Search Results (17)

Tamarix chinensis Lour. is a halophytic shrub native to coastal China, commonly used in afforestation and ecological restoration due to its high tolerance to salinity and drought. To understand how this species maintains genetic variation and adapts to extreme environments, we examined the genetic diversity, mating system, and spatial genetic structure of a natural T. chinensis population on the geographically isolated and environmentally harsh Wudi Seashell Island. Using both SSR and ISSR markers, we observed high levels of genetic diversity despite the small population size and spatial fragmentation. SSR markers revealed an average of 11.75 alleles per locus, with an expected heterozygosity (He) of 0.754 and an observed heterozygosity (Ho) of 0.702. ISSR markers showed a polymorphic locus rate of 97.87%, with a mean He of 0.402. Parentage analysis revealed relatively long seed and pollen dispersal distances, with most dispersal occurring within 150 m and seeds and pollens occasionally reaching 948 m and 447 m, respectively. The species exhibited a mixed mating system, with a multilocus outcrossing rate of 0.554, contributing to gene flow and reducing inbreeding. A fine-scale spatial genetic structure was detected within 75 m, consistent across both SSR and ISSR markers, suggesting limited local gene dispersal. These findings provide new insights into the adaptive strategies of T. chinensis in marginal habitats and offer valuable guidance for conservation and restoration efforts in vulnerable coastal ecosystems. Full article

Honeybees provide a variety of services and products that are beneficial to humans, including pollination, honey, propolis, and other harvested products. In South Africa, it is believed that honey harvesting from wild (unmanaged) honeybee (Apis mellifera L.) colonies is widely practiced. However, there is limited knowledge regarding this practice. Using structured questionnaire surveys and site visits for validation, we aimed to (1) confirm the practice of honey harvesting and ascertain the extent to which it is practiced; and (2) quantify the economic benefits of this practice to communities’ livelihoods. We found that honey and other products (i.e., brood and pollen) harvesting from wild honeybee colonies is still a common practice among the rural communities of selected areas within the Vhembe District, which was confirmed by 44% of the respondents. These products are either consumed by the harvesters or sold, helping to generate total household incomes ranging from R500.00 ($26USD) to R2000.00 ($112USD) South African Rands (ZAR), which contribute towards offsetting various household costs. Although the overall population and health status of the wild honeybees in the area is unknown, the survey respondents (29%) indicated that they are generally healthy. From these findings, we were able to establish a good level of dependence on wild honeybee colonies by rural communities for income generation, albeit at a small scale. Given the wide array of pressures on insect pollinators, particularly honeybees, from factors such as habitat loss, climate change, pests, pathogens, and pesticides, our findings serve as a strong basis for considering protection and preservation mechanisms for these populations. These could be accommodated under various local and provincial conservation efforts, especially those preventing habitat loss. Full article

The repeated application of herbicides has led to the development of herbicide resistance. Models are useful for identifying key processes and understanding the evolution of resistance. This study developed a spatially explicit model at a landscape scale to examine the dynamics of Lolium rigidum populations in dryland cereal crops and the evolution of herbicide resistance under various management strategies. Resistance evolved rapidly under repeated herbicide use, driven by weed fecundity and herbicide efficacy. Although fitness costs associated with resistant plants reduced the resistance evolution, they did not affect the speed of its spread. The most effective strategies for slow resistance involved diversifying cropping sequences and herbicide applications. Pollen flow was the main dispersal vector, with seed dispersal also making a significant contribution. Strategies limiting seed dispersal effectively decreased resistance spread. However, the use of a seed-catching device at harvest could unintentionally enrich resistance in the area. It would be beneficial to optimize the movement of harvesters between fields. The model presented here is a useful tool that could assist in the exploration of novel management strategies within the context of site-specific weed management at landscape scale as well as in the advancement of our understanding of resistance dynamics. Full article

The optimization of artificial pollination is crucial in breeding programs for allogamous plants. In maize, achieving a balance between the labor-intensive nature of controlled pollinations and the need for large-scale production of hybrid seeds, along with considerations of germinability and pollen production, determines the success of genetic improvement programs. Breeding programs in maize have resulted in a reduction in the number of tassel branches to increase light interception and plant density in production fields. However, despite this genetic improvement, the decreased pollen production per plant has raised critical concerns regarding pollination and subsequent ear filling, especially under adverse environmental conditions. The aim of this work was the analysis of factors that can contribute to increasing the efficiency of controlled pollination in maize. The data obtained showed that pollen diameter, flavonoid, and phenolic acid content do not influence the percentage of germination and therefore the efficiency of pollination. The quantity of pollen is a central factor in ensuring the efficiency of controlled pollinations, and the data obtained by comparing traditional varieties with modern hybrids of maize showed that an increase in pollen production is determined by the increase in branching of the male inflorescence. Furthermore, we propose the use of a “smart” pollination method to make this step in maize breeding programs easier and faster. Full article

