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Adventitious sprouting of short-lived plants in natural populations
MALÍKOVÁ, Lenka
Disturbance is one of most important selective factor causing removal of plant biomass. Man-made habitats are characterized by strong and unpredictable disturbances, providing bare soil surface colonized by plants with short life cycle. Populations of the short-lived plants are, however, vulnerable to the strong disturbance removing all stem parts with reserve axillary meristems in the case it occurs before plant flowering and fruiting. Nevertheless, 2 % of annual and 14 % of biennial plants are able to overcome meristem limitation by adventititous sprouting from hypocotyle or/and roots. This thesis is composed of four original studies describing the occurrence of adventitious sprouting in natural populations of 22 monocarpic weeds of Central Europe and one species in Indonesia. The studied phenomenon was analyzed in relation to various environmental factors and plant traits in the field and in experimental conditions.
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Ecological constraints limiting the root-sprouting ability in wetland plant species
SOSNOVÁ, Monika
Wetland plant species rely largely on vegetative reproduction. Although all types of clonal growth organs are found in wetlands, special adaptations, e.g., turions, fragmentation and budding, are more frequent in true aquatic communities. However, root-sprouting is underrepresented, although it can be beneficial under disturbed conditions. This thesis focuses on ecological constrains potentially hindering root-sprouting in wetlands. This ability was studied in a wetland herb Rorippa palustris in relation to life history, injury timing and carbon economy of a plant. In addition, plant regeneration following submergence and severe disturbance was assessed.
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The analysis of forest vegetation on the Hallasan volcano: evaluation of impact of disturbances and competition on growth and survival of tree populations along altitudinal gradient
ALTMAN, Jan
The study was conducted on Mt. Hallasan (1950 a.s.l.) in South Korea. Forest plots were established along altitudinal gradient (950-1770 a.s.l.) from oak-hornbeam (Quercus serrata, C. laxiflora), to mixed-oak (Quercus mongolica, Taxus cuspidata), and fir (Abies koreana, Sorbus commixta) forests. Vascular plants were identified to species, and their total cover and covers of individual species in herb ({>} 1 m), shrub (1 - 5 m) and tree ({<} 5 m) layers estimated using Braun-Blanquet scale. Dentrended Correspondence Analyses was used to analyze relationship between environment and species composition, lifeforms spectra and plant diversity. The spatio-temporal variations in stem dispersion, radial growth, and mode of competition among trees were examined using the mapped location of trees and tree-rings. Changes in radial-growth were used to analyse stand disturbance history using 36647 measured tree-rings. Histories of radial-growth of individuals trees were further examined using visual classification to 5 different groups of growth trends. Ripley´s K-function was used to determine whether the spatial distribution pattern of trees was random, regular or clumped. Spatial size autocorrelations were used to determine the mode and extant of neighbor interactions. Spatial associations of different groups of trees and random mortality test were also computed for tree stands where Abies koreana was a dominant species.
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Comparison choice cultural and weed kinds form stock Amaranthus
VÁLEK, Jan
Amaranthus (L.) belongs to among old cultural crops. Cultural forms of some species were already grown by Aztecs and Incs in ancient times. High nutritive value of seeds redounded to rediscovery of the crops. Tested varieties of cultural amaranth get to the interaction whit wild species of amaranth. This work would had contribute to better knowledge of ecology in the hybrid of cultural variety and weed (A. x turicensis = A. cruentus x A. retroflexus) The aim of this work was to describe production and morphometric characteristics of selected relative cultural and weed species of amaranth (Amaranthus hypochondriacus, Amaranthus cruentus, Amaranthus retroflexus), the hybrid A. x turicensis and to determinate occurrence and survival of weed species A. retroflexus onplaces, where cultural amarant was grown. A. retroflexus shows as a very resistant to damage. Cultural species responded on damage by reduction of majority observed parameters. Cultural species of amaranth responded more on different conditions substrate than the weed species. Response of hybrid on different substratum conditions was in the middle of spectrum of the response in cultural parents and the weed species. Indiference of the hybrid to substrate should be better clear up in the next studies. Weed species is little sensitive to competicion and his characteristics (total biomass, legth inflorescence, height of plants, number of leaves) are different not much. Effect of competition on hybrid shows his non - uniform response probably caused by his considerable variability Absence of cultural amarant and interspecific hybrids shows on relation of these plants to warmer weather that is probably the main factor for their occurrence.
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