Olga Volkova

Structural basis of harmomegathy: evidence from Boraginaceae pollen

Upon release from the anther, pollen grains can be exposed to dry environment and dehydrate. To survive in dry conditions, the pollen wall possesses the ability to fold itself due to water loss-harmomegathic mechanism. Apertures seem to function as the primary elements of harmomegathy as they are more elastic than the remainder of the pollen wall. Contribution of other sporoderm structures, surface features, and pseudocolpi in harmomegathy are usually not considered in palynological studies. The nature of pseudocolpi has not been properly understood until now, partly because of common use of acetolysis method as a standard procedure. Different structures involved in the harmomegathy mechanism were studied in Cryptantha celosioides, Cryptantha coryi, Heliotropium europaeum, Myosotis palustris, Rindera bungei, and Rindera tetraspis. Scanning electron microscopy was used to study harmomegathy in hydrated and dehydrated pollen grains. In addition, transmission electron microscopy was used to elucidate the ultrastructural basis of pseudocolpi and other harmomegathic structures with special attention to intine structure. Our data reveal that additional flexibility of the pollen wall in Boraginaceae is provided by pseudocolpi, rugulate surface, tectate–columellate ultrastructure, and a transverse groove. Curious triangular polar poroid areas are described in M. palustris.

A 6500-year pollen record from the Polistovo-Lovatskaya Mire System (northwest European Russia). Vegetation dynamics and signs of human impact

Abstract New pollen and plant macrofossil evidence from the Polistovo-Lovatskaya Mire System is presented. The results show that local vegetation of the mire system was affected by various factors such as climate, hydrogeology and autochthonous processes in the peat bog. An important palaeoecological event took place around 6500 cal bp and led to a dramatic increase of paludification processes and lateral expansion of the mire. Forests of spruce and broad-leaved species in various combinations represented primary vegetation of uplands; they began to degrade around 1500 years ago and disappeared in historical times (400–500 cal bp). First signs of arable farming in the area occurred around 4200 cal bp, regular and mild human pressure established about 1000 years cal bp, and a significant impact at the regional level became evident around 400 years ago.

Variations and trends of Betula pollen seasons in Moscow (Russia) in relation to meteorological parameters

This study investigates possible links of meteorological data and the start date, end date, duration, date of peak, peak value and Seasonal Pollen Index (SPI) of birch pollen seasons recorded in Moscow, Russia, during 1993–2015. Pollen data were collected by a volumetric spore trap. Correlation analysis was used to study relationships between various parameters of pollen seasons. Simple linear regression analysis was conducted to investigate trends over time; multiple stepwise regression analysis was used to describe SPI fluctuations as a function of seasonal or monthly climatic parameters. Air temperatures increased significantly during the study period, but no effect on the timing of the birch pollen season was found. Only the severity of the season showed significant changes that can be considered as a consequence of global warming. Rainfall in May and June of the year preceding flowering, total rainfall in the 40-day pre-season period and average temperature during the pollination were shown to be the most important parameters affecting birch pollen concentrations.

Six years of observation of airborne and deposited pollen in central European Russia: first results

Abstract The aim of the study was to compare the pollen spectra recorded in rural and urban environments in order to examine whether pollen data obtained in the urban environment could also represent the situation in surrounding rural areas and how urban planting affects the regional pollen spectrum. Daily airborne pollen observations were performed with a volumetric Hirst type trap in Moscow (Russia). Modified Tauber traps were located in the Moscow region. The Tauber traps were installed and treated according to Pollen Monitoring Programme (PMP) guidelines. Spearman correlation coefficients were determined between the percentage of total pollen recorded in the Tauber and Hirst type samplers. The data showed that the Tauber spectra are characterised by higher taxonomic variability, mainly due to the greater occurrence of local herbaceous plants. Pollen types registered by Hirst type samplers were predominantly represented by anemophilous arboreal species, used in urban planting. A significant correlation for annual sums was only observed for Betula pollen, the most abundant component in both sampler types. Data obtained in big cities for dominant taxa can be extrapolated to the surrounding rural territories. The simultaneous use of volumetric and gravimetric samplers can be very useful for palaeo-ecological studies to evaluate the presence of local and transported pollen.

Spruce and broadleaved trees pollen percentages and PAR values in the European part of Russia: 9 years of pollen trap monitoring implemented to the fossil data

Abstract. 9-years results of modern pollen monitoring in the Central European Russia are presented. We discuss some implementations of modern pollen data to the interpretation of fossil distribution for Picea and broadleaved trees pollen.

Botany-collection.bio.msu.ru: Information system on plant morphology and anatomy

An open access information system (http://botany-collection.bio.msu.ru) consolidating digital data on palynological, carpological, and wood anatomy collections has been established at the Department of Higher Plants of the Faculty of Biology of Moscow State University. The database includes both digital images and short morphological descriptions of samples collected during the last 70 years. The system has a joint interactive catalogue of all samples included and allows a user to make a search by the names of species, genera, families, and life forms. In addition, each collection has a separate catalogue with various search parameters. The complete catalogues of all collections are also available in Excel file format.