Pollen Source Research Articles

Pollen Characterization of English Honey from Worcestershire, West Midlands (UK)

Beekeeping in England, United Kingdom, is very popular since much of the country has favourable habitats for honey production. Worcestershire county, in the West Midlands region, has habitats typical of much of the lowland regions of England, comprising a patchwork of pasture with small woodlands, orchards, gardens, meadows, hedgerows, riverbanks and arable crops including oilseed rape and field bean, amongst others. While most beekeepers keep bees as a hobby, commercial honey companies do derive some of their honey from this region, from both smaller and large-scale producers. Pollen surveys of honey are useful for several reasons: to help determine honeybee forage activities for honey producers; to provide information for honey analysts and to compare with earlier surveys to see if habitat and climate change are altering foraging habits, which may also help with bee conservation. In the United Kingdom, peer-reviewed surveys of bee forage and honeys have been quite limited (Balfour, Fensome, Samuelson, & Ratnieks, 2015) but there are good sources of information available to the beekeeper about the likely sources of pollen, such as Kirk and Howes (2012) or Hodges (1984). Although observing bee activity can indicate which plants the bees are using for their various requirements, it may not always be clear which plants are contributing directly to the honey. Furthermore, an empirical, peer-reviewed study of the pollen content of honey in England has not been conducted since 1952 when Deans (1957) analysed 854 honey samples from across the British Isles, including 14 samples from Worcester (110 from the Midlands). Two recent DNA studies have also provided data on the floral composition of eight Welsh honeys and one from the Isle of Wight (Hawkins et al., 2015) and one for the National Botanic Garden of Wales (de Vere et al., 2017). The aim of this research was to characterize the typical pollen content of honey from Worcestershire in the West Midlands region of England.

Evaluation of Pollen and Chemical Composition of Honey Samples Sourced from Open Markets in Anambra State, Nigeria to Ascertain their Authenticity

Aims: To ascertain the predominant honey plants that served as major sources of nectar and or pollen to the honeybees and to determine the quantitative presence of some physico-chemical components of the honey samples.
 Study Design: The honey samples were collected from the various locations based on purposive sampling.
 Place and Duration of Study: The samples were collected from seven towns in three Local Government Areas of Anambra State as follows; Ukpor, Usumenyi and Ezinifite (Nnewi South LGA), Nnokwa, Alor and Nnobi (Idemmili South LGA) and Ezinifite (Aguata LGA) between January and April, 2013.
 Methodology: The honey samples were dissolved in warm (40ºC) acidified water and subsequently subjected to acetolysis treatment. The recovered residues were suspended in glycerol-alcohol mixture in vials from where samples were collected for routine pollen count and identification. The chemical analysis was carried out according to the analysis of the Association of Official Analytical Chemists with four replicates. The pollen data were converted to percentage, while data from chemical parameters were converted to mean and standard deviation.
 Results: A total of 67 pollen types belonging to 39 families were identified. The honey samples were grouped into two based on the botanical origin: three monofloral and four polyfloral honeys. The predominant honey plants include Hymenocardia acida, Combtretaceae/Melastomataceae, Lannea sp., Alchornea cordifolia and Phyllanthus muellerianus. The chemical analysis showed that the values of all the parameters (moisture, pH, Sucrose, Protein, Hydroxymethyl furfural, etc) tested were within the acceptable limits of international honey standard. However, the sum of glucose and fructose in three honey samples did not meet the 60g/100g recommended as minimum limit for blossom honeys.
 Conclusion: The chemical analysis showed that the honey samples contained acceptable standard concentrations of all the physicochemical parameters (such as HMF, protein, moisture, sucrose, etc.) tested with exception of the sum of glucose and fructose which did not meet the standard in some samples. The predominant honey plants that served as sources of nectar and pollen in the to the bees include Hymenocardia acida, Lannea sp., Phyllanthus muellerianus and members of the Combretaceae/Melastomataceae families.

