Experiments were carried out on the influence of quicklime, ammonia water, ‘Neguvon’ — Bayer and desiccation on the vitality of leeches. It was found that the efficacy of quicklime depends on its CaO content, on the dose of this compound, and, above all, on the pH of calcium hydroxide formed by mixing quicklime with water. The borderline value in this case is pH = 8.6. Quicklime containing 49% CaO did not affect the mature forms of leeches or their larvae in cocoons. The efficacy of other kinds of quicklime (53% CaO, 93% CaO and 99% CaO) also depended on the pH produced. Quicklime containing 99% CaO proved the most effective in destroying mature leeches and their cocoons; at the concentration of 250 ppm, it produces a pH higher than 8.6 (Table I).In acceptable doses, ammonia water affects neither mature leeches nor their larvae in cocoons.‘Neguvon’ — Bayer, though effective against mature leeches, does not affect the vitality of the larvae in cocoons in doses acceptable for practical use.Under laboratory conditions, drying up kills leech larvae in 24 h. This is therefore a radical means of combatting these parasites. 相似文献
Black seed of Scots pine are more resistant to damping-off. The content of certain elements and chemical compounds in the seed coats differs widely depending on seed colour and physiological state (resting, germinating and infected seeds). The quantitative and qualitative differences in fatty acids content, total nitrogen, amino acids, some metals and nonmetals, chlorogenic acid, phenol and a number of its derivatives seem to be some of the factors conditioning differences in resistance to damping-off. 相似文献
Soft rot and blackleg of potato caused by pectinolytic bacteria lead to severe economic losses in potato production worldwide. To investigate the species composition of bacteria causing soft rot and black leg of potato in Norway and Poland, bacteria were isolated from potato tubers and stems. Forty-one Norwegian strains and 42 Polish strains that formed cavities on pectate medium were selected for potato tuber maceration assays and sequencing of three housekeeping genes (dnaX, icdA and mdh) for species identification and phylogenetic analysis. The distribution of the species causing soft rot and blackleg in Norway and Poland differed: we have demonstrated that mainly P. atrosepticum and P. c. subsp. carotovorum are the causal agents of soft rot and blackleg of potatoes in Norway, while P. wasabiae was identified as one of the most important soft rot pathogens in Poland. In contrast to the other European countries, D. solani seem not to be a major pathogen of potato in Norway and Poland. The Norwegian and Polish P. c. subsp. carotovorum and P. wasabiae strains did not cluster with type strains of the respective species in the phylogenetic analysis, which underlines the taxonomic complexity of the genus Pectobacterium. No correlation between the country of origin and clustering of the strains was observed. All strains tested in this study were able to macerate potato tissue. The ability to macerate potato tissue was significantly greater for the P. c. subsp. carotovorum and Dickeya spp., compared to P. atrosepticum and P. wasabiae. 相似文献
Veränderungen in Rieselfeldböden während eines Säulenversuchs mit unterschiedlichen Beregnungslösungen. 1. Physikochemische Eigenschaften der Festphase In einem 2.5 Jahre dauernden Säulenexperiment wurden die physikochemischen Eigenschaften von zwei Sandböden, eines genutzten sowie eines ehemaligen Rieselfeldes, untersucht. Die Böden wurden gekalkt, beziehungsweise mit unterschiedlichen Beregnungslösungen beaufschlagt. Die Menge an austauschbaren basischen Kationen sowie die Basensättigung beider Böden veränderte sich deutlich während des Experiments. Diese Veränderungen wurden durch Boden-pH-Änderungen verursacht. Die spezifische Oberfläche und die Kationenaustauschkapazität dieser Standorte hängen vom Gehalt an organischer Substanz im Bodenprofil ab. Die Oberflächenladungsdichte war — unabhängig von der Tiefe — in beiden Böden gleich. 相似文献
In spite of a lack of acute toxicity of single metal ions, in 96 hour laboratory tests there was a long term toxicity againstS. carpocapsae andH. bacteriophora nematodes. The 96 hour laboratory tests were carried out in order to prove possible synergistic and antagonistic interactions between pairs of metal ions. Thus, the pairs of ions were arranged from each of Al, Cd, Co(II), Cr(III), Cr(VI), Cu(II), Fe(III), Li, Mo(VI), Ni(II), Sc(IV), V(V) and Zn on one side and Mn(II) and Mg on the other. Mn(II) and Mg ions considerably reduced the nematode mortality and increased their infectivity againstGalleria mellonella caterpillars. 相似文献
