Search Results (223)

This study sought to quantify and characterize diverse rootstock scion interactions in cacao around graft compatibility, disease resistance, nutrient use efficiency, vigor traits, and translocation of nonstructural carbohydrates. In total, 106 grafts were performed with three scion cultivars (Matina 1/6, Criollo 22, Pound 7) and nine diverse open-pollinated seedling populations (BYNC, EQX 3348, GNV 360, IMC 14, PA 107, SCA 6, T 294, T 384, T 484). We found evidence for both local and translocated graft incompatibility. Cross sections and Micro-XCT imaging revealed anatomical anomalies, including necrosis and cavitation at the junction and accumulation of starch in the rootstock directly below the graft junction. Scion genetics were a significant factor in explaining differences in graft take, and graft take varied from 47% (Criollo 22) to 72% (Pound 7). Rootstock and scion identity both accounted for differences in survival over the course of the 30-month greenhouse study, with a low of 28.5% survival of Criollo 22 scions and a high of 72% for Pound 7 scions. Survival by rootstocks varied from 14.3% on GNV 360 to 100% survival on T 294 rootstock. A positive correlation of 0.34 (p = 0.098) was found between the graft success of different rootstock–scion combinations and their kinship coefficient, suggesting that relatedness of stock and scion could be a driver of incompatibility. Significant rootstock–scion effects were also observed for nutrient use efficiency, plant vigor, and resistance to Phytophthora palmivora. These findings, while preliminary in nature, highlight the potential of rootstock breeding to improve plant nutrition, resilience, and disease resistance in cacao. Full article

Anthocyanins, a subclass of flavonoid pigments, impart vivid red, purple, and blue coloration to horticultural plants, playing essential roles in ornamental enhancement, stress resistance, and pollinator attraction. Recent studies have identified B-box (BBX) proteins as a critical class of transcription factors (TFs) involved in anthocyanin biosynthesis. Despite these advances, comprehensive reviews systematically addressing BBX proteins are urgently needed, especially given the complexity and diversity of their roles in regulating anthocyanin production. In this paper, we provide an in-depth overview of the fundamental structures, biological functions, and classification of BBX TFs, along with a detailed description of anthocyanin biosynthetic pathways and bioactivities. Furthermore, we emphasize the diverse molecular mechanisms through which BBX TFs regulate anthocyanin accumulation, including direct activation or repression of target genes, indirect modulation via interacting protein complexes, and co-regulation with other transcriptional regulators. Additionally, we summarize the known upstream regulatory signals and downstream target genes of BBX TFs, highlighting their significance in shaping anthocyanin biosynthesis pathways. Understanding these regulatory networks mediated by BBX proteins will not only advance fundamental horticultural science but also provide valuable insights for enhancing the aesthetic quality, nutritional benefits, and stress adaptability of horticultural crops. Full article

Anthropogenic noise can have diverse effects on natural ecosystems, but less is known about the degree to which noise can alter organisms in comparison to other disturbances. A variety of frequencies are produced by man-made objects, ranging from high to low frequencies, and we studied infrasound (<20 Hz) produced by wind turbines and trains. We estimated the number, mass and viability of seeds produced by flowers of Plains pricklypear (Opuntia polyacantha Haw.) that were left open to pollinators, hand-pollinated or bagged to exclude pollinators. Each pollination treatment was applied to plants at varying distances from wind turbines and railways (≤25 km). Self-pollinated Opuntia polyacantha and plants within the wind facility produced ≥1.6 times more seeds in the bagged treatments compared to more distant sites. Seed mass and the percent of viable seeds decreased with distance from infrasound. Viability of seeds was >70% for most treatments and sites. If wind facilities, railways and other man-made structures produce infrasound that increases self-pollination, crops and native plants near sources may produce heavier seeds with higher viability in the absence of pollinators, but genetic diversity of plants may decline due to decreased cross-pollination. Full article

Bombus haematurus (Hymenoptera: Apidae), which arrived from the Balkan Peninsula, was first reported in Italy in 2020 in the Friuli Venezia Giulia region (FVG) (northeastern Italy) near the border with Slovenia. To study the spread and biology of the species, a survey was conducted at several sites of the FVG in the period 2023–2025. Bombus haematurus was recorded at 22 new sites across all four districts of the FVG (Trieste, Gorizia, Udine, and Pordenone), indicating its expansion towards the west. Bumblebees of this species were detected in plain and hilly areas at sites between 10 and 364 m a.s.l. They were observed more frequently at forest edges, undergrowth paths or clearings and meadows adjacent to woods, confirming the species is hylophilous. The activity of adults from February to July confirms that the bumblebee is an univoltine spring species. Specimens were observed foraging on the flowers of 19 wild and ornamental plants belonging to 12 families (in particular, Lamiaceae), confirming that the species is polylectic. The data collected indicate that B. haematurus are permanently established in the FVG and that a further spread of the species towards the west in the neighbouring Veneto region is likely. Full article

