Comparison of Alnus,Corylus, Betula pollen seasons in Riga,Moscow and Vilnius

Research characterizes differences and similarities of the seasonal behaviour of Alnus, Betula, Corylus pollen in Riga, Moscow and Vilnius. An important uniting factor dealing with the research is that on the selected territories in spring there are abundance of Alnus, Corylus and Betula airborne pollen. The study is based on the 2004–2011 atmospheric pollen records. Differences and similarities of the analysed territories include the following: (1) the beginning of the Alnus and Corylus pollen season usually coincided in Riga and Vilnius, whereas significantly differed between Riga and Moscow; (2) no significant differences among separate stations have been estimated concerning the beginning of the Betula pollen season; (3) Moscow differed by the shortest period of pollen season, independently of the pollen type; (4) the biennial cycle of Betula pollen is characteristic to Riga only; (5) in the spectrum of spring plants’ pollen, Corylus pollen was found in the least amount (10–23 pgm^?3 per day on the average); (6) average concentration of Betula pollen per day significantly differed in all locations of the survey, in Moscow, the concentration (853 pgm^?3) was twice higher that in Riga and Vilnius; (7) Alnus, Corylus and Betula pollen seasons overlap each other in all locations surveyed, thus creating additional load of pollen; (8) in each of the stations, there were 13–15 days when concentration of Betula pollen exceeded 100 pgm^?3.     

Spatiotemporal models for predicting high pollen concentration level of Corylus,Alnus, and Betula

Corylus, Alnus, and Betula trees are among the most important sources of allergic pollen in the temperate zone of the Northern Hemisphere and have a large impact on the quality of life and productivity of allergy sufferers. Therefore, it is important to predict high pollen concentrations, both in time and space. The aim of this study was to create and evaluate spatiotemporal models for predicting high Corylus, Alnus, and Betula pollen concentration levels, based on gridded meteorological data. Aerobiological monitoring was carried out in 11 cities in Poland and gathered, depending on the site, between 2 and 16 years of measurements. According to the first allergy symptoms during exposure, a high pollen count level was established for each taxon. An optimizing probability threshold technique was used for mitigation of the problem of imbalance in the pollen concentration levels. For each taxon, the model was built using a random forest method. The study revealed the possibility of moderately reliable prediction of Corylus and highly reliable prediction of Alnus and Betula high pollen concentration levels, using preprocessed gridded meteorological data. Cumulative growing degree days and potential evaporation proved to be two of the most important predictor variables in the models. The final models predicted not only for single locations but also for continuous areas. Furthermore, the proposed modeling framework could be used to predict high pollen concentrations of Corylus, Alnus, Betula, and other taxa, and in other countries.     

Purification of maize pollen exines and analysis of associated proteins

Zea mays (maize) pollen exines have been purified with the use of differential centrifugation and sucrose gradients, followed by mild detergent and high salt treatment. The final exine fraction is highly purified from other organelles and subcellular structures as assayed by transmission electron microscopy. Using mature maize pollen as the starting material, 0.2 to 0.3% of the total pollen protein remained associated with the exine fraction throughout the purification. Seven abundant sodium dodecyl sulfate-extractable proteins are detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the final fraction. Amino acid analysis reveals that one of the proteins contains a substantial amount of hydroxyproline, a characteristic of some primary cell wall proteins. The amino acid composition of the 25-kD protein strongly implies that it is an arabinogalactan protein. When exines are purified from earlier pollen developmental stages, a subset of the proteins found in the mature pollen exine is seen.     

Substructure in exines of Artemisia vulgaris (Asteraceae)

Of the Silurian and Devonian macroplant genera described in the literature, about half have been recorded with spores. These in situ spores can be compared at generic level with only about a quarter of the dispersed spore genera described for the same period. Emphasis is here placed on the structure and sculpture of in situ and dispersed Silurian, Gedinnian and Siegenian spores, where records of macroplants with in situ spores are high compared with the Middle and Upper Devonian.A comparative study of the structure and sculpture of the in situ and dispersed spores, together with information from the macroplants recorded, suggests a fairly simple Silurian and Gedinnian flora, with the evolution of a more advanced upland flora during Siegenian times.     

