The Effect of Hot Air on Spruce Wood

Termickým zaťažením dreva dochádza k významným zmenám v jeho chemickom zložení a vlastnostiach. Štúdium týchto zmien je dôležité tiež z pohľadu požiarnej bezpečnosti pri využívaní dreva ako stavebného materiálu. V tejto práci boli vzorky smrekového dreva (Picea abies L. Karst.) tepelne zaťažené pri teplotách 100, 150, 200, 220, 240, 260, 280 a 300 °C po dobu 1, 3 a 5 hodín za prístupu vzduchu. Hmotnostný úbytok sa výrazne zvyšuje nad teplotou 220 °C počas celej doby termického zaťaženia. Zmeny v dreve spôsobené termickou úpravou boli sledované pomocou ATR-FTIR spektroskopie. Získané výsledky poukazujú na kondenzačné reakcie lignínu a zmeny v jeho štruktúre. Pri teplote okolo 240 °C bol pozorovaný začiatok degradácie celulózy.The thermal treatment of wood causes signifi cant alterations in its chemical composition and properties. The study of these alterations is important also from view point of fi re safety at the wood utilisation as a construction material. In this study the samples of spruce wood (Picea abies L. Karst.) were thermally treated at the temperatures 100, 150, 200, 220, 240, 260, 280 and 300°C during 1, 3 and 5 hour in the over at the air circulation. The weight loss considerably increases over temperature 220°C at all durations of treatment. The alterations in wood due to the thermal treatment were analysed by means of ATR-FTIR spectroscopy. Obtained results indicate condensation reactions in lignin and changes in its structure. The evidently beginning of degradation of cellulose at temperatures about 240°C was observed

Effects of Exogenous Application of Indole-3-Butyric Acid on Maize Plants Cultivated in the Presence or Absence of Cadmium

Auxins are plant hormones that affect plant growth, development, and improve a plant’s tolerance to stress. In this study, we found that the application of indole-3-butyric acid (IBA) had diverse effects on the growth of maize (Zea mays L.) roots treated without/with Cd. IBA caused changes in the growth and morphology of the roots under non-stress conditions; hence, we were able to select two concentrations of IBA (10−11 M as stimulatory and 10−7 M as inhibitory). IBA in stimulatory concentration did not affect the concentration of H2O2 or the activity of antioxidant enzymes while IBA in inhibitory concentration increased only the concentration of H2O2 (40.6%). The application of IBA also affected the concentrations of mineral nutrients. IBA in stimulatory concentration increased the concentration of N, K, Ca, S, and Zn (5.8–14.8%) and in inhibitory concentration decreased concentration of P, K, Ca, S, Fe, Mn, Zn, and Cu (5.5–36.6%). Moreover, IBA in the concentration 10−9 M had the most positive effects on the plants cultivated with Cd. It decreased the concentration of H2O2 (34.3%), the activity of antioxidant enzymes (23.7–36.4%), and increased the concentration of all followed elements, except Mg (5.5–34.1%), when compared to the Cd

Chemical Profiles of Wood Components of Poplar Clones for Their Energy Utilization

Selected and tested poplar clones are very suitable biomass resources for various applications such as biofuels, the pulp and paper industry as well as chemicals production. In this study, we determined the content of lignin, cellulose, holocellulose, and extractives, syringyl to guaiacyl (S/G) ratio in lignin, and also calculated higher heating values (HHV) among eight examined clones of Populus grown on three different experimental sites. The highest lignin content for all the examined sites was determined in ‘I-214’ and ‘Baka 5’ clones, whereas the highest content of extractives was found in ‘Villafranca’ and ‘Baka 5’ clones. The highest S/G ratio for all the examined sites was determined in ‘Villafranca’ and ‘Agathe F’ clones. The chemical profiles of main wood components, extractives, and the S/G ratio in lignin were also influenced by both the experimental site and the clone × site interaction. Higher heating values, derived from calculations based on the contents of lignin and extractives (or lignin only), were in close agreement with the previously published data. The highest heating values were found for ‘Baka 5’ and ‘I-214’ clones. The optimal method of poplar biomass utilization can be chosen on basis of the lignocellulosics chemical composition and the S/G ratio in lignin