Pollen analysis of Atlantic forest honey from the Vale do Ribeira Region,state of São Paulo,Brazil

The pollen contents of 34 Apis mellifera honey samples from the Quilombola Community of Porto Velho (Vale do Ribeira, state of São Paulo, Brazil) were studied in order to identify their botanical and geographical origin. A total number of 114 pollen types distributed in 43 families were identified. Fabaceae pollen types were the most diverse (20). Dominant pollen was observed in 27 samples. The dominant type Piper was found in 21 samples and Zanthoxylum, Mikania cordifolia, Cupania oblongifolia, Cecropia, Attalea and Poaceae only in one sample. The quantitative analysis revealed a predominance of very-high pollen concentrations in the samples (Category IV, 35.3%). A second frequency of occurrence analysis revealed 67 pollen types from 26 botanical families from nectariferous species. Fabaceae was also the family with the largest number of nectariferous pollen types (15), followed by Sapindaceae, Asteraceae (six pollen types each), and Euphorbiaceae (five types). Dominant pollen occurred in 19 samples. The main nectariferous sources of pollen in the present study were: Arecaceae (Attalea and Euterpe/Syagrus), Asteraceae (Mikania cordifolia), Fabaceae (Machaerium), Rutaceae (Zanthoxylum), and Sapindaceae (Cupania oblongifolia). The honey was classified as predominantly heterofloral (67.6%). Monofloral honey from Mikania cordifolia, Machaerium, Zanthoxylum, Cupania oblongifolia, Euterpe/Syagrus and Attalea were also identified. The geographical origin demonstrates Apis mellifera using nectariferous sources available from the Atlantic Rainforest in the south and southeast of Brazil, as well as in the brushwood, secondary forest and field plants. This is one of the first works about melissopalynology in the Vale do Ribeira Region.     

Pollen morphology and its effect on pollenl collection by honey bees,Apis Mellifera L. (Hymenoptera: Apidae), with special Reference to Upland Cotton,Gossypium Hirsutum L. (Malvaceae)

Honey bees, Apis mellifera, forage readily on flowers of upland cotton, Gossypium hirsutum, to harvest nectar. The abundant pollen gets caught in the haircoat of the bees, but cotton pollen is nevertheless rarely collected. Honey bee pollen collection effectiveness was therefore investigated in a flight room using cotton and five other spheroidal pollen taxa presented in sequence. Honey bees visited all pollen dishes, but okra pollen (Abelmoschus esculentus) was never packed successfully by the bees landing in the pollen dish. Cotton pollen was collected by 16% of the landing foragers, pumpkin pollen (Cucurbita pepo) by 71%, and pollen of corn (Zea mays), pigweed (Amaranthus palmeri), and sunflower (Helianthus annuus) were readily collected by nearly all foragers. The amount of time spent in the pollen dish was always short (1 to 9 seconds) and homogeneous among all pollen taxa, indicating that none of them was strongly repellent to the bees. The reduced effectiveness with which honey bees collected cotton pollen was demonstrated by the longer amount of time needed for pollen grooming and packing between two consecutive landings in the pollen dish and the small size of cotton pollen pellets (averages of 0.42 mg and 8.23 mg per pellet for cotton and corn pollen, respectively). This reduced efficiency in cotton pollen collection was associated primarily with the length of the spines on cotton pollen which physically interfered with the pollen aggregating process used by honey bees.     

Combined LM and SEM study of the middle Miocene (Sarmatian) palynoflora from the Lavanttal Basin,Austria: part IV. Magnoliophyta 2 – Fagales to Rosales

