Statistical treatment of the data presented leads to the following conclusions:
1. The cortex of the carrot contains more vitamin B than the xylem and the periderm more than the cortex.
2. Within the limitations imposed by the small number of animals and the variability of each group, the data show that lettuce, kohlrabi and tomatoes, when grown under glass, are as potent in vitamin B as when grown in the direct sunlight. However, more data are necessary for positive proof.
3. Kohlrabi is a relatively good source of vitamin B.
4. A storage period of five months, under the conditions mentioned, did not alter vitamin B content of the carrots.
House, Margaret C.; Nelson, P. Mabel; and Haber, E. S.
"The Vitamin B content of vegetables,"
Research Bulletin (Iowa Agriculture and Home Economics Experiment Station): Vol. 9
, Article 1.
Available at: https://lib.dr.iastate.edu/researchbulletin/vol9/iss120/1