Camellia drupifera is an important woody oil plant in South China, renowned for its seed oil that is rich in unsaturated fatty acids and possesses significant antioxidant, anti-cancer, and immune-enhancing properties. The low fruit-setting rate of C. drupifera is influenced by multiple factors, including flowering stage climate, flowering habits, pollination biology, soil conditions, and self-incompatibility. Among these, large-scale pure forest plantations are the primary cause of the low fruit-setting rate. Although previous studies have explored the impact of self-incompatibility on fruit-setting in C. drupifera, research on the dynamic changes of endogenous substances during the flowering stage in pure forest environments remains limited. Research findings indicate that tannase activity is relatively high in the pistils of C. drupifera, creating a favorable environment for pollen tube growth. Plant hormones such as indole-3-acetic acid (IAA), cytokinin (CTK), gibberellin (GA), and ethylene (ETH) regulate the development and aging of floral organs through complex interactions. Specifically, high levels of IAA in the pistil promote pollen tube growth, while changes in ETH and ABA are closely related to the aging of floral organs. Under oxidative stress conditions, high levels of H₂O₂ in the pistil may contribute to self-incompatibility. The activity of superoxide dismutase (SOD) in the floral organs during the flowering stage is significantly higher compared to peroxidase (POD) and catalase (CAT), highlighting the critical role of SOD in regulating oxidative stress during this stage. This study provides new insights into the changes in endogenous substances in the floral organs of C. drupifera during the flowering stage. It offers theoretical references for understanding its sexual reproduction process and for the application of plant growth regulators to improve fruit setting. Full article

The knowledge of beekeeping flora of an area and of each plant’s provision is crucial for beekeepers to plan their hive transfers when practicing nomadic beekeeping. Thus, in the present study, we evaluated the use of pollen traps as a means of identifying beekeeping plants in target areas, assessing their pollen percentage contributions and estimating their flowering seasons. The results were compared with the classical field observation method, widely used for flora recording. In total, 98.8% of the plants were recognized by using pollen traps and 89.4% from observations in the field, while for 73% there was found an agreement between population size (Wittig Scale) and Pollen Contribution Scale (PCS). The results showed that pollen traps can be helpful tools not only for defining the presence or absence of a beekeeping plant, but also for providing important information regarding the population size of a taxon of major beekeeping importance in the area surrounding the apiary. Finally, the estimation of the flowering season and its maximum point can be accurately predicted by using pollen traps on plants of beekeeping interest. Full article

Serra dos Carajás harbors a unique open plant community in Amazonia, known as canga vegetation, with several endemic species coexisting with the potential threat of large-scale iron ore mining. In this sense, Convolvulaceae occur in a wide variety of canga geoenvironments with multiple flower visitors, but the scarcity of data on its pollen morphology prevents the correct association between Convolvulaceae species with floral visitors, as well as the precise identification of their habitats throughout the Quaternary. Therefore, this study aims to contribute to the taxonomic knowledge and refinement of the identification of insect-plant networks of endangered plants, including Ipomoea cavalcantei. Pollen grains were examined by light and scanning electron microscopy (LM and SEM, respectively), and the morphological parameters obtained were statistically analyzed using principal component analysis. Therefore, all species were differentiated based on aperture types and exine ornamentation. The set of morphological characters indicated that echinae morphology, easily identified under LM, was effective for the identification of Ipomoea species. This work represents the first robust pollen database for a precise identification at the species level of Convolvulaceae from southeastern Amazonian cangas. Full article

