Anthropogenic change in the Great Plains of North America within the past two centuries has facilitated extensive woody encroachment by eastern redcedar (Juniperus virginiana, hereafter redcedar). Conversion of grassland to redcedar woodland occurs rapidly as a result of the interaction between changing disturbance and land use patterns. In addition, redcedar encroachment causes compositional shifts in grassland floral and faunal assemblages, and may alter abiotic factors such that grassland restoration efforts are limited. The objectives of this study were to: 1) track vegetation and faunal assemblages in grasslands along a gradient of redcedar encroachment, 2) assess the capacity for experimental tree removal to promote re-colonization of grasslands by associated flora and fauna, and 3) examine the influence of scale on spatial relationships between small-mammal abundance and redcedar cover. During the first phase of my study, I examined herbaceous vegetation, woody vegetation, and small-mammal assemblages at grassland sites along a redcedar encroachment gradient in north-central Oklahoma. I noted hump-shaped trends in the capture rate, species diversity, and species evenness of small mammals along the redcedar encroachment gradient. In addition, higher levels of encroachment were associated with compositional shifts from grassland- to woodland-associated small mammals. Characteristics of the small-mammal assemblage along the gradient corresponded to increases in redcedar cover and the frequency of episodic management events within the past two decades. Experimental redcedar removal during the second phase of my study generally increased vegetation and faunal diversity in 2 years following treatment, and treatment sites having the highest pre-treatment levels of redcedar cover exhibited the greatest responses to tree removal. The results of my study suggested that within the time frame I examined, redcedar encroachment had altered the biotic characteristics of this system, but did not facilitate abiotic shifts capable of constraining rapid grassland recovery. Tree removal also appeared to modulate the effects of consecutive drought and flood years on small-mammal diversity during post-treatment. During the third phase of my study, I examined the strength of association between differences in percent redcedar cover and spatial abundance patterns of 4 common small-mammal species. I examined small-mammal abundance at three relatively small spatial scales (38, 154, and 616 m2) to determine how redcedar-mammal associations were stronger with increases in spatial scale. In addition, I determined whether the influence of spatial scale on redcedar-mammal associations varied along a gradient of redcedar encroachment. The strength of redcedar-mammal associations increased with spatial scale, but was strongest at sites having the lowest levels of encroachment. These results corresponded to variation in the spatial distribution of redcedar cover and compositional differences in the small-mammal species assemblage along the encroachment gradient. Studies examining the effects of woody encroachment will extend our understanding of successional processes and ensure that appropriate management is implemented in the conservation of these imperiled grassland ecosystems.

The paper maps the community of Common Juniper (Juniperus Communis) encountered at Konrac, a site included in the Česká Kanada Nature Preserve. The site itself, or rather the common juniper growing there, does not have the benefit of special legal protection; consequently, no targeted steps have been taken to maintain the juniper community intact in the Konrac landscape - still, the site allowed to monitor the natural development of the community in conditions typical of the current methods of farming. The locality is described to encompass four main types of habitats: stony islands amid meadows; unplowed strips of land around former small fields; peripheries of open stands; and peripheries of close stands. The acquired (and subsequently processed) data point to the conclusion that the habitat at the unplowed margins of fields suits the common juniper communities quite well, even without any human intervention in the farming practices beyond what is implemented on the site now.

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy Student: Vendula Damborská Supervisor: PharmDr. Marie Kašparová, Ph.D. Title of diploma thesis: The Optimization of the growth of the plant tissue culture of Juniperus virginiana The main goal of this diploma thesis lies in the optimization of cultivation medium composition for the tissue culture of Juniperus virginiana (varieties 'Hetzii', 'Glauca', 'Grey Owl'). The best results of all tested media were achieved by using Schenk and Hildebrandt medium with an addition of α-NAA (3.0 mg.l-1 ), kinetin (0.2 mg.l-1 ) and ascorbic acid (15.0 mg.l-1 ). The cultures were cultivated at the temperature of 25 řC and light period of 16 hours light/8 hours dark. The growth curve for the tissue culture of Juniperus virginiana 'Glauca' was set for 2 different cases: with and without the addition of phenylalanin (biogenetic precursor of phenylpropans biosynthesis). The maximal growth was reached on 35th day of the cultivation in both cases, phenylalanin increases the growth rate by 29.65 %.

Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy Candidate: Gabriela Dohnalová Supervisor: PharmDr. Marie Kašparová, Ph.D. Title of diploma thesis: Plant tissue cultures as a potential source of phenylpropanoids I Explant cultures are the source of plant secondary metabolites. However, the production of secondary metabolites is usually low in explant cultures. Production can be increased by a method called elicitation. The basic prerequisite for successful elicitation is, among other things, finding a suitable elicitor, its concentration and optimal time of elicitor action on plant culture in vitro. The aim of this study was to observe the influence of lead chloride and ferrous sulfate (in four concentrations) on the production of podophyllotoxin in the suspension cultures of Juniperus virginiana L. (variety Hetzii and Glauca). The culture was cultured on Schenk and Hildebrandt nutrient medium with addition of 3.0 mg.l-1 α-naphthylacetic acid, 0.2 mg.l-1 kinetin and 15 mg.l-1 ascorbic acid. Cultivation proceed in 25 řC temperature and 16 hours light/8 hours dark period. Subsequently, the determination of the content of podophyllotoxin by HPLC was performed. Juniperus virginiana L. variety Hetzii produces a higher amount of podophyllotoxin than the Glauca...

