RESUMEN

Pollination services are crucial for maintaining ecological stability and ensuring food security for humans. Managed honey bees, which are economically valuable and are experiencing population growth due to the increasing demand for their products, play a significant role in pollination. To produce high-quality honey, beekeepers often choose natural high meadows, characterized by high plant species richness, for their apiaries. This practice, in turn, may contribute to the pollination of native plants, as managed honey bees are likely to forage on diverse floral resources within these meadows In this study, we investigated the nutritional position of managed bees in the pollination of native plants in Iran using the melissopalynology method to determine the extent of their contribution to the pollination of native plants. Ninety-four honey samples were collected from beekeepers located in the natural pastures of two biodiversity hotspots in Iran (Zagros and Alborz). Then, plant pollens were extracted from the honey and photographed by scanning electron microscopy. In the next step, plant species were identified, and their abundance was calculated. The results showed that managed bees visited 54 plant genera, seven of which were non-native plants. Additionally, more plant species and the highest abundance of pollen were observed at altitudes ranging from 1000 to 3000 m. Therefore, beekeepers set up their hives in this altitude range to obtain high-quality honey. In general, in this study, the results of melissopalynological analysis, involving the identification of plant genera and pollen counts, revealed that managed honey bees likely contributed less than 3% to the pollination of native plant species in Iran.

Asunto(s)

Miel , Polen , Polinización , Abejas/fisiología , Animales , Irán , Apicultura/métodos , Plantas , Biodiversidad

RESUMEN

Asthma is a respiratory disorder caused by airway inflammation which may worsen after allergen exposure. Recent cohort studies demonstrate a positive association between skin cancer and asthma or hay fever (allergy to outdoor allergens such as pollen). Nationally-representative data for adults in the United States remains limited. We aimed to characterize skin cancer prevalence among individuals in the United States who have asthma or hay fever. To achieve this aim, we extracted nationwide cross-sectional data from 16,277 adult participants (total survey-weighted sample = 174,765,931) of the Third National Health and Nutrition Examination Survey from 1988 to 1994. This study uses survey-weighted regression to compare the nationwide prevalence of skin cancer among participants with or without a history of asthma or hay fever. Sensitivity analysis examined the influence of sex, 25-hydroxyvitamin D, chronic bronchitis or emphysema, geographical region, urban proximity, and oral glucocorticoid use. Of the included participants, the age-adjusted prevalence of skin cancer was 7.2%, similar to national estimates. Skin cancer prevalence was higher among participants who had asthma with hay fever (adjusted prevalence ratio, 1.79; 95% confidence interval, 1.16, 2.76), but not among participants with asthma only or hay fever only. Similarly, skin cancer prevalence was higher for those with asthma and positive pollen allergen skin prick testing (SPT), but not for those with hay fever and positive pollen SPT. No association was noted between skin cancer and wheezing triggered by pollen. Hay fever or immunoglobulin-E sensitization to pollen may increase skin cancer prevalence among individuals with a history of asthma.

Asunto(s)

Asma , Encuestas Nutricionales , Rinitis Alérgica Estacional , Neoplasias Cutáneas , Humanos , Estudios Transversales , Masculino , Rinitis Alérgica Estacional/epidemiología , Rinitis Alérgica Estacional/inmunología , Rinitis Alérgica Estacional/diagnóstico , Femenino , Adulto , Persona de Mediana Edad , Estados Unidos/epidemiología , Neoplasias Cutáneas/epidemiología , Neoplasias Cutáneas/inmunología , Neoplasias Cutáneas/diagnóstico , Prevalencia , Asma/epidemiología , Asma/inmunología , Asma/diagnóstico , Alérgenos/inmunología , Alérgenos/efectos adversos , Pruebas Cutáneas , Anciano , Adulto Joven , Polen/inmunología , Polen/efectos adversos , Factores de Riesgo

