Articles
EFFECT OF SUPPLEMENTARY PRE-HARVEST LED LIGHTING ON THE ANTIOXIDANT AND NUTRITIONAL PROPERTIES OF GREEN VEGETABLES
Article number
939_10
Pages
85 – 91
Language
English
Abstract
We report on the application of supplementary solid-state lighting within an industrial greenhouse for pre-harvest treatment of various green vegetables (spinach, parsley, dill, mustard, rocket, and onion leaves) grown under high-pressure sodium lamps and natural solar illumination.
For 3 days before harvesting, supplementary lighting from red 638-nm light-emitting diodes (LEDs) was applied within a 19-h photoperiod in such a way that the net photosynthetically active flux density of at least ~300 µmol m-2 s-1 was maintained.
Such a pre-harvest treatment was found to remarkably enhance antioxidant and nutritional properties of green vegetables due to the increased activity of the metabolic system for the protection from a mild photooxidative stress.
However, the effect of supplementary red light was found to be species dependent.
The sensitivity of a species to the lighting conditions was determined by the natural level of phenolic compounds accumulated in the leaves.
Supplemental lighting evokes a metabolic unbalance in green vegetables that accumulate low amounts of antioxidant compounds, therefore the flux of red light even diminish the nutritional value of spinach and rocket.
Meanwhile, application of supplemental LED lighting to dill and parsley results in the accumulation of vitamin C and carbohydrates and in the enhancement of free radical binding activity and the activity of nitrate-reducing enzymes.
For 3 days before harvesting, supplementary lighting from red 638-nm light-emitting diodes (LEDs) was applied within a 19-h photoperiod in such a way that the net photosynthetically active flux density of at least ~300 µmol m-2 s-1 was maintained.
Such a pre-harvest treatment was found to remarkably enhance antioxidant and nutritional properties of green vegetables due to the increased activity of the metabolic system for the protection from a mild photooxidative stress.
However, the effect of supplementary red light was found to be species dependent.
The sensitivity of a species to the lighting conditions was determined by the natural level of phenolic compounds accumulated in the leaves.
Supplemental lighting evokes a metabolic unbalance in green vegetables that accumulate low amounts of antioxidant compounds, therefore the flux of red light even diminish the nutritional value of spinach and rocket.
Meanwhile, application of supplemental LED lighting to dill and parsley results in the accumulation of vitamin C and carbohydrates and in the enhancement of free radical binding activity and the activity of nitrate-reducing enzymes.
Authors
Z. Bliznikas, A. Zukauskas, G. Samuolienė, A. Viršilė, A. Brazaitytė, J. Jankauskienė, P. Duchovskis, A. Novičkovas
Keywords
vitamin C, free radicals, nitrates, phenols, solid-state illumination
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