Mating patterns in angiosperms are typically nonrandom,yet the mechanisms driving nonrandom mating remain unclear,especially regarding the effects of quantitative floral traits on plant mating success across male and ...Mating patterns in angiosperms are typically nonrandom,yet the mechanisms driving nonrandom mating remain unclear,especially regarding the effects of quantitative floral traits on plant mating success across male and female functions.In this study,we investigated how variation in spur length and flower number per plant influences mating patterns in Aquilegia rockii within a natural population.Using marker-based paternity analyses and manipulative experiments,we assessed the role of these traits in mating success across both sexual functions.We found significant variation in the mate composition between male and female function,with spur-length frequency positively associated with female outcrossing rate and mate number,but not with male outcrossing or mate number.Most mating events occurred within 10 m,and spur-length frequency positively correlated with mating distance.Regardless of selfing,there was evidence for assortative mating for spur length.Although spur length did not correlate with pollinator visitation,plants with mid-length spurs had higher seed set than those with shorter or longer spurs when autonomous selfing was excluded.Flowers number per plant was only associated with mating distance and female outcrossing rate.Our results suggest that spur length plays a key role in nonrandom mating by frequency-dependent mating,with implications for stabilizing selection and maintenance of genetic diversity.This study advances our understanding of floral diversity by dissecting the role of quantitative floral traits in plant mating through both female and male functions.展开更多
This study investigates the diurnal patterns of nectar secretion,sugar content,and caloric value in Epimedium wushanense,and their interaction mechanisms with pollinator behavior under varying environmental conditions...This study investigates the diurnal patterns of nectar secretion,sugar content,and caloric value in Epimedium wushanense,and their interaction mechanisms with pollinator behavior under varying environmental conditions.Nectar secretion exhibited a diurnal pattern,peaking between 11:00 and 13:00,with progressive increases in both volumes(19.07±1.66μL/day)and caloric value(6.03±0.55 cal/day)over four consecutive days,culminating in maximal production on Day 4(p<0.05).Floral bagging significantly altered nectar traits(Mann-Whitney U test,p<0.05),with bagged inflorescences demonstrating 61.82%higher nectar volume productivity relative to unbagged controls.Pollinator visitation,primarily by Bombus trifasciatus and Bombus grahami,was strongly correlated with nectar sugar concentration and distribution,peaking during midday when temperatures and humidity were optimal.Notably,B.trifasciatus displayed legitimate pollination behavior,while B.grahami exhibited nectar robbing.Bombus grahami peaked at 15:00(7.67±0.33 visits)under 22.8°C/58%RH,outperforming Bombus trifasciatus(5.67±0.27 at 13:00;p<0.05),highlighting differential pollinator effectiveness.Temperature negatively impacted unbagged nectar volume and caloric value but positively influenced bagged nectar,suggesting adaptive resource allocation strategies.These findings underscore the intricate relationship between environmental factors,nectar dynamics,and pollinator behavior,revealing how E.wushanense optimizes reproductive success through temporal and ecological adaptations.This study provides critical insights into the ecological mechanisms driving plant-pollinator interactions and resource allocation in changing environments.展开更多
[Objective] The aim was to research the rules of nectar quantity and sugar concentration of perfect and staminate flowers in a day. [Method] Based on nine Tianguang Yan pomegranate trees, nectar quantity and sugar con...[Objective] The aim was to research the rules of nectar quantity and sugar concentration of perfect and staminate flowers in a day. [Method] Based on nine Tianguang Yan pomegranate trees, nectar quantity and sugar concentration of per- fect and staminate flowers were measured and analyzed in morning and afternoon. [Result] Average nectar quantity and sugar concentration differed insignificantly in morning and afternoon of perfect flowers, which could also be applied to staminate flowers. However, average nectar quantity of perfect flower was 64.09 μI and of staminate flower was 44.07 μl. It is obvious that the two were of extremely signifi- cant differences （t=4.642, P〈0.01）, and the former was significantly higher by 45,43%. On the other hand, average sugar concentration of perfect flower was 48.44% and of staminate flower was 37.16%. The two were of extremely significant differences and the former is higher by 30.36%, compared with the latter. These suggested that nectar quantity and sugar concentration would maintain unchanged in different periods for a day, if nectars are not consumed by pollinators, such as bees and butterflies. In the same period, nectar quantity and sugar concentration of per- fect flowers were higher than those of staminate flowers. [Conclusion] The research provides references for benefits increase of bee farmers and fruit farmers, as well as exploration of bee pollination.展开更多
Phenotypic plasticity allows organisms to maximize fitness, by optimizing the expression of costly defensive traits. Broad bean, Vicia faba L. “Broad Windsor”, produces increased numbers of extrafloral nectaries (EF...Phenotypic plasticity allows organisms to maximize fitness, by optimizing the expression of costly defensive traits. Broad bean, Vicia faba L. “Broad Windsor”, produces increased numbers of extrafloral nectaries (EFNs) in response to leaf damage to attract mutualistic partners and reduce herbivory. It is currently unknown, however, whether EFN induction is cultivar-specific or is a more general phenomenon. It has also not been determined whether broad beans increase nectar secretion rates in conjunction with EFN induction. We hypothesized that: a) as all broad beans have conspicuous EFNs, all cultivars should produce additional EFNs in response to leaf damage, and b) overall nectar secretion rates should increase with EFN numbers, to attract additional mutualists. We tested our hypothesis by subjecting three broad bean cultivars, Vicia faba L. “Broad Windsor”, “Stereo”, and “Witkiem” to mechanical leaf damage. The degree of change in plant traits associated with growth, in addition to EFN induction, was assessed 1 week after leaf damage. Extrafloral nectar volumes were also assessed, every 24 hours, pre- and post-leaf damage. We confirmed our first, but rejected our second, hypothesis. All cultivars produced additional EFNs, but none increased extrafloral nectar volumes, when experiencing leaf damage. Further experimentation is required to determine if energetic tradeoffs limit multiple forms of defense (i.e., EFN vs. nectar induction), or if this alternative strategy is adaptive for attracting and retaining mutualists. Understanding the costs and benefits of EFN vs. nectar induction will provide insight into the evolution of defensive mutualisms between plants and predatory arthropods.展开更多
The aim of this work was to distinguish volatile organic compound（VOC） profiles of royal jelly（RJ） from different nectar plants. Headspace solid-phase microextraction（HS-SPME） was used to extract VOCs from raw R...The aim of this work was to distinguish volatile organic compound（VOC） profiles of royal jelly（RJ） from different nectar plants. Headspace solid-phase microextraction（HS-SPME） was used to extract VOCs from raw RJ harvested from 10 nectar plants in flowering seasons. Qualitative and semi-quantitative analysis of VOCs extracts were performed by gas chromatography-mass spectrometry（GC-MS）. Results showed that VOC profiles of RJ from the samples were rich in acid, ester and aldehyde compound classes, however, contents of them were differential, exemplified by the data from acetic acid, benzoic acid methyl ester, hexanoic acid and octanoic acid. As a conclusion, these four VOCs can be used for distinguishing RJ harvested in the seasons of different nectar plants.展开更多
