Effect of wall-disruption on nutrient composition and in vitro digestion of camellia and lotus bee pollens

The nutrient digestion,absorption and biological activity of bee pollen may be limited due to the complex pollen wall.Here,the effect of superfine grinding technology on the release of nutrients from bee pollen were investigated,and their antioxidant activities and in vitro digestion were explored in this study.Results showed that the content of nutrients in bee pollen increased after wall disruption.Among them,fat content increased by 22.55%-8.31%,protein content increased by 0.54%-4.91%,starch content increased by 36.31%-48.64%,soluble sugar content increased by 20.57%-29.67%,total phenolic acid content increased by 11.73%-86.98%and total flavonoids content increased by 14.29%-24.79%.At the same time,the antioxidant activity increased by 14.84%-46.00%.Furthermore,the active components such as phenolic compounds in the wall-disruption bee pollen were more readily to be released during the in vitro digestion,and easier to be absorbed because of their higher bioaccessibility.Antioxidant activities during in vitro digestion were also improved in walldisruption bee pollen.These findings provide evidence that bee pollen wall disruption was suggested,thus,it is more conducive to exerting the value of bee pollen in functional foods.

First Report of a Successful Development of Yam Hybrids(Dioscorea alata L.)from Lyophilized and Long-Term Stored Pollens

Various biological constraints including erratic and asynchronous flowering between male and female plants hinder successful hybrid development and genetic gains in greater yam breeding programs.Therefore,pollen storage has gained much attention to facilitate artificial pollinations and increase the genetic gains.This 4-year study aimed at developing a practical long-term pollen storage technique for the successful development of yam hybrids.Fresh pollens were collected from two Dioscorea alata males,then lyophilized(two lyophilization treatments were applied),followed by storage at room temperature(24℃–25℃)for 12 months.Moreover,the lyophilized and stored pollens were tested for viability by crossing with four female varieties.Our results showed that lyophilization is effective for achieving viable pollens after 12 months of storage.Treatment 1(48 h drying)showed higher pollen germination and fertility rates than Treatment 2(72 h drying).Although we observed a reduction in viability of lyophilized pollens after 12 months of storage,we generated hybrid seedlings with success rates from 12%to 21%compared to 21%–31%when using fresh pollens.Paternity testing based on molecular genotyping confirmed the hybrid status of the obtained seedlings,which grew well in a greenhouse.Lyophilization is a practical approach for a long-term storage of greater yam pollen samples.This protocol will positively impact yam breeding programs particularly in developing countries.

Cytomorphology and Cytochemical Localization of K-type and T-type Cytoplasmic Male Sterile Pollens in Wheat

By using the technology of microscopy, electron microscopy and enzyme cytochemical localization , comparison was made of the cytomorphology, ATPase and cytochrome oxidase activity in pollens during microspore formation and pollen development, for K-type cytoplasmic male sterile(CMS)lines,T-type CMS lines and their maintainer lines on wheat. The results indicated that pollen abortion of the T-type CMS lines mainly occurred at the later mononucleate pollen stage, and cytomorphological changes of the abortive pollen began with a vacuolar membrane, and pollen aborting was related to a lack of ATPase activity in the nucleus and nucleolus during the mononucleate pollen stage. Pollen abortion of the K-type CMS lines took place mainly during the later binucleate and trinucleate stages, and cytomorphological changes of the abortion first began with mitochondria. The abortion was related to intine disruption.

PRELIMINARY STUDIES ON AIR-BORNE SPORES AND POLLENS IN NORTHERN SUBURB OF BEIJING

Air borne spores and pollens were collected by using Durham Pollen Sampler from 38 metre building top platform in northern suburb of Beijing and observations were carried out accordingly. Distributed mainly in March to October in a year, both the amount and variations of pollens are affected by air temperature and precipitation in addition to that of florescence. The maximum pollen species are found in May, and the maximum pollen amount is found in early June, and then in September. Pollens of herbs predominate, mostly distributing in May to September. Xylophytes have smaller amount of pollens which are found mostly in March to June. The amount of air borne plant pollen and bacterial spores is much higher in hot sunny days than in the cloudy/rainy days. The alternation of hot sunny days with cloudy/rainy days is most favourable for bacterial spores dispersion.