Nectar robbing typically reduces nectar availability to pollinators, damages flower structure, and/or induces secondary robbing. Consequently, it may reduce pollen deposition and seed set, increase pollination efficiency and outcrossing, and/or not affect reproduction in some species. However, spatiotemporal variations in nectar robbing and their effects on plant reproduction have received little attention. In this study, we assessed the effects of nectar robbing on floral visits, seed set, nectar volume and concentration, and flower longevity in two populations of Salvia castanea Diels (Lamiaceae) in the Himalayan region of Southwestern China in 2014–2020. We also examined whether one or a few visits by pollinators can result in the stigma receiving sufficient pollen to fertilize all ovules of S. castanea. We found that significant differences in the nectar robbing rate did not affect seed set in any of the years for either population of S. castanea. In the robbed and unrobbed flowers, nectar was consistently replenished every night at higher concentrations. Bagging, nectar robbing, and sufficient pollination did not affect flower longevity. Salvia castanea required only 5–10 pollen grains to achieve the maximum seed set. However, pollinators depositing more than 10 pollen grains after a single visit ensured a high seed set of >80%. Our results suggest that nectar availability, floral longevity maintenance, and sufficient pollen deposition mitigate the effects of nectar robbing on the reproductive success of S. castanea. These results are expected to further our understanding of plant–animal interactions and the ecological consequences of nectar robbing. Full article

Climate change can severely impact plant-pollinator interactions and have serious effects on ecosystem services such as pollination. This study was carried out in 2023 and 2024, and it examined the effects of drought on flowering and nectar production in one cultivar of white mustard (Brassica alba cv. Palma), an important entomophilous crop of the temperate zone with several attributes that make it promising for sustainable agricultural practices. Drought-stressed plants delayed the flowering time, shortened the flowering duration, and developed significantly fewer flowers. Nectar production in white mustard depends on soil moisture levels and short-term changes in meteorological conditions (e.g., air humidity, air temperature). At reduced soil moisture, the total sugar yield per plant decreased by 60%, compared to control plants, resulting in lower availability of caloric food resources, which should be considered when developing strategies supporting pollinators. Changes in floral traits resulted in differences in the frequency of insect visits, which may exert a negative impact on white mustard pollination under drought stress and may have indirect consequences for seed yield resulting from increased drought intensity associated with climate change. The results provide important data for the management of the white mustard crop and indicate the need for broader evaluation of cultivars to promote drought-resistant B. alba cultivars. Full article

Lavandula angustifolia Mill., lavender, is an aromatic plant in the Lamiaceae family. Lavender, which is native to the Mediterranean region but cultivated throughout the world, is an important economic plant. Several studies have investigated two aspects of this aromatic plant: (1) which pollinators, particularly bees, pollinate lavender, and (2) the composition of lavender essential oil. However, little research has been conducted to investigate how pollination affects either the yield or phytochemistry of lavender. The current study, which was conducted in North America, investigates which bee species visit lavender and how pollination affects plant chemistry, specifically the essential oil produced by lavender. Over the course of the 5-week observational period, a total of 12 species (across 10 genera) of bees were identified visiting lavender. Compared to previous studies on cultivated lavender at the same site (Mt. Nebo Botanical Farm, Mona, UT), four bee species not previously observed on lavender were identified. These included Hoplitis producta, Nomada sp., Osmia trevoris, and Megachile snowi. Pollinated lavender, compared to lavender excluded from pollinators, produced more essential oil (yield (w/w) = 1.49% vs. 1.07%), lower relative amounts of linalool (35.4% vs. 39.9%), and higher relative amounts of linalyl acetate (21.3% vs. 16.8%). The findings of this study demonstrate the ecological interactions between pollinators and lavender, and how those interactions impact phytochemistry. Full article

