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1.
Gene ; 747: 144698, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32325091

RESUMO

Stamen development is an important developmental process controlled by multiple internal and external factors. Developmental abnormalities of stamens can disrupt the structure and function of anthers, and then result in male sterility. As well known, APETELA 3 (AP3) has a clear function in regulating stamen development, which may impact in male sterility. However, the mechanisms of stamen development and male sterility controlled by AP3 are still not very clear, particular in Pak-choi (Brassica rapa ssp. chinensis). In this work, BcAP3 encoded a protein containing a MADS-box domain, which was a homolog of AtAP3, was identified in Pak-choi. Sequence alignments and phylogenetic analysis indicated that BcAP3 was highly similar to AtAP3. BcAP3 was shown to be localized to the nucleus and exhibited the potential of transcription factor. The transcript of BcAP3 was only expressed in flowers of Pak-choi, indicating that it may act in flower development. Overexpression of BcAP3 in Arabidopsis resulted in developmental abnormalities of anther wall and low vigor pollen, which were associated with the phenotype of male sterility. Expression levels of NST1 and NST2, involved in secondary wall thickening in anther walls, were significantly higher in the BcAP3-transgenic plants than in control plants, suggesting that BcAP3 may affect anther wall development by regulating NST1 and NST2. Taken together, our study demonstrated that BcAP3 could play an essential role in stamen development and male sterility.


Assuntos
Brassica rapa/crescimento & desenvolvimento , Brassica rapa/genética , Flores/crescimento & desenvolvimento , Flores/genética , Genes de Plantas , Proteínas de Domínio MADS/genética , Infertilidade das Plantas/genética , Proteínas de Plantas/genética , Sequência de Aminoácidos , Regulação da Expressão Gênica de Plantas , Proteínas de Domínio MADS/metabolismo , Fenótipo , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Pólen , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
2.
Am J Bot ; 107(4): 587-598, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32227341

RESUMO

PREMISE: Variation in local density and sex ratio in dioecious plants can affect mating success through the actions of pollen vectors, principally generalist insects or wind. Increased density and male-biased sex ratios should promote pollen transfer and seed production, but their combined effects have not been investigated for ambophilous species, which exhibit both insect and wind pollination. METHODS: We manipulated density (low vs. high) and sex ratio (1:1 vs. 3:1 male-biased) in arrays of dioecious ambophilous Thalictrum pubescens. We quantified visitation rates and foraging times to examine whether pollinators exhibited sex-specific preferences and determined the seed set of arrays. RESULTS: Pollinators visited more plants per foraging bout at high than low density. Visitation rates and foraging times of visitors were greater for male than for female plants but did not depend on the density or sex ratio of arrays. However, whereas solitary bees displayed a strong preference for males, hover flies were indifferent to plant sex phenotype. Solitary bees also visited significantly more plants per foraging bout than hover flies. There was a significant interaction between density and sex ratio on seed set. At low density, seed set was greater for 3:1 than for 1:1 arrays, but at high density the opposite pattern occurred. CONCLUSIONS: The demographic factors we investigated had complex influences on pollinator foraging behavior and patterns of seed set. Several factors may explain our results, including the influence of density and sex ratio on pollen export from arrays, grooming by pollinators, and the contribution of wind pollination.


Assuntos
Magnoliopsida , Polinização , Animais , Abelhas , Feminino , Flores , Insetos , Masculino , Pólen , Razão de Masculinidade
3.
Oecologia ; 192(4): 1037-1045, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32274585

RESUMO

Plant-pollinator network studies have uncovered important generalities in the structure of these communities, rapidly advancing our understanding of the underlying drivers of such a structure. In spite of this, however, it is still unclear how changes in structural network properties influence overall plant pollination success. One key limitation is the lack of information on the relationship between network structural properties and aspects of pollination and plant reproductive success. Here, we estimate four plant species network structural metrics (interaction strength, weighted degree, closeness centrality, and specialization level), commonly used to describe their importance within plant-pollinator networks, at two different sites, and evaluate their effects on pollen deposition and pollen tube success. We found a positive effect of plant-pollinator specialization and a negative effect of closeness centrality on heterospecific pollen load size. We also found a marginal negative effect of closeness centrality on pollen tube success. Our results suggest that increasing plant-pollinator specialization within nested communities (pollinated by one or very few generalist insect species) may result in high levels of heterospecific pollen transfer. Furthermore, the differential effects of plant-pollinator network metrics on pollination success (pollen receipt and pollen tube success), highlight the need to integrate quantity (e.g. visitation rate) and quality (e.g. pollen delivery) aspects of pollination to achieve a more mechanistic understanding of the relationship between plant-pollinator network structure and function. Such knowledge is key to evaluate the resilience and stability of plant-pollinator communities and the services they provide in the face of increasing human disturbances.