Effects of Stored Pollens from Wild <i>Actinidia eriantha</i>Vines on Some Fruit Quality Traits

Our study was conducted to determine In vitro germination ability of pollens from 25 wild Actinidia eriantha genotypes after one year freeze storage, afterwards we examined fertilization ability of stored pollens of 8 genotypes selected according to In vitro test results from aforementioned 25 genotypes, and finally investigated effects of stored viable pollens from “MH67”, “MH55”, “MH48” and “MH45” genotypes on fruit quality characters of the female experimental plant “M3” as the main purpose. Non-pollinated “M3” kiwifruit plant was taken as control. We found that In vitro germination and fertilization ability of different stored pollen sources, and also fruit quality characters including dry matter, total sugar, titratable acid, vitamin C, total polyphenol, total flavonoid, chlorophyll (“a”, “b”, and total) and carotenoid contents except total soluble solid content were significantly different. MH67 and MH45 genotypes were evaluated as the most suitable pollenizers which can be recommended as new candidate cultivars because of long term storage ability and brought about desired fruit quality characters. They also will be investigated more at further breeding studies.

Analysis of Changing Factors on Airborne Allergenic Pollens Distribution in Taiyuan Downtown, North China

To study and analyse 2 surveys on airborne allergenic pollens distribution in Taiyuan Downtown, North China 30 years apart, the surveys focused on the phenomenon and the influence factors on types, counts, drift patterns, growth and decline rhythm and distribution features of airborne pollen with the same methods in the region in March 1977 to February 1978 and July 2008 to June 2009, respectively. The data of two airborne pollens surveys were treated with statistics, comparation and analysis, and the influence factors of pollen distribution in Taiyuan Downtown were explored. In the 2 surveys, 24 species and 35 species of pollen were collected in the region, respectively. Two pollen drift peaks were formed in spring and autumn in the two surveys. Artemisia L. is still the absolute dominant allergy airborne pollen. The types, counts, drift patterns and composition of pollen in air could be changed by the plants variation. Climate warming might affect pollen peak appearing time and lasting time, climate warming and Poplar & Willow contents changes in spring and autumn reversed the airborne pollen peak. It was found that Humulus L. had become the region’s main allergic pollen. Invasive strong allergen ragweed was spread to the inland city Taiyuan. Allergists should focus on exotic invasive harmful plants in the region.

Effect of different drying methods on the amino acids,α-dicarbonyls and volatile compounds of rape bee pollen

The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.

High temperature treatment induced production of unreduced 2n pollen in Camellia oleifera

Unreduced gametes through chromosome doubling play a major role in the process of plant polyploidization.Our previous work confirmed that Camellia oleifera can produce natural 2n pollen,and it is possible to induce the 2n pollen formation by high temperature treatment.This study focused on the optimization of the 2n pollen induction technique and the mechanisms of high temperature-induced2n pollen formation in C.oleifera.We found that the optimal protocol for inducing 2n pollen via high temperature was to perform 45℃with4 h at the prophaseⅠstage of the pollen mother cells(PMCs).Meanwhile,high temperature significantly decreased the yield and fertility of2n pollen.Through the observation of meiosis,abnormal chromosome and cytological behaviour was discovered under high-temperature treatment,and we confirmed that the formation of 2n pollen is caused by abnormal cell plate.Based on weighted gene co-expression network analysis,fifteen hub genes related to cell cycle control were identified.After male flower buds were exposed to heat shock,polygalacturonase gene(CoPGX3)was significantly upregulated.We inferred that high temperature causes the CoPGX3 gene to be overexpressed and that CoPGX3 is redistributed into the cytosol where it degrades cytoplasmic pectin,which leads to an abnormal cell plate.Furthermore,abnormal cytokinesis resulted in the formation of dyads and triads,and PMCs divided to produce 2n pollen.Our findings provide new insights into the mechanism of 2n pollen induced by high temperature in a woody plant and lay a foundation for further ploidy breeding of C.oleifera.

