Search Results (33)

Crops are continually subjected to frequent and extreme changes in climate, such as high temperatures and soil water deficits. Many studies have shown the individual effects of these factors on plants, but their combined effects on reproductive growth and subsequent seed germinability have received little attention. In this study, we used canola (Brassica napus) plants and grew them through their lifecycle under two temperature regimes (20/10 °C and 24/14 °C, 16 h light/8 h dark) in controlled-environment growth chambers. Half of the plants were watered to field capacity (well-watered) and the other half at wilting point (water-stressed). During the reproductive stage, the flower, silique, and seed traits were measured. Higher temperatures decreased the petal width by 1.17 times but increased petal anthocyanins by 1.03 times. The water deficit decreased the silique length and total seed number by 1.21 and 1.32 times, respectively, but increased nectar sugar concentration by 1.28 times. The total volume of nectar was affected by the interaction of temperature and water. The nectar volume was lowest in the water-stressed plants under higher temperatures (2.66 ± 0.29 µL per flower) but highest in the well-watered plants under the same temperature regime (5.73 ± 0.37 µL per flower). In conclusion, the combined effects of temperature and water were less pronounced than the individual effects of these factors on canola reproductive yield. Full article

Herbivores can negatively impact plant reproduction by altering floral traits, pollination, and fruit production. To counteract this, plants developed defense mechanisms, such as the biotic defense resulting from associations with ants. The aim of this study was to investigate whether leaf herbivory at different intensities influences reproductive success and extrafloral nectar secretion patterns in a savanna plant, Banisteriopsis malifolia (Malpighiaceae). Plants were subjected to simulated leaf herbivory and divided into three groups: Control (damage < 5%), T15 (15% leaf area removed), and T50 (50% leaf area removed). Assessments continued until fruiting. The findings indicate an increase in extrafloral nectar sugar concentration after simulated herbivory. Increasing foliar damage significantly delayed the time to bloom, decreased the number of inflorescences per plant, and reduced the size of buds and flowers. Foliar damage significantly decreased fruit size. Furthermore, ant foraging was influenced by herbivory, with a predominance of aggressive ants on plants with high levels of damage. Our study shows that varying levels of leaf damage affect extrafloral nectar secretion, ant foraging behavior, and plant reproductive structures. These findings highlight how insect herbivores and the level of damage they cause influence plant fitness and consequently community structure. Full article

Drought stress during the reproductive phase of sunflower can significantly reduce achene yield by affecting inflorescence size, nectar quality, and pollinator activity. This study aimed to analyze the morphological characteristics of the reproductive region, quantify nectar sugar components, and evaluate pollinator presence and pollination success in wild Helianthus species as an important genetic resource for breeding cultivated sunflowers under drought conditions. Morphological investigations were conducted during the flowering and achene development phases with a stereo microscope and calipers. Nectar sugar concentrations were analyzed via HPLC, and pollinator presence was monitored twice a week for two months. This study highlights the correlation between evaluated traits, emphasizing their importance as yield indicators. Significant differences were observed in reproductive characters, nectar quality, and pollination success among the species. Helianthus annuus and Helianthus argophyllus exhibited superior reproductive performance with high nectar sugar concentrations and larger inflorescences, enabling successful pollination and higher achene yield. In contrast, Helianthus debilis demonstrated lower reproductive efficiency, with a higher percentage of empty achenes. These findings provide valuable insights for breeding programs, highlighting H. argophyllus and H. annuus as promising genetic resources for developing sunflower genotypes with increased yield and improved floral traits adapted to drought conditions. Full article

