Plant Reproductive Traits Research Articles

Floral display and habitat quality affect cost of reproduction in Primula farinosa

Costs of reproduction should depend on resource availability and on reproductive effort, which in turn may depend on traits influencing reproductive success. Therefore, variation in both habitat quality and reproductive traits should be considered when assessing reproductive costs. We investigated the effect of habitat quality and floral display on the costs of reproduction in the perennial herb Primula farinosa. In the study area, P. farinosa occurs in habitats that differ in water availability, which strongly influences plant performance. Furthermore, it displays a scape length dimorphism, with two distinct scape morphs differing in attractiveness to pollinators and reproductive success. To test the hypothesis that the cost of fruit production is higher in the long‐scaped than in the short‐scaped morph, and depends on water availability, we manipulated reproductive investment in eight P. farinosa populations along a gradient of soil moisture. Fruit set was higher in long‐scaped individuals, and prevention of fruit set increased flower production in the following year among long‐scaped, but not among short‐scaped plants. Furthermore, costs of fruit production were evident at low and high moisture levels but not at intermediate levels. The results demonstrate an association between a genetically determined difference in floral display and cost of reproduction, and suggest that costs of reproduction are non‐linearly related to water availability. They thus indicate links between the evolution of plant reproductive traits and plant life histories, and between habitat quality and optimal life history.

Over-expression of AtPAP2 in Camelina sativa leads to faster plant growth and higher seed yield

BackgroundLipids extracted from seeds of Camelina sativa have been successfully used as a reliable source of aviation biofuels. This biofuel is environmentally friendly because the drought resistance, frost tolerance and low fertilizer requirement of Camelina sativa allow it to grow on marginal lands. Improving the species growth and seed yield by genetic engineering is therefore a target for the biofuels industry. In Arabidopsis, overexpression of purple acid phosphatase 2 encoded by Arabidopsis (AtPAP2) promotes plant growth by modulating carbon metabolism. Overexpression lines bolt earlier and produce 50% more seeds per plant than wild type. In this study, we explored the effects of overexpressing AtPAP2 in Camelina sativa.ResultsUnder controlled environmental conditions, overexpression of AtPAP2 in Camelina sativa resulted in longer hypocotyls, earlier flowering, faster growth rate, higher photosynthetic rate and stomatal conductance, increased seed yield and seed size in comparison with the wild-type line and null-lines. Similar to transgenic Arabidopsis, activity of sucrose phosphate synthase in leaves of transgenic Camelina was also significantly up-regulated. Sucrose produced in photosynthetic tissues supplies the building blocks for cellulose, starch and lipids for growth and fuel for anabolic metabolism. Changes in carbon flow and sink/source activities in transgenic lines may affect floral, architectural, and reproductive traits of plants.ConclusionsLipids extracted from the seeds of Camelina sativa have been used as a major constituent of aviation biofuels. The improved growth rate and seed yield of transgenic Camelina under controlled environmental conditions have the potential to boost oil yield on an area basis in field conditions and thus make Camelina-based biofuels more environmentally friendly and economically attractive.

INTELLIGENT IRRIGATION OF LOWBUSH BLUEBERRIES IN ATLANTIC CANADA

A four-year field study was conducted at two commercial sites in Atlantic Canada: Tracadie, New Brunswick and Debert, Nova Scotia to: 1) evaluate the use of the fully-automated Intelligent Irrigation System in the protection of lowbush blueberry plants from drought stress and spring frosts; and 2) investigate the impact of different irrigation regimes on plant vegetative and reproductive traits, vegetation dynamics and foliar diseases. The rainy conditions of the growing seasons minimized the need for irrigation and mitigated any treatment effects, thus rendering the results of the drought stress portion of the study inconclusive. However, the yield findings suggest that irrigating for frost protection holds promise where late spring frosts are common and coincide with flowering. The advisability of investing in any irrigation system for use in the commercial production of lowbush blueberries in Atlantic Canada will be dependent on emerging regional climate trends.

