On Factors determining the Auxin Content of the Root Tip

Boysen Jensen discovered in 1933 that cut root tips put on agar containing 10% of glucose delivered more auxin than those put on plain agar. This statement of Boysen Jensen was chosen as a starting point for the research reported in this paper. Generally speaking one may say that auxin mostly is present in young organs and not, or in distinctly smaller quantities, in adult tissues. In some cases auxin is regularly spread all over the organ concerned, e.g. in the hypocotyl of Lupinus (Dijkman, 1934) and in the epicotyl of Vicia Faba (Van der Laan, 1934). In other cases a part of the organ is richer in auxin content than the other parts; the auxin diffuses from this ,,auxin-centrum” towards the other cells of the young organ. The best known case of this is the coleoptile of the Gramineae, where auxin is continually produced in the tip and is transported from the tip to the basal regions.