The presence of adequate nectar sources along the migratory pathway is a prerequisite for moths of oriental armyworm, Mythimna separata, to reach target habitats and lay eggs. Identification of plant species and asses...The presence of adequate nectar sources along the migratory pathway is a prerequisite for moths of oriental armyworm, Mythimna separata, to reach target habitats and lay eggs. Identification of plant species and assessment of their suitability as wild nectar sources along the summer migration pathway of adult M. separata are critical steps in making effective forecasts of second-and third-generation armyworm outbreaks in North China. We explored five aspects of moth-nectar source relationships：（1） Field investigations in 2014 and 2015 showed that the florescence of chaste tree, Vitex negundo var. heterophylla, a primary nectar plant in apiculture, coincided with the summer migration of oriental armyworm moths. The flowers of chaste tree opened day and night and M. separata moths were found actively flying around and resting on tree.（2） Identification of moth-borne pollen by scanning electronic microscopy（SEM） micrographs in 2015 and 2016 revealed that 15.4% of 369 moths trapped by blacklight traps, 17.1% of 557 moths captured by vertical-pointing searchlight traps and 24.4% of 311 moths caught by pheromone traps were found with pollen attached to their proboscis. A total of 228 pollen-carrying individuals out of 1237 armyworm moths were captured by the three types of traps. The three highest percentages of pollen-bearing armyworm moths were carrying pollen of Toona sp.（59.65%）, Ligustrum sp.（27.19%） and Syringa sp.（4.39%）. In total, 14 types of pollen were detected where three were identified to species, 10 to genus and one as an unknown species.（3） Analysis of geographical distribution, flowering periods and relative abundances of candidate nectar plants suggested that Chinese toon, Toona sinensis, and privet, Ligustrum lucidum, were two important nectar plant species.（4） Analysis on relationship between pollen and ovarian development showed that 14, 15 and 10 females carrying pollen of T. sinensis had ovaries at developmental stages Ⅰ, Ⅱ and Ⅲ, respectively. Many T. sinensis pollen grains were present on the proboscises of female moths.（5） Comparison of trap effectiveness between blacklight and vertical-pointing searchlight traps indicated blacklight traps caught the highest proportion（35.2%） of female in ovarian stage Ⅴ, whereas vertical-pointing searchlight traps caught the highest proportion（43.5%） of female in ovarian stage I with additional proportions of decreasing percentages for stages Ⅱ, Ⅲ and Ⅳ. Integrated analysis on these five aspects suggests that T. sinensis is an important, suitable summer nectar source that potentially influences migration and reproduction of M. separata moths andthus contributes to outbreaks of this pest. The vertical-pointing searchlight trap was the most effective tool for monitoring the migratory flight of adult M. separata. Privet, Ligustrum lucidum, and clove, Syringa sp., are possible suitable summer nectar plants that need further study to elucidate their importance. The reason why field investigation results on chaste tree differed from the results of moth-borne pollen analyses was discussed.展开更多
Significant progress has been achieved in the use of heterosis in soybean and several soybean hybrids have been released in China. However, broad use of hybrid soybean seed is limited due to low seed setting of female...Significant progress has been achieved in the use of heterosis in soybean and several soybean hybrids have been released in China. However, broad use of hybrid soybean seed is limited due to low seed setting of female parents. Breeding cytoplasmic male sterile（CMS） lines with high out-crossing rate is necessary to solve the problem. The objective of this study was to determine the relationship between out-crossing rate of CMS lines and their nectar secretion. The daily nectar secretion rhythm, meteorological effect on nectar secretion, and differences in nectar secretion among genotypes and years were investigated in 27 soybean CMS lines（A-lines） with their maintainers（B-lines） and restorers（R-lines）. The correlation between out-crossing rate of CMS lines and nectar production was also evaluated. Nectar secretion had diurnal variation. Secretion initiated at about 06：00 for most materials and reached a peak at 07：00–08：30 after flower opened, then the nectar secretion decreased gradually. A sub-peak appeared at about 13：00, while the nectar could not be detected at 17：00. Nectar secretion was greatly influenced by the weather conditions. The amount of nectar secretion increased gradually over time during periods of high temperature and no rainfall for several days. Rainy weather and low temperatures inhibited nectar secretion. There were obvious variations of nectar amount among different genotypes tested. Significant nectar variation within a genotype among years was also observed, and the highest nectar secretion was 3-fold higher than the lowest. The amount of nectar secretion from R-lines was significantly higher than that of A-and B-lines. There was no significant difference in nectar secretion between A-and B-lines. A-and B-lines with higher out-crossing rates secreted more nectar. The amount of nectar secretion of A-and B-lines were significantly positively correlated with the out-crossing rate of A-lines.展开更多
The study is aiming at preparation of low-calorie fruit nectars for diabetes and weight maintaining approaches as well as consumer satisfaction. Therefore, twenty low-calorie fruit-based formulated nectars were prepar...The study is aiming at preparation of low-calorie fruit nectars for diabetes and weight maintaining approaches as well as consumer satisfaction. Therefore, twenty low-calorie fruit-based formulated nectars were prepared mainly from orange, pomegranate, guava and mango pulps which sweetened with sucrose or sucrose— replaced at 25%, 50%, 75% and 100% using stevioside. Primitively, the yield of fresh fruits had been calculated. Consequently, nutritional, chemical and organoleptical characteristics of prepared fruit nectars have been determined. Results indicated that total solids content was in range of 5.57% - 13.20%, 9.90% - 14.37%, 8.25% - 13.27% and 8.25% - 16.50% for orange, pomegranate, guava and mango nectars, respectively. Dependently, caloric value resulted 21.57 to 51.08, 38.31 to 55.62, 31.93 to 51.37 and 31.93 to 63.86 kcal 100 g-1 fw for orange, pomegranate, guava and mango nectars, respectively. Total phenols content [TPC, mg GAE 100 g-1 dw] ranged from 665.12 to 747.41, 1180.42 to 1319.47, 742.54 to 848.27 and 418.01 to 472.42 for orange, pomegranate, guava and mango nectars, respectively. The antioxidant capacity by DPPH method [μmol TE g-1 dw] ranged from (20.79 to 26.51), (47.13 to 56.56), (60.68 to 69.25) and (8.39 to 13.32) for orange, pomegranate, guava and mango nectars, respectively. Total carotenoids [mg 100 g-1 dw] were the highest in mango nectars ranged from (102.99 to 110.52) in mango nectar with 100% sugar and mango nectar with 100% stevioside, respectively. Anthocyanins content recorded 6.14 mg 100 g-1 dw in pomegranate nectar with 100% sugar, while increased to be 9.01 mg 00 g-1 dw in pomegranate nectar with 100% stevioside. Ascorbic acid [mg 100 g fw] ranged from 23.41 to 27.53, 15.73 to 18.32, 25.72 to 30.87 and 18.07 to 20.98 for orange, pomegranate, guava and mango nectars, respectively. The results of organoleptical attributes showed no effect of sugar substituting by stevioside on color, odor and mouth feel. The most dramatic effect of sugar substituting had been observed on taste, bitter after taste and the overall acceptability of prepared nectars with high substitution levels. Practically, using stevioside to produce low-calorie nectars was shown to be satisfactory up to 50% - 75% substituting level, resulting low-calorie nectars and could be applied commercially.展开更多