An assessment of ragweed pollen and allergen loads in an uninvaded area in the Western Black Sea region of Turkey

Ambrosia artemisiifolia L., known as common ragweed, is an invasive and allergenic plant that has begun to expand its presence in Turkey. Although ragweed pollen has been monitored for a long time—especially in the atmosphere of cities in Northern Anatolia—the invasion of the plant is more limited compared to that of other European countries. Here, we present the highest ragweed pollen concentration recorded in Turkey, as well as changes in the Amb a 1 allergen level in the air during 2015 and 2016 in Zonguldak, measured using a BGI 900 cascade impactor. The Seasonal Pollen Integral (SPIn) was found to be 709 pollen day/m3 and 1542 pollen day/m3 in 2015–2016, respectively. The sum of Amb a 1 in both stages was 8.42 × 10−3 U/m3 and 13.1 × 10−3 U/m3 over the same period. The number of days in which the Ambrosia pollen concentration was higher than 50 pollen/m3 doubled in 2016 compared to 2015, despite the negative effect of rainfall on pollen and allergen concentration in 2016. The pollen and allergen sources were evaluated by using simulated air mass movement with a Hybrid Single-Particle Lagrangian Integrated Trajectory model. Our findings suggest that individuals in Zonguldak are exposed as much to pollen—and possibly allergens—transported from the Ukraine, Russia and to a limited extent from Moldova. Furthermore, the allergen content of pollen in Zonguldak was much higher than other cities where Amb a 1 is monitored. We also demonstrated that the date of the peak pollen day may be an indicator of the source of long distance transportation.

Antibiotic treatment impairs protein digestion in the honeybee, Apis mellifera

Nutritional stress due to habitat transformation and loss is one of several factors contributing to current declines in global bee populations. Bees obtain protein from pollen, which in honeybees is consumed and digested by nurse bees. They then distribute the protein to the rest of the colony in the form of hypopharyngeal gland secretions. Little is known of how efficiently honeybees digest protein. Moreover, antibiotics are used by beekeepers as in-hive treatments for diseases and may interfere with microbial contributions to protein digestion. Caged, newly emerged workers of Apis mellifera scutellata were fed caseinate as protein source, to investigate the effects of protein intake and antibiotic treatment on digestive efficiency. These workers were fed protein:carbohydrate ratios of 1:120, 1:50 and 1:15 or pure sucrose for 9 days. Half the cages received dietary oxytetracycline at a concentration used by beekeepers. Antibiotic exposure did not affect survival or protein consumption. Protein digestive efficiency increased with increasing levels of protein in the diet, although a decrease would have contributed to maintaining nutrient balance. Importantly, we show that antibiotic exposure impaired protein digestive efficiency, especially on low-protein diets. This may be particularly important when colonies are restricted to a single protein deficient source of pollen.

Influence of a Municipal Solid Waste Landfill on the Surrounding Environment: Landfill Vegetation as a Potential Risk of Allergenic Pollen.

When the landfill use comes to end, important subsequent steps include aftercare, safety assurance, and ecological regeneration. Landfill revegetation is cost-effective and eco-friendly approach in the management of landfill areas, which serves the purpose of stabilization and provides a pleasant landscape. There are various vegetation types that can be planted, yet grass species are often used for low-cost reasons. Plants can be important sources of air pollution, particularly by grass pollen. The main goal of our study was to identify plant species that produce allergenic pollen. Long-term vegetation monitoring took place on three sites in the growing seasons of years 2008–2018. Studied objects were landfills located in the Czech Republic. The vegetation was assessed using a floristic survey of identified plant species. Plant species that produced allergens were recorded. During the monitoring, 298 plant species were determined. Plant species with allergenic pollen have a considerable share in the landfill vegetation. Thus, landfills are potential sources of various kinds of allergenic pollen. Moreover, our results indicated that there are three periods of pollen production: early spring, late spring, and early summer; late summer; and autumn. The second period is typical for the production of highly allergenic pollen by grasses. Most detected plant species with allergenic pollen are common for all monitored sites, which demonstrates that the vegetation of landfills is a significant source of allergenic pollen.

Levels of Chromium, Copper, Iron, Magnesium, Manganese, Selenium, Zinc, Cadmium, Lead and Aluminium of honey varieties produced in Turkey

Abstract Honey is a natural animal product. The elemental composition of honey varies greatly depending on the source of nectar, honeydew, pollen and environmental conditions. The aim of the present study was to determine the levels of chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), selenium (Se), zinc (Zn), cadmium (Cd), lead (Pb) and aluminium (Al) in a total of 65 honey samples procured from different regions of Turkey. Element levels were measured by using an inductively coupled plasma optical emission spectrophotometer (ICP-OES). Minimum and maximum levels of the elements, indicated as µg/g wet weight were as follows: Cr: 0.126-7.964, Cu: 0.223-198.361, Fe: 3.506-1278.778, Mg: 5.830-309.783, Mn: 0.096-29.496, Se: 0.418-19.879, Zn: 1.734-245.205, Cd: 0.000-0.297, Pb: 0.000-3.035, Al: 0.775-155.585.

