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Influence of growing conditions on the biologically active substances of non-traditional leafy vegetables.
FRIEDBERGEROVÁ, Markéta
Currently, most of the vegetables that are produced on the European continent are released in greenhouses. This method offers a considerable number of advantages, such as lower amount of water and heat consumption, protection against pests or meteorological phenomena, such as hail, and thus higher yields. However, one of the major disadvantages of these devices is the fact that glass is not permeable to UV-B radiation, which supports the biosynthesis of flavonoids, substances that have beneficial antioxidant effects for the human organism. This undesirable effect can be eliminated by installing LED (Light-Emitting Diode) lighting in greenhouses. This is because these lights provide a wide spectrum of electromagnetic radiation, i.e. wavelengths that plants use for a whole range of their processes. In this diploma thesis, the influence of growing conditions on the content of biologically active substances, especially quercetin and kaempferol in non-traditional types of Asian leafy vegetables, namely Namenia, Sagami, Golden Lion, Choy Sum and Tatsoi, was investigated. All the mentioned varieties were grown in two crops (spring and autumn) in the greenhouse and on the seedbed in the years 2019-2021. The highest concentration of total quercetin was recorded in the spring seed of Namenia grown in 2019 on the seedbed 1241 mg/kg of dry matter. Also, the highest content of total kaempferol 1753 mg/kg of dry matter was found in Namenia, it was the autumn period of 2020, also grown in a seedbed. When converted to fresh weight, the results were the same, the value for quercetin was 103 mg/kg of fresh weight and for kaempferol 142 mg/kg of fresh weight.
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