The Middle Jurassic in the north Western Desert, Egypt, was a time of complex tectonics and increased environmental perturbations attributed to the predominant sedimentation of organic carbon-rich fine siliciclastic and carbonate deposits of the Khatatba Formation. Although some studies have addressed the hydrocarbon potential and source rock characteristics of the Khatatba Formation, a regional-scale investigation of the prevalent paleoenvironmental conditions and organic matter characteristics is still necessary. In this study, the Khatatba Formation is investigated for detailed palynofacies analysis and palynomorph composition to assess organic matter kerogen types and reconstruct the depositional paleoenvironmental patterns on a regional scale. For this purpose, 116 drill cuttings were collected from five wells in the Matruh, Shushan, and Dahab-Mireir Basins. Moderately diverse assemblages of spores, pollen, and dinoflagellate cysts are reported. Age-diagnostic dinoflagellate cysts, including Adnatosphaeridium caulleryi, Dichadogonyaulax sellwoodii, Korystocysta gochtii, Wanaea acollaris, and Pareodinia ceratophora, along with occasional records of Systematophora areolate and Systematophora penicillate, defined a Bajocian–Callovian age. Based on particulate organic matter (POM) composition, four palynofacies assemblages (PFAs) are identified. PFA-1 is the most common within the Khatatba Formation in the five studied wells. It contains high proportions of phytoclast fragments versus low contents of amorphous organic matter (AOM) and palynomorphs and is defined by a gas-prone kerogen Type III. PFA-2 is comprised of moderate abundances of AOM and phytoclast characteristics of oil-prone kerogen Type II. PFA-3 is dominated by phytoclasts and moderate to low proportions of AOM and palynomorphs of kerogen Type III, whereas PFA-4 consists of AOM and palynomorphs defining kerogen Type II. PFA-1 indicates predominant deposition in proximal active fluvio-deltaic sources to marginal marine conditions with enhanced contributions of terrestrial/riverine influx. PFA-2 and PFA-3 reveal deposition under an enhanced dysoxic to anoxic proximal inner neritic shelf due to the abundant occurrences of spores and coastal to shallow marine dinoflagellate cysts. PFA-4 suggests deposition under enhanced suboxic to anoxic distal inner neritic conditions because of enhanced AOM and abundant proximate and some chorate dinoflagellate cysts. Thus, the Middle Jurassic experienced a predominantly marginal to shallow water column in this part of the southern margin of the Tethyan Ocean where the Matruh, Shushan, and Dahab-Mireir Basins were located. Full article

While the importance of the intestinal microbiome has been realised for a number of years, the significance of the phrase microbiota–gut–brain axis is only just beginning to be fully appreciated. Our recent work has focused on the microbiome as if it were a single entity, modifying the expression of the genetic inheritance of the individual by the generation of interkingdom signalling molecules, semiochemicals, such as dopamine. In our view, the purpose of the microbiome is to convey information about the microbial environment of the mother so as to calibrate the immune system of the new-born, giving it the ability to distinguish harmful pathogens from the harmless antigens of pollen, for example, or to help distinguish self from non-self. In turn, this requires the partition of nutrition between the adult and its microbiome to ensure that both entities remain viable until the process of reproduction. Accordingly, the failure of a degraded microbiome to interact with the developing gut of the neonate leads to failure of this partition in the adult: to low faecal energy excretion, excessive fat storage, and concomitant problems with the immune system. Similarly, a weakened gut–brain axis distorts interoceptive input to the brain, increasing the risk of psychiatric diseases such as autism. These effects account for David Barker’s 1990 suggestion of “the fetal and infant origins of adult disease”, including schizophrenia, and David Strachan’s 1989 observation of childhood immune system diseases, such as hay fever and asthma. The industrialisation of modern life is increasing the intensity and scale of these physical and psychiatric diseases and it seems likely that subclinical heavy metal poisoning of the microbiome contributes to these problems. Finally, the recent observation of Harald Brüssow, that reported intestinal bacterial composition does not adequately reflect the patterns of disease, would be accounted for if microbial eukaryotes were the key determinant of microbiome effectiveness. In this view, the relative success of “probiotic” bacteria is due to their temporary immune system activation of the gut–brain axis, in turn suggesting a potential mechanism for the placebo effect. Full article