Assuntos
Pólen , Polinização , Animais , Flores , Insetos , Plantas , Reprodução
4.
Medicine (Baltimore) ; 99(10): e19469, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32150106

RESUMO

The profiles of sensitization based on component-resolved diagnosis (CRD) differ from region to region in populations sensitized to birch pollen. We investigated the endotypes of birch pollen-sensitized Korean children with allergic diseases using CRD and distinguished the endotypes of oral allergy syndrome (OAS) among them.Thirty-one birch pollen-sensitized children with allergic diseases were enrolled. Specific immunoglobulin E (IgE) to birch pollen and fruit including apple, peach, and kiwi were evaluated via skin prick tests and ImmunoCAP in all subjects. Sensitization profiles based on CRD were evaluated with the Immuno-solid-phase Allergen Chip for birch pollen-sensitization using birch pollen components (Bet v 1, Bet v 2, and Bet v 4), and for OAS using the allergen families pathogenesis-related class 10 proteins (PR-10), lipid transfer proteins, and profilin.All patients (n = 13) with OAS were sensitive to Bet v 1. However, 61% (11/18) of patients without OAS were sensitized to Bet v 1. The level of specific IgE to Bet v 1 was higher in patients with OAS than in those without OAS. All birch pollen-sensitized Korean children with OAS were sensitized to PR-10, and 69% (9/13) of them were mono-sensitized to PR-10. Among patients without OAS, 33% (6/18) were not sensitized to any of the allergen families.Birch pollen-sensitized Korean children with allergic diseases showed unique patterns of sensitization to Bet v 1, Bet v 2, and Bet v 4, and the sensitization profiles based on CRD were totally different according to the presence of OAS.


Assuntos
Alérgenos/imunologia , Betula/imunologia , Hipersensibilidade Alimentar/imunologia , Pólen/imunologia , Adolescente , Criança , Pré-Escolar , Reações Cruzadas , Feminino , Hipersensibilidade Alimentar/complicações , Frutas/imunologia , Humanos , Masculino , Reprodutibilidade dos Testes , República da Coreia , Sensibilidade e Especificidade , Testes Cutâneos
5.
Plant Mol Biol ; 103(1-2): 9-32, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32124177

RESUMO

KEY MESSAGE: In light of the available discoveries in the field, this review manuscript discusses on plant reproduction mechanism and molecular players involved in the process. Sperm cells in angiosperms are immotile and are physically distant to the female gametophytes (FG). To secure the production of the next generation, plants have devised a clever approach by which the two sperm cells in each pollen are safely delivered to the female gametophyte where two fertilization events occur (by each sperm cell fertilizing an egg cell and central cell) to give rise to embryo and endosperm. Each of the successfully fertilized ovules later develops into a seed. Sets of macromolecules play roles in pollen tube (PT) guidance, from the stigma, through the transmitting tract and funiculus to the micropylar end of the ovule. Other sets of genetic players are involved in PT reception and in its rupture after it enters the ovule, and yet other sets of genes function in gametic fusion. Angiosperms have come long way from primitive reproductive structure development to today's sophisticated, diverse, and in most cases flamboyant organ. In this review, we will be discussing on the intricate yet complex molecular mechanism of double fertilization and how it might have been shaped by the evolutionary forces focusing particularly on the model plant Arabidopsis.