GAMYB transcription factor LoMYB65 from lily plays a vital role in pollen development

Lily(Lilium spp.)is an important horticultural crop,but its use is limited due to serious pollen contamination problems.There are many studies on pollen development in model plants,but few on flower crops such as lilies.Gibberellin(GA)is a large class of hormones and plays an important role in plant vegetative growth and reproductive development.GAMYB is a group of the R2R3-MYB family upregulated by gibberellin,and plays an important role in anther development.Here,we isolated a novel GAMYB,named LoMYB65,from lily,which was closely related to the AtMYB65 and AtMYB33 in Arabidopsis.Fluorescence quantitative PCR results showed that LoMYB65 was mainly expressed in lily anthers.LoMYB65 could be activated by 288μmol·L^(-1)GA3treatment and the LoMYB65 protein was located in the nucleus and cytoplasm,and had transactivation in yeast and tobacco leaf cells.The conserved motif within 226 amino acids of the C-terminal of LoMYB65 contributed to its transactivation.Overexpression of LoMYB65 caused dwarf phenotype,unnormal tapetum development,less seeds of siliques in transgenic Arabidopsis plants,the transgenic plants showed partly male sterile.Simultaneously,silencing of LoMYB65 with VIGS(Virus Induced Gene Silencing)in lily anthers caused unnormal pollen development and reduced the pollen amount.Overexpression of LoMYB65 in Arabidopsis and silencing of LoMYB65 in lily resulted in decreased pollen counts,so we speculate that LoMYB65 may be dose-dependent.Overall,these findings suggest that LoMYB65 may play an important role in anther development and pollen formation in lily.LoMYB65 may provide a useful candidate gene for pollenless breeding of lily.

Does ash dieback affect the reproductive ecology of Fraxinus excelsior L.?

Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest ecosystems.The ongoing ash dieback disease could affect the reproductive ecology of Fraxinus excelsior L.and have a major impact on the quantity and quality of pollen and seeds.In this study,we investigated pollen production and viability of pollen and seeds of ash trees with different health status from 2018 to 2022.Inflorescences were collected from 105 trees(pollen production),pollen from 125 trees(pollen viability),and seeds from 53 trees(seed quality)in two seed orchards and in one floodplain forest in southern Germany.Not all parameters were examined at every site every year.The average pollen production per tree was estimated at 471.2±647.9 billion pollen grains.In addition,we found that a high number of inflorescences did not equate to high pollen production per inflorescence.Pollen production of healthy and diseased trees did not differ significantly,although only 47%of severely diseased male trees(vs.72%for healthy trees)produced flowers.With regards to pollen viability,the TTC test showed an average viability of 73%±17%.Overall,there was a slight tendency for diseased trees to have less viable pollen.However,a significant difference could only be calculated for trees in the floodplain forest.The percentage of germinable seeds in 2018 was 38%in the floodplain forest and 57%in one of the seed orchards.The percentage of viable seeds(TTC test)ranged from 17 to 22%in the orchards in 2020.Non-viable seeds were usually heavily infested by insects.In general,seed quality was not significantly different between healthy and diseased trees.Our results indicate that ash dieback affects flower formation and pollen viability but not pollen production or seed quality.Nevertheless,the fact that hardly any flowering was observed,especially for trees that were seriously affected,suggests a negative effect of ash dieback on reproductive performance.Thus,severely diseased trees will transfer their genes to a smaller extent to the next generation.