RESUMEN

A new analytical method was developed and validated to determine fourteen bisphenols (A, B, C, E, F, M, P, S, Z, AF, AP, BP, FL, PH) in bee pollen using ultra-high-performance liquid chromatography-tandem mass spectrometry. Two different sample treatments were proposed and evaluated: one based on the QuEChERS (quick, easy, cheap, effective, rugged & safe) approach and the other utilizing microextraction with a supramolecular solvent (SUPRAS). In both cases, average analyte recovery ranged between 71 % and 114 %, and the matrix effect was between -45 % and +5 %, although it was not significant when using the QuEChERS-based method (<±20 %). The environmental impact of both sample treatments was assessed using different analytical metrics, with both procedures classified as environmentally friendly, though slightly better results were obtained for SUPRAS. The method was fully validated, showing that the QuEChERS approach had better overall performance, particularly regarding sensitivity and matrix effect. Consequently, the QuEChERS methodology was applied to determine bisphenols in thirty bee pollen samples from different Spanish regions. Residues of three bisphenols (M, P, and S) were detected, although only bisphenol S was quantified in several samples at low concentration levels (<7 µg kg-1), which is below the established specific migration limit (SML; 50 µg kg-1). However, regarding human health, the estimated daily intake, target hazard quotient, and hazard index assessed were higher than acceptable limits, suggesting a potential risk for human consumers.

Asunto(s)

Compuestos de Bencidrilo , Fenoles , Polen , Espectrometría de Masas en Tándem , Polen/química , Espectrometría de Masas en Tándem/métodos , Fenoles/análisis , Cromatografía Líquida de Alta Presión/métodos , Abejas , Animales , Compuestos de Bencidrilo/análisis , Reproducibilidad de los Resultados , Contaminación de Alimentos/análisis , Tecnología Química Verde/métodos

RESUMEN

MAIN CONCLUSION: Four cultivars of Paeonia lactiflora pollen have a different viability after cryopreservation, and that the difference of pollen viability is related to calcium ions and cell wall deposition. Cryopreservation is a vital technique for preserving germplasm resources, offering extensive application prospects. Understanding the factors influencing pollen viability after cryopreservation is crucial for the permanent preservation and exchange of pollen resources. This study investigated pollen from four Paeonia lactiflora cultivars with varying viability after cryopreservation, aiming to determine whether calcium ions (Ca2+) and cell wall deposition affect these viability changes. The results showed that Ca2+-ATPase activity and cytoplasmic Ca2+ of all four cultivars exhibited an increasing trend after cryopreservation; the calmodulin (CaM) content varied with cultivars. Correlation analysis showed that fresh pollen viability was significantly negatively correlated with cytoplasmic Ca2+ content and positively correlated with Ca2+-ATPase activity, while pollen viability after cryopreservation exhibited a significantly negative correlation with cytoplasmic Ca2+ content and a positive correlation with CaM content. The pollen cell wall of the cultivar 'Zi Feng Chao Yang' (ZFCY), which showed increased viability after cryopreservation, contained significantly higher levels of low-temperature tolerance-related phospholipids and proteins compared to other cultivars. Additionally, all cultivars maintained a clear Ca2+ gradient at the tips of pollen tubes after cryopreservation, without significant callose accumulation. These findings suggest that differences in Ca2+ signaling and cell wall components deposition influence changes in pollen viability after cryopreservation, and the Ca2+ gradient and callose at the tip of pollen tubes are not responsible for preventing pollen tube growth.

Asunto(s)

Calcio , Pared Celular , Criopreservación , Paeonia , Polen , Pared Celular/metabolismo , Criopreservación/métodos , Calcio/metabolismo , Polen/fisiología , Paeonia/fisiología , Paeonia/metabolismo , Calmodulina/metabolismo , Supervivencia Celular

RESUMEN

Tomato plants favor warmth, making them particularly susceptible to cold conditions, especially their reproductive development. Therefore, understanding how pollen reacts to cold stress is vital for selecting and improving cold-resistant tomato varieties. The programmed cell death (PCD) in the tapetum is particularly susceptible to cold temperatures which could hinder the degradation of the tapetal layer in the anthers, thus affecting pollen development. However, it is not clear yet how genes integral to tapetal degradation respond to cold stress. Here, we report that SlHB8, working upstream of the conserved genetic module DYT1-TDF1-AMS-MYB80, is crucial for regulating cold tolerance in tomato anthers. SlHB8 expression increases in the tapetum when exposed to low temperatures. CRISPR/Cas9-generated SlHB8-knockout mutants exhibit improved pollen cold tolerance due to the reduced temperature sensitivity of the tapetum. SlHB8 directly upregulates SlDYT1 and SlMYB80 by binding to their promoters. In normal anthers, cold treatment boosts SlHB8 levels, which then elevates the expression of genes like SlDYT1, SlTDF1, SlAMS, and SlMYB80; however, slhb8 mutants do not show this gene activation during cold stress, leading to a complete blockage of delayed tapetal programmed cell death (PCD). Furthermore, we found that SlHB8 can interact with both SlTDF1 and SlMYB80, suggesting the possibility that SlHB8 might regulate tapetal PCD at the protein level. This study sheds light on molecular mechanisms of anther adaptation to temperature fluctuations.