An ongoing investigation of the middle Miocene (Sarmatian) palynoflora from the Lavanttal Basin continues to show that it contains an extremely rich assemblage of angiosperm taxa. The Fagales to Rosales pollen record documented here contains 34 different taxa belonging to the Betulaceae (Alnus, Betula, Carpinus, Corylus, Ostrya), Fagaceae (Castanea, Fagus, Quercus Groups Cerris, Ilex, Cyclobalanopsis, Quercus/Lobatae), Juglandaceae (Engelhardioideae, Carya, Juglans, Pterocarya), Myricaceae (Morrella vel Myrica), Cannabaceae (Celtis), Elaeagnaceae (Elaeagnus), Rhamnaceae, Rosaceae (Prunus) and Ulmaceae (Cedrelospermum, Ulmus, Zelkova). Two of the pollen types represent extinct genera, Trigonobalanopsis and Cedrelospermum, and are also reported for the first time from the Lavanttal Basin along with pollen of Rhamnaceae and Prunus. The different types of Quercus pollen are now affiliated with Groups Cerris, Cyclobalanopsis, Ilex and Quercus/Lobatae based on sculpturing elements observed using scanning electron microscopy (SEM). Köppen signatures of potential modern analogues of the fossil Fagales and Rosales suggest a subtropical (Cfa, Cwa) climate at lower elevation and subsequent subtropical to temperate climate with altitudinal succession (Cfa → Cfb/Dfa→ Dfb; Cwa → Cwb → Dwb) in the Lavanttal area during accumulation of the palynoflora. Most of the fossil taxa have potential modern analogues that can be grouped as nemoral and/or merido-nemoral vegetation elements, and the diversity of Fagales indicates a varying landscape with a high variety of niches.     

Influence of wind direction on pollen concentration in the atmosphere

The daily pollen concentration in the atmosphere of Badajoz (SW Spain) was analysed over a 6-year period (1993–1998) using a volumetric aerobiological trap. The results for the main pollination period are compared with the number of hours of wind each day in the four quadrants: 1 (NE), 2 (SE), 3 (SW) and 4 (NW). The pollen source distribution allowed 16 pollen types to be analysed as a function of their distribution in the four quadrants with respect to the location of the trap. Four of them correspond to species growing in an irrigated farmland environment (Amaranthaceae-Chenopodiaceae, Plantago, Scirpus, and Typha), five to riparian and woodland species (Salix, Fraxinus, Alnus, Populus, and Eucalyptus), four to urban ornamentals (Ulmus, Arecaceae, Cupressaceae, and Casuarina), and three which include the most frequent pollen grains of widely distributed species (Poaceae, Quercus, and Olea). The results show that the distribution of the sources and the wind direction play a very major role in determining the pollen concentration in the atmosphere when these sources are located in certain quadrants, and that the widely distributed pollen sources show no relationship with wind direction. In some years the values of the correlations were not maintained, which leads one to presume that, in order to draw significant conclusions and establish clear patterns of the influence of wind direction, a continuous and more prolonged study will be required. Received: 6 May 1999 / Revised: 30 March 2000 / Accepted: 31 March 2000     

Entomophilous pollen incidence with reference to atmospheric dispersal in eastern India

This paper presents atmospheric pollen concentrations of fifteen entomophilous trees of Eastern India. The period of anthesis and anther dehiscence varied from morning to evening. Insects and other flower visitors were found to accelerate the mechanism of pollen dispersal. The highest pollen concentration was for 267/m³ in Aegle marmelos followed in decreasing order by Eucalyptus globosus (207/m³), Cassia siamea (186/m³), C. fistula (180/m³), Delonix regia (171/m³), Butea monosperma (159/m³), Bombax ceiba (156/m³), Tectona grandis (144/m³), Terminalia arjuna (138/m³), Moringa oleifera (126/m³), Anthocephalus chinensis (114/m³), Syzygium cumini (96/m³), Dillenia indica (30/m³), Syzygium jambos (27/m³), and Kleinhovia hospita (2/m³).     

Brassinosteroid‐mediated reactive oxygen species are essential for tapetum degradation and pollen fertility in tomato

Phytohormone brassinosteroids (BRs) are essential for plant growth and development, but the mechanisms of BR‐mediated pollen development remain largely unknown. In this study, we show that pollen viability, pollen germination and seed number decreased in the BR‐deficient mutant d^{^im}, which has a lesion in the BR biosynthetic gene DWARF (DWF), and in the bzr1 mutant, which is deficient in BR signaling regulator BRASSINAZOLE RESISTANT 1 (BZR1), compared with those in wild‐type plants, whereas plants overexpressing DWF or BZR1 exhibited the opposite effects. Loss or gain of function in the DWF or BZR1 genes altered the timing of reactive oxygen species (ROS) production and programmed cell death (PCD) in tapetal cells, resulting in delayed or premature tapetal degeneration, respectively. Further analysis revealed that BZR1 could directly bind to the promoter of RESPIRATORY BURST OXIDASE HOMOLOG 1 (RBOH1), and that RBOH1‐mediated ROS promote pollen and seed development by triggering PCD and tapetal cell degradation. In contrast, the suppression of RBOH1 compromised BR signaling‐mediated ROS production and pollen development. These findings provide strong evidence that BZR1‐dependent ROS production plays a critical role in the BR‐mediated regulation of tapetal cell degeneration and pollen development in Solanum lycopersicum (tomato) plants.     