The bioactive contents and antioxidant activity of honey bee nest extract of Apis dorsata Binghami from the North Sulawesi

Apis dorsata Binghami is a Sulawesi endemic honey bee. Apis dorsata Binghami cannot be bred, so it still lives wildlyin the forests of Sulawesi. However, Apis dorsata Binghami produces more honey, compared to all honey bee species. Furthermore, the diversity of plants as a source of nectar, pollen and plant resin, which is used in the formation of nests and honey is more, than all types of honey bees in the world. Ethnomedically, the Minahasa community has long used honeynest for degenerative diseases such as hyperlipidemia and cancer. Nevertheless, there have been no research reports on bioactive content and bioactivity of Apis dorsataBinghami nest extract. This research wasaimed to determinethe bioactive content of honey bee nest and to obtain the inhibitory concentration 50 (IC50) antioxidant activity of honey bee nest extractofApis dorsata Binghami. Honey bee nest was obtained directly from the forest of Minahasa peninsula, North Sulawesi, Indonesia. Extraction of fresh honey bee nest was conductedusingmaceration method. Bioactive content analysis was carried out by the Harborne method, followed by analysis using UV Vis spectrophotometer and High performance liquid chromatography. IC50antioxidant activity of honey bee nest extract was obtained using DPPH free radical reduction method. The results showed that Apis dorsata Binghami honey bee nest extract containedalkaloids, flavonoids, saponins, tannins, steroids and triterpenoids. Identified flavonoids displayed the highest phytochemical content. Based on the results of HPLC and UV Vis spectrophotometer analysis, there were 20 flavonoid derivatives found in honey bee nest samples in Minahasa. Ethanol extract and n-hexane extract showed high free radical reduction activity compared to vitamin C as a control treatment. However, ethanol extract produced the highest DPPH free radical reduction activity.

A citizen science supported study on seasonal diversity and monoflorality of pollen collected by honey bees in Austria

Austrian beekeepers participated in the “C.S.I. Pollen” study as citizen scientists and collected pollen from honey bee colonies in hive mounted traps every three weeks from April to September in 2014 and 2015 to uncover the seasonal availability of pollen sources for bees. 1622 pollen samples were collected and analysed using palynological light microscopy to the lowest taxonomic level possible. For 2014 and 2015 combined, 239 pollen types from more than 85 families were detected. ‘Various unknown’ species, Taraxacum-form and Plantago spp. were the pollen types collected by the majority of colonies (occurrence), whereas the most pollen grains collected were from Trifolium repens-form, Plantago spp. and Salix spp. (abundance). In spring, trees were found to be the most abundant pollen source, whereas in summer herbs dominated. On average, a colony collected pollen from 16.8 ± 4.7 (2014) and 15.0 ± 4.4 (2015) pollen types per sampling. Those numbers, however, vary between sampling dates and indicate a seasonal pattern. This is also supported by Simpson’s diversity index, which was on median 0.668. In both years, 50.0% of analysed pollen samples were partially (>50%) and 4.2% were highly monofloral (i.e. containing >90% of one pollen type). Prevalence of monofloral pollen samples peaked at the beginning and the end of the season, when pollen diversity was the lowest.

Allergenic pollen concentrations in the air of urban parks in relation to their vegetation