Chemical traits (primary and secondary metabolites) are important features of plants. An increasing number of studies have focused on the ecological significance of secondary metabolites in plant parts, especially in pollen. Ericaceae species exhibit significant morphological variations and diverse colors, are widely distributed throughout China and are popular ornamental garden plants. The chemical trait of pollen in Ericaceae species and their potential ecological significance remain unclear. We selected a total of nine Ericaceae species from three nature reserves in southwestern China, which were the predominant flowering Ericaceae plants for each site, and measured their floral characteristics, nectar volume and sugar concentration. We determined the types of pollinators of these species based on a literature review and used UPLC-QTOF-MS to analyze the types and relative contents of primary metabolites (amino acids and fatty acids) and secondary metabolites (terpenoids, phenolics and nitrogenous compounds) in the pollen and other tissues, including the stems, leaves, petals and nectar. The results showed that each species exhibited unique floral characteristics. Enkianthus ruber, Pieris formosa, Rhododendron agastum, R. irroratum, R. virgatum and R. rubiginosum were pollinated by bees, and R. delavayi, R. decorum and R. excellens were pollinated by diverse animals (bees, birds and Lepidoptera). The pollen of these Ericaceae species was rich in phenolics and terpenoids, especially flavonoids. Grayanotoxin, andromedotoxin and asebotin (toxic diterpene compounds) were also detected in the pollen of some of the Ericaceae species in our study, and their response value was low. The relative contents and diversity of secondary metabolites in the pollen were higher than those in the nectar but lower than those in the leaves, petals and stems. The five chemical compounds with the highest content (four flavonoids, one triterpene) in the pollen were also detected in the stems, leaves and petals, and the response value of most of these chemicals in pollen was not significantly correlated with that in other tissues. Rhododendron species has a closer relationship with chemical traits in pollen compared with Enkianthus and Pieris species. The response value of total secondary metabolites in the pollen of species pollinated only by bees was higher than that of species pollinated by diverse animals. Our research indicates that the pollen of ericaceous species contains a wide array of metabolites, establishing a foundation for advancing the nutritional potential of the pollen of horticultural ericaceous species and deepening our understanding of its chemical and ecological significance. Full article

Honey bees use pollen and nectar from flowers to produce food. Because they often forage on crops, they are at risk of being exposed to plant protection products (PPPs), both directly and in stored food. Due to the adverse effects of synthetic PPPs on pollinators, biopesticides may be a viable alternative. Common tansy extract is used as one of the natural substitutes for synthetic pesticides. In our study, the effect of fermented common tansy extract on aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and gamma-glutamyl transpeptidase (GGTP) activity and the concentration of triglycerides (TGs), total protein (TP), total antioxidant status (TAS), and glucose in honey bee workers’ hemolymph was assessed. These biochemical markers give valuable information about the immunity, detoxification, and nutrition of a bee’s body. Caged bees were given tansy extract added at various concentrations in sugar syrup for 24 h. Then, they were provided with only sugar syrup. After 7 days of the experiment, hemolymph was collected and analyzed. We observed changes in the activity of AST, ALT, GGTP enzymes and TG, TP, and glucose levels, but not all changes were statistically significant. In terms of AST activity, statistically significant differences were found. All groups tested, including the negative control group, showed reduced enzyme activity values compared to the positive control group. In TG concentration, differences were observed between the groups receiving 2% extract and 1% ethanol. Glucose levels differed between the groups receiving 1% extract and 2% extract and between the positive control group and 1% extract. Bee body proper functioning is affected by changes in enzyme activity, especially those responsible for immunity and detoxification, such as AST, ALT, ALP, and GGTP. Despite the short time of bees’ exposure to the agent, the results of study show visible effects. Our results provide a basis for further research on the impact of tansy extract on honey bees. Full article

The study aimed to estimate the levels of fructose, glucose, sucrose, and inositol levels in sweetened beverages with a newly developed method using HPLC coupled with a charged aerosol detector (CAD). In total, 85 commercially available non-alcoholic beverages, including 18 energy drinks, 8 sports drinks, 15 soft drinks, 14 fruit drinks, 7 fruit nectars, and 22 fruit juices were analyzed by HPLC-CAD. The method was validated, and it was characterized by a wide concentration range (1–150 µg/mL), sensitivity, and good accuracy (94.9–103%). The results showed significant variation in fructose, glucose, and sucrose concentrations in energy drinks, sports drinks, soft drinks, fruit drinks, fruit nectars, and juice. The highest total sugar contents (fructose, glucose, sucrose, and inositol) were found in energy drinks (14.2 g/100 mL), followed by fruit nectars (13.7 g/100 mL) and soft drinks (12.7 g/100 mL). Statistical analysis (Spearman correlation test, Kruskal–Wallis test) of the data showed significant relationships between particular sugars in the analyzed products. Full article