Aerobiology of Artemisia airborne pollen in Murcia (SE Spain) and its relationship with weather variables: annual and intradiurnal variations for three different species. Wind vectors as a tool in determining pollen origin

Detailed results from a 2-year survey of airborne pollen concentrations of Artemisia in Murcia are presented. Three consecutive pollen seasons of Artemisia occurring each year, related to three different species (A. campestris, A. herba-alba and A. barrelieri), were observed. A winter blooming of Artemisia could explain the incidence of subsequent pollinosis in the Murcia area. With regard to meteorological parameters, mathematical analyses showed relationships between daily pollen concentrations of Artemisia in summer–autumn and precipitations that occurred 6–8 weeks before. The cumulative percentage of insolation from 1 March seemed to be related to blooming onsets. Once pollination has begun, meteorological factors do not seem to influence pollen concentrations significantly. Intradiurnal patterns of pollen concentrations were similar for late summer and winter species (A. campestris and A. barrelieri). During autumn blooming (A. herba-alba), the intradiurnal pattern was particularly erratic. Theoretical values of wind run were obtained for each pollen season by the graphical sum of hourly wind vectors. When theoretical wind run was mapped onto the vegetation pattern, supposed pollen source locations were obtained for each hour. By comparing supposed hourly pollen origins with the intradiurnal patterns of pollen concentrations, it can be seen that this simple model explains variations in mean pollen concentrations throughout the day. Received: 6 May 1998 / Revised: 24 February 1999 / Accepted: 12 March 1999     

Variability in glacial and Holocene marine pollen records offshore from west southern Africa

The distribution of pollen in marine sediments is used to record vegetation changes over the past 30,000 years on the adjacent continent. A transect of marine pollen sequences from the mouth of the river Congo (∼5°S) to Walvis Bay and Lüderitz (∼25°S) shows vegetation changes in Congo, Angola and Namibia from the last glacial period into the Holocene. The comparison of pollen records from different latitudes provides information about the latitudinal shift of open forest and savannahs (Poaceae pollen), the extension of lowland forest (rain forest pollen) and Afromontane forest (Podocarpus pollen), and the position of the desert fringe (pollen of Caryophyllaceae, Chenopodiaceae and Amaranthaceae). High Cyperaceae pollen percentages in sediments from the last glacial period off the mouth of the river Congo suggest the presence of open swamps rather than savannah vegetation in the Congo Basin. Pollen from Restionaceae in combination with Stoebe-type pollen (probably from Elytropappus) indicates a possible northwards extension of winter rain vegetation during the last glacial period. The record of Rhizophora (mangrove) pollen is linked to erosion of the continental shelf and sea-level rise. Pollen influx is highest off river mouths (10–2000 grains year⁻¹ cm⁻²), close to the coast (300–6000 grains year⁻¹ cm⁻²), but is an order of magnitude lower at sites situated far from the continent (<10 grains year⁻¹ cm⁻²).     