In the face of the intensifying process of urbanization and the increased incidence of pollen allergies among urban residents, there is still a need to continuously monitor the airborne concentration of allergenic plant pollen. Urban green spaces (UGS) are a desirable element of the urban fabric and necessary for the proper functioning of cities, but they are a rich source of allergenic pollen that may pose a certain risk to people visiting them. The main aim of this study was to analyse the airborne allergenic pollen content in parks of different types relative to a reference point located on the roof of a building. Moreover, this study investigated the relationship between tree canopy volume and the number of recorded airborne pollen grains (SPIn- Seasonal Pollen Integral), and these parameters were compared with the potential impact of vegetation in the parks studied through the Index of Urban Green Zones Allergenicity (IUGZA). Aerobiological monitoring was carried out in Rzeszów, SE Poland in 2016. A volumetric Hirst-type device was used. The pollen seasons of many taxa largely overlapped at each site where the monitoring was carried out, but the concentration values clearly differed. Tree pollen concentration values were not dependent on total canopy volume, and the greatest disproportions were found for Acer, Betula, Quercus, and Tilia pollen. This may be due to the fact that a solitary tree produces more pollen than a tree growing near others of the same species. The downtown park, surrounded by densely built-up areas, exhibited the highest allergenic potential, and the concentration of pollen, in particular tree pollen, was highest there. It is undesirable to plant hedges of allergenic plants, as they are a rich local source of pollen. Aerobiological monitoring carried out in urban parks provides information about the real threat of allergenic pollen to park visitors.

Gene flow from herbicide resistant transgenic soybean to conventional soybean and wild soybean

Gene flow from transgenic crops to conventional cultivars or wild relatives is a major environmental and economic concern in many countries. South Korea is one of the major importer of transgenic crops for food and feed, although commercial cultivation of transgenic crops is not yet allowed in this country. This study evaluated gene flow from the herbicide glyphosate- and glufosinate-resistant transgenic soybean (Glycine max) to five non-transgenic soybean cultivars and three accessions of wild soybean (Glycine soja). Field trials were conducted over 2 years, and gene flow was monitored up to 10 m distance from the pollen source. The results indicated that the detectable rate of gene flow from transgenic to conventional soybeans varied between 0 and 0.049% in both 2014 and 2015 field trials, while no hybrids were detected among wild soybean progenies. The highest rate of gene flow was found in the progenies of the Bert cultivar, which exhibited the longest period of flowering synchronization between the pollen donor and the recipient. In addition, overall gene flow rates declined with increased distance from the transgenic soybean plot. Gene flow was observed up to 3 m and 8 m from the transgenic soybean plot in 2014 and 2015, respectively. Our results may be useful for developing measures to prevent gene flow from transgenic soybean.

On-Farm Diversification in an Agriculturally-Dominated Landscape Positively Influences Specialist Pollinators

Agricultural practices can either contribute to pollinator decline or provide opportunities to support pollinator communities. At the landscape-scale, agriculture can have negative impacts on pollinators, especially pollinators that specialize on limited floral or nesting resources. While increasing floral resources at the field-scale is positive for pollinator communities, little is known about how it affects specialist bees that depend on a specific pollen source (oligoleges). We studied pollinators on small-scale farms that contrasted in crop diversity (monocultures versus polycultures), embedded in the intensively managed agriculture region of the San Joaquin Valley in California, to understand how wild bee communities and specialist bees would respond to field-scale diversification practices. We used squash (Cucurbita pepo) as our focal crop, because it is visited by both specialist pollinators, “squash bees” in the genera Peponapis and Xenoglossa, and by generalist bees like those in the genera Apis and Agapostemon. We hypothesized that there would be a greater number of squash bees on monoculture farms, which have abundant squash flowers, than on polyculture farms. Contrary to our predictions, we found that increasing the number of non-squash floral resources at the field-scale in agroecosystems supports a greater abundance of squash bees but has no effect on the diversity of bees visiting squash flowers. This pattern of increased abundance was consistent for other wild bees and the total number of bees (i.e. including honey bees), but not for honey bee abundance alone. Further, the abundance of pollinators increased or remained the same on polyculture farms throughout the morning while decreasing on monoculture farms, suggesting that as squash flowers start to close in midmorning, bees on the monocultures go elsewhere because no other floral resources co-occur. However, they remain on the polycultures where other resources co-occur. Thus, on-farm diversification may be an important refuge for both specialist bees and other pollinator species that are vulnerable to floral resource simplification and loss in landscapes dominated by monoculture agriculture.