Floral nectar is mainly a reward in the form of food for pollinators. Its composition plays an important role when pollinators choose their food. Several studies have shown that the popularity of flowers with nectar is influenced by the concentration and ratio of sugars. Here, we present the nectar chemical composition with regard to three main sugars and their concentrations in correlation with abiotic factors for the plant species Salvia pratensis L. and Salvia glutinosa L. through their 2023 flowering season. We sampled nectar using microcapillaries at three different times during the day on sites in nature. Our results show that nectar production in both species is the highest at around 12 a.m. The abiotic factor that affects nectar production in both species is the soil temperature, while UVB radiation does not influence nectar production. Air temperature and air humidity affect the nectar production of S. glutinosa, while soil humidity affects nectar production in S. pratensis. The most represented sugar in S. glutinosa nectar is sucrose, while S. pratensis nectar has more glucose and fructose. Our results show that UVB radiation has an effect on the sucrose level, although it does not have any direct effect on nectar productivity. Full article

SWEET, sugars will eventually be exported transporter, is a novel class of sugar transporter proteins that can transport sugars across membranes down a concentration gradient. It plays a key role in plant photosynthetic assimilates, phloem loading, nectar secretion from nectar glands, seed grouting, pollen development, pathogen interactions, and adversity regulation, and has received widespread attention in recent years. To date, systematic analysis of the SWEET family in Zantedeschia has not been documented, although the genome has been reported in Zantedeschia elliottiana. In this study, 19 ZeSWEET genes were genome-wide identified in Z. elliottiana, and unevenly located in 10 chromosomes. They were further clustered into four clades by a phylogenetic tree, and almost every clade has its own unique motifs. Synthetic analysis confirmed two pairs of segmental duplication events of ZeSWEET genes. Heatmaps of tissue-specific and Pectobacterium carotovora subsp. Carotovora (Pcc) infection showed that ZeSWEET genes had different expression patterns, so SWEETs may play widely varying roles in development and stress tolerance in Zantedeschia. Moreover, quantitative reverse transcription-PCR (qRT-PCR) analysis revealed that some of the ZeSWEETs responded to Pcc infection, among which eight genes were significantly upregulated and six genes were significantly downregulated, revealing their potential functions in response to Pcc infection. The promoter sequences of ZeSWEETs contained 51 different types of the 1380 cis-regulatory elements, and each ZeSWEET gene contained at least two phytohormone responsive elements and one stress response element. In addition, a subcellular localization study indicated that ZeSWEET07 and ZeSWEET18 were found to be localized to the plasma membrane. These findings provide insights into the characteristics of SWEET genes and contribute to future studies on the functional characteristics of ZeSWEET genes, and then improve Pcc infection tolerance in Zantedeschia through molecular breeding. Full article

The growing beekeeping industry in South Korea has led to the establishment of new honey plant complexes. However, studies on honey production from each species are limited. This study aimed to assess the honey production potential of various Brassica napus cultivars and two wildflower species. The nectar characteristics of B. napus varied significantly among the cultivars. Absolute sugar concentrations differed among the cultivars, but sugar composition ratios were similar. In contrast, the amino acid content remained relatively uniform regarding percentage values, irrespective of the absolute concentrations. Estimations of honey potential production per hectare (kg/ha) resulted in the following ranking among cultivars: ‘JM7003’ (107.1) > ‘YS’ (73.0) > ‘JM7001’ (63.7) > ‘TL’ (52.7) > ‘TM’ (42.4). The nectar volume of Pseudolysimachion rotundum var. subintegrum and Leonurus japonicus increased during the flowering stage. P. rotundum var. subintegrum was sucrose-rich and L. japonicus was sucrose-dominant. Both species predominantly contained phenylalanine, P. rotundum var. subintegrum had glutamine as the second most abundant amino acid, and L. japonicus had tyrosine. The honey production potential was 152.4 kg/ha for P. rotundum var. subintegrum and 151.3 kg/ha for L. japonicus. These findings provide a basis for identifying food resources for pollinators and selecting plant species to establish honey plant complexes. Full article