Recent studies have documented declining trends of various groups of flower-visiting insects, even common butterfly species. Causes of these declines are still unclear but the loss of habitat quality across the wider ...Recent studies have documented declining trends of various groups of flower-visiting insects, even common butterfly species. Causes of these declines are still unclear but the loss of habitat quality across the wider countryside is thought to be a major factor. Nectar supply constitutes one of the main resources determining habitat quality. Yet, data on changes in nectar abundance are lacking. In this study, we provide the first analysis of changes in floral nectar abundance on a national scale and link these data to trends in butterfly species richness and abundance. We used transect data from the Dutch Butterfly Monitoring Scheme to compare two time periods： 1994-1995 and 2007-2008. The results show that butterfly decline can indeed be linked to a substantial decline in overall flower abundance and specific nectar plants, such as thistles. The decline is as severe in reported flower generalists as in flower specialists. We suggest that eutrophication is a main cause of the decline of nectar sources [Current Zoology 58 （3）： 384-391, 2012].展开更多
In nature,bees with damaged tongues are adapted to have a feat in collecting nectariferous sources in a large spectrum of concentrations(19%-69%)or viscosities(10^(-3)Pa·s to 10^(-1)Pa·s);however,eff ects of...In nature,bees with damaged tongues are adapted to have a feat in collecting nectariferous sources in a large spectrum of concentrations(19%-69%)or viscosities(10^(-3)Pa·s to 10^(-1)Pa·s);however,eff ects of nectar property on compensated dipping behavior remain elusive.Combining the bee tongue anatomy,high-speed videography,and mathematical models,we investigate responses of honey bees with damaged tongues to fluidic sources in various properties.We find that,bees with 80%damaged tongues are deprived of feeding capability and remarkably,the dipping frequency increases from 4.24 Hz to 5.08 Hz while ingesting 25%sugar water when the tongue loses 0-30%in length,while declines from 5.08 to 3.86 Hz in case of 30%damaged tongue when sucrose concentration increases from 25%to 45%.We employ the energetic compensation rate and energetic utilization rate to evaluate eff ectiveness of the compensation from the perspective of energetic regulation.The mathematical model indicates that the energetic compensation rate turns higher in bees with less damaged tongues for ingesting dilute sugar water,demonstrating its capability of functional compensation for combined factors.Also,the tongue-damaged bees achieve the highest energetic utilization rate when ingesting~30%sugar water.Beyond biology,the findings may shed lights on biomimetic materials and technologies that aim to compensate for geometrical degradations without regeneration.展开更多
The plant-pollinator‘arms race’model posits that a major driver of the evolution of elongated corollas in flowers is reciprocal selection for‘morphological fit’between pollinator-tongue length and access distance ...The plant-pollinator‘arms race’model posits that a major driver of the evolution of elongated corollas in flowers is reciprocal selection for‘morphological fit’between pollinator-tongue length and access distance to nectar(usually corolla-tube length).Evidence for the pollinator-mediated selection on tube length and evolution of multiple,correlated floral traits remains inconclusive.To gain possible insights into the strength of stabilizing selection by assessing standing phenotypic variation,we measured a series of functionally important floral traits,including corolla tube length and‘effective’tube depth and degree of style coiling.We then calculated coefficients of variation(CV)for these traits in three field populations of R.schneideriana.Unlike in most long-tubed flowers,the bottom part of the corolla tube is completely occupied by the style,with no room for nectar.The length of this portion of the corolla tube was more variable(higher CV)than the upper part of the corolla tube,suggesting that functional tube depth was under stronger stabilizing selection.The degree of style coiling was negatively related to the corolla-tube length in all three populations of R.schneideriana,suggesting that there may be conflicting selection acting on style length and corolla-tube length,which are otherwise usually tightly correlated.Given the lack of nectar in the flowers of this species,the long corolla tubes and long styles may represent morphological holdovers from ancestors that were pollinated by long-tongued pollinators,as is still seen in related species in the western Himalayas.展开更多
The Coastal Coral Tree (Erythrina caffra Thunb.) produces floral nectar (FN) that serves to attract pollinating insects, but also secretes nectar from extra-floral (EFN) glands that serves to attract predatory insects...The Coastal Coral Tree (Erythrina caffra Thunb.) produces floral nectar (FN) that serves to attract pollinating insects, but also secretes nectar from extra-floral (EFN) glands that serves to attract predatory insects, such as ants. While studies on myrmecophytes (i.e. specialized plants that attract and interact with ants) have primarily focused on interspecific evaluations of EFN chemistry, the Coastal Coral tree offers an opportunity to contrast intraspecific nectar chemistry with differing evolutionary and ecological functions. We hypothesized that the richness of (molecular) sugar species, relative concentrations, and diversity of sugars in FN and foliar EFN would diverge due to differences in the ecological role of the two types of nectar. High performance liquid chromatography with refractive index detection was used to identify the richness of sugar species (based on retention time), measure the relative concentrations, and evaluate the diversity of sugars in FN and foliar EFN secretions. We detected sugar species unique to each gland type and reported significant differences in the relative concentration of one sugar species common to both gland types. While the mean diversity index of sugars was similar for both gland types, the diversity of foliar EFN sugars was significantly more variable than that of FN sugars. The composition of FN showed little variation, and was reflective of its fundamental role in plant reproduction. Foliar EFN, however, demonstrated the variability expected of a context-dependent myrmecophyte that interacts with a facultative ant species assemblage across a mosaic of abiotic and biotic conditions.展开更多
Bumblebees are important pollinators for many natural and agricultural systems in temperate regions.Interspecific and intraspecific variation in floral resource preferences have been proposed to influence bumblebee co...Bumblebees are important pollinators for many natural and agricultural systems in temperate regions.Interspecific and intraspecific variation in floral resource preferences have been proposed to influence bumblebee community structure.In particular,sexual dimorphism is a major source of intraspecific niche variation.Although interspecific resource partitioning is well studied,few studies have explored the intraspecific dynamics between workers and males.Here,we report a study on a total of 11528 workers and 2220 males of 14 bumblebee species recorded over 5 years in the Hengduan Mountains of Southwest China.We first compared the potential for interspecific and intraspecific competition between workers and males using visitation records and resource partitioning indices(overlap index).We then evaluated the influence of nectar traits on flower preference,including nectar volume and the levels of hexose,sucrose and 10 essential amino acids(EAAs).We found that the niche overlap between intraspecific workers and males was higher than that between different species,and temporal overlap alone did not strongly determine diet overlap.Males of most species preferred flowers with high levels of EAAs and hexose,whereas workers of some species preferred flowers with high nectar volume and sucrose levels.This study suggests that there is floral resource partitioning among bumblebee species,and between workers and males,which may play a key role in alleviating interspecific and intraspecific competition.These findings also provide a useful guide for which kinds of plants might be most valuable for bumblebees,especially the understudied males,in this biodiversity hotspot.展开更多