Performance of basophil activation test and specific IgG4 as diagnostic tools in nonspecific lipid transfer protein allergy: Antwerp‐Barcelona comparison

Recent studies show that nsLTP sensitization is not limited to the Mediterranean basin and can present diverse clinical phenotypes. It remains challenging to predict clinical outcome when specific IgE antibodies (sIgE) to nsLTPs are present. This study compares both clinical and in vitro allergy characteristics but also diagnostic performance of a basophil activation test (BAT) and sIgG4 in nsLTP-sensitized patients from Antwerp (ANT, Belgium) and Barcelona (BCN, Spain). Adult subjects with positive sIgE rPru p 3 and/or rMal d 3≥0.10kUA /L (n=182) and healthy controls (n=37) were included. NsLTP-sensitized individuals were stratified according to clinical symptoms with peach/apple, respectively. BAT rPru p 3 and rMal d 3 were performed and sIgG4 antibodies to both components quantified. In BCN, only ratios of sIgG4/sIgE rMal d 3 and BAT rMal d 3 (0.001µg/mL) can identify clinically relevant Mal d 3 sensitization (sensitivity of 60%-63% and a specificity of 75%-67%, respectively). In ANT, only the sIgE/total IgE rPru p 3 ratio shows added value (sensitivity 60% and specificity 83%). Finally, it appears that symptomatic patients in BCN are more sensitive to lower allergen concentrations compared to ANT. In addition, it was shown that ANT patients were more often sensitized to pollen and that specific pollen sources differed between regions. NsLTP-related allergy profiles and diagnostic performance differ significantly between regions and are component-specific, which makes extrapolation of data difficult to do. In addition, it seems that basophil sensitivity might show geographical differences. Additional research is needed to confirm these findings.

Formulation of winged bean seeds as pollen substitute for outgrowth of honey bees (Apis mellifera L)

The availability of pollen in plants depends on the season. The rainy season becomes a limiting factor for honeybees to obtain a source of pollen because there are not many flowering plants this season. This causes the development of honey bee colonies to be inhibited, as pollen is the only source of protein for the naturally available bees that can affect the rate of reproduction and the life span of bees. The winged bean contains a high enough protein and amino acids that the bees require, so the winged beans can be used as artificial feed of pollen substitute. Winged bean seeds be processed into three types of processed, namely roasted winged bean seeds (TKS), boiled winged bean seeds (TKR), and fermented winged bean seeds (TKF). Winged bean seeds flour given to bees in pasta form. Based on the observations obtained the results that the consumption of the bee’s liked is roasted winged bean seeds, because it does not a bad odor. The smell is lost due to the roasting process. Protein content of fermented, boiled, and roasted of winged bean seeds was 6.46%; 7.36%; and 15.19%. While the fat content on fermented, boiled, and roasted of winged bean seeds were 8.35%; 8.31%; and 12.07%. This indicates that the most preferred type is roasted winged bean seeds with the highest protein and fat.

POLLEN GIVING PLANTS VISITED BY THE HONEY BEE (APIS MELLIFERA L.)

The analysis of the honey plants in the area of apiculture is very important about the development, reproduction and productivity of bee colonies. The knowledge of the floral specialization of Apis mellifera L. is main point for good beekeeping practices. The bees have visited 46 species of honey plants from 41 genera and 22 families. The honey bees prefer to collect pollen from 2 to 5-6 plant species during every single month. Bees mainly collect pollen from two or three plants every month. The agricultural species Brassica napus as well as the meadow flora – Сentaurea solstitialis and Centaurea cyanus are the most visited honey plants during their flowering. Bees prefer to collect pollen from 16 plants out of 46 visited taxons. Not all plants in the area serve as a source of pollen for the bees. The greatest amount of collected pollen comes from Brassica napus – 3798.69 g. The visited cultivated honey taxons are around 22 % but about 56.5 % of the total amount collected pollen. Around 78 % of the visited plants are common natural as well as about 43.5 % of the total amount collected pollen. Key words: honey bee, honey plants, pollen, pollen traps, melissopalynologia, specialization

Large-scale pollen distribution in marine surface sediments from the Bohai Sea, China: Insights into pollen provenance, transport, deposition, and coastal-shelf paleoenvironment

