Variation in the B-Carotene and Ascorbic Acid Contents of Lettuce and Carrots as Influenced by Seasonal Changes in Puerto Rico

Abstract

1. Climatic factors such as temperature, number of rainy days, and total rainfall, apparently have no effect on the synthesis of ß-carotene and ascorbic acid in lettuce and carrots, when these are determined during the entire growing period. 2. The ascorbic acid content of lettuce is inversely correlated with the sunlight received by the plant some 10 days prior to harvest. 3. Solar radiation received by lettuce plants during October, January, and February seems to be more favorable to the ß-carotene synthesis than that received during the rest of the year. Days are longer, but solar radiation is milder during this time of the year. 4. Solar radiation in Puerto Rico favors ascorbic acid synthesis in lettuce all year through. 5. Results obtained under the conditions of these studies demonstrate that temperature, number of rainy days, and rainfall have no effect on the ß-carotene and ascorbic acid content of carrots.