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Effect of biostimulants on growth and defence reactions in plants
Vlčková, Denisa ; Ryšlavá, Helena (advisor) ; Innemanová, Petra (referee)
Biostimulants are microorganisms or substances of natural origin that promote plant growth and defence against abiotic and biotic stress. The mechanism of action of biostimulants is still a subject of research. In this work, two biostimulants were studied: fermented nettles and vermicompost leachate. Both biostimulants possessed soluble proteins with lower relative molecular weights and peptides, carbohydrates, phenolic substances as well as active proteolytic enzymes and glycosidases. After application of biostimulants to the maize plants (Zea mays L.), growth parameters did not change significantly, but the plants had higher content of proteins and phenolic substances, higher antioxidant capacity and activity of some peroxidase isoforms. The effect of drought on plant growth, metabolism and antioxidant system after application of fermented nettles and vermicompost leachate was also studied. Maize plants under drought stress treated with biostimulants were able to maintain higher water content, showed higher content of proteins, phenolic compounds and higher glutathione reductase activity than untreated stressed control plants. Both tested biostimulants affected the metabolism of drought-stressed maize plants, with the positive effect being more pronounced in the lower-humus soil. Key words:...
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Antioxidant properties of tobacco plants grown in vitro with different nitrogen sources
Vlčková, Denisa ; Ryšlavá, Helena (advisor) ; Kubíčková, Božena (referee)
The established concept of plant nutrition with NO3 − and NH4 + ions, as the only absorbable forms of nitrogen, has been expanded in recent years to find that some plants are also able to use amino acids and peptides as a nitrogen source. In this work, the content of proteins, phenolic compounds and flavonoids, antioxidant capacity and activity of antioxidant enzymes in leaf extracts of six groups of tobacco plants grown in vitro were observed. The nutrition of these plants varied in the form and concentration of nitrogenous compounds. The experimental groups included: control plants grown on complete Murashige-Skoog agar rich in NH4 + and NO3 − ions (MS), plants grown in the presence of NO3 − ions, with reduced nitrogen concentration compared to MS (AD), plants grown in the presence of casein hydrolysate as the sole nitrogen source (H), plants grown in presence of both NO3 − ions and casein hydrolysate (AD+H) and AD and H plants grown in the presence of polyethylene glycol simulating drought stress (AD+PEG and H+PEG). Of all groups, plants H showed the highest content of phenolic compounds and flavonoids and the highest values of antioxidant capacity and antioxidant enzyme activity (catalase, glutathione reductase, superoxide dismutase, total peroxidases, ascorbate peroxidase, glutathione-S-...
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