Allergen degradation of bee pollen by lactic acid bacteria fermentation and its alleviatory effects on allergic reactions in BALB/c mice

Food allergy as a global health problem threatens food industry.Bee pollen(BP)is a typical food with allergenic potentials,although it performs various nutritional/pharmacological functions to humans.In this study,lactic acid bacteria(LAB)were used to ferment Brassica napus BP for alleviating its allergenicity.Four novel allergens(glutaredoxin,oleosin-B2,catalase and lipase)were identified with significant decreases in LAB-fermented BP(FBP)than natural BP by proteomics.Meanwhile,metabolomics analysis showed significant increases of 28 characteristic oligopeptides and amino acids in FBP versus BP,indicating the degradation of LAB on allergens.Moreover,FBP showed alleviatory effects in BALB/c mice,which relieved pathological symptoms and lowered production of allergic mediators.Microbial high-throughput sequencing analysis showed that FBP could regulate gut microbiota and metabolism to strengthen immunity,which were closely correlated with the alleviation of allergic reactivity.These findings could contribute to the development and utilization of hypoallergenic BP products.

DIA-based proteome profiling with PRM verification reveals the involvement of ER-associated protein processing in pollen abortion in Ogura CMS cabbage

Ogura cytoplasmic male sterility(Ogura CMS)is extensively applied in hybrid seed production in cruciferous crops.However,the posttranscriptional molecular basis of Ogura CMS in cruciferous crops remains elusive.Here,a data-independent acquisition-based proteomic approach coupled with a parallel reaction monitoring-based targeted proteomic assay was used to analyze the proteome dynamics of Ogura CMS cabbage line RM and its maintainer line RF during floral bud development to obtain insights into the mechanism underlying Ogura CMS in cruciferous crops.A total of 9162 proteins corresponding to 61464 peptides were identified in RM and RF floral buds.The proteomic fluctuation of RM was weaker than that of RF.Differences in protein expression between RM and RF gradually enlarged with floral bud development.Fifteen continually up-regulated and eight continually down-regulated proteins were found in RM relative to RF throughout floral bud development.Differentially expressed proteins between RM and RF during floral bud development were implicated in the endoplasmic reticulum(ER)-associated protein processing pathway,in which most of them exhibited down-regulated expression in RM.These data suggest that ER-associated protein processing may be involved in pollen abortion in Ogura CMS cabbage by inhibiting the expression of critical factors.Our findings not only deepen the understanding of the molecular mechanisms of Ogura CMS in cruciferous crops but also provide better guidance for applying Ogura CMS in the hybrid breeding of cruciferous crops.

Golgi 58K-like protein in pollens and pollen tubes of Lilium davidii

In animal cells, Golgi apparatus is located near the microtubule organizing center (MTOC) and its position is determined partly by 58K protein. By sodium dodecyl-sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immuno-blotting methods, a 58K-like protein has been found in pollen grains and pollen tubes of Lilium davidii. Its molecular weight is very similar to that of the 58K protein of animal cells. By immunofluorescence labeling, under a confocal laser scanning microscope (CLSM), the animal 58K antibody revealed a punctate staining in pollen grains and pollen tubes, which is consistent with the distribution of Golgi apparatus in plant cells. In addition, immuno-gold labeling and transmission electron microscopy showed that the 58K-like protein bound mainly to the membrane of vesicles-like structure near Golgi apparatus. This is the first demonstration of the 58K-like protein in plant cells.

Pollens derived magnetic porous particles for adsorption of low-density lipoprotein from plasma

Adsorption of low-density lipoprotein from plasma is vital for the treatment of dyslipidemia.Appropriate adsorbent material for efficient and selective adsorption of low-density lipoprotein is highly desired.In this work,we developed pollens-derived magnetic porous particles as adsorbents for this purpose.The natural pollen grains were modified to obtain high surface porosity,a large inner cavity,magnet responsiveness,and specific wettability.The resultant particles exhibited satisfying performance in the adsorption of a series of oils and organic solvents out of water.Besides,the particles were directly utilized to the adsorption of low-density lipoprotein in plasma,which showed high selectivity,and achieved an outstanding adsorption capacity as high as 34.9%within 2 h.Moreover,their salient biocompatibility was demonstrated through simulative hemoperfusion experiments.These features,together with its abundant source and facile fabrication,makes the pollens-derived magnetic porous particles excellent candidate for low-density lipoprotein-apheresis and water treatment applications.