The fossil pollen record of Araceae

The fossil record of Araceae pollen beginning in the late Early Cretaceous and peaking in the Paleocene/Eocene is very sparse up to now, consisting of three highly distinctive types: zona-aperturate pollen of the Monstera or Gonatopus type (very similar to Proxapertites operculatus), an ulcerate-spiny type typical for Limnobiophyllum, and a polyplicate, omniaperturate pollen type (an ephedroid pollen with non-gnetalean affinities) which was recently reported from the late Early Cretaceous (Mayoa portugallica). An extensive literature search has shown that some distinctive Ephedripites forms (the Paleogene Ephedripites vanegensis, and the Late Cretaceous Ephedripites elsikii) are very similar to pollen of Spathiphyllum and both species are here transferred from Ephedripites to Spathiphyllum (as comb. nov.). We also add new fossil findings to the Araceae record. The new findings include a zona-aperturate, microperforate to microreticulate pollen type from the Palaeocene of Colombia, highly similar to extant Gonatopus or Zamioculcas or Monstera pollen (Araceae) and to fossil Proxapertites operculatus, which is currently seen as a fossil equivalent; and, an ulcerate, spiny pollen from the Eocene of Stolzenbach, Germany, extending the range of Limnobiophyllum (Pandaniidites), which is thought to be an extinct member of extant Araceae. The three pollen types add considerably to the reliable fossil record of the family that now contains more than 20 records of these three pollen types: with the zona-aperturate type recorded from the tropical or subtropical regions of Northern and Southern America, Central Africa, Southern and Central Europe, from the Indian subcontinent and the Malayan Archipelago; the ulcerate type occurring in North America and Europe; and the polyplicate type mainly occurring in South America and South-West Europe. Now we have good evidence that some of the aroid subfamilies were already in existence in the Cretaceous, increasing in diversity and worldwide distribution in the Paleogene. Dedicated to Prof. Dr. Stefan Vogel on the occasion of his 80th birthday.     

Carbon and nutrients of indigestible pollen are transferred to zooplankton by chytrid fungi

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Palynological evaluation of selected honeys from Romania

Fifty-four honey samples collected over two consecutive harvest seasons (2009–2010) from different floristic areas of Romania were analysed. A melissopalynological analysis including qualitative and quantitative analyses was carried out in order to identify the principal pollen types in Romanian honeys and therefore, the important plants exploited by Apis mellifera in this country. Seventy-seven pollen types from 35 botanical families were identified. The main pollen forms were: Brassica napus-type, Tilia, Helianthus annuus, Robinia pseudoacacia, Prunus, Castanea sativa, Fragaria-type and Plantago-type. Honey samples were classified as: acacia honey (Robinia pseudoacacia), lime honey (Tilia), rape honey (Brassica napus-type), sunflower honey (Helianthus annuus), cherry honey (Prunus). Three of them were honeydew honeys whereas the others were all polyfloral. The results from this study can be used as a palynological baseline data of Romanian artisanal honeys.     

New insights into the pollen morphology of the genus Gunnera (Gunneraceae)

Pollen grains from ten species of Gunnera, chosen to represent the six different subgenera in the genus, were examined using light and scanning electron microscopy. The aim of the study was to explore characters that have the potential to define different types of pollen within Gunnera and to study the evolution of these characters in light of the phylogeny of the genus. According to our results, there are three main types of pollen in the examined species of Gunnera. Type 1, unique for the South American species G. herteri (subgenus Ostenigunnera), is characterised by an imperfect reticulum with sinuous undulating-creasted muri. A reticulum with equidimensional polygonal lumina is typical for the plesiomorphic type of pollen (type 2) present in subgenera Gunnera, Misandra and Panke. Lastly, pollen grains of subgenera Pseudogunnera and Milligania are characterised by a reticulum with lumina of variable shape and size (type 3). In G. macrophylla (subgenus Pseudogunnera), the lumina in the apocolpia are of a different shape and size from the lumina in the mesocolpia (type 3a), while in G. dentata, G. monoica and G. cordifolia (subgenus Milligania), the lumina are identical in the apocolpium and the mesocolpium (type 3b).

The identification of pollen types will possibly allow the interpretation of the different specimens of Tricolpites reticulatus, the fossil species believed to be allied to the extant Gunnera.

In addition to the revision on the pollen of Gunnera, a brief comparison between the pollen of this genus and its sister group Myrothamnus is reported.     

<Emphasis Type="Italic">Arabidopsis</Emphasis> AtVPS15 is essential for pollen development and germination through modulating phosphatidylinositol 3-phosphate formation

