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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.
In stressful and harsh environments, safe sites for seedling recruitment may be created by nurse plants, which accumulate propagules and subsequently facilitate the establishment of individuals. The main goal of the presented studies focused on observations of seedling recruitment in small and large tussocks of Deschampsia caespitosa derived from patches of unmanaged Molinietum caeruleae meadows situated along the successional gradient and dominated by small meadow species (Patch I), by macroforbs (Patch II), or overgrown by trees and shrubs (Patch III). The studies showed that, irrespective of patch character, Serratula tinctoria, Selinum carvifolia, Lysimachia vulgaris and Filipendula ulmaria are among the best colonizers of Deschampsia caespitosa tussocks. The gradual decrease in number of species and offspring abundance along the successional gradient may be connected with a prolonged period of water stagnation accelerating the development of fungal pathogens, a major cause of mortality for buried diaspores. The growing frequency of species present in standing vegetation and the gradually rising contribution of swamp and forest taxa in consecutive patches may be due to the production of non-persistent diaspores by early successional species, as well as reduced seed immigration from neighboring sites. The obtained results included evidence that, regardless of patch character, the percentage of seedlings representing species present in and absent from existing vegetation as well as taxa with various vegetation types is similar in small and large tussocks. Furthermore, in small tussocks, regardless of patch character, anemochorous and hydrochorous taxa dominated, the frequency of endo- and epizoochorous taxa was much lower, while the percentage of species characterized by other modes of diaspore dispersal attained the lowest rates. In large tussocks, anemochorous and epizoochorous species prevailed, the share of endozoochorous and hydrochorous taxa was lower, and the contribution of species characterized by other modes of dissemination was very scarce. On the basis of these studies it might be concluded that, despite the successive decrease of species and seedling abundance, and along with the increase in the recruitment of taxa resident in standing vegetation, especially woody species, the tussocks of Deschampsia caespitosa are reservoirs of meadow species even in advanced successional stages and may play a significant role in the process of long-term species turnover.
Seventy four ecotypes of the tufted hairgrass (Deschampsia caespitosa (L.) P. Beauv., collected from different regions of Poland were tested in 2001-2003 in a field experiment. Each ecotype was represented by twenty plants, planted in four replications. The objective of the study was to describe the ecotypes variability in reaction to natural stem rust infection under turf low maintenance, and to determine the efficiency of selecting ecotypes resistant to Puccinia graminis sub. sp. graminicola. Three - year observations showed big differences in susceptibility to stem rust not only among the ecotypes but also among the plants in ecotypes. There were no resistant ecotypes found in tested materials, but resistant or tolerant plants were in some ecotypes. Eighteen healthy plants were selected from twelve lowest infected ecotypes. Only ten of plants confirmed the resistance in 2004-2006. The study showed, that it may be possible to select the stem rust resistant plants from D. caespitosa ecotypes, but the effectiveness of selection is very low (0.7%).
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