Survival of boll weevil （Coleoptera： Curculionidae） adults after feeding on pollens from various sources

The survival of overwintering boll weevil, Anthonomus grandis grandis （Boheman）, adults on non-cotton hosts in the Lower Rio Grande Valley （LRGV） of Texas was examined from 2001 to 2006. The success of the Boll Weevil Eradication Program, which was reintroduced into the LRGV in 2005, depends on controlling overwintering boll weevil populations. Laboratory studies were conducted using boll weevil adults that were captured in pheromone traps from September through March. The number of adults captured per trap declined significantly in the field from fall to the beginning of spring （3.5-7.0-fold）. The proportion of trapped males and females did not differ significantly. The mean weight of boll weevil adults captured in September was 13.3 mg, while those of captured adults from November to February were significantly lower and ranged from 6.7 to 7.8 mg. Our results show that boll weevil adults can feed on different plant pollens. The highest longevity occurred when adults were fed almond pollen or mixed pollens （72.6 days and 69.2 days, respectively） and the lowest when they fed on citrus pollen or a non-food source （9.7 days or 7.4 days, respectively）. The highest adult survival occurred on almond and mixed pollens [88.0%-97. 6% after 1st feeding period （10 days）, 78.0%-90.8% after 3rd feeding period （10 days）, 55. 0%-83.6% after 5th feeding period （10 days）, and 15.2%-32.4% after lOth feeding period （10 days）]. The lowest adult survival occurred on citrus pollen [52.0%-56.0% after 1st feeding period （10 days）, 13.3% after 3rd and 5th feeding periods （10 days）, and 0 after 6th feeding period （10 days）]. Pollen feeding is not a behavior restricted to adult boll weevils of a specific sex or physiological state. Understanding how boll weevil adults survive in the absence of cotton is important to ensure ultimate success of eradicating this pest in the subtropics.

Does pollinator dependence decrease along elevational gradients?

Plants have long been thought to be less dependent on pollinators for seed production at higher elevations due to adverse pollination environments.However,recent research has yet to consistently support the generality of this expectation.In this study,we asked whether pollinator dependence decreases along an elevational gradient and how it varies with various reproductive traits.To answer these questions,we quantified pollinator-plant associations and various reproductive traits for 112 flowering plants spanning a large elevational gradient(990-4260 m a.s.l.)in the Qinghai-Tibet Plateau.We found that flowering plants in the Qinghai-Tibet Plateau region are highly dependent on pollinators for seed production(76.2%of seed production was contributed by animal pollinators and 44.6%of plants would produce no seed without pollinator visitation).Contrary to our expectation,there was no significant elevational gradient in pollinator dependence index.Although the pollinator dependence index was not significantly correlated with pollen limitation,flower size,floral longevity,or reward type,it was correlated with compatibility status and flowering time.These findings indicate that pollinator dependence does not decrease along an elevational gradient in the Qinghai-Tibet Plateau.Our study also highlights the severe vulnerability of flowering plant seed production to pollinator declines under global change in the Qinghai-Tibet Plateau region,particularly for early-flowering or self-incompatible plants growing at higher elevations(e.g.,subnival belt).

Environmental Changes and Human Impacts on Landscapes near Medieval Steklyanukha-2 Fortress in Russia from Early Iron Age to Modern Times

The development of landscapes in one of the most populated river basins of the southern Russian Far East was studied using pollen and diatom data. The study sites were a multi-layered mountain fortress, Steklyanukha-2, and an Upper Holocene high floodplain sequence of the Steklyanukha River. Buried soil from the fluvial section acts as an environmental archive of the time in which people from the Yankovskaya archeological cultures settled in the river basin. The soil was formed under conditions of decreasing water supply in the valley and prolonged droughts. Findings of pollen Fagopyrum and Urtica signal economic activity in the Early Iron Age.Floodplain lake sediments accumulated from 1.6 to 0.5 kyr, when the valley was actively developed during the Middle Ages. There are signals of the development of secondary birch and oak forests. In the cultural layer of the fortress and lake sediments formed in the Middle Ages, Ambrosia and Xanthium pollens were found and are reliable evidence of agricultural activity in the valley. The pollens of plants typically seen in human-disturbed areas were also found. Indirect evidence of human activity includes non-pollen palynomorphs.The study of diatoms in a depression near a rampart confirmed the archaeologists' assumption that it was used as a water reserve. Pollen spectra from surface soils reflect agricultural activity in the river basin since the second half of the 19th century. The largest amount of pollen of alien and synanthropic plants and weeds, as well as spores of pathogenic fungi and fire indicators, were found here.