Assuntos
Flores/fisiologia , Magnoliopsida/fisiologia , Polinização/fisiologia , Evolução Biológica , Gametogênese Vegetal , Óvulo Vegetal/fisiologia , Pólen/fisiologia , Sementes
6.
Am J Bot ; 107(4): 689-699, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32170723

RESUMO

PREMISE: Water-pollination (hydrophily) is a rare but important pollination mechanism that has allowed angiosperms to colonize marine and aquatic habitats. Hydrophilous plants face unique reproductive challenges, and many have evolved characteristic pollen traits and pollination strategies that may have downstream consequences for pollen performance. However, little is known about reproductive development in the life history stage between pollination and fertilization (the progamic phase) in hydrophilous plants. The purpose of this study was to characterize reproductive ecology and postpollination development in water-pollinated Ruppia maritima L. METHODS: Naturally pollinated inflorescences of R. maritima were collected from the field. Experimental pollinations using both putatively outcross and self pollen were conducted in the greenhouse and inflorescences were collected at appropriate intervals after pollination. Pollen reception, pollen germination, pollen tube growth, and carpel morphology were characterized. RESULTS: Ruppia maritima exhibits incomplete protogyny, allowing for delayed selfing. Pollen germinated within 15 min after pollination. The average shortest possible pollen tube pathway was 425 µm and pollen tubes first reached the ovule at 45 min after pollination. The mean adjusted pollen tube growth rate was 551 µm/h. CONCLUSIONS: Ruppia pollen is adapted for rapid pollen germination, which is likely advantageous in an aquatic habitat. Small effective pollen loads suggest that pollen competition intensity is low. Selection for traits such as a long period of stigma receptivity, fast pollen germination, and carpel morphology likely played a larger role in shaping postpollination reproductive development in Ruppia than evolution in pollen tube growth rates.


Assuntos
Alismatales , Magnoliopsida , Pólen , Polinização , Reprodução
7.
Int J Biometeorol ; 64(5): 791-801, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32006117

RESUMO

This paper analyzes a long-term (1991-2019) flowering period of birch in the Czech Republic. Temporal and spatial evaluation in timing of beginning and end of flowering (Fbegin and Fend) and flowering period (Fperiod) of Betula pendula were investigated in different zones of the Czech Republic. The field observations were carried out at 44 sites of the Czech Hydrometeorological Institute phenological network; the detailed analysis including growing degree days (GDD) evaluation to Fbegin and Fend onsets and time of flowering were made at 9 sites in different altitudes. The trends and Pearson's correlation coefficients between Fbegin (Fend) and GDDs were calculated as well. The timing of both phenological stages showed a significant advance to earlier onsets (e.g., - 7.0 d per decade at Medenec station) and the time of flowering shortens (e.g., - 3.8 d per decade at Rokytnice station). Nevertheless, the most marked shift was observed for mountain area in the north-western and north-eastern part of the Czech Republic. In contrast, the smallest shift was found in the southern part of the Czech Republic. The shift of the GDD values fluctuates from negative to positive values. Pearson's correlation coefficients calculated for both phenophases and period of flowering of Betula pendula showed the highest values in Fperiod (e.g., 0.846 at Modrava station) and in Fend (e.g., 0.711 at Rokytnice station) as well. Thus, our results indicate due to global warming symptoms that birch pollen allergy may appear earlier in the year but for a shorter period.


Assuntos
Betula , Mudança Climática , República Tcheca , Flores , Pólen , Estações do Ano , Temperatura
8.
Artigo em Chinês | MEDLINE | ID: mdl-32086889

RESUMO

Objective:There is no standard algorithm for the modulation of pharmacologic treatment of allergic rhinitis. This study aimed to recruited allergic rhinitis patients caused by cypress pollens, and compare the step-down pharmacotherapy guided by pollen count and the maintaining therapy which keeps the previous medicine dose when the pollen count decreased. Method:This was a randomized, open-labelled, parallel control study. During the period after the pollen peak when the cypress pollen count decreased and stayed at a low level, allergic rhinitis patients were randomly divided into two groups. In the step-down group(n=67) medicine dose was reduced, while the maintaining group(n=68) kept taking the same dose as in the peak season. The rhinitis symptom score and medicine score of these two groups were recorded and compared. Result:The daily rhinitis symptom score of the step-down group showed no significant difference with the symptom score of the maintaining group, 2.45±0.32 vs 2.43±0.41, P=0.788. But the medicine score of step-down group(3.67±0.98) was significantly lower than that of maintaining group(4.78±0.70), P<0.001. The compliance of step-down group(80.6%) was also better than maintaining group(60.3%), P=0.014. However, in the subgroup of patients with severe rhinitis symptoms, the symptoms of patients taking step-down therapy tended to be more severe than those maintaining the same dose. Conclusion:During the later period of the pollen season when the pollen count was relatively low, the step-down pharmacotherapy guided by pollen count could reduce the medication use, increase the compliance of patients while controlling their rhinitis symptoms effectively. But this strategy might be more suitable for patients with milder symptoms, the severe rhinitis sufferers should be cautious before reducing their medicine dose.


