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Bisexualism (and its derivatives) is a rare exception in species which already acquired the dioecious breeding system. Although it occurs in some tree species, it is still rather uncommon, except for willows, in which bisexualism occurs in at least 18 species. In most willows such unusual individuals are subdioecious, hermaphroditic or monoecious, or produce intersexes (staminate flowers transform into pistillate flowers or the other way round). The frequency of non-dioecy can vary from a single individual to whole populations, but is in principle rare. Its possible causes are both environmental and genetic. In Salix sex lability is known to be affected by parasites and anthropogenic habitat change. In interspecific willow crosses there are numerous exceptions from dioecy that are mostly caused by polyploidization. Since sex determination in willows is genetic, environmental factors are expected to determine exclusively phenotypic sex traits.
The aim of this research was to investigate formaldehyde content in and volatile organic compounds release from particleboards produced from fibrous chips. The object of the tests were panels produced from fibrous chips of black locust Robinia Pseudoacacia L. and willow Salix Viminalis L., as well as from typical industrial particles. The results show that formaldehyde content in the panels produced from willow fibrous chips is similar to the content in the panels made of industrial particles. The concentration of total volatile organic compounds measured after 4 weeks of storage is significantly lower than the required by the existing regulations.
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The aim of the research was to investigate the face screw withdrawal resistance of panels produced from fibrous chips of willow Salix Viminalis L. and black locust Robinia Pseudoacacia L. A series of laboratory 3-layer panels were produced from fibrous chips as well as from industrial particles. The results were compared to commercial industrial panel performance. The investigation shows that the panels from black locust have lower screw withdrawal resistance in comparison with the industrial panel. In the case of higher density willow panel the screw withdrawal resistance was better than that of the industrial panel.
The influence of different doses of nitrogen applied in the sewage sludge and mineral fertilizers on the content and uptake of Mo, Fe, B, Mn, Se and Ti by willow (Salix viminalis) was investigated. In the field experiment the willow was cultivated on the objects fertilized with sewage sludge which contained the nitrogen in following doses in kg ha⁻¹: 100, 150 and 200. Also the objects with mineral nitrogen contained 150 kg N ha⁻¹, phosphorus and potassium in doses where the ratio N:P:K was equal 1:0.35:1 was used. The content of Mo and Fe in willow’s branches cultivated on the objects fertilized with sewage sludge was the highest after use of the smallest dose of nitrogen (100 kg N ha⁻¹). The content of Se, Ti and Mn in investigated biomass of willow branches was the highest after use of sewage sludge in the highest dose (200 kg N ha⁻¹). The content of boron marked in studied branches did not depend on applied fertilization. The total uptake of marked vestigial chemical elements by the biomass of willow in period 3 years of experiment was the most often highest on objects fertilized with the highest dose of sewage sludge (200 kg N ha⁻¹). The most of Fe, B and Ti taken willow cultivated in second year, however Mo, Mn and Se in third year of experiment.
The paper is a review of classical and recent studies on willow rusts in Europe, with special reference to short rotation coppice willows used for biomass production, such as common osier willow (Salix viminalis L.). The review presents the taxonomic classification of rust fungi from the genus Melampsora spp. We present a list of telial hosts (genus Salix) as well as aecial hosts for different rust species. The life cycle of this fungal pathogen is described in detail from the epidemiological and genetic point of view. The DNA polymorphism of M. lariciepitea, the rust species most responsible for severe yield losses of plant biomass, is characterised based on RAPD, AFLP and RFLP-PCR methods.
Two previously unknown willow hybrids, Salix × velchevii (S. amplexicaulis Bory × S. xanthicola K.I. Chr.) and S. × ardana (S. alba L. × S. xanthicola K.I. Chr.), are described from the Bulgarian Rhodope Mts. This is the first report on hybridization in the endemic Balkan species S. xanthicola.
Our study investigated the accumulation of chromium, nickel, lead and cadmium by maize (Zea mays L.), sunflower (Helianthus annuus L.), willow (Salix x smithiana Willd.), and poplar (Populus nigra L. x P. maximowiczii), and the realtionship between the contaminants in soil and in plants. The experiment was performed in contaminated soil (former waste incineration plant) at the Hradec Králové (Czech Republic) site. Plant and soil samples were collected from three plots with different risk element contents (higher amounts of Cd, Cu, Hg, Zn, Cr, Ni, and Pb). The total and available soil metal concentrations in soil were investigated. Only a low portion of risk elements were available for plants (6% Ni, 14% Cd, 1.3 % Pb, and less than 1% of Cr). Chromium, nickel, and lead showed a similar trend to element accumulation where the highest amount was found in plant roots, higher in herbs than in trees (6.83 mg Cr·kg⁻¹, 5.04 mg Ni·kg⁻¹, and 7.76 mg Pb·kg⁻¹). The highest cadmium concentration was found in leaves of willow (1.87 mg Cd·kg⁻¹) and roots of willow (3.05 mg Cd·kg⁻¹). The correlation between the concentration of risk elements in soil and in plants was the highest in the case of lead reaching up to R= 0.89. Results also indicated that translocation of Cr, Ni, Cd, and Pb from roots to aboveground biomass of willow and poplar was low (89-98% of risk elements was retained in roots). The highest translocation from plant roots to aboveground biomass of maize and sunflower was found in the case of Cd and Pb (57 and 83% of Cd, 56 and 76% of Pb). The behaviour of these elements concerning soil and plants differed among fields with unknown history of contamination and type of contaminants.
The aim of the study was to analyze the kinetic parameters (activation energy Ea, pre-exponential coefficient A, rate constant k) of thermolysis in torrefied and raw willow wood (Salix viminalis L.), as well as to determine the effect of thermal modification conditions on the kinetics of this process. Samples of raw and torrefied willow wood in a steam atmosphere were analysed. The samples were subjected to thermogravimetric analysis under isothermal conditions. Analyses were conducted in an atmosphere of helium at 270–330°C. TG and DTG curves were recorded. The thermal characteristics of the samples were based on thermogravimetric analysis under dynamic conditions at a temperature of up to 600°C. On the basis of the data obtained from the TGA analyses, the kinetic parameters were calculated and statistical and mathematical analyses of the results were performed.
Plantations of energy plants are the alternative form of post-agricultural and degraded land management. Particularly, small-area plantations of the tree species, including the willow Salix sp., raise local natural values of degraded habitats and are a dwelling place for numerous entomofauna, birds and mammals. Herbaceous vegetation accompanying short-rotation coppice (SRC) constitutes at the beginning a competition for energy species plantings and therefore is subject to chemical and mechanical control. In successive years, it may increase local biodiversity at the level of plant species and associations, both in ruderal habitats and extensively used agricultural lands. In the presented paper, results of the study referring to evaluation of the floristic and phytosociological diversity of herbaceous vegetation accompanying selected 4–5-year-old willow short-rotation coppices (SRC) situated on lands adjacent to the Odra River estuary (Western Pomerania) in different soil-habitat conditions are showed. Investigations were carried out in willow SRCs located on degraded sandy silts and sewage sludge-fertilised silts, fallow post-farmland and degraded grassland. The largest number of species onfirmed by the highest Shannon-Wiener’s diversity index (H) and species evenness index (J) was characteristic of SRCs set on sandy silt fertilised with sewage sludge, wet grassland and fallow post-farmland when compared to those on sandy silt and over-dried grassland. The analysis of vegetation showed a strong predominance of anthropogenic associations (synanthropic and seminatural) over autogenic (natural) ones.
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