Evolutionary changes in plant reproductive traits following habitat fragmentation and their consequences for population fitness

Summary1. The effects of habitat fragmentation on plant population genetic structure and diversity are relatively well studied. Yet, most of these studies used molecular tools focusing on neutral genetic markers, and much less is known about the potential evolutionary consequences of habitat fragmentation on ecologically relevant plant traits.2. It can be expected that the altered biotic and abiotic conditions and limited gene flow following habitat fragmentation may impose strong selection pressures on traits important for plant fitness. Responses to these selection pressures may, however, be hampered by reduced genetic diversity through genetic drift. Conversely, evolutionary changes in flower or dispersal traits may itself impact the strength of inbreeding and genetic drift.3. In this review, we highlight different reproductive plant traits that may be under selection following habitat fragmentation, and we examine studies that have shown indications for rapid evolutionary responses.4. There are still relatively few studies that have convincingly shown that habitat fragmentation generates rapid evolutionary responses. Separating genetic from plastic trait responses and quantifying the long‐term fitness consequences of evolutionary changes in plant traits also remain major challenges.5. Synthesis. Many plant traits may be subject to selection following habitat fragmentation, but, until now, studies that quantified evolutionary responses to habitat fragmentation are limited. To study the consequences of changing plant traits for population fitness, we advocate applying population models that link demographic vital rates, the responding plant traits and their heritability.

Glacial history and local adaptation explain differentiation in phenotypic traits in the Alpine grassland herb Campanula barbata

Background: Quaternary glaciations have affected the phylogeographic structure of many widespread plant species of the European Alps. Survival of plants in isolated refugia on the fringes of the Alps has been proposed as a main driver for molecular differentiation within species across the Alps, and could also be responsible for phenotypic differentiation. Aims: To establish if phenotypic differentiation is in accordance with phylogeographic structure and if population differentiation reflects adaptive processes. Methods: In a common garden we measured vegetative and reproductive traits of plants from 15 populations of two phylogeographic lineages of Campanula barbata from subalpine grasslands across the Alps. Results: The two phylogeographic lineages were differentiated in plant height and number of inflorescences, suggesting that glacial history affected phenotypic differentiation, either through neutral processes or adaptation. Furthermore, negative correlations of number of leaves, plant height, number of flowers and above-ground biomass with altitude of population origin indicated that part of the observed differentiation among populations was due to adaptation to current altitude-related conditions either during or after recolonisation. Conclusions: Our results suggest that phenotypic differentiation across the investigated regions may be due to glacial history-related processes as well as due to more recent processes of local adaptation.

Correlation between phenotype and proteome in the Ni hyperaccumulator Noccaea caerulescens subsp. caerulescens

The metallicolous population Noccaea caerulescens subsp. caerulescens (formerly Thlaspi caerulescens) of Monte Prinzera (MP) (Italy) is a well-known example of a hyperaccumulator. MP has a serpentine soil in which concentrations of Ni can be as high as 2500 mg kg −1. The absence of N. caerulescens in the nearby non-ophiolitic soils along with its growth and reproductive traits, make this population an interesting model to study adaptation to extreme environments. Different phenotypes of N. caerulescens were identified in sub-sites differing in their geo-morphology. Differences in morphological and reproductive traits of plants were found through multivariate statistical analysis and were correlated with soil parameters, such as pH, organic matter content, water and Ni content. Phenotypic variability was correlated at the molecular level with proteome variation. Transcriptional regulators and signal transduction factors were differentially abundant in the sub-populations. We hypothesise that these proteomic variations may be relevant for adaptation of N. caerulescens to specific micro-habitats, at the same time revealing a general trade-off between plants and environment in terms of costs and benefits.

Checking the status of infraspecific taxa within Galactia jussiaeana (Fabaceae) using Berg's correlation-pleiades hypothesis

Berg's correlation-pleiades hypothesis proposes that phenotypic variation between plant vegetative and reproductive traits is decoupled (i.e. varies independently) due to different selective pressures: pollinators in reproductive traits and environment in vegetative traits. We used this hypothesis to check if the intraspecific leaf variation in Galactia jussiaeana is accompanied by an equal variation in floral traits. If so, we might be facing a process of divergence between the two lineages, since differences in floral morphology could restrict gene flow due to a mismatch with pollinators. Our results showed that there was no correlation between the variation in vegetative and reproductive traits in G. jussiaeana var. angustifolia, demonstrating that both are genetically uncoupled and respond to different selective pressures. There were also no significant differences in reproductive structures between the alternative and the typical variety. For these reasons, we propose the synonymization of G. jussiaeana var. angustifolia under G. jussiaeana.