Assuntos
Esquema de Medicação , Rinite Alérgica Sazonal/tratamento farmacológico , Alérgenos , Cupressus , Humanos , Pólen , Estações do Ano
9.
BMC Ecol ; 20(1): 8, 2020 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-32039719

RESUMO

BACKGROUND: Breeding programs and research activities where artificial buzz-pollinations are required to have primarily relied upon using tuning forks, and bumble bees. However, these methods can be expensive, unreliable, and inefficient. To find an alternative, we tested the efficiency of pollen collection using electric toothbrushes and compared it with tuning forks at three vibration frequencies-low, medium, and high and two extraction times at 3 s and 16 s- from two buzz-pollinated species (Solanum lycopersicum and Solanum elaeagnifolium). RESULTS: Our results show that species, and extraction time significantly influenced pollen extraction, while there were no significant differences for the different vibration frequencies and more importantly, the use of a toothbrush over tuning fork. More pollen was extracted from S. elaeagnifolium when compared to S. lycopersicum, and at longer buzzing time regardless of the instrument used. CONCLUSIONS: Our results suggest that electric toothbrushes can be a viable and inexpensive alternative to tuning forks, and regardless of the instrument used and buzzing frequency, length of buzzing time is also critical in pollen extraction.


Assuntos
Lycopersicon esculentum , Polinização , Animais , Abelhas , Flores , Pólen
10.
Sci Total Environ ; 715: 136861, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32040996

RESUMO

Betulaceae family is a dominant tree pollen type in the atmosphere at Northwest Spain, being a major cause of allergenic rhinitis or asthma symptoms. Alnus pollen cause symptoms in the 9-20% of the total hay fever sufferers mean while the 41.89% of patients present a positive skin-prick-test for Betula allergens. Aln g1 and Bet v1 aeroallergens belong to PR-10 protein family and are associated to cross-reactivity processes. Airborne pollen and aeroallergens from Alnus and Betula were sampled during their Main Pollen Season from 2016 to 2019. Pollen sampling was conducted by means of a Hirst volumetric trap and aeroallergens were sampled using a Multi Vial Cyclone Sampler. Alnus flowering took place from January to February, with an average duration of 44 days. Betula bloom occurred from April to May with an average pollen season of 33 days. The major innovation of our study was the first detection of Aln g1 allergens in the atmosphere by using Bet v1 antibodies. This fact verified the cross-reactivity between the main allergens of Betula and Alnus pollen. Along the study period, an average of 18 days/year and 14 days/year with high potential risk of allergy due to Alnus pollen and allergen respectively, was registered. For Betula an average of 16 days/year with high potential risk of allergy due to pollen and 22 days for allergen was registered. The main consequence of the successive bloom of both trees would be the so-called "priming effect". Urban population sensitized to Betula pollen could suffer allergic symptoms during winter (as a consequence of Alnus), and in spring with the manifestation of higher symptoms under low birch pollen grain levels in the atmosphere. The traditional information to prevent allergies, such as the airborne pollen concentrations, should be combined with the data of aeroallergen to identify the real allergenic load in the atmosphere.


Assuntos
Betulaceae , Alérgenos , Betula , Pólen , Espanha
11.
Am J Bot ; 107(3): 445-455, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32086803

RESUMO

PREMISE: Flowering time may influence pollination success and seed set through a variety of mechanisms, including seasonal changes in total pollinator visitation or the composition and effectiveness of pollinator visitors. METHODS: We investigated mechanisms by which changes in flowering phenology influence pollination and reproductive success of Mertensia ciliata (Boraginaceae). We manipulated flowering onset of potted plants and assessed the frequency and composition of pollinator visitors, as well as seed set. We tested whether floral visitors differed in their effectiveness as pollinators by measuring pollen receipt and seed set resulting from single visits to virgin flowers. RESULTS: Despite a five-fold decrease in pollinator visitation over four weeks, we detected no significant difference in seed set among plants blooming at different times. On a per-visit basis, each bumblebee transferred more conspecific pollen than did a solitary bee or a fly. The proportion of visits by bumblebees increased over the season, countering the decrease in visitation rate so that flowering time had little net effect on seed set. CONCLUSIONS: This work illustrates the need to consider pollinator effectiveness, along with changes in pollinator visitation and species composition to understand the mechanisms by which phenology affects levels of pollination.