Water vapor adsorption isotherms were measured for samples of kaolin and quartz amended with different amounts of humic acid extracted from a Cambic Arenosol under forest. Applying the approximation of the adsorption isotherms with the BET equation the monolayer capacities (surface areas) for the studied systems were calculated. For kaolin systems the surface area decreased sharply at low humic acid additions and this slowly increased with the further rise of the humic acid content, whereas for the quartz the increase of surface area was only noted for high humic acid contents. Using an exponential isotherm equation with a local BET model, the adsorption energy distribution functions were calculated for kaolin systems. The shape of the adsorption energy distributions showed that the increase in humic acid content changed the character of the surface from more hydrophilic to more hydrophobic. For intermediate humic acid contents, the energy distribution function had two maxima – more polar and less polar. At high humic acid contents the energy distribution function tended to the estimated value for pure humic acid, indicating high surface coverage with organic material. As measured by the mercury intrusion porosimetry, for the kaolin samples the amount of the largest pores decreases and the amount of the smallest pores increases with the accumulation of humic acid. For the quartz systems only very high doses of humic acid are reflected in changes of pore size distribution. 相似文献
Kura clover (Trifolium ambiguum M. Bieb.) is a rhizomatous perennial legume that is native to Caucasia, is extremely persistent in North America, but its performance has not been adequately evaluated in Europe. The objective of this research was to compare forage yield and nutritive value of Kura clover to lucerne (Medicago sativa L.), red clover (Trifolium pretense L.) and white clover (Trifolium repens L.) at two locations in Poland. All clover stands thinned markedly by spring of the second production year because of infection by Sclerotinia crown and stem rot, but lucerne stands remained dense and this legume produced the highest total yield over 3 or 4 production years. Kura clover yields of 7.2–8.3?Mg?ha?1 were second to lucerne by the third production year but long-term performance was diminished by stand thinning. Kura clover and white clover had lower fiber concentrations and greater protein concentrations and forage digestibility than red clover and lucerne. Kura clover can be a source of high-quality forage in Europe, but cannot be recommended for use in areas with known Sclerotinia trifoliorum presence until resistance to this pathogen is developed. 相似文献
The purpose of this study was to compare effects of two biostimulating substances (compost and bird droppings) on the proliferation of microorganisms, enzymatic activity, and resistance of spring barley in soil exposed to tebuconazole fungicide. Both biostimulating substances were also assessed for their efficacy in tebuconazole degradation in soil.
Materials and methods
A pot vegetation experiment was performed with soil belonging to the Eutric Cambisols to test the effect of tebuconazole on the biological activity of soil. Its adverse effect on the biological properties of soil was minimized through the use of biostimulating substances (compost and bird droppings), the effect of which was expressed with the IFC/BD index. The RCh index was used to determine the effect of tebuconazole on the proliferation of soil microorganisms and enzymes, the BA21 index was used to express soil fertility based on the activity of soil enzymes, whereas the RS index—to express the resistance of spring barley to the administered doses of tebuconazole. Finally, analyses were conducted to determine the efficacy of soil amendment with biostimulating substances in tebuconazole degradation.
Results and discussion
Study results demonstrate that tebuconazole caused significant changes in the proliferation of the tested groups of microorganisms, in the activity of soil enzymes, and in spring barley yield. It was especially noticeable in pots in which the soil was exposed to its highest dose, i.e., 2.499 mg kg?1. Soil supplementation with bird droppings had a positive effect on the development of soil microorganisms and on the enzymatic activity in the soil. In turn, compost addition to soil exerted various effects on the biological properties of soil. Both biostimulating substances failed to improve spring barley yield. Tebuconazole degradation was more intense in the soil fertilized with bird droppings than with compost.
Conclusions
Results of this study suggest that tebuconazole can affect the stability and health status of soil ecosystems by modifying their biological properties. The high sensitivity of soil microorganisms and enzymes to stress conditions makes them reliable environmental bioindicators. The strive for eliminating the adverse impact of fungicides on soil microbiome through the use of appropriate remediation methods, like, e.g., biostimulation, is of greater concern from the ecological perspective.
