Aleksej Tarasjev

Fluctuating asymmetry in Robinia pseudoacacia leaves—possible in situ biomarker?

In this study, we analyzed fluctuating asymmetry (FA) of black locust (Robinia pseudoacacia) leaf traits as a measure of developmental instability in polluted and unpolluted habitats. We aimed to evaluate the potential of this method as a biomarker and its applicability on widely distributed species under in situ conditions. Leaf samples were taken from seven sites—three categorized as unpolluted (natural protected and rural) and four categorized as polluted covering the broad spectrum of intense pollution (industrial and traffic), from 1,489 individual trees in total. Results revealed significant differences in FA with expected higher values in polluted environments. Applicability of FA of R. pseudoaccacia leaf traits as a biomarker for testing potential pollution level, as well as the amount and distribution of sampling effort needed for its application, are discussed.

Phenotypic plasticity and between population differentiation in Iris pumila transplants between native open and anthropogenic shade habitats.

Response to environmental heterogeneity caused by human activity was analyzed on Iris pumila reciprocal transplants between native steppe and anthropogenic (planted pine forest) habitats that were monitored during several growing seasons in a protected area of Deliblato Sand. Morphometric traits exhibited significant plastic responses to the environmental variability between native and anthropogenic habitats that differed in light quantity and quality, as well as in some other ecological indices. Significant differentiation between populations occupying those habitats was also detected. Plastic responses and population differences were substantially related to the variation in general size and had the same direction, plastic responses being larger in magnitude. Estimates of reproductive and vegetative performance of reciprocal transplants detected home site advantage in the native open but not in the secondary shade habitat created under anthropogenic influence.

Spatial autocorrelation in two Iris pumila populations estimated on morphological data from natural clones and their samples grown in two different habitats

Morphological data from two Iris pumila populations (measured on native clones, on their replants into the same habitat, and on their transplants into alternative habitat) were combined with native clones spatial position and spatial autocorrelations (SA) were calculated. Naturally growing I. pumila clones revealed significant SA that were positive on small distances and negative on medium ones in both open Hillock and shaded Woodland populations. No significant SA were detected when calculated with original clone positions, but with morphometric data from replants into the experimental plot in the same habitat. Some significant SA were, however, detected when morphometric data from transplants to alternative habitat were used. Detected SA on I. pumila clones were primarily a consequence of spatial structuring of environmental factors but also, in a lesser degree, a result of genetic spatial arrangements (most probably due to patterns of gene flow).

Ontogeny of flower parts on naturally growing Iris pumila clones: Implications for population differentiation and phenotypic plasticity studies

Previous studies revealed significant phenotypic plasticity, genetic variability and population differentiation of flower morphometric traits on dwarf bearded iris Iris pumila. Also, study of I. pumila flowering phenology revealed significant impact of habitat type as well as population differentiation for flowering time. Since the flowering time can influence other flower traits, we performed this analysis of flower morphometric traits in three time points during the flower bud ontogenic development in two habitat types (open vs. shaded). Analysis revealed that for most of the traits greater trait values were recorded for open habitat but only on latter time points. For most of the analyzed traits direction of differences in bud stage was the opposite to the direction of differences in mature flower stage detected in previous studies. However, length of the stem, a trait that showed the greatest variability between habitats and populations and therefore greatest genetic differentiation and phenotypic plasticity, was significantly greater in the samples from the late flowering shaded habitat in all time samples, indicating that in case of this trait different mechanisms were involved. Those findings have implications for design of the future studies on I. pumila.

Ontogenetic plasticity of anatomical and ecophysiological traits and their correlations in Iris pumila plants grown in contrasting light conditions

To better understand what directs and limits the evolution of phenotype, constraints in the realization of the optimal phenotype need to be addressed. That includes estimations of variability of adaptively important traits as well as their correlation structures, but also evaluation of how they are affected by relevant environmental conditions and development phases. The aims of this study were to analyze phenotypic plasticity, genetic variability and correlation structures of important Iris pumila leaf traits in different light environments and ontogenetic phases, and estimate its evolutionary potential. Stomatal density, specific leaf area, total chlorophyll concentration and chlorophyll a/b ratio were analyzed on I. pumila full‐sib families in the seedling phase and on the same plants after 3 years of growth in contrasting light conditions typical for ontogenetic stage in question. There was a significant phenotypic plasticity in both ontogenetic stages, but significant genetic variability was detected only for chlorophyll concentrations. Correlations of the same trait between different stages were weak due to changes in environmental conditions and difference in ontogenetic reaction norms of different genotypes. Ontogenetic variability of correlation structures was detected, where correlations and integration were higher in seedlings compared with adult plants 3 years later. Correlations were affected by environmental conditions, with integration being higher in the lower light conditions, but correlations between phases being stronger in the higher light treatment. These findings demonstrated that the analyzed traits can be selected and can mostly evolve independently in different environments and ontogenetic stages, with low genetic variability as a potentially main constraint.

Genetic differences between populations and habitats in Lamium purpureum plastic response to conspecific density.

Plants from Open and Shade habitats in two natural populations (Vršac and Avala) were grown in two densities (High and Low). As expected, density had significant effect on most of measured traits and that effect was concordant with Shade avoidance syndrome predictions. Genetic differences between populations both in mean trait values and in plastic responses to density were also detected. Number of leaves and flowers showed plasticity in Avala population only, while shoot weight was plastic in both populations but with greater plasticity in Avala population. Differences between habitats for plant height and number of internodes were present in Vršac population only. Habitat difference in response to density was revealed for seed weight and it was due to lack of response in plants originated from Shade habitat in Vršac population. This study showed that not only populations, but also subpopulations occupying different habitats can differ genetically in their plastic response to density, and that between-habitat differences can be population-specific.