Junipers and pines exhibit contrasting patterns of growth decline and mortality with climate change-type warming and drought; yet, the underlying physiological mechanisms are not fully understood. Does warming exacerbate the effects of drought on gas exchange physiology and growth? Do the combined effects of drought and warming differ for pines and junipers? To what extent do isohydric vs. anisohydric responses to water limitation in pines and junipers constrain net leaf CO2 exchange and plant growth response to drought and warming? To address these questions, we compared responses of leaf gas exchange and growth in seedlings of juniper (Juniperus scopulorum, J. virginiana) and pine (Pinus edulis, P. taeda) species of contrasting arid and mesic origin in a study of combined warming (ambient, +1.8 °C) and enhanced summer drought (long-term mean, -40%). Warming and enhanced summer drought each reduced photosynthesis and growth and effects were largely independent, suggesting that warming exacerbates drought effects on growth. Enhanced summer drought and warming had distinct impacts on photosynthetic carbon gain that were differentially revealed depending upon soil water content. Warming reduced light-saturated net photosynthesis (Asat) under low soil water contents, whereas carry-over effects of drought treatment were evident under well-watered conditions. Short-term soil drying led to greater reduction of Asat in pines (-51%) rather than junipers (-30%). Under short-term water-limited conditions, Asat and gs were about two-times higher for junipers compared to pines. Relative growth rate of junipers declined with warming (-28%) and drought (-50%) treatments. In contrast, pine growth and Asat declined more with warming than drought. Only P. edulis exhibited increased mortality in response to warming and drought, reaching 75% in the combined warming and drought treatment. Diminished sensitivity of R to water limitations, coupled with steeper reductions in Asat with decreasing soil water content in isohydric pines compared to anisohydric junipers could account for the greater sensitivity of pines to warming and drought under climate change.

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy Student: Nikola Urbanová Supervisor: PharmDr. Marie Kašparová, Ph.D. Title of diploma thesis: The study of secondary metabolites in plant tissue cultures II The aim of this work was to determine the effect of the potential elicitor chitosan on production of podophyllotoxin in callus and suspension cultures of Juniperus virginiana Glauca variety and suspension cultures of Juniperus virginiana Hetzii variety. Schenk and Hildebrandt medium supplemented with α-naphtylacetic acid (3.0 mg/l), kinetin (0.2 mg/l) and ascorbic acid (15.0 mg/l) was used for the cultivation. Chitosan solutions of various concentrations (0.001; 0.01; 0.1; 1 g/100 ml) were affecting the cultures for 6, 24, 48 and 168 hours. The content of chitosan was determined by HPLC. Higher values of podophyllotoxin content were measured in cultures derived from the Glauca variety. The best chitosan effect on podophyllotoxin production was manifested in callus cultures after 24 hours application of 0.001 g/100ml concentration. A podophyllotoxin content of 0.210 % was determined, which was about 320 % higher in comparison with the control. The maximum content (0.140 %) in suspension culture was induced by 24-hours application of a 0.1 g/100 ml concentration;...

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy Student: Veronika Vargovčíková Supervisor: PharmDr. Marie Kašparová, Ph.D. Title of diploma thesis: Production of podophyllotoxin by plant tissue cultures of Juniperus virginiana Key words: Juniperus virginiana, callus cultures, suspension cultures, podophyllotoxin Elicitor and precursor adding method can be used to enhance the production of secondary metabolites in explantate cultures. This master's thesis is focused on the evaluation of the effects of biotic elicitor (salicylic acid) and phenylpropanoid metabolism precursor (cinnamic acid) on podophylotoxin production in Juniperus virginiana (var. 'Glauca' and 'Hetzii') suspension cell culture. Suspension cultures were cultivated on Schenk and Hildebrandt medium at 25řC and circadial period of 16 hours light and 8 hours dark. Medium contained 15 mg.l-1 ascorbic acid and growth regulators 3.0 mg.l-1 , α-naphthaleneacetic acid, 0.2 mg.l-1 kinetin. The effects of salicylic acid aqueous solution 0.01 mmol.l-1 , 0.10 mmol.l-1 , 1.00 mmol.l-1 , 10.0 mmol.l-1 and cinnamic acid 60% alcohol solution 0.10 mmol.l-1 , 1.00 mmol.l-1 , 10.0 mmol.l-1 , 100 mmol.l-1. were examined after 6, 24, 48 and 168 hours. Podophylotoxin content was evaluated using HPLC method. In 'Glauca'...

Common juniper (Juniperus communis) is a tree or a shrub. This species is original in the Czech Republic which was very widespread in the landscape. It is from the lowland to the mountain range, which means that it is completely unmistakable for the soil species. It is classified as a critically endangered species in the Czech Republic, due to changes in landscape management. The aim of this work was mapping and surveying the situation on the mentioned localities, where the research was carried out in 2004-2005 and in 2015. At the Na Mšálech locality there were found 135 individuals. Based on the data found, the overall health condition was greatly aggravated by the populations under study, specifically at the Paris site.

Description of Juniperus communis. Description of general natural conditions in studied area and their relation to referred species. List of characteristics surveyed on each specimen. Statistical evaluation of all data which I collected during my fieldwork. Outcome comparison with other similar works on given topic.

In this work, I ´ve been monitoring occurrence of Juniperus communis in south part of {\clqq}CHKO Třeboňsko``, which is protected area. At first I´ve been studying literature specialized in focusing on problems of occurence Juniperus communis in the world and in this concrete area. Than I was systematically creating a net of all the exemplars in proper area, I ´ve been noting their characteristics and taking a photos. I was statistically analyzing the data and compare with other works, which are engaged in this issue.