Further Studies on the Relationship between Illumination and the Ascorbic Acid Content of Tomato Fruits

Abstract

Experiments with tomato plants grown in sand culture show that the amount of illumination of the fruits is of importance in determining their ascorbic acid content. Shaded fruits contain less ascorbic acid than comparable fruits exposed to sunshine. On the other hand, the amount of illumination received by the leaves for a few weeks prior to harvest apparently has much less effect, or possibly no effect at all, upon the ascorbic acid content of the fruits produced. In view of this relationship, it would be expected that under field conditions where large differences in foliation were obtained at different locations there probably would be little or no correlation between the total amounts of sunlight at these locations and the ascorbic acid content of the tomatoes produced. The variation in the direct illumination of the fruits as a result of the differences in foliation probably would mask any possible effects resulting from variations in the illumination of the foliage. Data obtained from field experiments are presented to support this contention.