Floral nectar is thought to be one of the most important rewards that attract pollinators in Pedicularis; however, few studies have examined variation of nectary structure and/or nectar secretion in the genus, particu...Floral nectar is thought to be one of the most important rewards that attract pollinators in Pedicularis; however, few studies have examined variation of nectary structure and/or nectar secretion in the genus, particularly among closely related species. Here we investigated nectary morphology, nectar quality, and nectar production dynamics in flowers of Pedicularis section Cyathophora. We found a conical floral nectary at the base of the ovary in species of the rex-thamnophila clade. Stomata were found on the sudace of the nectary, and copious starch grains were detected in the nectary tissues. In contrast, a semi-annular nectary was found in flowers of the species of the superba clade. Only a few starch grains were observed in tissues of the semi-annular nectary, and the nectar sugar concentration in these flowers was much lower than that in the flowers of the rexthamnophila clade. Our results indicate that the floral nectary has experienced considerable morphological, structural, and functional differentiation among closely related species of Pedicularis. This could have affected nectar production, leading to a shift of the pollination mode. Our results also imply that variation of the nectary morphology and nectar production may have played an important role in the speciation of sect. Cyathophora.展开更多
Distortions caused by the neutron spectrum and scattered neutrons are major problems in fast neutron radiography and should be considered for improving the image quality. This paper puts emphasis on the removal of the...Distortions caused by the neutron spectrum and scattered neutrons are major problems in fast neutron radiography and should be considered for improving the image quality. This paper puts emphasis on the removal of these image distortions and deviations for fast neutron radiography performed at the NECTAR facility of the research reactor FRM-II in Technische Universit/it Mfinchen （TUM）, Germany. The NECTAR energy spectrum is analyzed and established to modify the influence caused by the neutron spectrum, and the Point Scattered Function （PSeF） simulated by the Monte-Carlo program MCNPX is used to evaluate scattering effects from the object and improve image quality. Good analysis results prove the sound effects of the above two corrections.展开更多
Aims Adaptive convergence in floral phenotype among plants sharing a pollinator guild has been acknowledged in the concept of pollination syndrome.However,many plants display traits associated with a given syndrome,bu...Aims Adaptive convergence in floral phenotype among plants sharing a pollinator guild has been acknowledged in the concept of pollination syndrome.However,many plants display traits associated with a given syndrome,but are visited by multiple pollinators.This situation may indicate the beginning of a pollinator shift or may result in a stable situation with adaptations to different pollinators.In Salvia stachydifolia,a previous study suggested that flower shape is optimized to maximize the contribution to pollination of bees and hummingbirds.Here,we studied three additional aspects of its floral biology:sexual phases,nectar dynamics and breeding system,and examined their connection with pollinators’behaviour to explore the presence of adaptations to bee and/or hummingbird pollination.Methods Using a greenhouse population,we applied five pollination treatments to characterize breeding system.To determine sexual phases,we recorded flower opening,anther dehiscence,corolla fall and stigma receptivity.Additionally,we characterized nectar volume and concentration dynamics along the day.Finally,to determine pollinator assemblage and visitation patterns,we performed field observations and recorded pollinators’behaviour.Important Findings Salvia stachydifolia was partially protandrous and self-compatible,but open-pollinated plants attained the highest reproductive success,suggesting that reproduction is mainly dependent on pollinator activity.Bombus opifex bumblebees were the most frequent visitors,but Sappho sparganura hummingbirds dominated visits early in the morning and at dusk.Nectar was typical of bumblebee pollination.We suggest that the bee–hummingbird mixed visitation constitutes an unstable evolutionary situation,making S.stachydifolia an ideal system to understand the ecological circumstances in which pollination shifts occur.展开更多
Aims Floral nectar plays a vital role in plant reproductive success by attracting pollinators.Nectar traits of a flower can depend directly on plant characteristics other than environmental factors and exhibit extensi...Aims Floral nectar plays a vital role in plant reproductive success by attracting pollinators.Nectar traits of a flower can depend directly on plant characteristics other than environmental factors and exhibit extensive flower-and plant-level variations.studies on nectar traits frequently focused on intraplant variation for dichogamous plants,but few have paid attention to both intra-and interplant nectar variations in relation to plant characteristics.revealing within-and among-plant variation and its relative magnitude is important for our understanding of how pollinator-mediated selection can act on nectar traits and evolution of nectar traits.Methods Through investigating protandrous Aconitum gymnandrum populations at the alpine meadows and Wetland Ecosystems research station of lanzhou university,we examined the relationships between nectar production per flower and plant characteristics(e.g.flower position within inflorescences,flo-ral sexual phases,flowering time,inflorescence size and floral attractive traits).Important Findings A.gymnandrum exhibited a declining gradient in the nectar volume along inflorescences,with more nectar in basal flowers than distal ones.Protandrous flowers of A.gymnandrum did not show gender-biased nectar production while the nectar volume varied with differ-ent stages of floral sexual phases.The significant correlation between the first flowering date of individuals and the mean nectar volume per flower was positive in 2013,but became negative in 2014,sug-gesting complex effects of biotic and abiotic factors.The mean nectar volume per flower was not related to inflorescence size(the num-ber of total flowers per plant).Furthermore,nectar production was weakly associated with floral attractive traits(the petal width and the galea height),even if the effect of flowering time of individuals was removed,suggesting that the honesty of floral traits as signals of nec-tar reward for pollinators is not stable in this species.展开更多
In the present study, nectar and pollen sources for honeybee （Apls cerana cerana Fabr.） were studied in Qlnglan mangrove area, Hainan Island, China, based on microscopic analysis of honey and pollen load （corblcula...In the present study, nectar and pollen sources for honeybee （Apls cerana cerana Fabr.） were studied in Qlnglan mangrove area, Hainan Island, China, based on microscopic analysis of honey and pollen load （corblcular and gut contents） from honeybees collected In October and November 2004. Qualitative and quantitative melittopalynologlcal analysis of the natural honey sample showed that the honey is of unlfloral type with Mimosa pudlca L. （Mlmosaceae） as the predominant （89.14%） source of nectar and pollen for A. cerana cerana In October. Members of Araceae are an Important minor （3%-15%） pollen type, whereas those of Arecaceae are a minor （〈3%） pollen type. Pollen grains of Nypa fruticans Wurmb., Rhlzophora spp., Excoecarla agallocha L., Lumnitzera spp., Brugulera spp., Kandella candel Druce, and Ceriops tagal （Perr.） C. B. Rob. are among the notable mangrove texa growing In Qinglan mangrove area recorded as minor taxa In the honey. The absolute pollen count （I.e. the number of pollen grains/10 g honey sample） suggests that the honey belongs to Group V （〉1 000 000）. Pollen analysis from the corblcular and gut contents of A. cerana cerana revealed the highest representation （95.60%） of members of Sonneratia spp. （Sonneratlaceae）, followed by Bruguiera spp. （Rhizophoraceae）, Euphorblaceae, Poaceae, Fabaceae, Arecaceae, Araceae, Anacardlaceae, and Rublaceae. Of these plants, those belonging to Sonneratla plants are the most Important nectar and pollen sources for A. cerana cerana and are frequently foraged and pollinated by these bees in November.展开更多
基金financially supported by the National Natural Science Foundation of China(32271693)the Cultivating Plan Program for the Leader in Science and Technology of Yunnan Province(202405AC350111)to ZQZ.