Arabidopsis thaliana phosphatidylinositol 3-kinase (AtVPS34) functions in the development and germination of pollen by catalyzing the biosynthesis of phosphatidylinositol 3-phosphate (PI3P). In yeast, Vps15p is required for the membrane targeting and activity of Vps34. The expression of Arabidopsis thaliana VPS15 (AtVPS15), an ortholog of yeast Vps15, is mainly detected in pollen grains and pollen tubes. To determine its role in pollen development and pollen tube growth, we attempted to isolate the T-DNA insertion mutants of AtVPS15; however, homozygous lines of atvps15 were not obtained from the progeny of atvps15/+ heterozygotes. Genetic analysis revealed that the abnormal segregation is due to the failure of transmission of the atvps15 allele through pollen. Most pollen grains from the atvps15/+ genotype are viable, with normal exine structure and nuclei, but some mature pollen grains are characterized with unusual large vacuoles that are not observed in pollen grains from the wild AtVPS15 genotype. The germination ratio of pollen from the atvps15/+ genotype is about half when compared to that from the wild AtVPS15 genotype. When supplied with PI3P, in vitro pollen germination of the atvps15/+ genotype is greatly improved. Presumably, AtVPS15 functions in pollen development and germination by regulating PI3P biosynthesis in Arabidopsis.     

<Emphasis Type="Italic">Hieracium</Emphasis> subgen. <Emphasis Type="Italic">Pilosella</Emphasis>: pollen stainability in sexual,apomictic and sterile plants

Two pollen stainability tests (Alexander’s stain and acetocarmine) were used to detect differences in pollen viability of the sexual, apomictic and sterile plants of Hieracium subgen. Pilosella. In sexual taxa (Hieracium bauhini and H. densiflorum), the average stainability was 93.7–98.4%. Similarly high stainability (92.2–97.2%) was found in the apomictic Hieracium pilosellinum and in the majority of the apomictic populations (or plants) of the pentaploid and hexaploid H. bauhini. In some apomictic plants of Hieracium bauhini the average pollen stainability was 49.0–75.4%. The lowest pollen stainability was found in the sterile plants, i.e. the triploid H. pistoriense (33.6%) and the pentaploid H. brachiatum (29.6%).     

Spring airborne pollen data in two sites in Trentino (Northern Italy): a comparison with meteorological data

In this paper airborne pollen concentration is compared to meteorological data of Trento and S. Michele all’Adige, two sites in the Adige Valley, in Trentino (North Italy). Pollen ofCorylus, Alnus, Betula andOstrya, four winter-spring flowering plants are considered. Pollen sampling was carried out in 1996 by volumetric Hirst-type samplers. For all pollen types considered, maximum pollen concentration coincided in both stations and there was a good overlap of the main pollen season length; the pollen curves of S. Michele a/A and Trento showed a highly positive correlation. The daily airborne pollen concentrations, defined as the number of pollen grains per cubic meter of air (P/m³), were compared to daily meteorological data: minimum and maximum air temperature (°C), average relative humidity (%), precipitation (mm), global incident radiation (cal/cm²), average wind direction (°) and wind speed (m/s). A highly positive correlation was found forCorylus and maximum temperature in both monitoring stations.Betula was positively, whereasOstrya was negatively correlated to relative humidity. With this first analytical approach sharp differences in the atmospheric pollen presence between the stations located at Trento and S. Michele all’Adige were not found.     

Stamen movements in flowers ofOpuntia (Cactaceae) favour oligolectic pollinators

Opuntia brunneogemmia andO. viridirubra occur sympatrically in the Serra do Sudeste, Rio Grande do Sul, Brazil. Their flowers have 450–600 thigmonastic stamens and provide large amounts of pollen and nectar for bees. Bees of 41 species were registered at the flowers ofO. brunneogemmia and 30 at the flowers ofO. viridirubra. Females of three oligolectic species are the only effective pollinators:Ptilothrix fructifera (Anthophoridae),Lithurgus rufiventris (Megachilidae), andCephalocolletes rugata (Colletidae). During their visits inOpuntia-flowers, bees touch the filaments and stimulate the movement of the stamens to the centre of the flower. At the end of this movement, the anthers are densely packed around the style. As a consequence the pollen is presented in an easily accessible upper layer of anthers and various, nearly inaccessible lower layers. The lower layers contain about 80% of the pollen reward. Only females of the three oligolectic pollinators exploit the pollen from the lower layers and reach the nectar furrow. Therefore, through their stamen movements,Opuntia flowers hide most of their pollen from flower visitors but favour effectively pollinating, oligolectic bees.     