The ongoing fragmentation of ash populations due to ash dieback requires an effective gene flow between individuals; thus, investigations on ash pollen transport are essential. In this study, comprehensive aerobiological field experiments at two seed plantations in Baden-Württemberg were conducted in 2019 and 2020 in order to study the influence of phenology and meteorology (especially wind) on pollen transport using self-constructed gravimetric pollen traps located 1.5 and 5 m a.g.l. Our main objectives were to investigate the local scale dispersion of ash pollen and to evaluate the recommended distance (i.e., 400 m) from seed plantations to other ash trees according to the German Forest Reproduction Act. Our results showed a link between pollen transport and meteorology, the onset of phenological development, and the topography of the plantation. The plantation at Schorndorf was characterized by a slope and associated cold air flows, suggesting that this could be a factor contributing to higher pollen levels at the downslope traps. In addition, in many cases, the cardinal direction associated with the highest pollen impaction was also identical with the predominant wind direction. Analyzing pollen data for single traps in detail, we found that the highest total pollen catch (31%) was measured outside the plantations in 2019, a year with very low flower development. In contrast, most pollen (33%) was caught within the plantation in 2020, which presented a much stronger pollen year than 2019 (with a factor of 11 regarding total sums). This indicates, in the lower pollen year, a potential higher contribution of trees from outside the plantation, and thus it can be recommended that seed harvesting of ash trees in the plantations should preferentially take place in full mast years. Interestingly, the total pollen deposition in Emmendingen at 5 m height showed little difference compared to the traps at 1.5 m height, but there was a large temporal difference pointing to vertical variations in pollen availability. In general, we found that ash pollen was transported for a larger distance than 400 m, but the amount of pollen decreased substantially with increasing distance. At a distance of 200 m, there was already approx. 50% less pollen captured from the air. However, even at a distance of 500 m, more than 10% of the pollen was still captured. In order to ensure cross-pollination of healthy ash trees, the distance of ash individuals or stands should not be too large, and there should be no spatial separation (e.g., by conifer stands). Full article

In this paper, forces and torques on solid, non-spherical, orthotropic particles in Stokes flow are investigated by using a numerical approach on the basis of the Boundary Element Method. Different flow patterns around a particle are considered, taking into account the contributions of uniform, rotational and shear flows, to the force and the torque exerted on the particle. The expressions for the force and the toque are proposed, by introducing translation, rotation and deformation resistance tensors, which capture each of the flow patterns individually. A parametric study is conducted, considering a wide range of non-spherical particles, determined by the parametric superellipsoid surface equation. Using the results of the parametric study, an approximation scheme is derived on the basis of a multivariate polynomial expression. A coefficient matrix for the polynomial model is introduced, which is used as a tunable parameter for a minimization problem, whereby the polynomials are fitted to the data. The developed model is then put to the test by considering a few examples of particles with different shapes, while also being compared to other, currently available solutions. On top of that, the full functionality of the model is demonstrated by considering an example of a pollen grain, as a realistic non-spherical particle. First, a superellipsoid, which best fits the actual particle shape, is found from the considered range. After that, the coefficients of the translation, rotation and deformation resistance tensors are obtained from the present model and compared to the results of other available models. In the conclusion, a superior accuracy of the present model, for the considered range of particles, is established. To the best of the authors knowledge, this is also one of the first models to extend the torque prediction capabilities beyond sphere and prolate particles. At the same time, the model was demonstrated to be simple to implement and very conservative with the computational resources. As such, it is suitable for large scale studies of dispersed two-phase flows, with a large number of particles. Full article

Purpose—knowing in advance vineyard yield is a critical success factor so growers and winemakers can achieve the best balance between vegetative and reproductive growth. It is also essential for planning and regulatory purposes at the regional level. Estimation errors are mainly due to the high inter-annual and spatial variability and inadequate or poor performance sampling methods; therefore, improved applied methodologies are needed at different spatial scales. This paper aims to identify the alternatives to traditional estimation methods. Design/methodology/approach—this study consists of a systematic literature review of academic articles indexed on four databases collected based on multiple query strings conducted on title, abstract, and keywords. The articles were reviewed based on the research topic, methodology, data requirements, practical application, and scale using PRISMA as a guideline. Findings—the methodological approaches for yield estimation based on indirect methods are primarily applicable at a small scale and can provide better estimates than the traditional manual sampling. Nevertheless, most of these approaches are still in the research domain and lack practical applicability in real vineyards by the actual farmers. They mainly depend on computer vision and image processing algorithms, data-driven models based on vegetation indices and pollen data, and on relating climate, soil, vegetation, and crop management variables that can support dynamic crop simulation models. Research limitations—this work is based on academic articles published before June 2021. Therefore, scientific outputs published after this date are not included. Originality/value—this study contributes to perceiving the approaches for estimating vineyard yield and identifying research gaps for future developments, and supporting a future research agenda on this topic. To the best of the authors’ knowledge, it is the first systematic literature review fully dedicated to vineyard yield estimation, prediction, and forecasting methods. Full article