Assuntos
Boraginaceae , Polinização , Animais , Abelhas , Flores , Pólen , Reprodução
12.
Plant Reprod ; 33(1): 43-58, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32080762

RESUMO

Polyploidy or whole genome duplication is a frequent and recurrent phenomenon in flowering plants that has played a major role in their diversification, adaptation and speciation. The adaptive success of polyploids relates to the different evolutionary fates of duplicated genes. In this study, we explored the impact of the whole genome triplication (WGT) event in the Brassiceae tribe on the genes involved in the self-incompatibility (SI) signalling pathway, a mechanism allowing recognition and rejection of self-pollen in hermaphrodite plants. By taking advantage of the knowledge acquired on this pathway as well as of several reference genomes in Brassicaceae species, we determined copy number of the different genes involved in this pathway and investigated their structural and functional evolutionary dynamics. We could infer that whereas most genes involved in the SI signalling returned to single copies after the WGT event (i.e. ARC1, JDP1, THL1, THL2, Exo70A01) in diploid Brassica species, a few were retained in duplicated (GLO1 and PLDα) or triplicated copies (MLPK). We also carefully studied the gene structure of these latter duplicated genes (including the conservation of functional domains and active sites) and tested their transcription in the stigma to identify which copies seem to be involved in the SI signalling pathway. By taking advantage of these analyses, we then explored the putative origin of a contrasted SI phenotype between two Brassica rapa varieties that have been fully sequenced and shared the same S-allele (S60).


Assuntos
Evolução Biológica , Brassica , Genoma de Planta , Transdução de Sinais , Brassica/genética , Genoma de Planta/genética , Pólen , Transdução de Sinais/genética
13.
Am J Bot ; 107(2): 364-374, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32052420

RESUMO

PREMISE: Spiny pollen has evolved independently in multiple entomophilous lineages. Sexual selection may act on exine traits that facilitate male mating success by influencing the transfer of pollen from the anther to the body of the pollinator, while natural selection acts to increase pollen survival. We postulated that relative to sexual congeners, apomictic dandelions undergo relaxed selection on traits associated with male mating success. METHODS: We explored sexual selection on exine traits by measuring the propensity for Taraxacum spp. pollen to attach to hairs of flower-visiting bumblebees (Bombus spp.) or flies (Diptera: Syrphidae and Muscoidea) and assessed natural selection by testing whether pollen traits defend against consumption. RESULTS: Pollen picked up by bumblebees exhibited a narrower subset of spine-spacing phenotypes, consistent with stabilizing selection. Flies picked up larger pollen from flowers than expected at random. Surveys of corbiculae (pollen basket) contents from foraging bumblebees and feces of flies showed that pollen grains consumed by both kinds of visitors are similar in spine characteristics and size to those produced by the donor. When bees visit inflorescences of apomictic T. officinale, they pick up pollen with spine-spacing phenotypes above the mean and shifted toward those of sexual T. ceratophorum. CONCLUSIONS: We demonstrate that traits under sexual selection during pollen pickup vary among pollinators, while natural selection for pollen defense is nil in T. ceratophorum. In hybrid zones between apomictic and sexual dandelions, pollen traits place apomictic donors at a dispersal disadvantage, potentially reinforcing reproductive isolation.


