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The changes of morphological features of stems and leaves during 3-year experiments of two hybrid cultivars and one population cultivar of oilseed sunflower are described in this paper. Effects of variable environmental factors, sowing density, and different levels of nitrogen fertilization were analysed. The tested sunflower line hybrids were characterised by only slightly more consistent morphological features than the population variety. The most heritable features were the number of leaves on the shoots. The variability of other features were to the largest extent influenced by random factors.
Celem pracy było wykazanie zmienności morfologicznej różnych typów odmian lnu zwyczajnego. Przebadano nasiona czterech odmian: oleistej, włóknistej pośredniej i ozdobnej. Doświadczenia prowadzono w latach 2005 i 2008, różniących się warunkami pogodowymi. Analizowano wielkość nasion oraz ich liczbę w torebce i MTN. W latach badań największe nasiona miała odmiana ozdobna, cechowała się też ona najmniejszą ich liczbą. U wszystkich typów odmian długość, szerokość i liczba nasion były podobne, natomiast grubość i MTN osiągnęły znacznie większe wartości w 2008 roku, pomimo suszy przypadającej na wschody lnu oraz w okresie jego dojrzewania. Spośród badanych cech nasion najbardziej zmienną była ich liczba w torebce.
Changes in shoot length during development of two hybrid cultivars and one population cultivar of oilseed sunflower were compared in 3-year trials. Effects of cultivar, climatic factors, sowing density, and fertilization on plant height were analysed. In the conducted experiments, hybrid cultivars had higher shoots than cultivar ‘Wielkopolski’ since the first studied developmental stage (star stage). However, the large plant height does not have a positive effect on their agronomic value. Results of this study show that sunflowers were the highest in 1999 at all developmental stages, which resulted from more favourable weather conditions and soil type. The lowest final plant height was recorded when sunflowers were grown on brown-earth soil. This study confirms that increased sowing density caused a stronger elongation of shoots since the earliest developmental stages.
During the last 10 years (2005–2014) the population of Epipactis palustris within the former ecological use “Kopanina 1” was observed five times. In subsequent years, on the area of 4400 m2 at least 1000 to more than 4000 ramets were noted. The ramets in generative phase of development always predominated. It might indicate good condition of the population. The highest density per unit of area was observed in the first year of the study. The length of stems and number of leaves were the most constant features in orchid population. Then the width of the bract was characterized by the greatest values of the coefficient of variation. During the entire study period the number of ramets in population of E. palustris fluctuated, mainly resulting from the biology of the species, and only substantially from the impact of weather conditions. Negative impact of diverse human activities and excessive expansion of the other plant species, which resulted in the shading of the orchid sites, are the major threats to E. palustris existence in the described object.
In recent years extensive attention has been given to the Rubus genus, but knowledge on the ecology of most of its species, including rhythmic development, is still insuffi cient. Such data may have practical applications, since blackberry species are economically important. The goal of the study was to analyse phenology and growth rate of vegetative and generative stems in 10 Rubus species of different systematic affi nity (belonging to two subspecies and three sections), growing in the Dendrological Garden of the Poznań University of Life Sciences. Some habitat factors were also taken into consideration. Field investigations were carried out for three growing seasons. The plants were evaluated for phenology twice a week, while the length of their stems was measured once a week. Diff erences were observed in the seasonal rhythm of individual species. Weather factors distinctly infl uenced the course of development phases in all the Rubus species. Drought during the growing season caused fl owering disorders, withering of fruit, earlier autumn leaf coloration, and fall of leaves. Rubus idaeus and R. fabrimontanus ripened all of their fruits each year of observations and seemed to be the most adapted for fruit production. Rubus fabrimontanus, R. kuleszae and R. praecox were the most vigorous species with reference to shoot growth. This study revealed that only some species were fully acclimated to the conditions of the Dendrological Garden, since they successfully completed their entire fl owering and fruiting cycles.
The aim of this study was to determine the current status of the population of marsh helleborine at a locality in the Wielkopolska National Park. Variability in generative shoots was analysed. Recorded results were compared with a study published in the 1990's, in which this locality was described. Since that time the area covered by that population has decreased; nevertheless, it exhibits characteristics of being in a good condition. In that population three forms of that species were reported: f. palustris, f. longibracteata and f. ochroleuca. The greatest threat for the existence of that heliophilous orchid was connected with the overgrowing of its habitat, for this reason measures should be taken to prevent succession and encroachment of trees and shrubs to that area.
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