Effects of Light Intensity, Day Length, Temperature, and Other Environmental Factors on the Ascorbic Acid Content of Tomatoes

Abstract
The influence of environmental variables on the ascorbic acid content of tomatoes has been studied in the field and under controlled conditions in the laboratory. Evidence is presented that ascorbic acid content is only slightly, if at all, influenced by: (1) degree of ripeness after the fruit is “mature green”, (2) storage of the fruit for 10 to 14 days at temperatures from 65°F. to 90°F., (3) fertilizer treatment of the plants (although nitrogen fertilization may cause a slight decrease), and (4) relative humidity to which the plants are exposed. Under controlled growing conditions fruits produced under lowered temperatures and shortened day length were somewhat lower in ascorbic acid. By far the greatest influence on ascorbic acid content was produced by variations in light intensity previous to harvest. Increases in the ripe fruit of 66% in ascorbic acid resulted when plants were transferred from shade to sunshine at the time the fruit was mature green. A discussion is given of the possible significance of these results with the suggestion that the light intensity to which the plants are exposed just previous to harvest may be the dominant factor in determining the ascorbic acid content of ripe fruit.