The role of reproductive plant traits and biotic interactions in the dynamics of semi-arid plant communities

The dynamics of semi-arid plant communities are determined by the interplay between competition and facilitation among plants. The sign and strength of these biotic interactions depend on plant traits. However, the relationships between plant traits and biotic interactions, and the consequences for plant communities are still poorly understood. Our objective here was to investigate, with a modelling approach, the role of plant reproductive traits on biotic interactions, and the consequences for processes such as plant succession and invasion. The dynamics of two plant types were modelled with a spatially-explicit integrodifferential model: (1) a plant with seed dispersal (colonizer of bare soil) and (2) a plant with local vegetative propagation (local competitor). Both plant types were involved in facilitation due to a local positive feedback between vegetation biomass and soil water availability, which promoted establishment and growth. Plants in the system also competed for limited water. The efficiency in water acquisition (dependent on reproductive and growth plant traits) determined which plant type dominated the community at the steady state. Facilitative interactions between plant types also played an important role in the community dynamics, promoting establishment in the driest conditions and recovery from low biomass. Plants with vegetative propagation took advantage of the ability of seed dispersers to establish on bare soil from a low initial biomass. Seed dispersers were good invaders, maintained high biomass at intermediate and high rainfall and showed a high ability in taking profit from the positive feedback originated by plants with vegetative propagation under the driest conditions. However, seed dispersers lost competitiveness with an increasing investment in fecundity. All together, our results showed that reproductive plant traits can affect the balance between facilitative and competitive interactions. Understanding this effect of plant traits on biotic interactions provides insights in processes such as plant succession and shrub encroachment.

Personal perspectives in the life sciences for the Royal Society's 350th anniversary

2010 is the 350th anniversary of the Royal Society. The Philosophical Transactions of the Royal Society , first published in 1665, while being a few years younger than the society itself, is still the oldest scientific journal printed in the English-speaking world and the world's longest running

Conservation and restoration of plant–animal mutualisms on oceanic islands

Islands harbour much of the world’s threatened biodiversity. Recent work has highlighted how it is not species diversity per se but rather the interactions between organisms that breathes life into ecosystems. Thus, the real challenge to preserving and restoring biodiversity on islands is not to only focus on species themselves, but more importantly on maintaining and restoring the integrity of interactions between the species. Here we argue that mutualistic plant–animal interactions play a pivotal role with regards to conservation and restoration on islands. Furthermore, these interactions are ideally suited for inter-island comparisons due to ecological and evolutionary similarities across geographical and taxonomical boundaries. The similarities include highly generalised mutualistic systems, the evolution and readjustment of plant reproductive traits, and a disharmony in taxonomic groups of mutualists, compared to continental ecosystems. We highlight past and present threats to island plant–animal mutualisms, as well as the challenges and opportunities inherent to these interactions. In particular, we (1) argue that mutualistic networks provide an ideal approach to collect information and advance our knowledge on the systems, (2) suggest the use of interactions as biodiversity monitoring and assessment tools, (3) highlight the differences and similarities between pollination and seed dispersal interactions in the context of restoration, and (4) briefly discuss the ambiguous role of alien invasive species in the management of mutualistic interactions. Finally, we highlight how a recently proposed but controversial restoration strategy, rewilding, can be gainfully applied to and further advanced in island settings. & 2009 R ¨

Host specificity, phenotype matching and the evolution of reproductive isolation in a coevolved plant–pollinator mutualism

Coevolutionary interactions between plants and their associated pollinators and seed dispersers are thought to have promoted the diversification of flowering plants (Raven 1977; Regal 1977; Stebbins 1981). The actual mechanisms by which pollinators could drive species diversification in plants are not fully understood. However, it is thought that pollinator host specialization can influence the evolution of reproductive isolation among plant populations because the pollinator's choice of host is what determines patterns of gene flow in its host plant, and host choice may also have important consequences on pollinator and host fitness (Grant 1949; Bawa 1992). In this issue of Molecular Ecology, Smith et al. (2009) present a very interesting study that addresses how host specialization affects pollinator fitness and patterns of gene flow in a plant host. Several aspects of this study match elements of a seminal mathematical model of plant-pollinator codivergence (Kiester et al. 1984) suggesting that reciprocal selection for matched plant and pollinator reproductive traits may lead to speciation in the host and its pollinator when there is strong host specialization and a pattern of geographic subdivision. Smith et al.'s study represents an important step to fill the gap in our understanding of how reciprocal selection may lead to speciation in coevolved plant-pollinator mutualisms.