To elucidate the mechanisms responsible for pollen and spore transportation and deposition in the Bohai Sea, fully covered seafloor-surface sediment samples were collected for palynological and grain size analysis. The results reveal that the pollen and spore concentrations were higher in the head of Liaodong Bay and in the muddy area of the Bohai Sea. The Yellow River was the main source of pollen and spores in the Bohai Sea. The sediments with relatively high pollen concentrations consisted mainly of clay and fine silt, whereas sediment with lower pollen concentrations was mostly fine sand. In addition, the percentages of Pinus pollen and pteridophyte spores increased with increasing sea water depth, while other arboreal (excluding Pinus) and herbaceous pollen generally decreased with increasing distance from the shore. The relationship between the pollen taxa and the water depth of the sampling points shows that the fluvial water plays a predominant role in pollen transmission within 20 m of water depth, while the wind is the main driving force for pollen transmission when the water depth exceeds 20 m. Although Pinus pollen and pteridophyte spores were over-represented, there was good correlation between marine pollen signals and terrestrial vegetation. Apart from the influence of rivers and wind on pollen and spore deposition, the tidal currents and circulation were also main force responsible for transporting sediment and determining the differentiation of pollen and spores in the Bohai Sea. The comparison of pollen and spore percentages between surface sediment and fossil records from sedimentary cores made it possible to identify changes in pollen sources and transport mechanisms. Meanwhile, the percentage fluctuations of fossil Pinus and herbaceous pollen revealed concomitant changes of the sea level and climate. These findings are of paramount importance to the interpretation of Quaternary marine pollen data from the Bohai Sea, China.

Artificial neural networks can be used for Ambrosia pollen emission parameterization in COSMO-ART

The emission parameterization is a crucial part of numerical pollen dispersion models. This paper shows that Artificial Neural Networks (ANNs) can substantially improve the performance of the Ambrosia pollen emission in numerical pollen dispersion models such as COSMO-ART. Based on simultaneous measurement of Ambrosia pollen concentrations and meteorological variables in the source area, ANNs were trained to predict the diurnal profile of pollen emission. Six different combinations of explanatory meteorological variables were trained with five different ANN configurations resulting in 30 candidate emission models. The best network configuration for each combination of explanatory variables were used as emission parameterization in the numerical pollen dispersion model COSMO-ART. In addition, two benchmarks were implemented: an emission parameterization based on sigmoid functions and an artificial neural network using only time as an explanatory variable. The Ambrosia pollen seasons of 2015 and 2016 were simulated using the two benchmarks and the six emission parameterizations. The modelled diurnal profile of emission fluxes at 15 different sites from Serbia, Hungary and France with strong local pollen sources were compared with observed concentrations. Artificial Neural Networks based emission parameterization substantially improved the performance of the Ambrosia pollen emission in COSMO-ART compared to the emission based on the sigmoid functions in all these three countries. However, a time-related explanatory variable must be used. This suggests that the ANN-based emission parameterizations can be used at distant locations as well. On the other hand, the use of meteorological related parameters did not increase the performance compared with the time-only benchmark.

Auxin Induced Haploid Induction in Wide Crosses of Durum Wheat

Doubled haploidy breeding via wide hybridization has been used in durum wheat haploid production for creating homozygosity in the shortest possible time. Post pollination treatment with hormones is a key factor for inducing haploid embryos in durum wheat wide crosses. An intergeneric hybridization experiment was carried out in seven durum wheat genotypes using Imperata cylindrica and two composites of Maize viz., Bajaura Makka and Early Composite, as pollen sources. The pollinated spikes were injected with 2,4-Dichlorophenoxyacetic acid (2,4-D) in five different concentrations i.e., 100, 150, 200, 250 and 300 ppm, for three consecutive days at 24, 48 and 72 hrs after pollination. Analysis of variance revealed that the five concentrations of 2,4-D significantly differed in their ability to induce haploid embryos and 2,4-D at 250 ppm was found to be most effective in durum wheat haploid production through wide hybridization. The highest frequency of embryo carrying seeds was recorded to be 65.75 and 36.73 percent, at 250 ppm with I. cylindrica and Bajaura Makka, respectively in first cropping season. During second season, embryo formation frequency was observed to be maximum, 70.69, 32.84 and 27.59 percent, at 250 ppm 2,4-D with all three pollen sources, viz., I. cylindrica, Bajaura Makka and Early Composite, respectively.

