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Influence of biotic and abiotic factors on population dynamics of a critically endangered species Spiranthes spiralis
IPSER, Zdeněk
A population of a critically endangered species Spiranthes spiralis was discovered in 1980 in the National Natural Monument Pastviště u Fínů near village Albrechtice, close to Sušice city. Since 1985 the number of flowering individuals in this population has been annually monitored. Since autumn 1998 all the specimen found there have been marked and biometrically measured. During these periods (12 or 26 years, respectively), large year-on-year fluctuations in the number of flowering plants and in the survival of the individual rosettes have been recorded. The main aim of my work was to assess the effect of weather conditions (temperature, precipitation, the number of days of snow) on the population dynamics and on the fitness of plants (leaf area, probability of flowering and probability of death). The year-round lower temperature and the wet end of autumn during the previous year (t-1) together with the wet spring of the following year (t) had a positive effect on the leaf area during the period of maximal rosette growth (end May in the year t). The probability of flowering was positively affected by the lower temperatures in May and June in the previous year (t-1) and in August just before flowering (year t). The probability of death (in the year t) was increased when the March precipitation (in t) and October temperatures (in t-1) were low. The average number of seeds in the capsule was 1528 ? 885 (s.d.). The number of flowers was positively correlated with the number of mature capsules. However, it did not affect the ratio of mature capsules. Capsules developed on average from 44% ? 24.6 % (s.d.) of the flowers. The average life time of individual plant cohorts was 4.7 years. The number of rosettes per each position was variable from 1 to 7 rosettes (73.2% positions had only 1 rosette). The annual life cycle of the underground organs is described at the end of the thesis.
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Different reaction of cultivars poppy seeds after nonthermal plasma treatment
Banulescu, G. ; Gajdová, Iveta ; Šerá, Božena ; Kuchtová, P. ; Šerý, M. ; Špatenka, P. ; Hnatiuc, E.
The influence of low-temperature atmospheric plasma treatment generated between the electrodes (GlidArc) on poppy seed growth was tested. Treatment times were 0 s, 180 s, 300 s, and 600 s. Working gas was air. We monitored germination and initial growth of two cultivars of poppy seeds (Papaver somniferum L., cultivars Major and Orfeus). The values of control measurements (exposure time 0 s) of the tested cultivars were different. Therefore we analysed both cultivars separately with adequate control during the data procesing. A positive influence was found mainly in the lengths of sprouts in cultivar Major (22 %, time 180 s). The number of germinated seeds was not affected by plasma treatment in both cultivars.
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Effect of various plasma sources on seed growth. Laboratory experimen in Buckwheat
Šerá, Božena ; Gajdová, Iveta ; Čermák, M. ; Gavril, B. ; Hnatiuc, E. ; Kováčik, D. ; Kříha, V. ; Sláma, J. ; Šerý, M. ; Špatenka, P.
Germination and early growth of buckwheat (Fagopyrum aesculentum) after low-temperature plasma discharge treatment in air gas generated in various apparatus were tested. Three pretreatment times were used: 180 s, 300 s and 600 s. Number of germinating achene, length and weight of sprouts were measured. The data was analysed with two-way ANOVA. A significant influence of the type of plasma apparatus, time of exposure and combination of both factors were found. The positive effect on germination and early growth was observed after application of GlidArc plasma. The opposite effect of PDBV apparatus, which is characterized by plasma with a high power density, was observed. Shorter pre-treatment times for this apparatus must be therefore used.
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Germination ecology in orchids
TĚŠITELOVÁ, Tamara
Germination ecology of four Epipactis species (E. albensis, E. atrorubens, E. helleborine, E. purpurata) was studied. Habitat preferences of adult plants were analyzed using phytosociological relevés from the Czech Phytosociological Database. A field experiment was carried out to determine course of germination of Epipactis seeds sown in different habitat types. Relationship between ecological preferences and germination ecology, and spatial aspects of seed dispersal and seedling recruitment are discussed.
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Ecological requirements of the critically endangered species \kur{Sedum villosum}
PRŮŠOVÁ, Monika
Hairy stonecrop (Sedum villosum) belongs to the group of plants that are endangered by real risk of extinction. If appropriate measures are not soon undertaken, it may disappear from the territory of the Czech republic. Preparation of an action plan should be a prerequisite for undertaking such measures. The aim of this diploma thesis was to verify ecological demands of this critically endangered species. I tested the effects of soil acidity and shading on seed germination and growth of hairy stonecrop plants in experimental conditions.
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Suppressive efect of knotweed and other selected plant species on the germination and foliar necrosis
Šerá, Božena ; Plachká, E. ; Vrchotová, Naděžda
Selected plant species Reynoutria sachalinensis, Carum carvi, Sophora japonica and Impatiens glandulifera was used for testing the toxic effects on the model species of white mustard (Leucosinapis album) and oilseed rape (Brassica napus). Two types of test were used. First, the growth of seeds was tested on the model species in the soil mixed with the various aboveground parts of selected plants. Second, leaves of the model plants were treated with extracts from selected plant species and with the pathogen of Leptosphaeria maculans isolate. The reaction to the impact of selected plant species in the soil substrate was analogue in both of white mustard and oilseed rape. Greater phytotoxicity was recorded for the leaves of Reynoutria sachalinensis and the fruits of Carum carvi. Small phytotoxicity was relatively low when the substrate with the tree bark of Sophora japonica was used.
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