Assuntos
Taraxacum , Animais , Abelhas , Flores , Pólen , Polinização , Seleção Genética
14.
Sci Total Environ ; 714: 136625, 2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-32018949

RESUMO

Understanding the mechanisms of pollen release and dispersion in the atmosphere is of high importance, not only for getting an insight on the patterns of movement of these biological particles that are necessary for plants' reproduction, but also because exposure to airborne pollen is a major concern for respiratory allergies worldwide. In this work, a synoptic circulation-to-environment classification method was adopted to elucidate the relationship between distinct atmospheric patterns and pollen levels for the 11 most abundant but also allergenic taxa in Thessaloniki, Greece, for the 15-year period 1987-2001. It was found that the NW1 depressional weather type is associated with the "low winter pollen season" and high levels of pollen from Carpinus spp., Corylus spp., Cupressaceae, Platanus spp., Pinaceae, Quercus spp. and Urticaceae. In contrast, the SW1 cyclonic type is linked to the "high spring-summer pollen season" and high levels of pollen from Oleaceae and Urticaceae. On the other hand, anticyclonic weather is associated with the "summer-autumn pollen season" and high levels of Poaceae and Chenopodiaceae pollen in the atmosphere. Regional transport of Alnus pollen is linked to a strong high-pressure system centered over Italy, giving light NE winds over northern Greece. These findings shed light to the synoptic climatology of airborne pollen in Thessaloniki and could feed early-warning systems for alerting vulnerable groups of the allergic population.


Assuntos
Pólen/química , Alérgenos , Monitoramento Ambiental , Grécia , Itália , Meteorologia , Estações do Ano
15.
PLoS One ; 15(2): e0228169, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32049993

RESUMO

Honey bee (Apis mellifera) colonies are valued for the pollination services that they provide. However, colony mortality has increased to unsustainable levels in some countries, including the United States. Landscape conversion to monocrop agriculture likely plays a role in this increased mortality by decreasing the food sources available to honey bees. Many land owners and organizations in the Upper Midwest region of the United States would like to restore/reconstruct native prairie habitats. With increasing public awareness of high bee mortality, many landowners and beekeepers have wondered whether these restored prairies could significantly improve honey bee colony nutrition. Conveniently, honey bees have a unique communication signal called a waggle dance, which indicates the locations of the flower patches that foragers perceive as highly profitable food sources. We used these communication signals to answer two main questions: First, is there any part of the season in which the foraging force of a honey bee colony will devote a large proportion of its recruitment efforts (waggle dances) to flower patches within prairies? Second, will honey bee foragers advertise specific taxa of native prairie flowers as profitable pollen sources? We decoded 1528 waggle dances in colonies located near two large, reconstructed prairies. We also collected pollen loads from a subset of waggle-dancing bees, which we then analyzed to determine the flower taxon advertised. Most dances advertised flower patches outside of reconstructed prairies, but the proportion of dances advertising nectar sources within prairies increased significantly in the late summer/fall at one site. Honey bees advertised seven native prairie taxa as profitable pollen sources, although the three most commonly advertised pollen taxa were non-native. Our results suggest that including certain native prairie flower taxa in reconstructed prairies may increase the chances that colonies will use those prairies as major food sources during the period of greatest colony growth and honey production.


Assuntos
Comunicação Animal , Abelhas , Pradaria , Comportamento de Nidação , Animais , Abelhas/metabolismo , Pólen/metabolismo
16.
Oecologia ; 192(4): 989-997, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32078036

RESUMO

Seed production is critical to the persistence of most flowering plant populations, but may be strongly pollen limited. To what extent long-lived plants can compensate pollen limitation by increasing future reproduction is poorly understood. We tested for compensation in two Dactylorhiza species that differ in reproductive investment by experimentally reducing and increasing pollination in two independent annual cohorts and monitoring demographic responses in the subsequent 2 years for the 2014 cohort and in 1 year for the 2015 cohort. Demographic rates in the second year were significantly affected by pollination treatment in both species, but specific responses differed both between species and years. There was no effect of pollination treatment on demographic responses in the third year. In sum, effects were too weak to make up for the lost reproduction; total fruit production across all 3 years was by far highest in the increased pollination treatment in both species. These results show that long-lived plants do not necessarily compensate for pollen limitation by increasing future reproduction. It further suggests that even periodic declines in pollination rates may have severe demographic consequences, particularly in populations where germination is not density dependent. This has implications for predicting plant population viability in response to changes in pollination intensity.