Pollen storage studies in sugar apple (Annona squamosa L.) cv. Balanagar

Annona cv. ‘Arka Sahan’ essentially needs assisted pollination with sugar apple pollen for commercial fruit production. However, there is no perfect synchronization in flowering of the pollen source sugar apple cv. Balanagar with that of cv. ‘Arka Sahan’. So, an attempt was made to store the pollen of the former to assure its availability as and when cv. ‘Arka Sahan’ flowers need to be pollinated. In vitro pollen germination was assessed using different concentrations of sucrose (5%, 10% and 15%) with and without boric acid (100 ppm). Pollen collected on the second day of anthesis showed maximum germination (43.47%) in 5% sucrose + 100 ppm boric acid while those collected on first day of anthesis did not show any germination. Pollen collected at different times of the day showed a rapid decrease in pollen germination from maximum germination at 6 am (36.55%) to no germination at 2 pm. The maximum pollen germination was in 10% sucrose + 100 ppm boric acid combination for the stored pollen as well as pollen collected during late hours of the day. Pollen stored under varying temperatures lost viability within 1 month at 4°C while pollen stored at −196°C in liquid nitrogen retained germination for 2 months. Pollen germination and pollen tube growth were progressively reduced with storage time. Structure of stored pollen examined using Scanning Electron Microscope (SEM), revealed deformed and shriveled pollen structure. The results of this study indicated that the Annona pollen tends to be viable for a period of 2 months.

Seasonal shifts and complementary use of pollen sources by two bees, a lacewing and a ladybeetle species in European agricultural landscapes

Abstract Continuous availability of food resources, such as pollen, is vital for many insects that provide pollination and pest control services to agriculture. However, there is a lack of knowledge about the shared or complementary use of floral resources by such species, which hampers more effective landscape management to simultaneously promote them in agroecosystems. Here, we simultaneously quantified pollen use by a bumblebee (Bombus terrestris) and a mason bee (Osmia bicornis), two bee species recognized as important crop pollinators, as well as a lacewing (Chrysoperla carnea) and a ladybeetle species (Harmonia axyridis), both common predators of crop aphids, throughout the season in 23 agricultural landscapes in Germany and Switzerland. Pollen diets were more diverse and similar among C. carnea and H. axyridis compared to the two bee species, but all four species shared key pollen types early in the season such as Acer, Quercus, Salix and Prunus. All species exhibited a pronounced shift in pollen sources from primarily woody plants (mainly trees) in spring to primarily herbaceous plants in summer. The majority of pollen (overall ≥64%) came from non‐agricultural plants even in crop‐dominated landscapes. Synthesis and applications. Our results highlight the importance of trees as pollen sources for many insect species, particularly early in the season. Our findings support incentives that promote heterogeneous agricultural landscapes including both woody and herbaceous semi‐natural habitats, ensuring phenological complementarity of floral resources for insect species that can provide pollination and pest control services to agriculture. The identified key plant species can help to design and optimize agri‐environment schemes to promote these functionally important insects.

Determination of in-Field Gene Flow Between Sugarcane Cultivars

Genetically modified (GM) sugarcane is being developed for use in commercial production in several countries. Regulatory approval is required before these cultivars can be released and grown. Part of the approval process is to understand and assess the potential for environmental harm that might result from introduction of a GM organism. A key piece of biological information to assist in this analysis is to determine if and over what distance transgenes could be transferred by pollen from the GM plants and passed onto the next generation of sugarcane seeds. This is not known for sugarcane. Consequently, a field experiment was designed and conducted in Australia to determine the level of pollination between sugarcane cultivars (Saccharum spp. hybrids), and the distance over which it occurs, by placing non-GM flowering plants of cultivar Open image in new window in the centre of a field of non-GM cultivar Open image in new window . Mature inflorescences of the pollen receptor ( Open image in new window ) were collected in eight directions up to 200 m from the centre of the field. Parentage of the seeds from the mother plants germinating in controlled conditions was determined by molecular markers. At a distance of 1 m in all directions from the pollen source, relatively high levels of hybridisation were found, though this was highest (100%) in the upwind direction. The level of hybridisation decreased in the shape of an exponential decay curve but detectable levels of hybridisation still occurred at 200 m downwind from the pollen source. The high level of cross- pollination at close distance was confirmed in a second experiment. The potential for pollen to travel several hundred metres and effect pollination and the subsequent production of sugarcane seeds means that containment of a transgene by distance cannot be assumed for sugarcane. The potential for cross- pollination of sugarcane plants or of compatible, sympatric relatives will be dependent upon local conditions. The risk of harm as a result of pollen carrying a transgene subsequently pollinating and producing seed will have to be evaluated against the likelihood of germination and survival of the seed and the nature and effects of the transgene.