Asunto(s)

Frío , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas , Solanum lycopersicum , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Solanum lycopersicum/fisiología , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Respuesta al Choque por Frío/genética , Muerte Celular/genética , Flores/genética , Flores/crecimiento & desarrollo , Flores/fisiología , Polen/genética , Polen/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo

RESUMEN

Epigenetic modifications are crucial for plant development. EFD (Exine Formation Defect) encodes a SAM-dependent methyltransferase that is essential for the pollen wall pattern formation and male fertility in Arabidopsis. In this study, we find that the expression of DRM2, a de novo DNA methyltransferase in plants, complements for the defects in efd, suggesting its potential de novo DNA methyltransferase activity. Genetic analysis indicates that EFD functions through HB21, as the knockout of HB21 fully restores fertility in efd mutants. DNA methylation and histone modification analyses reveal that EFD represses the transcription of HB21 through epigenetic mechanisms. Additionally, we demonstrate that HB21 directly represses the expression of genes crucial for pollen formation and anther dehiscence, including CalS5, RPG1/SWEET8, CYP703A2 and NST2. Collectively, our findings unveil a double negative regulatory cascade mediated by epigenetic modifications that coordinates anther development, offering insights into the epigenetic regulation of this process.

Asunto(s)

Proteínas de Arabidopsis , Arabidopsis , Metilación de ADN , Epigénesis Genética , Flores , Regulación de la Expresión Génica de las Plantas , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Flores/genética , Flores/crecimiento & desarrollo , Polen/crecimiento & desarrollo , Polen/genética , Polen/metabolismo , Metiltransferasas/metabolismo , Metiltransferasas/genética , Mutación , Plantas Modificadas Genéticamente

RESUMEN

BACKGROUND: Ragweed (Ambrosia elatior) has become invasive in Europe, causing significant respiratory issues. Subcutaneous allergen immunotherapy (SCIT) has long been used to manage pollen allergies, but sublingual immunotherapy (SLIT) has gained interest. OBJECTIVE: This study aimed to evaluate the clinical benefits of ragweed SLIT under real-world in a cohort of Hungarian patients allergic to ragweed pollen. METHODS: We retrospectively reviewed the clinical records of 57 patients during the 2015 and 2016 ragweed pollen seasons. Patients were divided into two groups: Group 1 (n = 29), who had not received immunotherapy, and Group 2 (n = 28), who had previously undergone immunotherapy with another sublingual preparation. All patients were treated with Oraltek® ragweed for 4-6 months, initiating 2-4 months before the pollen season and rest of the period was 2 months of the 2016 pollen season. Symptom score (SS), medication score (MS), and combined symptom and medication score (CSMS) were evaluated intra- and intergroup. RESULTS: Pollen counts were consistent between 2015 and 2016. All patients showed significant improvement in SS, MS, and CSMS, with a large effect size (>0.8). Group 2 had significantly lower SS and CSMS in 2015 because of prior immunotherapy. By 2016, both groups exhibited marked improvements, with Group 1 showing a 75% improvement in CSMS. No local or systemic reactions were recorded, indicating a high safety profile. CONCLUSIONS: Ragweed SLIT significantly improved symptoms and reduced use of medication in patients allergic to ragweed pollen. The treatment was effective even in patients with previous immunotherapy, with a high benefit-risk ratio demonstrated by the absence of adverse reactions. These findings support the use of Oraltek SLIT for managing ragweed pollen allergy.