文摘Mating patterns in angiosperms are typically nonrandom,yet the mechanisms driving nonrandom mating remain unclear,especially regarding the effects of quantitative floral traits on plant mating success across male and female functions.In this study,we investigated how variation in spur length and flower number per plant influences mating patterns in Aquilegia rockii within a natural population.Using marker-based paternity analyses and manipulative experiments,we assessed the role of these traits in mating success across both sexual functions.We found significant variation in the mate composition between male and female function,with spur-length frequency positively associated with female outcrossing rate and mate number,but not with male outcrossing or mate number.Most mating events occurred within 10 m,and spur-length frequency positively correlated with mating distance.Regardless of selfing,there was evidence for assortative mating for spur length.Although spur length did not correlate with pollinator visitation,plants with mid-length spurs had higher seed set than those with shorter or longer spurs when autonomous selfing was excluded.Flowers number per plant was only associated with mating distance and female outcrossing rate.Our results suggest that spur length plays a key role in nonrandom mating by frequency-dependent mating,with implications for stabilizing selection and maintenance of genetic diversity.This study advances our understanding of floral diversity by dissecting the role of quantitative floral traits in plant mating through both female and male functions.
基金supported by Sichuan Science and Technology Program(No.2023NSFSC1282)Talent Foundation of China West Normal University(Nos.17YC142 and 17YC137)+1 种基金the National General Cultivation Project of China West Normal University(No.19B029)Youth Foundation Specialization of West China Normal University(No.22KB004).
文摘This study investigates the diurnal patterns of nectar secretion,sugar content,and caloric value in Epimedium wushanense,and their interaction mechanisms with pollinator behavior under varying environmental conditions.Nectar secretion exhibited a diurnal pattern,peaking between 11:00 and 13:00,with progressive increases in both volumes(19.07±1.66μL/day)and caloric value(6.03±0.55 cal/day)over four consecutive days,culminating in maximal production on Day 4(p<0.05).Floral bagging significantly altered nectar traits(Mann-Whitney U test,p<0.05),with bagged inflorescences demonstrating 61.82%higher nectar volume productivity relative to unbagged controls.Pollinator visitation,primarily by Bombus trifasciatus and Bombus grahami,was strongly correlated with nectar sugar concentration and distribution,peaking during midday when temperatures and humidity were optimal.Notably,B.trifasciatus displayed legitimate pollination behavior,while B.grahami exhibited nectar robbing.Bombus grahami peaked at 15:00(7.67±0.33 visits)under 22.8°C/58%RH,outperforming Bombus trifasciatus(5.67±0.27 at 13:00;p<0.05),highlighting differential pollinator effectiveness.Temperature negatively impacted unbagged nectar volume and caloric value but positively influenced bagged nectar,suggesting adaptive resource allocation strategies.These findings underscore the intricate relationship between environmental factors,nectar dynamics,and pollinator behavior,revealing how E.wushanense optimizes reproductive success through temporal and ecological adaptations.This study provides critical insights into the ecological mechanisms driving plant-pollinator interactions and resource allocation in changing environments.
基金Supported by National Modern Agriculture (Bee Industry) Technolgy System (CARS-45-SYZ17)~~
文摘[Objective] The aim was to research the rules of nectar quantity and sugar concentration of perfect and staminate flowers in a day. [Method] Based on nine Tianguang Yan pomegranate trees, nectar quantity and sugar concentration of per- fect and staminate flowers were measured and analyzed in morning and afternoon. [Result] Average nectar quantity and sugar concentration differed insignificantly in morning and afternoon of perfect flowers, which could also be applied to staminate flowers. However, average nectar quantity of perfect flower was 64.09 μI and of staminate flower was 44.07 μl. It is obvious that the two were of extremely signifi- cant differences （t=4.642, P〈0.01）, and the former was significantly higher by 45,43%. On the other hand, average sugar concentration of perfect flower was 48.44% and of staminate flower was 37.16%. The two were of extremely significant differences and the former is higher by 30.36%, compared with the latter. These suggested that nectar quantity and sugar concentration would maintain unchanged in different periods for a day, if nectars are not consumed by pollinators, such as bees and butterflies. In the same period, nectar quantity and sugar concentration of per- fect flowers were higher than those of staminate flowers. [Conclusion] The research provides references for benefits increase of bee farmers and fruit farmers, as well as exploration of bee pollination.
文摘Phenotypic plasticity allows organisms to maximize fitness, by optimizing the expression of costly defensive traits. Broad bean, Vicia faba L. “Broad Windsor”, produces increased numbers of extrafloral nectaries (EFNs) in response to leaf damage to attract mutualistic partners and reduce herbivory. It is currently unknown, however, whether EFN induction is cultivar-specific or is a more general phenomenon. It has also not been determined whether broad beans increase nectar secretion rates in conjunction with EFN induction. We hypothesized that: a) as all broad beans have conspicuous EFNs, all cultivars should produce additional EFNs in response to leaf damage, and b) overall nectar secretion rates should increase with EFN numbers, to attract additional mutualists. We tested our hypothesis by subjecting three broad bean cultivars, Vicia faba L. “Broad Windsor”, “Stereo”, and “Witkiem” to mechanical leaf damage. The degree of change in plant traits associated with growth, in addition to EFN induction, was assessed 1 week after leaf damage. Extrafloral nectar volumes were also assessed, every 24 hours, pre- and post-leaf damage. We confirmed our first, but rejected our second, hypothesis. All cultivars produced additional EFNs, but none increased extrafloral nectar volumes, when experiencing leaf damage. Further experimentation is required to determine if energetic tradeoffs limit multiple forms of defense (i.e., EFN vs. nectar induction), or if this alternative strategy is adaptive for attracting and retaining mutualists. Understanding the costs and benefits of EFN vs. nectar induction will provide insight into the evolution of defensive mutualisms between plants and predatory arthropods.
基金supported by the Agricultural Science and Technology Innovation Program, China (ASTIP)the Building of Modern Agricultural Industry (Bees) R&D Systems in China (NYCYTI-43-KXJ17)
文摘The aim of this work was to distinguish volatile organic compound（VOC） profiles of royal jelly（RJ） from different nectar plants. Headspace solid-phase microextraction（HS-SPME） was used to extract VOCs from raw RJ harvested from 10 nectar plants in flowering seasons. Qualitative and semi-quantitative analysis of VOCs extracts were performed by gas chromatography-mass spectrometry（GC-MS）. Results showed that VOC profiles of RJ from the samples were rich in acid, ester and aldehyde compound classes, however, contents of them were differential, exemplified by the data from acetic acid, benzoic acid methyl ester, hexanoic acid and octanoic acid. As a conclusion, these four VOCs can be used for distinguishing RJ harvested in the seasons of different nectar plants.