Assuntos
Magnoliopsida , Pólen , Flores , Polinização , Reprodução , Sementes
17.
Am J Bot ; 107(1): 164-170, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31889299

RESUMO

PREMISE: Variation in pollen-ovule ratios is thought to reflect the degree of pollen transfer efficiency-the more efficient the process, the fewer pollen grains needed. Few studies have directly examined the relationship between pollen-ovule ratio and pollen transfer efficiency. For active pollination in the pollination brood mutualisms of yuccas and yucca moths, figs and fig wasps, senita and senita moths, and leafflowers and leafflower moths, pollinators purposefully collect pollen and place it directly on the stigmatic surface of conspecific flowers. The tight coupling of insect reproductive interests with pollination of the flowers in which larvae develop ensures that pollination is highly efficient. METHODS: We used the multiple evolutionary transitions between passive pollination and more efficient active pollination to test if increased pollen transfer efficiency leads to reduced pollen-ovule ratios. We collected pollen and ovule data from a suite of plant species from each of the pollination brood mutualisms and used phylogenetically controlled tests and sister-group comparisons to examine whether the shift to active pollination resulted in reduced pollen-ovule ratios. RESULTS: Across all transitions between passive and active pollination in plants, actively pollinated plants had significantly lower pollen-ovule ratios than closely related passively pollinated taxa. Phylogenetically corrected comparisons demonstrated that actively pollinated plant species had an average 76% reduction in the pollen-ovule ratio. CONCLUSIONS: The results for active pollination systems support the general utility of pollen-ovule ratios as indicators of pollination efficiency and the central importance of pollen transfer efficiency in the evolution of pollen-ovule ratio.


Assuntos
Óvulo Vegetal , Polinização , Animais , Flores , Pólen , Simbiose
19.
Ecol Lett ; 23(3): 545-554, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31943632

RESUMO

Preventing malnutrition through consuming nutritionally appropriate resources represents a challenge for foraging animals. This is due to often high variation in the nutritional quality of available resources. Foragers consequently need to evaluate different food sources. However, even the same food source can provide a plethora of nutritional and non-nutritional cues, which could serve for quality assessment. We show that bumblebees, Bombus terrestris, overcome this challenge by relying on lipids as nutritional cue when selecting pollen. The bees 'prioritised' lipid perception in learning experiments and avoided lipid consumption in feeding experiments, which supported survival and reproduction. In contrast, survival and reproduction were severely reduced by increased lipid contents. Our study highlights the importance of fat regulation for pollen foraging bumblebees. It also reveals that nutrient perception, nutrient regulation and reproductive fitness can be linked, which represents an effective strategy enabling quick foraging decisions that prevent malnutrition and maximise fitness.


Assuntos
Comportamento Alimentar , Pólen , Animais , Abelhas , Nutrientes , Reprodução
20.
Sci Total Environ ; 713: 136611, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31958727

RESUMO

Artemisia pollen grains are important aeroallergens worldwide. The amount of allergenic proteins produced by pollen, or pollen allergenicity, is regulated by both genes and the environment. As a result, even closely related plant taxa may release pollen with distinctly different allergen contents. Here, we determined the variability in atmospheric exposure to the major Artemisia pollen allergen, Art v 1, during the pollination seasons of two common species, i.e., A. vulgaris (early flowering species) and A. campestris (late flowering species), in Poznan, Poland (2013-2015). Artemisia pollen grains were collected using Hirst-type volumetric trap, while Art v 1 was collected by a two-stage cascade impactor (PM10 and PM>10 air fractions) and quantified by immunoenzymatic analysis. The results showed that daily Art v 1 levels correlated significantly with mean daily concentrations of Artemisia pollen (from r = 0.426 to r = 0.949, depending on air fraction and peak of the season). Significant differences were observed between 1) the median pollen allergenicity in different seasons (from 2.5 to 4.7 pg Art v 1/pollen) and 2) the median pollen allergenicity in different peak periods of the season (from 1.8 to 6.7 pg Art v 1/pollen). During the late peak (flowering of A. campestris), the median pollen allergenicity was significantly higher (on average by 63%, p < 0.05) than that during A. vulgaris flowering. The highest mean seasonal pollen allergenicity was observed during the wettest season, while the lowest was observed during the driest season (from July-August). In summary, our study showed distinct differences in Artemisia pollen allergenicity, that were not only related to daily and seasonal variability, which may exceed 800% and 80%, respectively but also noticeable when two common Artemisia species were compared. Therefore, we argue that variability in pollen allergenicity (both seasonal and species-specific) should be considered in future studies assessing pollen exposure.


Assuntos
Artemisia , Alérgenos , Polônia , Pólen , Tempo (Meteorologia)
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