The Cerrado, the world’s most diverse savanna, has several adaptations to fire. However, intense and frequent fires, especially after frosts, can severely impact this ecosystem. Despite this, few studies have evaluated the combined effects of frost followed by fire. We investigated how these disturbances affect plant traits, floral resources, floral visitor richness, and the structures of plant–pollinator interaction networks by using Byrsonima intermedia, a common Malpighiaceae shrub, as a model. We compared areas affected by frost alone and frost followed by fire and the same fire-affected area two years later. We examined pollen, oil volume, buds, and racemes and recorded floral visitors. Our main hypothesis was that fire-affected areas would exhibit higher floral visitor richness, more conspicuous plant traits, and greater fruit production than areas affected by frost only, which would show higher interaction generalization due to stronger negative impacts. The results confirmed that frost drastically reduced floral traits, visitor richness, and reproductive success. In contrast, fire facilitated faster recovery, triggering increased floral resource quantities, richer pollinator communities, more specialized interactions, and greater fruit production. Our findings highlight that fire, despite its impact, promotes faster ecosystem recovery compared to frost, reinforcing its ecological role in the Cerrado’s resilience. Full article

Synthetic herbicides such as glyphosate and 2,4-D are widely used in agriculture but can negatively impact non-target organisms, including microorganisms essential for ecological balance. Yeasts associated with pollinating insects play crucial roles in plant–insect interactions, yet their responses to herbicides remain understudied. This study aimed to evaluate the capacity of yeasts isolated from bees and beetles to produce indole-3-acetic acid (IAA), a plant-growth-promoting hormone, as well as their ability to tolerate or degrade glyphosate (in the commercial herbicide Zapp QI 620^®) and 2,4-D (in the commercial Aminol 806^®). Seven yeast strains were isolated from insects, identified via ITS sequencing, and assessed for IAA production in YPD medium. Growth assays were conducted under varying herbicide concentrations, and 2,4-D degradation was analyzed using high-performance liquid chromatography. All strains produced IAA, with Papiliotrema siamensis CHAP-239 exhibiting the highest yield (4.17 mg/L). Glyphosate completely inhibited growth in all strains, while 2,4-D showed dose-dependent effects, with four strains tolerating lower concentrations. Notably, Meyerozyma caribbica CHAP-248 degraded up to 46% of 2,4-D at 6.045 g/L. These findings highlight the ecological risks herbicides pose to beneficial yeasts and suggest the potential of certain strains for bioremediation in herbicide-contaminated environments. Overall, the study underscores the importance of preserving microbial biodiversity in the context of sustainable agriculture. Full article

Knowledge of how wind turbines interact with vertebrate animals is growing rapidly; however, less is known about plants and insects. Turbines produce infrasound (≤20 Hz), and these vibrations decrease with distance from turbines. We measured seed set and pollinators at six sites 0 to 28 km from turbines. We measured the number and mass of seeds produced by self-pollination, insect pollination, and when pollen was not limiting for nine native plants. We assessed pollinators by target netting bees and butterflies during transects, and by using blue vane traps (bees only). Most plants produced fewer or lighter developed seeds through self-pollination. Seed set did not vary between the open- and hand-pollinated treatments, indicating that the pollen was not limiting. The number and mass of seeds in the self-pollination treatment decreased with distance from the turbines. Bees and butterflies were more abundant near the wind facility, based on transects. The vane traps collected the fewest insects within the wind facility, likely due to bees being attracted to the turbine bases. The pollinator assemblage at the wind facility was distinct compared to other sites. Infrasound produced by the turbines appeared to enhance self-pollination, and the turbine bases attracted pollinators. We provide data on a seldom studied yet critical topic to inform land management and agricultural decisions, and to promote new strategies as wind energy development grows. Full article

Taraxacum, a genus in the Asteraceae family, is widely distributed across temperate regions and plays a vital ecological role by providing nectar and pollen to pollinators during the early flowering season. Floral nectar is a key reward that plants use to attract pollinators, and its production is tightly regulated by genes such as SWEET sugar transporters and CELL WALL INVERTASE (CWIN), which govern sugar efflux and hydrolysis. Despite their ecological importance, the molecular mechanisms underlying nectar secretion in Taraxacum remain poorly understood. In this study, we performed RNA sequencing of flower tissues from five Taraxacum species—T. coreanum, T. monogolicum, T. ohwianum, T. hallaisanense, and T. officinale—to investigate the expression of nectar-related genes. De novo transcriptome assembly revealed that T. coreanum had the highest unigene count (74,689), followed by T. monogolicum (69,234), T. ohwianum (64,296), T. hallaisanense (59,599), and T. officinale (58,924). Functional annotation and phylogenetic analyses identified 17 putative SWEET and 18 CWIN genes across the five species. Differential gene expression analysis highlighted tarSWEET9 and tarCWIN4 as consistently up-regulated during the flowering stage. Quantitative PCR in T. officinale further validated that tarSWEET9, tarCWIN4, tarCWIN6, and tarSPAS2 show significant expression during floral development but are down-regulated after pollination. These genes are likely central to the regulation of nectar secretion in response to pollination cues. Our findings suggest that T. officinale may have evolved to have an efficient, pollinator-responsive nectar secretion system, contributing to its global adaptability. This study sheds light on how pollinator interactions influence gene expression patterns and may drive evolutionary divergence among Taraxacum species. Full article