Asunto(s)

Alérgenos , Ambrosia , Antígenos de Plantas , Rinitis Alérgica Estacional , Inmunoterapia Sublingual , Humanos , Inmunoterapia Sublingual/métodos , Masculino , Femenino , Estudios Retrospectivos , Rinitis Alérgica Estacional/terapia , Rinitis Alérgica Estacional/inmunología , Adulto , Ambrosia/inmunología , Alérgenos/inmunología , Alérgenos/administración & dosificación , Hungría , Antígenos de Plantas/inmunología , Antígenos de Plantas/administración & dosificación , Persona de Mediana Edad , Adulto Joven , Extractos Vegetales/administración & dosificación , Resultado del Tratamiento , Adolescente , Polen/inmunología

RESUMEN

BACKGROUND: Cross-reactivity between nonspecific lipid transfer proteins could cause anaphylaxis, further influencing food avoidance and nutrient deficiencies. The one affecting olive pollen (Ole e 7) and peach (Pru p 3) may underlie a variety of pollen-food syndromes, though a deep molecular analysis is necessary. METHODS: Three Ole e 7-monosensitised patients (MON_OLE), three Pru p 3-monosensitised patients (MON_PRU) and three bisensitised patients (BI) were selected. For epitope mapping, both digested proteins were incubated with patient sera, and the captured IgE-bound peptides were characterised by LC-MS. RESULTS: The analysis revealed two Ole e 7 epitopes and the three Pru p 3 epitopes previously described. Interestingly, the "KSALALVGNKV" Ole e 7 peptide was recognised by MON_OLE, BI and MON_PRU patients. Conversely, all patients recognised the "ISASTNCATVK" Pru p 3 peptide. Although complete sequence alignment between both proteins revealed 32.6% identity, local alignment considering seven residue fragments showed 50 and 57% identity when comparing "ISASTNCATVK" with Ole e 7 and "KSALALVGNKV" with Pru p 3. CONCLUSIONS: This study mapped sIgE-Ole e 7-binding epitopes, paving the way for more precise diagnostic tools. Assuming non-significant sequence similarity, structural homology and shared key residues may underlie the potential cross-reactivity between Ole e 7 and Pru p 3 nsLTPs.

Asunto(s)

Antígenos de Plantas , Reacciones Cruzadas , Hipersensibilidad a los Alimentos , Inmunoglobulina E , Olea , Proteínas de Plantas , Polen , Prunus persica , Humanos , Antígenos de Plantas/inmunología , Hipersensibilidad a los Alimentos/inmunología , Polen/inmunología , Inmunoglobulina E/inmunología , Inmunoglobulina E/sangre , Olea/inmunología , Proteínas de Plantas/inmunología , Femenino , Masculino , Prunus persica/inmunología , Mapeo Epitopo , Adulto , Rinitis Alérgica Estacional/inmunología , Secuencia de Aminoácidos , Epítopos/inmunología , Alérgenos/inmunología , Persona de Mediana Edad , Proteínas Portadoras/inmunología

RESUMEN

For the recently legalized US hemp industry (Cannabis sativa), cross-pollination between neighboring fields has become a significant challenge, leading to contaminated seeds, reduced oil yields, and in some cases, mandated crop destruction. As a step towards assessing hemp cross-pollination risk, this study characterizes the seasonal and spatial patterns in windborne hemp pollen dispersal spanning the conterminous United States (CONUS). By leveraging meteorological data obtained through mesoscale model simulations, we have driven Lagrangian Stochastic models to simulate wind-borne hemp pollen dispersion across CONUS on a county-by-county basis for five months from July to November, encompassing the potential flowering season for industrial hemp. Our findings reveal that pollen deposition rates escalate from summer to autumn due to the reduction in convective activity during daytime and the increase in wind shear at night as the season progresses. We find diurnal variations in pollen dispersion: nighttime conditions favor deposition in proximity to the source, while daytime conditions facilitate broader dispersal albeit with reduced deposition rates. These shifting weather patterns give rise to specific regions of CONUS more vulnerable to hemp cross-pollination.

