The storage ability of lamb’s lettuce cultivated in the greenhouse under LED or HPS lamps

anglais. Leafy vegetables are the source of many valuable components like vitamins, minerals and phenolic compounds as antioxidants. Chlorophyll derivatives have antioxidant and anticarcinogenic activity, or may even act as signalling molecules in organisms. However, during the storage of the leafy vegetables in the cold and darkness, numerous biochemical changes usually occurs, demonstrated as the breakdown of chlorophyll. Storage ability of plants depends to some extent on the conditions under which plants grew. Lamb’s lettuce plants were grown in the greenhouse in different light regimes – emitted with sodium (HPS-control) and LED lamps (100% red, 90% red + 10% blue, 70% red + 30% blue and 50% red + 50% blue light). The intensity of radiation at the height of the leaves of the plants was the same in every treatment. After harvesting, the plants were stored at the temperature of 5 °C and high humidity in plastic bags. The analyses of the material were done four times: after harvest and three times during storage at weekly intervals. Fresh weight lost, dry matter, phenolics and chlorophyll content were analysed. Additionally, the fluorescence of chlorophyll a was carried out. Changes in plant fresh weight and dry matter content during storage did not depend on the lighting used during cultivation. After 3 weeks of storage, higher value of indicator of the vitality of PSII (PIABS – Performance Index) was noticed in leaves treated with higher red light intensity during cultivation (100%, 90% and 70% red). LED lamps, which emitted 100% and 90% red light, enhanced concentration of total phenolics in lamb’s lettuce leaves. Light of HPS lamps decreased radical scavenging activity in leaves. Quality and usefulness of plants produced under LED lamps was just as good as those grown under HPS lamps.

anglais. Valerianella locusta, health-promoting substances, leaf senescence, chlorophyll fluorescence

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159-165

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