Beiträge zur Pollenmorphologie und Systematik der Convolvulaceen-Gattungen Maripa und Mouroucoa

Suggested by a previous communication on the occurence of two types of apertures among the pollen grains of Maripa s. l. (Convolvulaceae), 16 species of this genus were investigated palynologically. 3-zonocolpare grains mixed with 4–6-pantocolpate and 6–15-pantocolpate grains were found. The structure of the exine (infratectale bacula with or without supratectale processes) reveals further differences. The combination of these characters in the genus Maripa offers the separation into four types of pollen grains. The genus Mouroucoa is represented by its own type. These facts stress the necessity of the generical separation of the two genera. Consideration of pollen morphology yields some new aspects for subdivision of the genus Maripa.     

Isolation and Characterization of an Anther-Specific Polygalacturonase Gene, BcMF16, in Brassica campestris ssp. chinensis

Many genes in the genic male sterile A/B line (Bajh97-01A/B) of Chinese cabbage pak choi (Brassica campestris L. subsp. chinensis Makino) are expressed differentially, and some play critical roles in the formation of pollen walls. In this study, one of these genes, Brassica campestris Male Fertility 16 (BcMF16), has been isolated and characterized. The BcMF16 gene shares approximately 85% nucleotide sequence homology with two exopolygalacturonase (EC3.2.1.67) genes of Arabidopsis thaliana. Cluster analysis of polygalacturonase peptides indicate that BcMF16 belongs to the pollen polygalacturonase clade. Quantitative real-time PCR analysis has revealed that BcMF16 is specifically expressed in reproductive tissues of the fertile line of genic male sterile A/B line of Chinese cabbage pak choi, and that expression levels dramatically increased during later stages of pollen development. In situ hybridization has demonstrated that BcMF16 is specifically and transiently expressed in both tapetum and pollen following microspore separation at the tetrad stage.     

Gametes with somatic chromosome number and their significance in interspecific hybridization in Fuchsia

Sexual polyploidization has both a theoretical as well as an applied significance. Morphological screening for large pollen grains and shape of pollen produced by the individual, cytological investigation of hybrid progeny, and unbalanced separation of chromosomes at anaphase I in pollen mother cells were used to detect the gametes with somatic chromosome number in Fuchsia. The interspecific hybrids of F. fulgens (sect. Ellobium) × F. magellanica (sect. Quelusia), F. fulgens (sect. Ellobium) × F. splendens (sect. Ellobium), and F. triphylla (sect. Fuchsia) × F. splendens (sect. Ellobium) produced at the University of Auckland, New Zealand, showed both large and normal pollen grains in the same anther indicating the presence of unreduced gametes. Cytological investigation carried out on the hybrid progeny of F. fulgens (diploid, 2n=22, sect. Ellobium) × F. magellanica (tetraploid, 2n=44, sect. Quelusia) and F. triphylla (diploid, sect. Fuchsia) × F. arborescens (diploid, sect. Schufia) revealed unexpected chromosome numbers of 2n=44 and 2n=33, respectively. In general, the hybrids showed low fertility caused by genetically unbalanced gametes resulted from random disjunction of chromosomes at anaphase I. Studies on meiosis together with the presence of different shapes and sizes of pollen grains in Fuchsia proved indirectly that unreduced gametes are the products of first division meiotic nuclear restitution. These unreduced gametes were viable irrespective of pollen shape, their predominance in the hybrids, nuclear DNA amount and species phylogenetic position.     

Pollen morphology in Cytisus (Papilionoideae,Leguminosae) from Morocco and the Iberian Peninsula

Although it is generally accepted that the tribe Genisteae has rather homogeneous pollen, we have found considerable variation in pollen size and morphology in Cytisus and related genera (Argyrocytisus and Chamaecytisus), which match taxonomic groups defined on morphological grounds. The results of Principal Component Analysis of pollen characteristics show the following: Cytisus Sect. Alburnoides is well-delimited, with the smallest pollen grains and the simplest pattern in the tectum, fossulate-perforate to perforate; No separation of C. villosus (Sect. Cytisus) from Sect. Alburnoides is observed; Cytisus Sect. Spartopsis, with the largest pollen grains and reticulate to reticulate-fossulate ornamentation, forms an isolated group; C. fontanesii (Sect. Heterocytisus) stands apart from other Cytisus species by its homogeneous ornamentation and the perforate instead of psilate-punctate margo. Thus, the pollen data supports its transfer to the separated genus Chronanthos; Pollen ornamentation and morphology also support the separation of Argyrocytisus battandieri and Chamaecytisus mollis from Cytisus.