Asunto(s)

Cannabis , Polen , Estaciones del Año , Viento , Estados Unidos , Polinización

RESUMEN

PURPOSE OF REVIEW: There is growing evidence that enolase is involved in allergy. This manuscript reviews the impact of enolase in allergic disease and describes several sources of this allergen including molds, plants, animals, and pollens, among others. IgE epitopes are carefully analyzed as they may account for cross-reactivity. RECENT FINDINGS: Enolase has been previously associated to food allergy and contact dermatitis. However, other groups and we have identified recently novel enolases derived from diverse pollens in patients suffering asthma and allergic rhinitis. Exposure to outdoor enolases may cause respiratory disease. Enolase has been identified across various species and its amino acid sequence is highly conserved among different sources of this allergen. The demonstration that enolase is involved in many allergic diseases including respiratory allergies, is of clinic relevance. Thus, the development of novel molecular-based diagnostic and therapeutic strategies may pave the way for improved diagnosis and therapeutics.

Asunto(s)

Alérgenos , Hipersensibilidad , Fosfopiruvato Hidratasa , Humanos , Fosfopiruvato Hidratasa/inmunología , Animales , Alérgenos/inmunología , Hipersensibilidad/inmunología , Reacciones Cruzadas/inmunología , Inmunoglobulina E/inmunología , Polen/inmunología

RESUMEN

Pollination is the first step in the plant's fruit development. Therefore, fruit setting does not occur without pollination. Some problems encountered in natural pollination cause pollination not to be achieved as desired and cause significant losses in yield and fruit quality. Artificial pollination applications with drones are the best way to solve these problems. In this study, the AirPoll artificial pollination machine, which performs artificial pollination through the air using drone technology, was developed and the operating success of the machine was tested in walnut gardens. In the experiment gardens, female flowers on 18 branches of 5 trees each in the artificially pollinated area with a drone and in the control area were marked with colored strings. Control trees were selected from a distance that would not be possible to transport pollen with a drone. As a result of the study carried out in 2020 and 2021, the average fruit setting rate in trees pollinated by drone was determined as 94.61%. In control trees, 32.33% fruit setting was achieved. Thus, it was determined that the productivity increase in artificial pollination with AirPoll was 62.28%. In addition, in the study, Computational Fluid Dynamics (CFD) simulation analysis was performed using ANSYS Fluent 2024 R1 software to predict the downward air flow and pollen distribution in the walnut tree crown. The analysis was carried out in 680 iterations using drone propellers at a rotation speed of 4500 rpm, 4 m/s airflow and a k-w viscous model. In the analysis, it was observed that the pollen was distributed homogeneously with the determined height and the created artificial pollination environment. Based on the results obtained from the simulations, a convergence criterion of 5e-3 for continuity and 1e-6 for speed, k, w was determined. Considering all the results, the ease of use of the developed AirPoll artificial pollination machine and the successful results obtained in field trials reveal the effectiveness of the AirPoll artificial pollination machine.

Asunto(s)

Juglans , Polinización , Juglans/fisiología , Árboles , Frutas/crecimiento & desarrollo , Polen , Flores

RESUMEN

The topic of ragweed pollen (RW) versus house dust mites (HDMs) has often been deliberated, but the increasing incidence of co-sensitization between them has been scarcely addressed. Utilizing Sprague Dawley rats, we explored the effects of co-sensitization with the combination of HDMs and RW pollen extracts in correlation with high-fructose diet (HFrD) by in vitro tracheal reactivity analysis in isolated organ bath and biological explorations. Our findings unveiled interrelated connections between allergic asthma, dyslipidemia, and HFrD-induced obesity, shedding light on their compounding role through inflammation. The increased CRP values and airway hyperresponsiveness to the methacholine challenge suggest a synergistic effect of obesity on amplifying the existing inflammation induced by asthma. One of the major outcomes is that the co-sensitization to HDMs and RW pollen led to the development of a severe allergic asthma phenotype in rats, especially in those with HFrD. Therefore, the co-sensitization to these allergens as well as the HFrD may play a crucial role in the modulation of systemic inflammation, obesity, and airway reactivity.