Floral nectar contains sugars and numerous other compounds, including amino acids, but little is known about their function and origin in nectar. Therefore, the amino acid, sugar, and inorganic ion concentrations, as well as the activity of alanine aminotransferase (AlaAT) and glutamine synthetase (GS) in nectar, nectaries, and leaves were analyzed in 30 Pitcairnia species. These data were compared with various floral traits, the pollinator type, and the phylogenetic relationships of the species to find possible causes for the high amino acid concentrations in the nectar of some species. The highest concentrations of amino acids (especially alanine) in nectar were found in species with reddish flowers. Furthermore, the concentration of amino acids in nectar and nectaries is determined through analyzing flower color/pollination type rather than phylogenetic relations. This study provides new insights into the origin of amino acids in nectar. The presence of almost all amino acids in nectar is mainly due to their transport in the phloem to the nectaries, with the exception of alanine, which is partially produced in nectaries. In addition, active regulatory mechanisms are required in nectaries that retain most of the amino acids and allow the selective secretion of specific amino acids, such as alanine. Full article

To serve human needs, non-native species are selected based on an array of functional traits, which generally confer competitive advantages to these species in their recipient environments. Identifying non-obvious functional traits that indirectly inform human selection of non-natives to introduce into urban greenspaces is not yet part of common discussions in invasion biology. We tested whether functional traits integrated within a phylogenetic framework, may reveal those subtle criteria underlying the introduction of non-native plants into urban greenspaces. We found no differences in terms of functional traits between natives and non-natives. We also found no evidence that functional traits predict nectar production, irrespective of how nectar production was measured. Finally, we found that the mean sugar concentration of nectar per flower is evolutionarily shared both within closely related non-native plants as well as within close native plants. However, phylogenetically close species share similar intraspecific variation in mass of nectar sugar per flower, but this is true only for non-native plants, thus revealing a non-obvious selection criteria of non-native plants for urban greenspaces. Our results indicate that the phylogenetic patterns of intraspecific variation in mass of nectar sugar per flower is the major criterion distinguishing non-natives from native plants in urban greenspaces in Southern England. Full article

Bunching onion as well as onion show great variability in seed yield among cultivars. Understanding the role of floral rewards and attractants to pollinator species is crucial to improving crop seed yield. Nectar sugar concentration is one of the most important factors affecting bee–flower interaction. The objective of this work was to determine the differences in nectar sugar composition between onion and bunching onion lines grown in the same location during two consecutive cultivation cycles and in two different productive areas under open field conditions, and the relationship of these sugars with seed yield. The results obtained showed that, regardless of the season and the location, bunching onion produced higher seed yields than onion, and the sugar content was always higher than in onion. Fructose represented on average 56% of the total sugars, glucose 34% and, sucrose 9% of the total amount of sugars in nectar. There were differences between the two locations studied. Fructose content had a significant correlation with seed yield. The amount of sugars in bunching onion could be the reason why this species does not have pollination problems in contrast to onion plants. In addition, the differences found in seed yield between locations could provide options for seed companies to make production decisions. Full article

In light of pollinator decline, plant species suitable for the restoration and conservation of pollinators need to be selected. In this systemic review, we concentrated on the importance of NFWV (non-forest woody vegetation, i.e., linear or grouped trees/shrubs) for pollinators across agricultural landscapes. In the temperate climate zone, flowering trees and shrubs provide nectar sugar (energy) and pollen (nutrients) for managed and wild pollinators. They also create nesting niches and serve as host plants that support the full life cycle of wild pollinators. The creation of woodland strips/groups is a cost-effective and time-saving strategy to improve self-repeatable nectar and pollen resources on a landscape scale. The spatial distribution of NFWV can help to create an entire network of pollinator-friendly habitats. NFWV can support the continuity of food resources outside of the crop flowering season, i.e., during seasonal bottlenecks. This concept also offers other environmental benefits (e.g., water and air quality improvement, climate mitigation). However, future work should address the usefulness of trees/shrubs for different crops and regions to develop a network of flower-rich corridors. Likewise, more advanced and detailed studies are necessary to determine the qualitative characteristics of nectar and pollen, which may result in optimization of pollinator nutrition. Full article