Cytoplasmic male sterility (CMS) is important for large-scale hybrid seed production. Rearrangements in the mitochondrial DNA (mtDNA) for the cotton (Gossypium hirsutum L.) CMS line J4A were responsible for pollen abortion. However, the expression patterns of nuclear genes associated with pollen abortion and the molecular basis of CMS for J4A are unknown, and were the objectives of this study by comparing J4A with the J4B maintainer line. Cytological evaluation of J4A anthers showed that microspore abortion occurs during meiosis preventing pollen development. Changes in enzyme activity of mitochondrial respiratory chain complex IV and mitochondrial respiratory chain complex V and the content of ribosomal protein and ATP during anther abortion were observed for J4A suggesting insufficient synthesis of ATP hindered pollen production. Additionally, levels of sucrose, starch, soluble sugar, and fructose were significantly altered in J4A during the meiosis stage, suggesting reduced sugar metabolism contributed to sterility. Transcriptome and miRNAomics analyses identified 4461 differentially expressed mRNAs (DEGs) and 26 differentially expressed microRNAs (DEMIs). Pathway enrichment analysis indicated that the DEMIs were associated with starch and sugar metabolism. Six deduced target gene regulatory pairs that may participate in CMS were identified, ghi-MIR7484-10/mitogen-activated protein kinase kinase 6 (MAPKK6), ghi-undef-156/agamous-like MADS-box protein AGL19 (AGL19), ghi-MIR171-1-22/SNF1-related protein kinase regulatory subunit gamma-1 and protein trichome birefringence-like 38, and ghi-MIR156-(8/36)/WRKY transcription factor 28 (WRKY28). Overall, a putative CMS mechanism involving mitochondrial dysfunction, the ghi-MIR7484-10/MAPKK6 network, and reduced glucose metabolism was suggested, and ghi-MIR7484-10/MAPKK6 may be related to abnormal microspore meiosis and induction of excessive sucrose accumulation in anthers. Full article

Chromosome doubling of maize haploids is a bottleneck in the large-scale application of doubled haploid (DH) technology. Spontaneous chromosome doubling (SCD) of haploid has been taken as an important method in the production of DH lines and low haploid male fertility (HMF) is a main limiting factor for the use of SCD. To study its genetic basis, haploids of 119 DH lines derived from a cross between inbred lines Qi319 and Chang7-2 were used to map the quantitative trait locus (QTL) contributing to HMF. Three traits including anther emergence rate (AER), anther emergence score (AES) and pollen production score (PPS) of the haploid population were evaluated at two locations. The heritability of the three traits ranged from 0.70 to 0.81. The QTL contributing to AER, AES and PPS were identified on the chromosomes 1, 2, 3, 4, 5, 7, 9 and 10. Five major QTL, qAER5-1, qAER5-2, qAES3, qPPS1 and qPPS5, were found and each could explain more than 15% of the phenotypic variance at least in one environment. Two major QTL, qPPS1 and qPPS5, and two minor QTL, qAES2 and qAER3, were repeatedly detected at both locations. To increase the application efficiency of HMF in breeding programs, genomic prediction for the three traits were carried out with ridge regression best linear unbiased prediction (rrBLUP) and rrBLUP adding QTL effects (rrBLUP-QTL). The prediction accuracies of rrBLUP-QTL were significantly higher than that by rrBLUP for three traits (p < 0.001), which indirectly indicates these QTL were effective. The prediction accuracies for PPS were 0.604 (rrBLUP) and 0.703 (rrBLUP-QTL) across both locations, which were higher than that of AER and AES. Overall, this study provides important information to understand the genetic architecture of SCD of maize haploids. Full article

The pollen stores of bumble bees host diverse microbiota that influence overall colony fitness. Yet, the taxonomic identity of these symbiotic microbes is relatively unknown. In this descriptive study, we characterized the microbial community of pollen provisions within captive-bred bumble bee hives obtained from two commercial suppliers located in North America. Findings from 16S rRNA and ITS gene-based analyses revealed that pollen provisions from the captive-bred hives shared several microbial taxa that have been previously detected among wild populations. While diverse microbes across phyla Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, and Ascomycota were detected in all commercial hives, significant differences were detected at finer-scale taxonomic resolution based on the supplier source. The causative agent of chalkbrood disease in honey bees, Ascosphaera apis, was detected in all hives obtained from one supplier source, although none of the hives showed symptoms of infection. The shared core microbiota across both commercial supplier sources consisted of two ubiquitous bee-associated groups, Lactobacillus and Wickerhamiella/Starmerella clade yeasts that potentially contribute to the beneficial function of the microbiome of bumble bee pollen provisions. Full article