Determinants of fruit removal in Geonoma pauciflora, an understory palm of neotropical forests

AbstractCompetition for seed dispersers is supposedly a selective force that drives the evolution of plant reproductive traits. In the understory of tropical forests, such competition should be especially severe among bird‐dispersed plant species because (i) the production of copious fruit crops is limited by low light availability; (ii) there usually is a high density of fleshy fruited plants, and (iii) understory frugivorous birds are not abundant. In this paper, we took advantage of a high‐density population of Geonoma pauciflora, a bird‐dispersed palm species growing in the understory of the Brazilian Atlantic forest, to investigate the influence of plant traits and its immediate neighborhood on fruit removal. Intrinsic (crop and fruit sizes) and extrinsic traits (related to light availability) affected the fruit removal of G. pauciflora. Crop size had a greater influence than fruit size on the absolute number of fruits removed, whereas none of the investigated traits influenced decisively fruit removal efficiency (i.e., the proportion of an individual's crop removed). The influence of light availability was mostly indirect, through its positive influence on fruit production. A significant positive spatial autocorrelation in removal efficiency occurred among neighboring plants within a 7‐m radius, which is indicative of facilitation among neighboring individuals. The consequence of such positive spatial autocorrelation in removal efficiency for clonal plants such as G. pauciflora is that by attracting a frugivore a given ramet may promote the removal of fruits of other ramets, thus enhancing the reproductive output of the genet as a whole.

Reproductive output of invasive versus native plants

ABSTRACTAim Propagule size and output are critical for the ability of a plant species to colonize new environments. If invasive species have a greater reproductive output than native species (via more and/or larger seeds), then they will have a greater dispersal and establishment ability. Previous comparisons within plant genera, families or environments have conflicted over the differences in reproductive traits between native and invasive species. We went beyond a genus‐, family‐ or habitat‐specific approach and analysed data for plant reproductive traits from the global literature, to investigate whether: (1) seed mass and production differ between the original and introduced ranges of invasive species; (2) seed mass and production differ between invasives and natives; and (3) invasives produce more seeds per unit seed mass than natives.Location Global.Methods We combined an existing data set of native plant reproductive data with a new data compilation for invasive species. We used t‐tests to compare original and introduced range populations, two‐way ANOVAs to compare natives and invasives, and an ANCOVA to examine the relationship between seed mass and production for natives and invasives. The ANCOVA was performed again incorporating phylogenetically independent contrasts to overcome any phylogenetic bias in the data sets.Results Neither seed mass nor seed production of invasive species differed between their introduced and original ranges. We found no significant difference in seed mass between invasives and natives after growth form had been accounted for. Seed production was greater for invasive species overall and within herb and woody growth forms. For a given seed mass, invasive species produced 6.7‐fold (all species), 6.9‐fold (herbs only) and 26.1‐fold (woody species only) more seeds per individual per year than native species. The phylogenetic ANCOVA verified that this trend did not appear to be influenced by phylogenetic bias within either data set.Main conclusions This study provides the first global examination of both seed mass and production traits in native and invasive species. Invasive species express a strategy of greater seed production both overall and per unit seed mass compared with natives. The consequent increased likelihood of establishment from long‐distance seed dispersal may significantly contribute to the invasiveness of many exotic species.

The genetic diversity of perennial Leymus chinensis originating from China

Summary Leymus chinensis is an economically and ecologically important grass that is widely distributed across eastern areas of the Eurasian steppe. A better knowledge of genetic diversity of L. chinensis could be valuable in the efficient utilization, conservation and management of germplasm collections. Genetic diversity in thirty‐seven morphological characters of 293 accessions was assessed in three successive years. Based on these qualitative and quantitative characters, the genetic diversity indices (Shannon indices) of traits and geographical populations were estimated, and a principal coordinates analysis and a path analysis were undertaken. Compared with the yellow‐green type of L. chinensis, the grey‐green type had significantly (P < 0·05) more genetic diversity. In addition, the path analysis suggested that the combined effects of genetic diversity and vegetative traits could explain 0·206 of the total variance in plant reproductive traits. The highest Shannon genetic diversity index of accessions (H = 2·252) was observed in accessions from the region of longitude of 124–128°E, suggesting the most abundant germplasm of L. chinensis in this region.