Climate change significantly influences plants’ physiology, flowering phenology, and nectar production, affecting pollinator interactions and apicultural sustainability. This study examines the physiological responses of Pseudolysimachion rotundum (Nakai) Holub var. subintegrum (Nakai) T.Yamaz. (Plantaginaceae) under projected climate change scenarios, focusing on flowering traits, nectar secretion, and honey production potential. Elevated CO₂ levels enhanced its net photosynthesis and water-use efficiency, supporting sustained carbohydrate assimilation and promoting aboveground biomass accumulation. However, the increased nitrogen demand for vegetative growth and inflorescence production may have led to reduced allocation of nitrogen to the nectar, contributing to a decline in its amino acid concentrations. The flowering period advanced with rising temperatures, with peak bloom occurring up to four days earlier under the SSP5 conditions. While the nectar secretion per flower remained stable, an increase in floral abundance led to a 3.8-fold rise in the estimated honey production per hectare. The analysis of the nectar’s composition revealed that sucrose hydrolysis intensified under higher temperatures, shifting the nectar toward a hexose-rich profile. Although nectar quality slightly declined due to reductions in sucrose and nitrogen-rich amino acids, phenylalanine—the most preferred amino acid by honeybees—remained dominant across all scenarios. These findings confirm the strong climate resilience of P. rotundum var. subintegrum, highlighting its potential as a sustainable nectar source in future apicultural landscapes. Given the crucial role of nitrogen in both plant growth and nectar composition, future research should explore soil nitrogen dynamics and plant nitrogen metabolism to ensure long-term sustainability in plant–pollinator interactions and apicultural practices. Full article

Current understanding of synergistic trait effects in plant–pollinator systems remains limited, particularly regarding combined visual and mechanical screening mechanisms. Given the specialized flower opening mechanisms and diverse color signals in the Papilionoideae of Fabaceae, this study examines how floral color and mechanical traits jointly mediate pollinator selection in five co-flowering sympatric species. The flower structure of Papilionoideae typically features a keel formed by fused petal lobes that encloses reproductive organs, with flower operative strength thresholds directly reflecting the mechanical resistance required to dehisce the keel and access nectar/pollen. Flower operative strength thresholds and insect mechanical capabilities were quantified, and visitation behaviors were observed under natural conditions. Significant interspecific variation in flower mechanical strength (12.59–20.25 mN) was identified, with visiting insects consistently exhibiting strengths exceeding these thresholds, suggesting mechanical barriers selectively filter pollinators. Non-visiting insects exhibited either insufficient or excessive strength relative to floral thresholds, which is related to the flower-visiting preferences of different insects. Although no linear correlation was found between flower color (RGB color space) and mechanical strength, the combined analysis revealed synergistic screening where color attracted specific pollinators from a subset capable of overcoming mechanical barriers. These findings demonstrate that flower color and mechanical traits function as complementary filters, optimizing pollinator efficiency and excluding ineffective visitors. The study highlights the necessity to explore multi-trait interactions in plant–pollinator co-evolution, with implications for biodiversity conservation and ecosystem service management. Full article

Many plant groups exhibit complex evolutionary processes, including hybridization, incomplete lineage sorting, and variable evolutionary rates, which make species delimitation challenging. Molecular data have been essential for studying such groups, including Petunia, where local adaptation, allopatric speciation, pollinator interactions, and hybridization shape diversity and population structure. In this study, we produced the first broadly inclusive phylogenetic tree of Petunia using high-throughput DNA sequence data generated by genome complexity reduction-based sequencing (DArT), and incorporating all currently accepted taxa. Additionally, we reviewed previously published phylogenetic and phylogeographic studies on these species to support the taxonomic revision. Phylogenetic analyses based on SNPs were largely congruent, revealing two well-supported clades divided by corolla tube length, consistent with previous studies. These clades likely originated and diversified during the Pleistocene. The phylogenetic trees provided strong support for taxonomic changes, resolving long-standing uncertainties. We recognize P. axillaris, P. parodii, and P. subandina as independent species, elevate P. integrifolia subsp. depauperata to P. dichotoma Sendtn., and resurrect P. guarapuavensis. Additionally, our results highlighted unsolved questions regarding the evolutionary history of the short corolla tube clade, suggesting the need for further investigation into its diversification and genetic structure. Full article