N2 fixation and cycling in Alnus glutinosa, Betula pendula and Fagus sylvatica woodland exposed to free air CO2 enrichment

We measured the effect of elevated atmospheric CO(2) on atmospheric nitrogen (N(2)) fixation in the tree species Alnus glutinosa growing in monoculture or in mixture with the non-N(2)-fixing tree species Betula pendula and Fagus sylvatica. We addressed the hypotheses that (1) N(2) fixation in A. glutinosa will increase in response to increased atmospheric CO(2) concentrations, when growing in monoculture, (2) the impact of elevated CO(2) on N(2) fixation in A. glutinosa is the same in mixture and in monoculture and (3) the impacts of elevated CO(2) on N cycling will be evident by a decrease in leaf δ(15)N and by the soil-leaf enrichment factor (EF), and that these impacts will not differ between mixed and single species stands. Trees were grown in a forest plantation on former agricultural fields for four growing seasons, after which the trees were on average 3.8 m tall and canopy closure had occurred. Atmospheric CO(2) concentrations were maintained at either ambient or elevated (by 200 ppm) concentrations using a free-air CO(2) enrichment (FACE) system. Leaf δ(15)N was measured and used to estimate the amount (N(dfa)) and proportion (%N(dfa)) of N derived from atmospheric fixation. On average, 62% of the N in A. glutinosa leaves was from fixation. The %N(dfa) and N(dfa) for A. glutinosa trees in monoculture did not increase under elevated CO(2), despite higher growth rates. However, N(2) fixation did increase for trees growing in mixture, despite the absence of significant growth stimulation. There was evidence that fixed N(2) was transferred from A. glutinosa to F. sylvatica and B. pendula, but no evidence that this affected their CO(2) response. The results of this study show that N(2) fixation in A. glutinosa may be higher in a future elevated CO(2) world, but that this effect will only occur where the trees are growing in mixed species stands.     

叶下珠科花粉组织化学、花粉数和胚珠数及其与传粉者关系的研究

植物花粉中营养物质的储存形式以及单花的花粉数与胚珠数被认为与其传粉系统有一定的联系。本文研究了叶下珠科部分种类的花粉组织化学、花粉数和胚珠数, 以及它们与传粉者之间的关系。结果显示: 在叶下珠科内, 植物花粉所含营养成分和传粉者之间存在相关性: 蛾类传粉的类群主要属“淀粉型”花粉, 蝇类和蜂类传粉的类群主要属“非淀粉型”花粉。蝇类传粉和蛾类传粉的植物花粉数没有一定规律。蝇类传粉的类群比蛾类传粉的类群胚珠数少, 这可能是由于蝇类携带花粉能力及传粉精确性均较小, 导致植物以减少胚珠数来适应的结果。对同一属内不同生活型植物的花粉数比较, 发现乔木的单花花粉数高于灌木, 灌木的单花花粉数明显高于草本。这可能是由于不同生活型的植株, 其花朵大小不同, 导致花粉数出现明显差别。另外, 通过扫描电子显微镜对花粉形态的观察, 发现蝇类传粉的类群和蛾类传粉的类群间的花粉表面纹饰存在显著差异。     

