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Puccinellia distans is a non-agricultural halophytic grass that has become another host plant for Epichloe typhina, hitherto not reported from Poland. In 1992 we noticed the first symptoms of choke disease in a single population of P. distans in central Poland. Since then we have observed choke disease in 5 populations of P. distans only in man-made habitats. These habitats are strongly anthropogenically salinated but they exhibit the pattern of species composition characteristic of natural salines. In this paper we test the hypothesis that the level of salinity affects the infection of P. distans by the fungus E. typhina. Seven plots were established in the field and each plot was divided into 25 subplots. Within each plot the level of infection in a spring generation of shoots was negatively correlated with salinity (common regression within the plots, beta = -0.674, df = 117, p < 0.001). Negative correlation was also found in an autumn generation within the plots (beta = -0.682, df = 94, p < 0.001) after excluding plot P in which the frequency of infected individuals was the lowest and equal only to 0.05. The proportion of individuals infected by the endophytic stage of the fungus in the populations was assessed using diagnostic polymerase chain reaction. The greatest percentage (98.3%) of infected individuals was found in the population growing in the habitat of the lowest salinity. The high salinity reduces the chance of P. distans to become infected, but may promote the stroma formation of E. typhina twice in the season. Disease expression in autumn clearly represents a misadaptation which could be explained by the fact that the species interactions described here appeared relatively recently as a result of human activity. This hypothesis requires further experimental verification.
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Long-lived clonal plants provide an optimal place for the natural storage of seeds as a ‘non-soil seed bank’. We tested the hypothesis that the size and species diversity of a non-soil seed bank deposited within the clonal plant Carex cespitosa depends mainly on the plant's size. To verify this hypothesis, an experiment was conducted on an unmown meadow in the Białowieża National Park. The emerging seedlings of different species originating from C. cespitosa tussocks of different size (large and small) were observed under greenhouse conditions for four years. The size of a non-soil seed bank was evaluated based on the number of seedlings. Significant differences in the seedling number were found between large and small sedge tussocks (Mann-Whitney test Z = 3.96, P < 0.001). However, the number of recorded species was independent of tussock size. Both types of tussocks were dominated by meadow, forest and swamp species (in decreasing order). Some of these species are no longer present in the studied area, or their occurrence is limited to small groups at the meadow's edges. A non-soil seed bank within the tussock cores of C. cespitosamay be, similar to a soil seed bank, a tool for studying the changes occurring in plant communities.
Genetic diversity and spatial variation of two populations of Filipendula ulmaria (L.) were analysed at the initial stage (macroforbs) and the late succession stage (forest community) during a 30-year succession on the abandoned meadows in Białowieża National Park. The study demonstrated a high level of genetic diversity in both populations (D = 0.86 and D = 0.79 in the population at the initial and late succession stage, respectively). Significant genetic differentiation was observed at the cross-population level (FST = 0.008, P <0.001). Among 303 ramets in the population at the initial stage 261 genotypes were detected, of which 24 were clonal, and the remaining (237) were unique (91%). In the population at the late succession stage 92 genotypes were detected among 116 ramets of which 10 were clonal, and 82 unique (89%). The results did not confirm a hypothesis that the low level of the population’s genetic diversity should be expected at the late succession stage. Additionally, the study demonstrates that the prolonged clonal spreading does not always result in genetic monotony of a population. It has been demonstrated that the high level of genetic diversity in the population of clonal species F. ulmaria could be the result of temporal changes in life history traits of long-lived genets. The formation of gaps caused by the disintegration of senile genets and the permanent recruitment of seedlings over 30 years of population development reinforce the appearance of new genets. This process was reflected in both populations by the domination of unique genets and spatial pattern of genotypic diversity.
Carex secalina, a species recognized as extinct in Poland for 40 years, was re-discovered in 2000 and it’s natural populations covered by monitoring. From among nine historic localities, only for two - Jacewo and Turzany, in the vicinity of Inowrocław - the occurrence of the species was confirmed. In the course of the field studies, six new localities, not previously recorded in literature, were discovered. The sedge occupies sub-halophytic habitats in which it occurs along with halophytic species (particularly, such as Glaux maritima and Pucinellia distans) and a group of ruderal taxons. One of the newly discovered localities of C. secalina comprises an anthropogenic habitat. On the whole, the population sizes ranged from 20 to 350 individuals. The studies revealed a positive correlation between the size of a population and cattle pasturing, i.e. C. secalina forms the largest populations in the habitats remaining under the intense pressure of grazing and treading. Moreover, it was found that the high generative reproduction rate compensates the damage caused by animal grazing. The results suggest that an active protection of the sedge populations through the agricultural use of its habitats is the only effective way of securing it’s further occurrence in Poland, while including the sub-halophytic pastures with C. secalina in the agricultural and environmental program should be a priority task in the nearest future.
Two closely related species of the genus Barbilophozia: B. lycopodioides and B. hatcheri were studied in populations from the Tatra Range (S Poland), where they are frequent and widely distributed. Both species play an important role in plant communities and grow here very often side by side. Typically developed plants are quite easy to distinguish (even in the field), however morphologically intermediate forms, difficult to recognize by using of classical taxonomic methods, sometimes are found. We found enzymatic markers, that allow to recognize the critical forms. Both studied species are different in enzymatic patterns of glutamate oxaloacetate transaminase (GOT) and peroxidases (PX). In GOT four different phenotypes were detected. The first two (GOT 1 and GOT 2) were characteristic for B. hatcheri and next two (GOT 3 and GOT 4) for B. lycopodioides. Peroxidase patterns, that were monomorphic and specific for each species, exhibit different mobility in anodal and cathodal parts of gel. Results of the studies allowed us to draw the conclusion, that PX and GOT are good isoenzymatic markers and they can have practical application for identification of Barbilophozia species.
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