基金funded by the project under the National Department of Public Benefit Research Foundation of China (201403031)
文摘The presence of adequate nectar sources along the migratory pathway is a prerequisite for moths of oriental armyworm, Mythimna separata, to reach target habitats and lay eggs. Identification of plant species and assessment of their suitability as wild nectar sources along the summer migration pathway of adult M. separata are critical steps in making effective forecasts of second-and third-generation armyworm outbreaks in North China. We explored five aspects of moth-nectar source relationships：（1） Field investigations in 2014 and 2015 showed that the florescence of chaste tree, Vitex negundo var. heterophylla, a primary nectar plant in apiculture, coincided with the summer migration of oriental armyworm moths. The flowers of chaste tree opened day and night and M. separata moths were found actively flying around and resting on tree.（2） Identification of moth-borne pollen by scanning electronic microscopy（SEM） micrographs in 2015 and 2016 revealed that 15.4% of 369 moths trapped by blacklight traps, 17.1% of 557 moths captured by vertical-pointing searchlight traps and 24.4% of 311 moths caught by pheromone traps were found with pollen attached to their proboscis. A total of 228 pollen-carrying individuals out of 1237 armyworm moths were captured by the three types of traps. The three highest percentages of pollen-bearing armyworm moths were carrying pollen of Toona sp.（59.65%）, Ligustrum sp.（27.19%） and Syringa sp.（4.39%）. In total, 14 types of pollen were detected where three were identified to species, 10 to genus and one as an unknown species.（3） Analysis of geographical distribution, flowering periods and relative abundances of candidate nectar plants suggested that Chinese toon, Toona sinensis, and privet, Ligustrum lucidum, were two important nectar plant species.（4） Analysis on relationship between pollen and ovarian development showed that 14, 15 and 10 females carrying pollen of T. sinensis had ovaries at developmental stages Ⅰ, Ⅱ and Ⅲ, respectively. Many T. sinensis pollen grains were present on the proboscises of female moths.（5） Comparison of trap effectiveness between blacklight and vertical-pointing searchlight traps indicated blacklight traps caught the highest proportion（35.2%） of female in ovarian stage Ⅴ, whereas vertical-pointing searchlight traps caught the highest proportion（43.5%） of female in ovarian stage I with additional proportions of decreasing percentages for stages Ⅱ, Ⅲ and Ⅳ. Integrated analysis on these five aspects suggests that T. sinensis is an important, suitable summer nectar source that potentially influences migration and reproduction of M. separata moths andthus contributes to outbreaks of this pest. The vertical-pointing searchlight trap was the most effective tool for monitoring the migratory flight of adult M. separata. Privet, Ligustrum lucidum, and clove, Syringa sp., are possible suitable summer nectar plants that need further study to elucidate their importance. The reason why field investigation results on chaste tree differed from the results of moth-borne pollen analyses was discussed.
基金supported by the National Key Research and Development Program of China (2016YFD0101500, 2016YFD0101502)the Agricultural Science and Technology Innovation Project of Jilin Province, China (CXGC2017Z004)
文摘Significant progress has been achieved in the use of heterosis in soybean and several soybean hybrids have been released in China. However, broad use of hybrid soybean seed is limited due to low seed setting of female parents. Breeding cytoplasmic male sterile（CMS） lines with high out-crossing rate is necessary to solve the problem. The objective of this study was to determine the relationship between out-crossing rate of CMS lines and their nectar secretion. The daily nectar secretion rhythm, meteorological effect on nectar secretion, and differences in nectar secretion among genotypes and years were investigated in 27 soybean CMS lines（A-lines） with their maintainers（B-lines） and restorers（R-lines）. The correlation between out-crossing rate of CMS lines and nectar production was also evaluated. Nectar secretion had diurnal variation. Secretion initiated at about 06：00 for most materials and reached a peak at 07：00–08：30 after flower opened, then the nectar secretion decreased gradually. A sub-peak appeared at about 13：00, while the nectar could not be detected at 17：00. Nectar secretion was greatly influenced by the weather conditions. The amount of nectar secretion increased gradually over time during periods of high temperature and no rainfall for several days. Rainy weather and low temperatures inhibited nectar secretion. There were obvious variations of nectar amount among different genotypes tested. Significant nectar variation within a genotype among years was also observed, and the highest nectar secretion was 3-fold higher than the lowest. The amount of nectar secretion from R-lines was significantly higher than that of A-and B-lines. There was no significant difference in nectar secretion between A-and B-lines. A-and B-lines with higher out-crossing rates secreted more nectar. The amount of nectar secretion of A-and B-lines were significantly positively correlated with the out-crossing rate of A-lines.
文摘The study is aiming at preparation of low-calorie fruit nectars for diabetes and weight maintaining approaches as well as consumer satisfaction. Therefore, twenty low-calorie fruit-based formulated nectars were prepared mainly from orange, pomegranate, guava and mango pulps which sweetened with sucrose or sucrose— replaced at 25%, 50%, 75% and 100% using stevioside. Primitively, the yield of fresh fruits had been calculated. Consequently, nutritional, chemical and organoleptical characteristics of prepared fruit nectars have been determined. Results indicated that total solids content was in range of 5.57% - 13.20%, 9.90% - 14.37%, 8.25% - 13.27% and 8.25% - 16.50% for orange, pomegranate, guava and mango nectars, respectively. Dependently, caloric value resulted 21.57 to 51.08, 38.31 to 55.62, 31.93 to 51.37 and 31.93 to 63.86 kcal 100 g-1 fw for orange, pomegranate, guava and mango nectars, respectively. Total phenols content [TPC, mg GAE 100 g-1 dw] ranged from 665.12 to 747.41, 1180.42 to 1319.47, 742.54 to 848.27 and 418.01 to 472.42 for orange, pomegranate, guava and mango nectars, respectively. The antioxidant capacity by DPPH method [μmol TE g-1 dw] ranged from (20.79 to 26.51), (47.13 to 56.56), (60.68 to 69.25) and (8.39 to 13.32) for orange, pomegranate, guava and mango nectars, respectively. Total carotenoids [mg 100 g-1 dw] were the highest in mango nectars ranged from (102.99 to 110.52) in mango nectar with 100% sugar and mango nectar with 100% stevioside, respectively. Anthocyanins content recorded 6.14 mg 100 g-1 dw in pomegranate nectar with 100% sugar, while increased to be 9.01 mg 00 g-1 dw in pomegranate nectar with 100% stevioside. Ascorbic acid [mg 100 g fw] ranged from 23.41 to 27.53, 15.73 to 18.32, 25.72 to 30.87 and 18.07 to 20.98 for orange, pomegranate, guava and mango nectars, respectively. The results of organoleptical attributes showed no effect of sugar substituting by stevioside on color, odor and mouth feel. The most dramatic effect of sugar substituting had been observed on taste, bitter after taste and the overall acceptability of prepared nectars with high substitution levels. Practically, using stevioside to produce low-calorie nectars was shown to be satisfactory up to 50% - 75% substituting level, resulting low-calorie nectars and could be applied commercially.