Fern spore and pollen airspora profile of Singapore

Monitoring atmospheric fern spore and pollen loads in Singapore was initiated in June 1990. Aside from the more numerous fungal spores, fern spores and pollen grains made up 6.2–8.6% and 4.4–5.4% of the total airspora sampled, respectively. The most frequently encountered fern spores, in descending order, were those of Nephrolepis auriculata, Dicranopteris linearis, Stenochlaena palustris, Asplenium nidus, Pteridium aquilinum, and Dicranopteris curranii. For pollen grains, the most frequently encountered, in descending order, were Elaeis guineensis, Casuarina equisetifolia, Acacia auriculiformis, Kyllingia polyphylla, Podocarpus, and Poaceae pollen grains. Seasonal patterns for individual fern spore or pollen types were discernible despite the relatively uniform tropical climate in Singapore. The fern spore and pollen calendar for the period 1991–1995 was compared to that of 2005–2006 as a follow-up study to keep abreast with the rapidly changing landscape of Singapore. Diurnal patterns showing a late morning to afternoon peak period were seen in fern spores, while the peak period was in the morning for pollen types studied with the exception to oil palm pollen. Additionally, association between fern spore and pollen counts and local meteorological conditions were also analyzed and found to be highly correlated. This study has thus identified the fern spores and pollen airspora components, and determined the calendars, as well as diurnal profiles of the Singapore airspora and provides invaluable information for allergy studies by highlighting the trigger sources present in the environment.     

Comparison of Glycolipids and Plastids in Callus Cells and Leaves of Alnus and Betula

The fine structure of plastids and fatty acid composition ofglycolipids (e.g. monogalactosyl diacylglycerides, MGDG; digalactosyldiacylglycerides, DGDG) in callus cells of Alnus glutinosa,A. incana and Betula pendula cultured in light was comparedwith that in intact leaves. The tissues were qualitatively verysimilar but a rather high amount oflignoceric acid (24:0) wascharacteristic for the callus of A. incana. This fatty acidwas found only in trace amount in other tissues. Linolenic (18:3)and palmitic (16:0) acids are the most abundant (25–65%and 17–27% respectively) fatty acids in all tissues studied.The proportion of 18:1 and 18:2 was much higher in the calluscompared with corresponding intact leaves, which are especiallyrich (48–65%) in 18:3. In callus cultures a higher proportion(17–19%) of linoleic acid (18:2) is found in both Alnusspecies than in the two callus strains of Betula (9–12%). All leaf and callus samples contained esterified steryl glycosidesand two cerebrosidelike spots in thin-layer chromatography,but they were more prominent in callus cultures than in leaves.The callus cells have plastids with rather well developed thylakoidswhich explains the similarity of the main glycolipid components(MGDG and DGDG) to that of leaves. (Received April 23, 1984; Accepted August 17, 1984)     

Relationships of pollen size,pistil length and pollen tube growth rates in Rhododendron and their influence on hybridization

Summary Pollen size and pistil length data have been collected for 93 species of Rhododendron (Ericaceae) belonging to a number of different subgeneric taxa. For a sample of eight species in section Vireya, pollen tube growth in the style after selfor interspecific pollination has been quantified. Pollen volume and the time taken for pollen tubes to reach the ovary were both related to pistil length. Pollen-tube growth rates were generally greater for species with longer pistils and larger pollen. Increasing temperature increased the rate of pollen-tube growth. There was no detectable effect of pollen tube density on tube growth rate in the style. After interspecific pollinations tube growth rates in foreign styles could be faster or slower than in self styles. A semisterile individual with two viable pollen grains per tetrad and a plant grafted as scion to a longer-styled stock both showed more rapid pollen-tube growth than expected on the basis of pistil size. Data collected for 26 species in section Vireya showed that where extreme disparity of pollen/pistil size causes failure of interspecific crosses, one or more bridging species with intermediate pollen/pistil size can generally be selected.     

