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Uplatnění vybraných forem selenu při pěstování máku setého (Papaver somniferum L.)
Tobek, Ladislav
Selenium is an essential element for human organism. One of the possible ways to increase its quantity in food is a biofortification of crops. Czech Republic is the largest producer of poppy seeds in the world, it could be therefore viable to increase the nutritional value of selenium in this crop. The goal of this thesis was a recognition of suitability of selected forms of selenium for biofortification of seeds of opium poppy (Papaver somniferum). Aside from the distribution of selenium in the plant of poppy and its accumulation in the harvested seeds this study also investigates the effect of its soil and foliar application on the yield and weight of a thousand of seeds. The selenium was applied into the soil in 150, 300, and 600 g Se.ha-1 doses in the form of SeO32- and SeO42- in our one-year container experiment. The same forms of selenium were also applied foliarly in the 20 and 40 g Se.ha-1 doses in our one-year small-plot experiment. It is evident from the analysis of the distribution of selenium in the individual parts of the plant that selenite was accumulated primarily in the lower part of the plant (stalk and leafs) and only a maximum of 25.1% of the total was integrated in the capsule. Selenium, in the form of selenate, was contained in the capsule at a rate of 39.9 to 62.6% of the overall weight of the selenium contained in the whole plant. Soil and foliar application did not influence the yield and weight of a thousand of seeds. In both the container and field experiment the application of an increasing amount of selenium in the form of both selenite and selenate has significantly increased its presence in the harvested seed. Our results suggest that selenate is a better form of selenium for the biofortification of poppy.
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Selenium as a cancer-protective agent
Nedvědová, Magdaléna ; Schierová, Michaela (advisor) ; Španielová, Hana (referee)
Selenium plays an important role in cancer prevention and treatment. Selenoproteins, mainly thioredoxin reductase and glutathion peroxidase, are involved in the antioxidative defense system. Sodium selenite in physiologic concentrations blocks apoptosis. Selenomethionin takes part in DNA repair and protects cells from DNA damage. Selenium toxicity is used for cancer treatment. Sodium selenite in high concentrations induces apoptosis in tumor cells and also causes DNA damage. Selenomethionin and sodium selenite in high concentrations inhibit metastasis due to regulation of gene expression for collagen. Selenium inhibits angiogenesis, because it decreases vesicular endothelial growth factor (VEGF) amount in tumor cells. Thioredoxin reductase protects normal as well as tumor cells. Inhibitors of its activity are used for cancer treatment. Clinical trials estabilished, that low selenium intake increases the risk of cancer.
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Účinek aplikace vybraných forem selenu na výnos a kvalitu máku (Papaver somniferum L)
Hajátková, Iveta
Selenium belongs to important mineral nutrients in terms of animal and human diet. Insufficient amount of this element in diet has been a worldwide problem. The study objective was to determine the effect of its foliar application on the poppy yield (Papaver somniferum L) and its content within the seed. The test was based on a pot experiment. Selenium was applied as a foliar feeding in minerals form of selenate and selenite in dosages of 20 and 40 g Se/ha. Foliar applications with selenium had no effect on plant weight and the poppy yield. The application of selenium proved to increase the weight of 1000 seeds and the selenium content within the poppy seed. The effect of foliar application of selenate on the Se content within the poppy seed compared to fertilization with selenite was higher ranging from 40 to 50%. The form of selenate with increased rate of application increased the content of selenium in the seed of the poppy 1.19 times and in the form of selenite 1.11 times against the lower of the applied dose. The combination of positive influence in production parameters and the most significant increase of Se content within poppy seeds suggests that the most appropriate application is 40 g Se/ha in form of selenate.
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Biofortifikace slunečnice roční (Helianthus annuus L.) selenem
Vágnerová, Lucie
The diploma thesis is focused on a small-plot year-long experiment, carried out in 2013. The experiment monitored reaction of sunflower's (Helianthus annuus L.) hybrid NK Brio to foliar fertilizing with selenium, applied in the form of sodium selenite (Na2SeO3) during growth stage R1, at rates 50, 100, 150 and 200 g Se.ha-1. Foliar application of selenium at rates 50 - 150 g.ha-1 caused stimulation of weight of a plant biomass and nutrient uptake (esp. N, Mg and Se). Rate of 200 g Se.ha-1 inhibited plants' growth. Sunflower achenes yields were not statistically significantly influenced by foliar application of Se (p0,05). The most significant effect of foliar application of Se was its content in sunflower achenes; the amount of Se increased significantly (p0,05) in a linear relationship (r = 0.9824) to the graded rates.
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