The influence of photoperiod on the Vrn-H2 locus (4H) which is a major determinant of plant development and reproductive fitness traits in a facultative�נwinter barley (Hordeum vulgare L.) mapping population

To determine the effect of Vrn-H2 locus on plant developmental and agronomic traits, detailed controlled environment tests involving a factorial set of vernalization and photoperiod treatments were carried out using doubled haploid lines developed from a facultative (Vrn-H2 - ) x winter (Vrn-H2 + ) barley cross. The allele phase at the Vrn-H2 locus influenced heading date as well as the developmental and agronomic traits. The performance of Vrn-H2 + lines was significantly influenced by vernalization: reproductive fitness traits showed significant decreases without vernalization. However, the effects of alleles at the Vrn-H2 locus extended beyond simple satisfaction of the vernalization requirement. Vrn-H2 + lines showed increased reproductive fitness compared with Vrn-H2 - lines when vernalization was followed by a long photoperiod. The responses of the two Vrn-H2 allele classes to photoperiod duration were quite different in terms of heading date, developmental and agronomic traits. These results suggest that alleles at the Vrn-H2 locus - and/or tightly linked gene(s) - respond primarily to the exogenous signal of vernalization (temperature), but when the vernalization requirement has been fulfilled, they also respond to photoperiod duration.

The diversity and conservation of plant reproductive and dispersal functional traits in human‐dominated tropical landscapes

Summary Human‐altered landscapes dominate the planet, yet little is known about their capacity to sustain plant functional diversity. Most conservation‐orientated studies of such landscapes focus on species diversity, whereas less attention is given to functional traits and their conservation. We examine the functional diversity of herbaceous and shrubby plant communities in three forest habitats (understorey, tree‐fall gaps and riverbanks) and three deforested habitats (pasture, roadside vegetation and pasture riverbanks), each replicated in three human‐dominated landscapes in southern Costa Rica. We focus on six categorical traits related to forest regeneration, reproduction and dispersal: pollination mechanism, dispersal mechanism, growth form, fruit type, fruit size and seed size. We compared trait state richness and composition of each trait in forested and deforested habitats and how three pollination states (bat, bird and bee pollination) and three dispersal states (fur, bird and monkey dispersal) of conservation interest were distributed across these landscapes. Only one trait state was missing from forest, and none was missing from deforested habitats. Understorey and pasture were consistently trait state poor. Forested and deforested plots differed in trait state composition for all traits. Pasture riverbanks and road verges were compositionally similar to forest riverbanks and tree‐fall gaps, for multiple traits. There were more compositional similarities between forested and deforested habitat types when abundance of individuals with a trait state was used as the basis for similarity measures than when the number of species with each trait state was used. Bat‐, bird‐ and bee‐pollinated plants and plants with bird‐ and monkey‐dispersed fruits were most common in forest and pasture riverbanks whereas species with fur‐dispersed seeds were more common in all deforested habitats. Functional diversity patterns were inconsistent across habitat types and locations but overall functional similarity was high between forested and deforested communities. Patterns of functional diversity were far more variable between habitats and landscapes than the consistent patterns found previously for species diversity.

