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Ecophysiological relevance of extreme sensitivity of orchids to nitrates
Figura, Tomáš ; Ponert, Jan (advisor) ; Tylová, Edita (referee)
Many orchid species are seriously endangered at present. Reasons for their disappearing from natural habitats remain often unclear. Orchids depend on mycorrhizal symbiosis in nature, however only little is known about this symbiosis. Seeds of some species do not germinate in vitro, making their cultivation for scientific and rescue purposes impossible. We found that seed germination of one of such reluctant species, Pseudorchis albida, is strongly inhibited by nitrates even at extremely low concentrations. As this species prefers oligotrophic mountain meadows, nitrate-induced inhibition probably take place in natural conditions. Surprisingly, we found similar but slightly weaker inhibitory effect also in typical mesophillic species and even in slightly eutrophic ones. The sensitivity to nitrates correlates with trophy level of species canopy. This inhibitory effect of nitrates could be weakened by application of a range of growth regulators, including auxins, cytokinins and gibberellins, and also by mycorrhizal fungi. The action of nitratereductase is essential for this inhibitory effect of nitrates. Experiments with NO donors, scavengers, and NO quantification are pointing right at NO as compound which perhaps mediates nitrate inhibitory effect. Based on these results, the nitrate inhibitory...
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Cemical composition of hemp (\kur{Cannabis sativa}) and possibilities of its utilization as animal feed
NĚMCOVÁ, Michaela
Cannabis sativa L. is an annual cultural plant used from ancient times up to the present in many spheres of the human life. The aim of this bachelor study was to summarize on the basis of literature sources the information about chemical composition of the hemp seed (basic composition, content of amino acids, fiber, vitamins and specific substances, etc.), genetic variability in the substances content, and possibilities of utilization of the hemp seed and also plant residues as feed. Feeding hemp seeds to poultry increases egg production and enriches egg yolk with carotenoids, - 3 and - 6 fatty acids and decreases the cholesterol content. In case of broilers, hemp seeds increases the weight of the breasts, thighs, liver, stomach, intestines and the portion of abdominal fat. Hemp seed cakes have a positive effect on rumen function, support reception of neutral detergent fiber and increases the unsaturated fatty acids content in the meat. Hemp oil relieves stress and improves immunity of the fed animals.
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Vývoj pěstování máku setého (Papaver somniferum L.) na území České republiky
Petrželová, Lenka
The objective of this thesis was to summarize present knowledge of opium poppy cultivation in the Czech Republic. There are described the biological characteristics and poppy growing technologies. The first chapter is devoted to the origin and biological characterization of opium poppy. The growing areas and poppy agro techniques cultivators are discussed in the second charter. Other chapters are dedicated to legislative and economic sides of the problem. The main diseases and poppy pests are mentioned in final chapters of this thesis. Current problems of poppy cultivation in the Czech Republic are pointed out in the whole thesis.
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Ant food preferences (Formica genus) on the seeds with elaiosomes
ENGLICKÝ, Tomáš
The topic of the presented bachelor thesis is the determination of the ants g. Formica preference for specific seeds with elaiosomes. The ant dispersion of the seeds with elaiosomes is called myrmecochory. The theoretical part of this thesis describes the myrmecochory phenomenon in the context of the seed dispersal. The conclusion of the theoretical part evaluates considerable benefit of myrmecochory for ants and plants despite its disadvantages. The practical part of this thesis describes the experiment held with the intention to determine the preferences of the ants. The seeds with elaiosomes from five experimental plants were presented to the ants from two experimental anthills. Obtained data were processed into tables and graphs and subsequently evaluated. The results show that the ants prefer certain types of seeds. The cause for this preference is discussed.
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Populační dynamika ruderálních druhů ve vztahu k limitujícím podmínkám prostředí
Modrý, Martin ; Tenčík, Aleš ; Hofmeister, Jeňýk ; Hošek, Jan
Hlavním cílem projektu je identifikace a ocenění významu hlavních podmínek pro rozvoj expanzních druhů rostlin náročných na živiny v lesní vegetaci. Téma je rozděleno do dílčích částí: a) analýza vegetace modelových ploch a její interpretace zaměřená na expanzní druhy, ustupující druhy, indikačně významné druhy, b) stanovení zásoby živých semen v půdě (analýza semenné banky), c) analýza intenzity deště semen, d) stanovení obsahu hlavních živin a organického uhlíku v půdě, event. pomocných půdních charakteristik, e) popis světelných poměrů stanoviště, především kvantifikace celkového světelného požitku a spektrálních poměrů významných pro klíčení semen, f) popis významných spolupůsobících faktorů (vlhkostní poměry, poměry řídící akumulaci opadu, mikro a mezomorfologie stanoviště, spouštěcí faktorys - mechanické disturbance apod.), g) formulace zásad hospodaření podporující zachování biodiverzity na vybraných lokalitách.
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