Asunto(s)

Biomarcadores , Fructosa , Pyroglyphidae , Ratas Sprague-Dawley , Animales , Ratas , Biomarcadores/sangre , Pyroglyphidae/inmunología , Asma/inmunología , Asma/sangre , Asma/etiología , Masculino , Alérgenos/inmunología , Obesidad/inmunología , Obesidad/sangre , Antígenos de Plantas/inmunología , Polen/inmunología , Extractos Vegetales

RESUMEN

The pollen wall protects pollen during dispersal and is critical for pollination recognition. In the Poaceae family, the pollen exine stereostructure exhibits a high degree of conservation with similar patterns across species. However, there remains controversy regarding the conservation of key factors involved in its formation among various Poaceae species. EPAD1, as a gene specific to the Poaceae family, and its orthologous genes play a conserved role in pollen wall formation in wheat and rice. However, they do not appear to have significant functions in maize. To further confirm the conserved function of EPAD1 in Poaceae, we performed an analysis on four EPAD1 orthologs from two distinct sub-clades within the Poaceae family. The two functional redundant barley EPAD1 genes (HvEPAD1 and HvEPAD2) from the BOP clade, along with the single copy of sorghum (SbEPAD1) and millet (SiEPAD1) from the PACMAD clade were examined. The CRISPR-Cas9-generated mutants all exhibited defects in pollen wall formation, consistent with previous findings on EPAD1 in rice and wheat. Interestingly, in barley, hvepad2 single mutant also showed apical spikelets abortion, aligning with a decreased expression level of HvEPAD1 and HvEPAD2 from the apical to the bottom of the spike. Our finding provides evidence that EPAD1 orthologs contribute to Poaceae specific pollen exine pattern formation via maintaining primexine integrity despite potential variations in copy numbers across different species.

Asunto(s)

Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas , Polen , Polen/genética , Polen/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Hordeum/genética , Hordeum/metabolismo , Oryza/genética , Oryza/metabolismo , Filogenia , Sorghum/genética , Sorghum/metabolismo , Zea mays/genética , Mutación

RESUMEN

Polyploids are essential in plant evolution and species formation, providing a rich genetic reservoir and increasing species diversity. Complex polyploids with higher ploidy levels often have a dosage effect on the phenotype, which can be highly detrimental to gametes, making them rare. In this study, offspring plants resulting from an autoallotetraploid (RRRC) derived from the interspecific hybridization between allotetraploid Raphanobrassica (RRCC, 2n = 36) and diploid radish (RR, 2n = 18) were obtained. Fluorescence in situ hybridization (FISH) using C-genome-specific repeats as probes revealed two main genome configurations in these offspring plants: RRRCC (2n = 43, 44, 45) and RRRRCC (2n = 54, 55), showing more complex genome configurations and higher ploidy levels compared to the parental plants. These offspring plants exhibited extensive variation in phenotypic characteristics, including leaf type and flower type and color, as well as seed and pollen fertility. Analysis of chromosome behavior showed that homoeologous chromosome pairing events are widely observed at the diakinesis stage in the pollen mother cells (PMCs) of these allopolyploids, with a range of 58.73% to 78.33%. Moreover, the unreduced C subgenome at meiosis anaphase II in PMCs was observed, which provides compelling evidence for the formation of complex allopolyploid offspring. These complex allopolyploids serve as valuable genetic resources for further analysis and contribute to our understanding of the mechanisms underlying the formation of complex allopolyploids.

Asunto(s)

Aneuploidia , Cromosomas de las Plantas , Poliploidía , Raphanus , Raphanus/genética , Cromosomas de las Plantas/genética , Hibridación Fluorescente in Situ , Brassica/genética , Hibridación Genética , Meiosis/genética , Genoma de Planta , Polen/genética , Fenotipo

RESUMEN

Spatio-temporal assessment of phylogenetic diversity gradients during the Holocene (past 12,000 years) provides an opportunity for a deeper understanding of the dynamics of species co-occurrence patterns under environmental fluctuations. Using two robust metrics of phylogenetic dispersion (PD) and 99 fossil pollen sequences containing 6557 samples/assemblages, we analyse spatio-temporal variation in PD of angiosperms and its relationship with Holocene climate in central Asia. Overall, PD throughout the Holocene decreases linearly with increasing latitude, except for a rise in mean nearest taxon distance from ca. 25 to 35° N. This indicates that phylogenetically divergent taxa decrease progressively with increasing latitude, leaving more phylogenetically closely related taxa in the assemblages, thereby increasing phylogenetic relatedness among the co-occurring taxa. The latitudinal gradient of PD has not been consistent during the Holocene, and this temporal variation is concordant with the Holocene climate dynamics. In general, profound temporal changes in the latitudinal PD toward higher latitudes implies that the major environmental changes during the Holocene have driven considerable spatio-temporal changes in the phylogenetic assembly of high-latitude angiosperm assemblages. Our results suggest that environmental filtering and the tendency of taxa and lineages to retain ancestral ecological features and geographic distributions (phylogenetic niche conservatism) are the main mechanisms underlying the phylogenetic assembly of angiosperms along the climate-latitudinal gradient. Ongoing environmental changes may pose future profound phylogenetic changes in high-latitude plant assemblages, which are adapted to harsh environmental conditions, and therefore are phylogenetically less dispersed (more conservative or clustered).