A REVIEW ON RESPONSES OF PLANT SEXUAL REPRODUCTION TO ELEVATED CO<inf>2</inf>

Plant reproductive traits are key characteristics for predicting the impacts of global changes on plant community, agro_ecosystem and plant ecological fitness. This review seeks to integrate current results about the effects of elevated CO_2 on plant reproductive traits in detail based on the existing experimental data in the past few decades. Earlier investigations demonstrate that elevated CO_2 advances the flowering time through increasing relative growth rate and accelerating developmental process. All the numbers of flowers, fruits, and seeds, the mass of seed as well as the production of pollen and nectar of plants have been found to be stimulated by CO_2 enrichment. It is further revealed that the increase in plant yields results largely from an increase in seed number rather than from individual seed mass. Elevated CO_2 concentrations have little effect on seed [N] of legumes, but significantly reduce seed [N] of most nonlegumes. Contents of proteins, amino acids, and some mineral ions usually decrease in seeds of most nonlegumes. Different functional groups of plants are often found to differ markedly in their reproductive responses to elevated CO_2: 1) crops allocate more mass to reproduction and produce more fruits and seeds than do undomesticated species; 2) indeterminate plants have stronger responses to elevated CO_2 in comparison with determinate species; 3) legumes are most responsive to elevated CO_2, followed by nonlegume C_3 species, then C_4 species. Based on the data available, it seems rational to believe that changes in plant reproductive traits resulting from elevated CO_2 may alter the competitive hierarchy, the species composition, and hence the functioning of plant community. Finally, some issues noteworthy for future researches in this field are also put forward with reference to the existing unsolved questions.

The relationship between psyllid leaf galls and redbay (Persea borbonia) fitness traits in sun and shade

The interactions between Persea borbonia (redbay), its psyllid leaf gallers, and its seed predators were examined in field conditions using natural differences in light levels in order to determine (a) the distribution of galls relative to light availability, (b) the relationship between galls and plant growth and reproductive traits and (c) the relationship between gallers and seed predators. Galls were more abundant in shade than sun across sites. This finding is consistent with the Sink Competition Hypothesis, which predicts higher gall loads on plants with longer internodes (as those in shade) and hence less competition among sinks. Galled leaves were smaller and senesced more rapidly, and galled shoots grew less. In the sun, galled branches produced fewer flowers, but there was ultimately no relationship between gall load and seed production in the year sampled. Gall load was not correlated with seed predation in sun or shade, suggesting no indirect interactions between herbivores. This work suggests that gall insects negatively affect plant growth and reproduction, but manipulative experiments must be conducted to confirm this. Additionally, this study suggests that relationships between leaf gall load and plant fitness traits may not be clearly regulated by the availability of sunlight resources to the plant.

Unexpected insularity effects in invasive plant mating systems: the case of Carpobrotus (Aizoaceae) taxa in the Mediterranean Basin

Although biological invasions are currently recognized as being especially severe on islands, little attention has been given to detecting parameters influencing this pattern. This study tested the common perceptions that uniparental reproductive modes are associated with invasive and/or island plant populations due to a lack of pollinator vectors and/or small initial population sizes, and that pollinator services and biparental seed production modes will subsequently be associated with adjacent mainland sites. Using controlled pollination and germination experiments on invasive Carpobrotus edulis and C. aff. acinaciformis populations in both island and mainland habitats in south-east France, we found no evidence to support these hypotheses. All significant mean differences found between locations for reproductive indices describing uniparental reproductive modes were significantly smaller in island populations. In contrast, seedling sizes issuing from manual outcrossing and manual hybridization experiments, regardless of taxon, as well as C. aff. acinaciformis hybridization indices, were larger in island populations. The presence of significant, though limited, pollinator service was detected for all populations, and stressed the importance of such mutualisms. We suggest that invasive plant reproductive traits could be highly contextual, and that islands may have a potential role in the acceleration of the invasion process through the production of highly variable populations. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 65‐79. ADDITIONAL KEYWORDS: agamospermy ‐ hybrid vigour ‐ inbreeding depression ‐ island invasion ‐ pollinator limitation ‐ self fertilization.

Sexual selection: an evolutionary force in plants?

Sexual selection has traditionally been used to explain exaggerated sexual traits in male animals. Today the concept has been developed and various other sexually related traits have been suggested to evolve in the same manner. In nearly all new areas where the theory of sexual selection has been applied, there has been an intense debate as to whether the application is justified. Is it the case that some scientists are all too ready to employ fashionable ideas? Or are there too many dogmatic researchers refusing to accept that science develops and old ideas are transformed? Maybe the controversies are simply a reflection of the difficulty of defining a theory under constant re-evaluation. Thus, we begin by summarizing the theory of sexual selection in order to assess the influence of sexual selection on the evolution of plant morphology. We discuss empirical findings concerning potentially affected traits. Although we have tried to address criticisms fairly, we still conclude that sexual selection can be a useful tool when studying the evolution of reproductive traits in plants. Furthermore, by including the evidence from an additional kingdom, a fuller understanding of the processes involved in sexual selection can be gained.