Abstract
All previous reviews of research on light-emitting diodes (LEDs) have been focused on how different light spectra generally influence plant yield and quality. There are no or almost no reviews on the effect of spectra on sugars or pigment concentration, or yield and growth etc. The role of visible light in food production, as in agriculture and horticulture, is obvious, as light drives photosynthesis, which is crucial for plant growth and development. Solid state lighting using LEDs represents a fundamentally different technology from gaseous discharge-type lamps currently in use. LEDs are important lamp types because the concentration of the light spectrum they emit can be changed to provide plants at various developmental stages with the light spectrum needed. A great deal of studies have been done on the effect of wavelengths of light on growth, yield and nutritional quality of greenhouse vegetables. However, little is known about the mechanisms by which the spectra affect sugar and pigment concentration, and yield, and growth. This article provides a list of how spectra influence the yield, growth, and nutritional quality of greenhouse-grown vegetables. Based on the given information we can conclude that blue, green, and red light are the main light colours that influence positively plant yield, growth and nutrient quality. Sometimes in specific situations, some other light colours are also beneficial, like far red light, orange light and UVA light. Future work on light colour manipulation has potential for producing lamps and greenhouse covers that better support plant yield, growth, and nutrition.