The accumulation of nitrate in vegetables is a complex process, which is controlled by nitrate nitrogen absorption, reduction and assimilation, and is affected by light conditions. The main way of nitrogen assimilation in plants is that the ammonia generated by the reduction of nitrate nitrogen directly participates in the synthesis and transformation of amino acids, during which key enzymes such as nitrate reductase participate in the catalysis and regulation. Using amino acids as the main substrate to synthesize proteins in cells, and then modifying, classifying, transporting and storing proteins, etc., become an integral part of plant organisms, and at the same time coordinate with the physiological processes of plants such as carbon metabolism.
Light quality affects the carbon and nitrogen metabolism of plants and regulates carbohydrate and protein metabolism (Li Chengzhi et al., 2005). Plants grown under red light were higher in carbohydrates, while those grown under blue light were higher in protein. The regulation of nitrate reductase by blue light is positive and possibly direct. Because the flavin adenine dinucleotide (FAD) and purine in the blue light acceptor chromophore are the prosthetic groups of nitrate reductase (Campbell et al., 1996), blue light irradiation promotes the reduction of nitrate and increases the source of ammonia supply.
In addition, blue light can promote nitrogen metabolism in plants such as spinach and tomato, which is associated with enhanced respiration. Blue light significantly promotes mitochondrial dark respiration, glycolysis pathway regulatory enzyme pyruvate kinase and many enzymes in the tricarboxylic acid cycle are regulated by blue light (Kowallik, 1982), among which, α-ketoglutarate dehydrogenase activity is inhibited effect.
Qi Liandong et al. (2007) used color fluorescent lamps to obtain red, blue and yellow light sources to study the effects of different light qualities on spinach yield and nitrate accumulation. Studies have shown that, compared with white light and yellow light, the biomass under red light treatment is not high, but red light treatment is beneficial to the formation and accumulation of dry matter and carbohydrates, and can also reduce nitrate content.
Effect of LED Grow Light Quality on Nitrate Content（一）
The accumulation of nitrate in vegetables is a complex process, which is controlled by nitrate nitrogen absorption, reduction and assimilation, and is affected by light conditions. The main way of nitrogen assimilation in plants is that the ammonia generated by the reduction of nitrate nitrogen directly participates in the synthesis and transformation of amino acids, during which key enzymes such as nitrate reductase participate in the catalysis and regulation. Using amino acids as the main substrate to synthesize proteins in cells, and then modifying, classifying, transporting and storing proteins, etc., become an integral part of plant organisms, and at the same time coordinate with the physiological processes of plants such as carbon metabolism.
Light quality affects the carbon and nitrogen metabolism of plants and regulates carbohydrate and protein metabolism (Li Chengzhi et al., 2005). Plants grown under red light were higher in carbohydrates, while those grown under blue light were higher in protein. The regulation of nitrate reductase by blue light is positive and possibly direct. Because the flavin adenine dinucleotide (FAD) and purine in the blue light acceptor chromophore are the prosthetic groups of nitrate reductase (Campbell et al., 1996), blue light irradiation promotes the reduction of nitrate and increases the source of ammonia supply.
In addition, blue light can promote nitrogen metabolism in plants such as spinach and tomato, which is associated with enhanced respiration. Blue light significantly promotes mitochondrial dark respiration, glycolysis pathway regulatory enzyme pyruvate kinase and many enzymes in the tricarboxylic acid cycle are regulated by blue light (Kowallik, 1982), among which, α-ketoglutarate dehydrogenase activity is inhibited effect.
Qi Liandong et al. (2007) used color fluorescent lamps to obtain red, blue and yellow light sources to study the effects of different light qualities on spinach yield and nitrate accumulation. Studies have shown that, compared with white light and yellow light, the biomass under red light treatment is not high, but red light treatment is beneficial to the formation and accumulation of dry matter and carbohydrates, and can also reduce nitrate content.