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Masting, the highly variable production of synchronized large seed crops, is a common reproductive strategy in plant populations. In wind-pollinated trees, flowering and pollination dynamics are hypothesized to provide the mechanistic link for the well-known relationship between weather and population-level seed production. Several hypotheses make predictions about the effect of weather on annual pollination success. The pollen coupling hypothesis predicts that weather and plant resources drive the flowering effort of trees, which directly translates into the size of seed crops through efficient pollination. In contrast, the pollination Moran effect hypothesis predicts that weather affects pollination efficiency, leading to occasional bumper crops. Furthermore, the recently formulated phenology synchrony hypothesis predicts that Moran effects can arise because of weather effects on flowering synchrony, which, in turn, drives pollination efficiency. We investigated the relationship between weather, airborne pollen, and seed production in common European trees, two oak species (Quercus petraea and Q. robur) and beech (Fagus sylvatica) with a 19-yr data set from three sites in Poland. Our results show that warm summers preceding flowering correlated with high pollen abundance and warm springs resulted in short pollen seasons (i.e., high flowering synchrony) for all three species. Pollen abundance was the best predictor for seed crops in beech, as predicted under pollen coupling. In oaks, short pollen seasons, rather than pollen abundance, correlated with large seed crops, providing support for the pollination Moran effect and phenology synchrony hypotheses. Fundamentally different mechanisms may therefore drive masting in species of the family Fagacae., (© 2017 by the Ecological Society of America.)

The global rise in air temperature has major implications for ecosystems, populations, ecology of many living organisms, public health as well as economy. Plants, like silver birch (Betula pendula Roth.), strongly respond to the climatic variation. Therefore, the species is a good indicator of the global climate change, especially warming. The phenological observation was undertaken to verify the hypothesis on an acceleration of the start of Betula pendula pollen release in the season. The investigations were carried out in 2000-2015 (16 years) in the Rzeszow area, SE Poland. On average, Betula pendula started to pollinate in the middle of April; the difference between the earliest and latest dates was nearly 1 month. The full pollination started on 18 April, on average. The timing of pollination strongly depended on the course of weather in February and March. The most crucial was temperature in the first half of March. Considering the synergistic impact of meteorological parameters, the most important were temperature and rainfall in January and February, rainfall in March and temperature just before the pollination. It was found that North Atlantic Circulation influenced pollen release in Betula pendula. The positive North Atlantic Oscillation in March and in December-March periods resulted in pollination onset. Tendency towards warmer average annual temperature was recorded, however the timing of phenophases did not follow it. Despite the strong relationship with temperature there was no acceleration of Betula pendula pollination. Probably, the climate warming effect on the onset and duration in Betula pendula phenophases would be detectable in longer than a 16-year period. [ABSTRACT FROM AUTHOR]

Despite the continuous and intensive development of laboratory techniques, a light microscope is still the most common tool used in pollen grains differentiation. However, microscopy is time-consuming and needs well-educated and experienced researchers. Other currently used techniques can be categorised as images and non-images analysis, but each has certain limitations. We propose a new approach to differentiate pollen grains using the Imaging Flow Cytometry (IFC) technique. It allows for high-throughput fluorescence data recording, which, in contrast to the standard FC, also enables real-time control of the results thanks to the possibility of digital image recording of cells flowing through the measuring capillary. The developed method allows us to determine the characteristics of the pollen grains population based on the obtained fluorescence data, using various combinations of parameters available in the IDEAS software, which can be analysed on different fluorescence channels. On this basis, we distinguished pollen grains both between and within different genera belonging to the Betulaceae, Oleaceae, Urticaceae and Asteraceae families. Thereby, we prove that the proposed methodology is sufficient for accurate, fast, and cost-effective identification and potentially can be used in the routine analysis of allergenic pollen grains. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the pollen-vegetation relationship for Pinus and Picea. Pollen deposition was monitored using Tauber traps in the Roztocze region of Poland. The pine and spruce pollen sums obtained were compared with annual sums recorded in volumetric samplers in the cities of Lublin and Rzeszow. Average values of pollen deposition were compared to a detailed inventory of vegetation within a radius of 1 km of the monitoring sites. A more robust vegetation survey, conducted at a distance of 15 km, was used to estimate the proportion of pine and spruce pollen in regional pollen rain. The occurrence of high and low pollen deposition years was studied. Between 2001 and 2006, the data from Lublin and Roztocze produced similar trends in the high or low Pinus pollen sums. The representation of pine in the pollen spectra was very high, due to both its abundance in the regional vegetation and the prevalence of long-distance transport of pine pollen. Comparison of pollen and vegetation data indicates that, in the case of spruce, the distance from the monitoring site and forest structure are the most important factors influencing pollen representation. The problems associated with estimating pollen productivity of both pine and spruce in relation to Poaceae is discussed. [ABSTRACT FROM AUTHOR]