Illuminating tomato fruit enhances fruit Vitamin C content

L-ascorbate (AsA; Vitamin C) is an anti-and pro-oxidant phytochemical essential for the proper functioning of the human body. Field grown tomato fruit (Solanum lycopersicum) contain substantial amounts of AsA. When grown in the greenhouse, tomato fruit typically have low levels of AsA. Light is the major regulatory abiotic factor for AsA in plants. The introduction of light emitting diodes (LED) in horticulture provides the opportunity for improving quality of plant products. AsA levels of tomato fruit increase with additional light applied to the plant. In this work we examine the effects of irradiance on AsA levels of tomato fruit when light is applied to the fruit. Detached tomato fruit were treated with different irradiance levels provided by LEDs in a climate controlled environment. Tomato fruit treated with 263 μmol m-2 s-1 of white light for 13 days contained 32% more AsA than fruit kept at lower irradiances or in darkness. The light induced biosynthesis of AsA and the role of soluble carbohydrates in AsA regulation is discussed.