Asunto(s)

Fósiles , Magnoliopsida , Filogenia , Magnoliopsida/genética , Magnoliopsida/clasificación , Asia , Clima , Polen/genética , Biodiversidad

RESUMEN

Arabidopsis thaliana developing pollen grains serve as an excellent system for studying vacuole dynamics. Here, we present a methodological approach that utilizes the serial tomography package in Etomo software from IMOD to generate whole-cell tomograms on A. thaliana developing pollens for visualizing vacuoles on the whole-cell scale. In order to understand the vacuole dynamics along with the pollen maturation, we also introduce a sampling method aimed at harvesting the pollen grains at various stages, marked by the vegetative nucleus or generative cell. The cryo-fixation/freeze-substitution technique can then be applied to preserve the fine structures of the pollen grains and facilitate detailed ultrastructure examination. Through this method, large-volume whole-cell electron tomograms regarding vacuolar morphologies and ultrastructural changes during pollen development and maturation have been obtained. Overall, the method presented here provides valuable insights into the dynamic nature of vacuoles in Arabidopsis developing pollen.

Asunto(s)

Arabidopsis , Tomografía con Microscopio Electrónico , Polen , Vacuolas , Arabidopsis/ultraestructura , Arabidopsis/crecimiento & desarrollo , Vacuolas/ultraestructura , Polen/ultraestructura , Polen/crecimiento & desarrollo , Tomografía con Microscopio Electrónico/métodos

RESUMEN

The targeted pollination strategy has shown positive results in directing honey bees to crop flowers offering nectar along with pollen as reward. Kiwifruit is a functionally dioecious species, which relies on bees to transport pollen from staminate to pistillate nectarless flowers. Following the targeted pollination procedures recently validated, we first developed a mimic odor (KM) based on kiwifruit floral volatiles for which bees showed the highest level of generalization to the natural floral scent, although the response towards pistillate flowers was higher than towards staminate flowers. Then, in the field, feeding colonies KM-scented sucrose solution resulted in higher amounts of kiwifruit pollen collected by honey bees compared to control colonies fed unscented sucrose solution. Our results support the hypothesis that olfactory conditioning bees biases their foraging preferences in a nectarless crop, given the higher visitation to target flowers despite having provided the mimic odor paired with a sugar reward.

Asunto(s)

Flores , Odorantes , Néctar de las Plantas , Polinización , Animales , Abejas/fisiología , Odorantes/análisis , Azúcares/análisis , Azúcares/metabolismo , Polen/química , Conducta Alimentaria/fisiología , Actinidia , Sacarosa/metabolismo , Compuestos Orgánicos Volátiles/análisis

RESUMEN

To gain a deeper understanding of the flowering pattern and reproductive characteristics of Epimedium sagittatum, to enrich the research on the flower development of E. sagittatum and its reproductive regulation, and to screen the methods suitable for the rapid detection of pollen viability of E. sagittatum and to promote its cross-breeding. The characteristics of its flower parts were observed, recorded and measured, and the pollen viability of E. sagittatumwas determined by five methods, including TTC staining, I2-KI staining, red ink staining, peroxidase method and in vitro germination method. The flowering process of E. sagittatum can be divided into five stages: calyx dehiscence, bract spathe, petal outgrowth, pollen dispersal, and pollination and withering. The results of I2-KI staining and peroxidase method were significantly higher than those of other methods; the in vitro germination method was intuitive and accurate, but the operation was complicated and time-consuming; the red ink staining method was easy to operate and had obvious staining effect, and the results were the closest to those of the in vitro germination method; and it was found that the pollen of E. sagittatum was not as effective as the in vitro germination method at the bud stamen stage, the flower stigma and the flower bud. It was also found that the pollen viability and germination rate of E. sagittatum pollen were higher in the three periods of bud spitting, petal adductor and pollen dispersal. Comparing the five methods, the red ink staining method was found to be a better method for the rapid detection of pollen viability; the best pollination periods of E. sagittatum were the bud stamen stage, petal adductor stage, and pollen dispersal stage of flowers at the peak of bloom. This study on the flowering and fruiting pattern of E. sagittatum, and the related mechanism of sexual reproduction, can be used as a reference for the next step of research on the breeding of E. sagittatum.