Identification and functional analysis of arabinogalactan protein expressed in pear pollen tubes

Arabinogalactan proteins(AGPs)are widely distributed in the plant kingdom and play a vital role during the process of plant sexual reproduction.In this study,we performed a comprehensive identification of the PbrAGPs expressed in pear pollen and further explored their influences on pollen tube growth.Among the 187 PbrAGPs that were found to be expressed in pear pollen tubes,38 PbrAGPs were specifically expressed in pollen according to the RNA-seq data.The PbrAGPs were divided into two groups of highly expressed and specifically expressed in pear pollen.We further tested their expression patterns using RT-PCR and RT-qPCR.Most of the PbrAGPs were expressed in multiple tissues and their expression levels were consistent with reads per kilobase per million map reads(RPKM)values during pollen tube growth,implying that PbrAGPs might be involved in the regulation of pear pollen tube growth.We also constructed phylogenetic trees to identify the functional genes in pear pollen tube growth.Therefore,19 PbrAGPs(PbrAGP1 to PbrAGP19)were selected to test their influences on pollen tube growth.Recombinant proteins of the 19 PbrAGP-His were purified and used to treat pear pollen,and 11 of the PbrAGP-His recombinant proteins could promote pear pollen tube growth.Additionally,pollen tube growth was inhibited when the expression levels of PbrAGP1 and PbrAGP5 were knocked down using an antisense oligonucleotide assay.PbrAGP1 and PbrAGP5 were localized in the plasma membrane and might not alter the distribution of pectin in the pollen tube.In summary,this study identified the PbrAGPs expressed in pear pollen and lays the foundation for further exploring their functions in pollen tube growth.

Observation of Flowering Process of Grape(Vitis vinifera L.)—Insight into the Starting of Pollination of Flower Hiding in Calyptras(Cap)

It is generally agreed that many Vitis vinifera L.cultivars are self-fertile,where self-pollination often occurs before capfall in a process called cleistogamy.Therefore,it is difficult to identify the right time to remove stamens before self-pollination during the cross-breeding of grape.For this paper,we observed the process of grape flowering and measured the pollen viability and stigma receptivity of grape flowers of‘Shine Muscat’in order to identify the starting time of self-pollination before capfall and to provide useful information for improving the efficiency of cross-breeding.The results demonstrate that the anther is not cracked during the visible clusters and separated clusters stages.Meanwhile,in the separated floral buds,flowering begins,and full bloom stages,the pollen viability is 60.7%,73.2%and 80.3%,respectively;however,at the berry set stage,pollen viability drops to zero.The top of the mature stigma is composed of a layer of nearly cylindrical papillary cells,and the stigma receptivity for pollen changes with the development of flowers:in particular,no reaction was observed in the visible clusters stage;weak positive reaction at the separated clusters stage;strong positive reaction at the separated floral buds,flowering begins,and full bloom stages;and no reaction at the berry set stage.In the separated floral buds stage,pollen tubes were seen germinating in the style.In the flowering begins stage,more pollen tubes were observed at the entry of the ovary.During the full bloom stage,most pollen tubes elongated into the ovary base and some entered the pearl hole.At the berry set stage,newborn endosperm nucleus could be seen in the ovule.From the above,we can conclude that the initiation time of closed fertilization for‘Shine Muscat’grape can be judged as the separated floral buds stage,and it is best to discard the stamen before the separated floral buds stage when conducting cross-breeding.