Genetic transformation of 9 in vitro clones of Alnus and Betula by Agrobacterium tumefaciens

Crown gall tumorigenesis, integration and expression of T-DNA encoded genes from Agrobacterium tumefaciens were investigated in 9 clones of Alnus glutinosa, A. incana and Betula papyrifera. Tumor formation on in vitro shoots was frequent in all clones with strain Ach5 and present in 8 clones with strain C58. Tumors excised from shoots were selected for autotrophic growth in vitro and axenic cultures were established. Octopine or nopaline, respective of the strain type used for inoculation, was detected in tumorous cultures. Southern blot analyses demonstrated T-DNA integration by hybridization of DNA from tumors with tmr and nos gene probes. One clone of B. papyrifera produced tumors with a morphogenic character, unusual in calli of this species, generating viable shoots which did not synthesize opine.Abbreviations Cb Carbenicillin - Cf Cefotaxime - 2,4-D 2,4-Dichloro-phenoxyacetic acid     

One-Year pollen and spore calendars of Saudi Arabia Al-Khobar, Abha and Hofuf

Airborne Pollen grains and Spores of three different cities viz., Al-Khobar (1987–1988), Abha (1991–1992) and Hofuf (1992–1993) in Saudi Arabia were studied using Burkard Volumetric Seven-Day Spore Trap. The data were analyzed in relation to their allergenic capability and one-year pollen and spore calendars were designed to correlate the patients’ symptoms as well as for selection of appropriate allergen extracts for diagnosis and treatment of allergic diseases. Amongst pollen group, Amaranthus viridis, Plantago spp., Chenopodium album, Ricinus communis, Rumex vesicarius, Juniperus spp., Parkinsonia aculeata, Prosopis spp., and Phoenix dactylifera were some of the frequent types. Amongst the fungal spores group Cladosporium, Smuts spores, Colored basidiospores, Alternaria, Ulocladium and Drechslera were the dominant types.     

长白山毛赤杨和白桦-沼泽生态交错带群落生物量分布格局

采用样带网格、树干解析和经验模型方法,研究了长白山毛赤杨和白桦．沼泽交错群落生物量分布格局。揭示群落建群种生长过程、器官生物量分布、群落生物量水平分布和垂直分布规律性,结果表明,毛赤杨和白桦在生长过程及适宜生境方面存在差异．毛赤杨生长速度是白桦的2～3倍,随交错区环境梯度旱化。其生长呈减缓趋势,而白桦生长呈加快趋势,故白桦是耐水湿树种,毛赤杨是喜湿树种,毛赤杨和白桦个体营养器官生物量表现出相似的分布规律．两者营养器官生物量分布格局为树干1／2、树根1／4、树枝1／10、树皮1．5／20、树叶1／20,乔木层生物量占群落生物量的87％～90％、灌木层占7％～9％、草本层占2％～3％,群落生物量沿沼泽到森林交错区环境梯度呈显著线性递增趋势。     

Sugar composition of pollen grain and pollen tube cell walls

The sugar composition of pollen grain and pollen tube cell walls was studied for Camellia japonica, C. sasanqua, C. sinensis, Tulipa gesneriana and Lilium longiflorum. In all species, the main components of pollen grain walls were arabinose, galactose, glucose and uronic acid. On the other hand, the pollen tube walls consisted mostly of glucose. The pollen tube wall of C. japonica was fractionated into hemicellulose, α-cellulose and pectic substance fractions in yields of 61, 19 and 3 %, respectively. The hemicellulose fraction was composed essentially of glucose. The sugar composition of the pollen tube wall was not influenced by the nature of exogenously supplied sugars. Rapid growth of the pollen tube seemed to correlate with the synthesis of hemicellulosic glucan.     

Trends in pollen season characteristics of Alnus,Poaceae and Artemisia allergenic taxa in Bratislava,central Europe