The purpose of our study was to determine the role of flower structure and nectar composition in shaping the reproductive success (RS) of the generalist orchid Epipactis helleborine in natural and anthropogenic populations. We supposed that the distinct character of two groups of habitats creates different conditions for plant–pollinator relationships, thus influencing reproductive success in E. helleborine populations. Both pollinaria removal (PR) and fruiting (FRS) were differentiated between the populations. On average, FRS was almost two times higher in the anthropogenic than in the natural populations. The difference between the two population groups in PR was smaller but still statistically significant. RS parameters were correlated with some floral display and flower traits. Floral display influenced RS only in three anthropogenic populations. Flower traits had a weak influence on RS (10 of the 192 cases analyzed). The more important trait in shaping RS was nectar chemistry. The nectar of E. helleborine is relatively diluted with a lower sugar concentration in the anthropogenic than in the natural populations. In the natural populations, domination of sucrose over hexoses was found, while in the anthropogenic populations, hexoses were more abundant and the participation of sugars was balanced. In some populations, sugars influenced RS. In E. helleborine nectar, 20 proteogenic and 7 non-proteogenic amino acids (AAs) were found with a clear domination of glutamic acid. We noted relationships between some AAs and RS, but distinct AAs shaped RS in different populations, and their impact was independent of their participation. Our results indicate that the flower structure and nectar composition of E. helleborine reflect its generalistic character and meet the requirements of a wide range of pollinators. Simultaneously, the differentiation of flower traits suggests a variation in pollinator assemblages in particular populations. Knowledge about the factors influencing RS in distinct habitats helps to understand the evolutionary potential of species and to understand mechanisms and processes crucial for shaping interactions between plants and pollinators. Full article

The proboscis extension response (PER) assay revealed the responsiveness of three subspecies of the honeybee Apis mellifera [A. m. jemenitica (AMJ), A. m. carnica (AMC), and A. m. ligustica (AML)] to water and different concentrations (0.00001, 0.0001, 0.001, 0.01, 0.1, 0.5, 1.0, and 1.5 M) of three sugars (fructose, glucose, and sucrose) during the summer and fall seasons. The tested bee subspecies showed significantly different PERs to sugar types across the seasons. The water responsiveness of AMJ, a native bee subspecies, was significantly lower than that of AMC and AML, which showed an equally higher water response in both seasons. During the summer season, AMJ and AMC were equally responsive to each sugar type at all tested concentrations. AML was relatively less responsive to glucose at 0.001, 0.001, 0.01, 0.1, 0.5, and 1.0 M than to fructose and sucrose during the summer season. During the fall season, AMJ was equally responsive to glucose and sucrose at all tested concentrations but showed a significantly different response between fructose and sucrose at 0.001, 0.01, 0.1, 0.5, and 1.0 M concentrations. The PER of AMJ to fructose was lower than that of glucose and sucrose. AMC was equally responsive to all tested sugars at all concentrations, and AML showed a differential response between glucose and sucrose at different concentrations during the fall season. The inter-specific species comparisons revealed that all tested subspecies were equally responsive to fructose at all tested concentrations, and AMJ was more responsive to glucose and sucrose than AMC and AML during both seasons. AMC and AML showed no differences in PER to glucose and sucrose in either season. The AMJ, AMC, and AML nectar and pollen foragers showed no significant differences in PER to glucose and sucrose. The AMC nectar foragers were highly responsive to sucrose than pollen foragers at higher sucrose concentrations (0.1, 0.5, 1.0, and 1.5 M). The AML (nectar forager vs. pollen forgers) showed identical PER to sucrose and glucose but a higher response of nectar foragers to high glucose concentrations (0.5, 1.0, and 1.5 M) than pollen foragers. For water responsiveness, AMJ nectar and pollen foragers showed similar PER to water, whereas AMC and AML pollen foragers were significantly more responsive to water than nectar foragers. Full article