文摘Recent studies have documented declining trends of various groups of flower-visiting insects, even common butterfly species. Causes of these declines are still unclear but the loss of habitat quality across the wider countryside is thought to be a major factor. Nectar supply constitutes one of the main resources determining habitat quality. Yet, data on changes in nectar abundance are lacking. In this study, we provide the first analysis of changes in floral nectar abundance on a national scale and link these data to trends in butterfly species richness and abundance. We used transect data from the Dutch Butterfly Monitoring Scheme to compare two time periods： 1994-1995 and 2007-2008. The results show that butterfly decline can indeed be linked to a substantial decline in overall flower abundance and specific nectar plants, such as thistles. The decline is as severe in reported flower generalists as in flower specialists. We suggest that eutrophication is a main cause of the decline of nectar sources [Current Zoology 58 （3）： 384-391, 2012].
基金supported by the National Natural Science Foundation of China(Grant no.51905556)the research grant of Sun Yat-Sen University for Bairen Plan(Grant no.76200-18841223).
文摘In nature,bees with damaged tongues are adapted to have a feat in collecting nectariferous sources in a large spectrum of concentrations(19%-69%)or viscosities(10^(-3)Pa·s to 10^(-1)Pa·s);however,eff ects of nectar property on compensated dipping behavior remain elusive.Combining the bee tongue anatomy,high-speed videography,and mathematical models,we investigate responses of honey bees with damaged tongues to fluidic sources in various properties.We find that,bees with 80%damaged tongues are deprived of feeding capability and remarkably,the dipping frequency increases from 4.24 Hz to 5.08 Hz while ingesting 25%sugar water when the tongue loses 0-30%in length,while declines from 5.08 to 3.86 Hz in case of 30%damaged tongue when sucrose concentration increases from 25%to 45%.We employ the energetic compensation rate and energetic utilization rate to evaluate eff ectiveness of the compensation from the perspective of energetic regulation.The mathematical model indicates that the energetic compensation rate turns higher in bees with less damaged tongues for ingesting dilute sugar water,demonstrating its capability of functional compensation for combined factors.Also,the tongue-damaged bees achieve the highest energetic utilization rate when ingesting~30%sugar water.Beyond biology,the findings may shed lights on biomimetic materials and technologies that aim to compensate for geometrical degradations without regeneration.
基金This work was supported by the National Natural Science Foundation of China(grant nos.31270281,32030071)to SQHNNSFC(32071671)to ZYT.
文摘The plant-pollinator‘arms race’model posits that a major driver of the evolution of elongated corollas in flowers is reciprocal selection for‘morphological fit’between pollinator-tongue length and access distance to nectar(usually corolla-tube length).Evidence for the pollinator-mediated selection on tube length and evolution of multiple,correlated floral traits remains inconclusive.To gain possible insights into the strength of stabilizing selection by assessing standing phenotypic variation,we measured a series of functionally important floral traits,including corolla tube length and‘effective’tube depth and degree of style coiling.We then calculated coefficients of variation(CV)for these traits in three field populations of R.schneideriana.Unlike in most long-tubed flowers,the bottom part of the corolla tube is completely occupied by the style,with no room for nectar.The length of this portion of the corolla tube was more variable(higher CV)than the upper part of the corolla tube,suggesting that functional tube depth was under stronger stabilizing selection.The degree of style coiling was negatively related to the corolla-tube length in all three populations of R.schneideriana,suggesting that there may be conflicting selection acting on style length and corolla-tube length,which are otherwise usually tightly correlated.Given the lack of nectar in the flowers of this species,the long corolla tubes and long styles may represent morphological holdovers from ancestors that were pollinated by long-tongued pollinators,as is still seen in related species in the western Himalayas.
基金supported by a Kadner-Pitts Research Grant from the Loyola Marymount University(LMU)Biology Departmenta Continuing Faculty Grant from the LMU Frank R.Seaver College of Science&Engineering+2 种基金Student support was funded by a grant from the Beta Beta Beta National Biological Honor Societythrough stipends from both the LMU Undergraduate Research Opportunities Programthe LMU Summer Undergraduate Research Program.
文摘The Coastal Coral Tree (Erythrina caffra Thunb.) produces floral nectar (FN) that serves to attract pollinating insects, but also secretes nectar from extra-floral (EFN) glands that serves to attract predatory insects, such as ants. While studies on myrmecophytes (i.e. specialized plants that attract and interact with ants) have primarily focused on interspecific evaluations of EFN chemistry, the Coastal Coral tree offers an opportunity to contrast intraspecific nectar chemistry with differing evolutionary and ecological functions. We hypothesized that the richness of (molecular) sugar species, relative concentrations, and diversity of sugars in FN and foliar EFN would diverge due to differences in the ecological role of the two types of nectar. High performance liquid chromatography with refractive index detection was used to identify the richness of sugar species (based on retention time), measure the relative concentrations, and evaluate the diversity of sugars in FN and foliar EFN secretions. We detected sugar species unique to each gland type and reported significant differences in the relative concentration of one sugar species common to both gland types. While the mean diversity index of sugars was similar for both gland types, the diversity of foliar EFN sugars was significantly more variable than that of FN sugars. The composition of FN showed little variation, and was reflective of its fundamental role in plant reproduction. Foliar EFN, however, demonstrated the variability expected of a context-dependent myrmecophyte that interacts with a facultative ant species assemblage across a mosaic of abiotic and biotic conditions.
基金supported by the National Natural Science Foundation of China(grants 31800194 and 32170241 to ZMY,grants 31970253 and 32270243 to CFY)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant XDB31010000 to QFW)+1 种基金supported by the Key Laboratory of the Zoological Systematics and Evolution of the Chinese Academy of Sciences(grant 2008DP173354)supported by the Chinese Academy of Science's President's International Fellowship Initiative(PIFI)(grant 2024PVC0046).
文摘Bumblebees are important pollinators for many natural and agricultural systems in temperate regions.Interspecific and intraspecific variation in floral resource preferences have been proposed to influence bumblebee community structure.In particular,sexual dimorphism is a major source of intraspecific niche variation.Although interspecific resource partitioning is well studied,few studies have explored the intraspecific dynamics between workers and males.Here,we report a study on a total of 11528 workers and 2220 males of 14 bumblebee species recorded over 5 years in the Hengduan Mountains of Southwest China.We first compared the potential for interspecific and intraspecific competition between workers and males using visitation records and resource partitioning indices(overlap index).We then evaluated the influence of nectar traits on flower preference,including nectar volume and the levels of hexose,sucrose and 10 essential amino acids(EAAs).We found that the niche overlap between intraspecific workers and males was higher than that between different species,and temporal overlap alone did not strongly determine diet overlap.Males of most species preferred flowers with high levels of EAAs and hexose,whereas workers of some species preferred flowers with high nectar volume and sucrose levels.This study suggests that there is floral resource partitioning among bumblebee species,and between workers and males,which may play a key role in alleviating interspecific and intraspecific competition.These findings also provide a useful guide for which kinds of plants might be most valuable for bumblebees,especially the understudied males,in this biodiversity hotspot.