Over the period 2002–2019, air temperature and precipitation significantly increased regionally for Bratislava, which could lead to phenological changes in some plant species. This study aimed to analyse the changes in the intensity, timing, and duration of pollen seasons of three allergological important plant taxa (Alnus, Poaceae, Artemisia) in the study area over 18 years. The pollen sampling was performed using a Hirst-type sampler. Mann–Kendall tau test was used to determine trends in pollen season characteristics, while Spearman’s correlation analysis was used to identify the relationships between the characteristics of pollen seasons and both air temperature and precipitation trends. The notable changes in the pollen-season-related features were observed for all analysed taxa. The Alnus pollen season now reaches the peak earlier and its intensity is rising in line with the summer-autumn temperature increasing trend, while unexpectedly intensity and duration of the Artemisia pollen season are declining in line with the increased precipitation and/or temperature trends. On the other hand, the intensity of the Poaceae pollen season is also declining, however, without statistically significant correlations with recorded increases in meteorological parameters considered. This phenomenon is probably related to both the reduction of the area of grasslands due to urbanization and the implementation of effective maintenance of urban green areas (e.g., timely mowing preventing the repeatedly flowering of grasses).

     

Incompatibility and pollen competition in Alnus glutinosa: Evidence from pollination experiments

Different types of incompatibility systems were found to operate simultaneously in alnus glutinosa in the course of numerous pollination experiments, including self-pollination and pollination with controlled pollen mixtures. Isozyme genetic markers were used to identify the pollen parent of each offspring from the mixed pollination experiments, thus allowing specification of the fertilization success of each pollen parent. In a first step, these results were compared with observations on in vitro pollen germination experiments. This comparison allows for exploration of the explanatory value of different germination media as models of germination conditions on stigmas. In most cases, the data suggest that the in vitro germination conditions resemble the fertilization conditions in vivo, at least in the sense that they favor the same pollen parents. By providing a generic and operable definition of the two basic types of incompatibility, eliminating (inability to fertilize ovules) and cryptic (resulting in lowered fertilization success of a pollen parent under competition), evidence was detected for the existence of both types of incompatibility in alnus glutinosa, where eliminating incompatibility occurred as self-incompatibility only. However, since this incompatibility seems to act primarily via pollen elimination, seed production is not likely to be negatively affected in natural populations, even for comparatively large amounts of self-pollination. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genotype-environment interactions in pollen competitive ability in an anemophilous tree,Betula pendula Roth

This study describes genotype-environment interactions in pollen competitive ability expressed as pollen-tube growth rate and seed-siring success in Betula pendula Roth. A factorial crossing design was applied using the same maternal and paternal clones in two different environmental conditions, in a B. pendula seed orchard established in a greenhouse and at an outdoor clone collection. Both single donor and two-donor pollinations were employed. Female inflorescences were collected after a fixed time of germination, pollen-tube lengths were measured for each cross, and paternity of the seeds sired by two-donor pollen mixtures was analyzed using isozyme markers. The pollination site had a significant influence on pollen-tube growth rate and seed-siring success. Significant interactions between pollination site and pollen donor indicated genotype-environment interactions in pollen-tube growth rate and seed-siring success. A highly significant positive correlation between pollen-tube growth rate and seed-siring success was found in the greenhouse but not at the outdoor clone collection. These results suggest that the pollen-tube growth rate can be a predictor of seed-siring success in controlled greenhouse conditions, where differences among maternal plants are mainly of genetic origin, but not in more heterogeneous outdoor conditions. In natural birch stands, environmental maternal effects probably diminish the significance of pollen competition for sexual selection in Betula pendula. At seed orchards, the effects of environmental conditions on pollen competitive ability can have important consequences for the genetic composition of the seed crop.     

Microsatellite analysis of pollen flow in Rhododendron metternichii var. hondoense

Microsatellite analysis was used to characterize the patterns of pollen flow in a 150 m × 70 m quadrat containing 18 flowering trees of Rhododendron metternichii Sieb. et Zucc. var. hondoense Nakai. Using six microsatellite genetic markers and exclusion analysis, we determined the paternal trees of 216 seedlings germinated from five fruits produced by four adults. Each fruit was pollinated by a small number of largely adjacent trees, but 20–30% of pollen came from outside the quadrat. Adult trees that produced many flowers had a high self-pollination rate. A directional flow of pollen from late-blooming trees to early ones was observed.