The titanium and its alloys belong at present to the most preferred and commonly applied biomaterials for loadbearing implants. The surfaces of biomaterials are subjected to modification, including the hydroxyapatite coatings deposited in order to ensure corrosion resistance and better joining between an implant and a bone through the possibility of ingrowth bone into the coating. In this paper, the morphology and properties of the nanohydroxyapatite coating deposited on the Ti13Zr13Nb flat surfaces using electrophoretic method are presented. Electrophoretic deposition at two different current values and two electrolytes (first -ethanol with nanoHAp, second -methanol with nanoHAp) was applied. The scanning electron microscopy examinations and wettability angle measurements showed an increase in the coating thickness, the surface coverage and decrease in biocompatibility with increasing voltage. The surface condition and biocompatibility of coatings were better when using methanol/nanoHAp solution as compared to the ethanol/nanoHAp one.
Main conclusion
The dormancy release in Avena fatua caryopses was associated with a reduction in the ABA content in embryos, coleorhiza and radicle. The coleorhiza proved more sensitive to KAR1 and less sensitive to ABA than the radicle. The inability of dormant caryopses and ABA-treated non-dormant caryopses to complete germination is related to inhibition and delayed of cell-cycle activation, respectively.
Abstract
As freshly harvested Avena fatua caryopses are dormant at 20 °C, they cannot complete germination; the radicle is not able to emerge. Both karrikin 1 (KAR1) and dry after-ripening release dormancy, enabling the emergence of, first, the coleorhiza and later the radicle. The after-ripening removes caryopse sensitivity to KAR1 and decreases the sensitivity to abscisic acid (ABA). The coleorhiza was found to be more sensitive to KAR1, and less sensitive to ABA, than radicles. Effects of KAR1 and after-ripening were associated with a reduction of the embryo’s ABA content during caryopsis germination. KAR1 was found to decrease the ABA content in the coleorhiza and radicles. Germination of after-ripened caryopses was associated with the progress of cell-cycle activation before coleorhiza emergence. Inhibition of the germination completion due to dormancy or treating the non-dormant caryopses with ABA was associated with a total and partial inhibition of cell-cycle activation, respectively.
This paper presents the results of observation of mould growth in laboratory colonies of termites. It also attempts to determine the species of mould fungi present in the research laboratory and the main colonies and their entomopathogenic for the termites. The following four species were found in test termite colonies: <em>Trichoderme viride</em>, <em>Mucor</em> <em>himeralis</em>, <em>Rhizopus</em> <em>nigricans</em>, <em>Aspergillus</em> sp., <em>Aspergillus</em> <em>flavus</em>, <em>Alternaria</em> sp., <em>Penicylium</em> <em>verucosum</em> and <em>Fusarium</em> sp. were recognisable in test colonies with domestic and exotic wood. Morphological observations of the fungi were carried out using a microscope with a 40x magnification. The growth of mould fungi in test containers caused death of whole termite colonies.
Abstract. The main aim of the study was to compare the rearing effect of calves kept outdoor in individual hutches and indoor in group pens. During the experiments, the following measure ments were carried out: body weight, daily gains, feed intake, morbidity and mortality. The study was conducted on 90 calves from 5th to 90th day of age; all calves were fed the same feed and according to the same schedule. Results revealed that during the first month, the calves from both groups achieved the same daily gains. However, older calves kept indoor were characterised by better daily gains, feed intake and as a result, body weight. The outdoor system has positive effect on morbidity, especially in case of pneumonia and diarrhoea. During the experiment, only two calves were lost (mortality rate – 2.2 %).
Main conclusion
NO releases caryopsis dormancy in Avena fatua, the effect being dependent on the level of dormancy. The NO effect involves also the reduction of caryopsis sensitivity to ABA and to a decrease in the ABA to GAs ratio due to a decrease in ABA levels and the lack of effect on GAs levels before germination is completed.
Abstract
Nitric oxide (NO) from various donors (i.e. SNP, GSNO and acidified KNO2), applied to dry caryopses or during initial germination, released primary dormancy in caryopses. Dormancy in caryopses was gradually lost during dry storage (after-ripening) at 25 °C, enabling germination at 20 °C in the dark. The after-ripening effect is associated with a decrease in NO required for germination. In addition, NO decreased the sensitivity of dormant caryopses to exogenous abscisic acid (ABA) and decreased the embryos’ ABA content before germination was completed. However, NO did not affect the content of bioactive gibberellins (GAs) from non-13-hydroxylation (GA4, GA7) and 13-hydroxylation (GA1, GA3, GA6.) pathways. Paclobutrazol (PAC), commonly regarded as a GAs biosynthesis inhibitor, counteracted the dormancy-releasing effect of NO and did not affect the GAs level; however, it increased the ABA content in embryos before germination was completed. Ascorbic acid, sodium benzoate and tiron, scavengers of reactive oxygen species (ROS), reduced the stimulatory effect of NO on caryopsis germination. This work provides new insight on the participation of NO in releasing A. fatua caryopses dormancy and on the relationship of NO with endogenous ABA and GAs.
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