julia Sánchez-Vilas a , E-mail The Corresponding Author and Rubén Retuerto Corresponding Author Contact Information , a , E-mail The ... sex ([Lloyd and Web, 1977], [Dawson and Bliss, 1989], [Dawson and Ehleringer, 1993], [Gehring and Monson, 1994], [Laporte and Delph ...
Research Interests:
Changes in the sex allocation (i.e. in pollen versus seed production) of hermaphroditic plants often occur in response to the environment. In some homosporous ferns, gametophytes choose their gender in response to chemical cues sent by... more
Changes in the sex allocation (i.e. in pollen versus seed production) of hermaphroditic plants often occur in response to the environment. In some homosporous ferns, gametophytes choose their gender in response to chemical cues sent by neighbours, such that spores develop as male gametophytes if they perceive a female or hermaphrodite nearby. Here it is considered whether a similar process might occur in the androdioecious angiosperm species Mercurialis annua, in which males co-occur with hermaphrodites; previous work on a Spanish population of M. annua found that individuals were more likely to develop as males at high density. Using a novel approach to treat plants with leachate from pots containing males or hermaphrodites of M. annua, the hypothesis that individuals assess their mating opportunities, and adjust their sex expression accordingly, was tested through an exchange of chemical cues through the soil. For the population under study, from Morocco, no evidence was found for...