基金supported by the National Natural Science Foundation of China(31330008 and 31160047)the Key Research Program of the Chinese Academy of Sciences (KJZD-EW-L07)Science and Technology Basic Work (2013FY112100)
文摘Floral nectar is thought to be one of the most important rewards that attract pollinators in Pedicularis; however, few studies have examined variation of nectary structure and/or nectar secretion in the genus, particularly among closely related species. Here we investigated nectary morphology, nectar quality, and nectar production dynamics in flowers of Pedicularis section Cyathophora. We found a conical floral nectary at the base of the ovary in species of the rex-thamnophila clade. Stomata were found on the sudace of the nectary, and copious starch grains were detected in the nectary tissues. In contrast, a semi-annular nectary was found in flowers of the species of the superba clade. Only a few starch grains were observed in tissues of the semi-annular nectary, and the nectar sugar concentration in these flowers was much lower than that in the flowers of the rexthamnophila clade. Our results indicate that the floral nectary has experienced considerable morphological, structural, and functional differentiation among closely related species of Pedicularis. This could have affected nectar production, leading to a shift of the pollination mode. Our results also imply that variation of the nectary morphology and nectar production may have played an important role in the speciation of sect. Cyathophora.
基金Supported by National Natural Science Foundation of China(11079001)
文摘Distortions caused by the neutron spectrum and scattered neutrons are major problems in fast neutron radiography and should be considered for improving the image quality. This paper puts emphasis on the removal of these image distortions and deviations for fast neutron radiography performed at the NECTAR facility of the research reactor FRM-II in Technische Universit/it Mfinchen （TUM）, Germany. The NECTAR energy spectrum is analyzed and established to modify the influence caused by the neutron spectrum, and the Point Scattered Function （PSeF） simulated by the Monte-Carlo program MCNPX is used to evaluate scattering effects from the object and improve image quality. Good analysis results prove the sound effects of the above two corrections.
基金This study was supported by Fondo para la Investigacion Cientffica y Tecnoldgica(FONCyT)grant PICT 2017-2196 to S.B.V.and by FONCyT grant PICT-2018-03192 to F.S.
文摘Aims Adaptive convergence in floral phenotype among plants sharing a pollinator guild has been acknowledged in the concept of pollination syndrome.However,many plants display traits associated with a given syndrome,but are visited by multiple pollinators.This situation may indicate the beginning of a pollinator shift or may result in a stable situation with adaptations to different pollinators.In Salvia stachydifolia,a previous study suggested that flower shape is optimized to maximize the contribution to pollination of bees and hummingbirds.Here,we studied three additional aspects of its floral biology:sexual phases,nectar dynamics and breeding system,and examined their connection with pollinators’behaviour to explore the presence of adaptations to bee and/or hummingbird pollination.Methods Using a greenhouse population,we applied five pollination treatments to characterize breeding system.To determine sexual phases,we recorded flower opening,anther dehiscence,corolla fall and stigma receptivity.Additionally,we characterized nectar volume and concentration dynamics along the day.Finally,to determine pollinator assemblage and visitation patterns,we performed field observations and recorded pollinators’behaviour.Important Findings Salvia stachydifolia was partially protandrous and self-compatible,but open-pollinated plants attained the highest reproductive success,suggesting that reproduction is mainly dependent on pollinator activity.Bombus opifex bumblebees were the most frequent visitors,but Sappho sparganura hummingbirds dominated visits early in the morning and at dusk.Nectar was typical of bumblebee pollination.We suggest that the bee–hummingbird mixed visitation constitutes an unstable evolutionary situation,making S.stachydifolia an ideal system to understand the ecological circumstances in which pollination shifts occur.
基金Natural Science Foundation of Gansu Province(145RJZA166)Natural Science Foundation of China(30900162,31370402)Fundamental Research Funds for the Central Universities(lzujbky-2013-102).
文摘Aims Floral nectar plays a vital role in plant reproductive success by attracting pollinators.Nectar traits of a flower can depend directly on plant characteristics other than environmental factors and exhibit extensive flower-and plant-level variations.studies on nectar traits frequently focused on intraplant variation for dichogamous plants,but few have paid attention to both intra-and interplant nectar variations in relation to plant characteristics.revealing within-and among-plant variation and its relative magnitude is important for our understanding of how pollinator-mediated selection can act on nectar traits and evolution of nectar traits.Methods Through investigating protandrous Aconitum gymnandrum populations at the alpine meadows and Wetland Ecosystems research station of lanzhou university,we examined the relationships between nectar production per flower and plant characteristics(e.g.flower position within inflorescences,flo-ral sexual phases,flowering time,inflorescence size and floral attractive traits).Important Findings A.gymnandrum exhibited a declining gradient in the nectar volume along inflorescences,with more nectar in basal flowers than distal ones.Protandrous flowers of A.gymnandrum did not show gender-biased nectar production while the nectar volume varied with differ-ent stages of floral sexual phases.The significant correlation between the first flowering date of individuals and the mean nectar volume per flower was positive in 2013,but became negative in 2014,sug-gesting complex effects of biotic and abiotic factors.The mean nectar volume per flower was not related to inflorescence size(the num-ber of total flowers per plant).Furthermore,nectar production was weakly associated with floral attractive traits(the petal width and the galea height),even if the effect of flowering time of individuals was removed,suggesting that the honesty of floral traits as signals of nec-tar reward for pollinators is not stable in this species.
基金Supported by the National Natural Science Foundation of China （40342013）.The authors are grateful to Professor Nai-Qiu Du and Dr XiaoYan Song （Institute of Botany, the ChineseAcademy of Sciences） and Professors Jian-Hua Jin and Wen-Bo Liao （Sun Yat-sen University, Guangzhou, China） for their support for this work.
文摘In the present study, nectar and pollen sources for honeybee （Apls cerana cerana Fabr.） were studied in Qlnglan mangrove area, Hainan Island, China, based on microscopic analysis of honey and pollen load （corblcular and gut contents） from honeybees collected In October and November 2004. Qualitative and quantitative melittopalynologlcal analysis of the natural honey sample showed that the honey is of unlfloral type with Mimosa pudlca L. （Mlmosaceae） as the predominant （89.14%） source of nectar and pollen for A. cerana cerana In October. Members of Araceae are an Important minor （3%-15%） pollen type, whereas those of Arecaceae are a minor （〈3%） pollen type. Pollen grains of Nypa fruticans Wurmb., Rhlzophora spp., Excoecarla agallocha L., Lumnitzera spp., Brugulera spp., Kandella candel Druce, and Ceriops tagal （Perr.） C. B. Rob. are among the notable mangrove texa growing In Qinglan mangrove area recorded as minor taxa In the honey. The absolute pollen count （I.e. the number of pollen grains/10 g honey sample） suggests that the honey belongs to Group V （〉1 000 000）. Pollen analysis from the corblcular and gut contents of A. cerana cerana revealed the highest representation （95.60%） of members of Sonneratia spp. （Sonneratlaceae）, followed by Bruguiera spp. （Rhizophoraceae）, Euphorblaceae, Poaceae, Fabaceae, Arecaceae, Araceae, Anacardlaceae, and Rublaceae. Of these plants, those belonging to Sonneratla plants are the most Important nectar and pollen sources for A. cerana cerana and are frequently foraged and pollinated by these bees in November.