Asunto(s)

Epimedium , Flores , Germinación , Polen , Flores/crecimiento & desarrollo , Polen/crecimiento & desarrollo , Germinación/fisiología , Polinización

RESUMEN

What conditions select flowering patterns within inflorescences, or variation in the anthesis interval within inflorescences among plants? Under what conditions are gradual blooming and simultaneous blooming, both traits related to floral display size, advantageous? We constructed a simulation model in which the opening times and longevities of individual flowers within inflorescences, the sizes of attractive structures of individual flowers, and the numbers of ovules and pollen grains produced by individual flowers evolve. Individual plants in the population compete for pollinators, and plants are selected by pollinators according to their floral display sizes and amounts of resources allocated to attractive structures. We found that, if the proportion of pollen on a pollinator deposited on a stigma was low, gradual blooming did not evolve even if inbreeding depression was greater than 0.5. This is because the amount of outcross-pollen on pollinators decreased at a low rate during flower visits within a single inflorescence, and the selfing rate was suppressed to a low level even if the floral display size was large. On the other hand, if the proportion of pollen deposition was high, gradual blooming evolved even if inbreeding depression was smaller than 0.5. This may be because gradual blooming can enhance pollen delivery to other plants by reducing the loss of self-pollen by geitonogamy. On the other hand, allocation ratios among floral organs (female and male organs and attractive structures) were independent of the degree of simultaneous and gradual blooming within inflorescences. We concluded that the evolution of gradual blooming is more strongly affected by the proportion of pollen on a pollinator deposited on a stigma than by inbreeding depression.

Asunto(s)

Evolución Biológica , Flores , Polinización , Polinización/fisiología , Flores/fisiología , Inflorescencia/fisiología , Simulación por Computador , Modelos Biológicos , Polen/fisiología , Animales

RESUMEN

Male sterile lines are key resources for hybrid seed production and for ensuring high varietal purity. However, the genes and mechanisms underlying sesame male sterility remain largely unknown. Hence, this study identified an O-acetylserine(thiol)lyase gene SiOASTL1 and functionally characterized its roles in inducing defective anther development. Spatiotemporal expression analysis revealed that SiOASTL1 is significantly (2.7 fold) up-regulated in sterile sesame anthers at the microspore stage compared with fertile ones. Sequence and phylogenetic analyses showed that SiOASTL1 is homologous to Arabidopsis OAS-TL plastid isoforms. We thus overexpressed SiOASTL1 in Arabidopsis to unravel its regulatory roles. Cytological observation revealed that SiOASTL1 overexpression transformed transgenic plants into male sterile lines arising at the microspore development stage. SiOASTL1 overexpression decreased cysteine biosynthesis and down-regulated the expression of the sporopollenin synthesis-related genes, including AtTKPR1, AtTKPR2, AtPKSA, and AtPKSB in transgenic Arabidopsis. Consequently, the tapetum programmed cell death (PCD) was delayed, resulting in the formation of defective pollen grains with irregular walls and empty cytoplasm. Our findings prove that the induction of SiOASTL1 expression disrupts pollen development and contributes to sesame male sterility. Moreover, these results suggest that genetic manipulation of SiOASTL1 expression may facilitate the development of new hybrid varieties in sesame and other crops.

Asunto(s)

Apoptosis , Arabidopsis , Regulación de la Expresión Génica de las Plantas , Infertilidad Vegetal , Plantas Modificadas Genéticamente , Sesamum , Sesamum/genética , Sesamum/metabolismo , Infertilidad Vegetal/genética , Arabidopsis/genética , Apoptosis/genética , Polen/genética , Polen/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Flores/genética , Filogenia