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The aim of the present research was to determine the total selenium content in soil and plants from a microplot experiment with different nitrogen fertilization regimes, and to identify the relationships of the selenium content in soil and plants versus the soil catalase activity. The experiment was conducted in randomized blocks with three replications. The soil and plant samples were collected from a microplot experiment established at the IUNG in Pulawy. The soil was enriched with mineral nitrogen and with nitrogen supplied in slurry, both applied at doses of 100 kg N ha-1. The total selenium content in soil under each of the crop rotation systems was no more than 0.2 mg kg-1. Data from the references imply that the soil was deficient in selenium. The highest amount of selenium was under winter wheat and spring barley with undersown crop in crop rotation A, and in soil under maize crop rotation B. Slurry fertilization significantly stimulated the activity of catalase in soil, as compared with the control and mineral nitrogen fertilization treatments. The highest catalase activity – nearly double the control – was detected in soil under winter wheat in crop rotation A and under spring barley in crop rotation B; winter wheat, regardless of the type of crop rotation, accumulated on average 0.3 mg Se kg-1 d.w. in aerial parts and 0.344 mg Se kg-1 d.w. in roots. The highest amounts of selenium in the investigated parts of plants were reported in the control plots and in the plots with slurry fertilization. Mineral fertilization reduced selenium availability to plants. In both crop rotation systems, the highest bioaccumulation of selenium was noted in winter wheat roots from control plots, while the lowest one was detectetd in aerial parts of plants from the plots with slurry fertilization. Despite the fertilization applied, the selenium content in plant roots was higher than its content in aerial parts. The correlation analysis of the results on selenium concentration in soil and plants as well as the catalase activity of soil identified only a significant dependence between the total selenium content and catalase activity in soil from crop rotation B.
To evaluate the small-scale (100 m²) spatial variability of selected soil biological properties in a beech stand and the influence of soil properties on soil microbial activity, we collected soil samples on April 2, July 2 and October 30 (2002) from three (9 ¥ 10 m) plots, distributed on a 1 ¥ 1 m grid, from the top 10 cm of the mineral soil (A horizon). In soil samples, soil respiration and catalase activity were measured. Within-plot coefficients of variation of catalase activity varied from 19 to 23%, those of soil respiration rate ranged from 37 to 54%. Catalase activity exhibited highly significant correlations with soil reaction, whereas soil respiration rate correlated with moisture and humus content. Soil respiration rates appear to be randomly distributed over the sampling area. On the other hand, catalase activity exhibits a rather distinct patchy structure. No relationships between the position of trees and soil respiration rates were found. For catalase activities, the highest values were observed on transsections of perimeters of dominant-tree crowns.
The study was designed to determine the possible relationship between Brassica oleracea var. italica seedlings stored at 2°C in the dark for seven and fourteen days, respectively, and the level of certain antioxidant parameters in particular organs. A parallel objective of the experiment was to determine if the reaction of seedlings to low temperature might be persistent in fully developed plants until harvest time. After 14 days of chilling a significant increase in the glutathione content was observed in the seedling leaves in comparison to the non-chilled plants. During vegetation in field conditions this effect was maintained in leaves up to the stage of formation of flower buds. At harvest the highest content of glutathione was demonstrated in broccoli heads, obtained from plants, which were previously chilled in the seedling phase for two weeks. Peroxidase activity in broccoli seedlings increased each year of the three-year study due to the duration of the cooling time, whereas in the case of catalase the changes were not so distinct. At harvest time the activity of both enzymes in the leaves and flower buds fluctuated according to the particular year of study.
Three-day-old 105 Ross race female broiler chicks were used. The chickens were divided into 5 groups comprising 1 control and 4 experimental groups. Animals in the control group (group 1) were provided with normal drinking water, whereas the experimental groups, namely, group 2, group 3, group 4 and group 5 were administered with tilmicosin at doses of 20 ppm, 40 ppm, 80 ppm and 160 ppm (approximately, 5 mg/kg/b.w./d, 10 mg/kg/b.w./d, 20 mg/kg/b.w./d, and 40 mg/kg/b.w./d), respectively, via drinking water for a period of 3 d. Seven animals were euthanized from each group, on the 1st d (first period), 4th d (second period) and 7th d (third period) of the experiment for the assessment of blood malondialdehyde (MDA) levels and catalase (CAT) activity. Statistically significant differences in comparison with the control group were observed in plasma MDA levels of all experimental groups in the first period, groups 2 and 5 in the second period, and group 4 in the third period. With regards to CAT activity, a statistically significant decrease was found in all experimental groups only in the first period.
Soil enzyme activity indicates potential of the soil to sustain biochemical processes, which are essential for the maintenance of soil fertility. Dehydrogenase activity reflects total oxidative activity of soil microflora, catalase activity is responsible for the decomposition of H2O2. Redox potential (Eh) is an index of the soil aeration status. Effects of soil temperature and water content on Eh, soil dehydrogenase activity and catalasc activity in an Eutric Histosol at three different fields planted with Papulus nigra, Salix amencana, and grasses (with Alopecurits pratensis, Phalaris arundinacea, Festuca pratensis is as dominating species) were studied at the depths of 10, 30, 50, 70 cm. Enzyme activity and redox potential showed seasonal fluctuations following natural changes of soil water content and temperature. Dehydrogenase activity was significantly correlated with soil temperature and water content (r=0.37** and r=0.27***, respectively). Redox potential showed a significant correlation with soil water content (r=-0.32*** ). Catalase activity did not exhibit any correlation with the tested parameters. The type of plantation influenced enzyme activities; tree cover was characterised by higher dehydrogenase and catalase activities than meadow soils.
Previous studies argue that salicylic acid (SA) plays an important role in the plant signal transduction pathway(s) leading to disease resistance. It has been proposed that one of its modes of action is inhibition of catalase and elevation of H₂O₂ level in the tissue. To verify the role of SA and H₂O₂ during pathogenesis, transgenic tobacco plants expressing Saccharomyces cerevisiae CTA1 gene coding for peroxisomal catalase were constructed. These plants possess 2-4-fold higher total catalase activity under normal growth conditions. No symptoms of chlorosis and/or necrosis were observed. Levels of pathogenesis-related proteins (PR) and their respective mRNAs were significantly reduced in the infected leaves of the transgenic plants. No change in PR expression was detected in uninfected leaves of both CTA1 and control plants challenged with TMV. These results suggest that elevation in catalase activity and resulting reduction of H₂O₂ level results in more severe local disease symptoms, apparently due to alteration of the hypersensitive response mechanism and does not influence systemic acquired resistance after viral infection.
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