Early experiments involving the use of various growth-promoting substances were concerned generally with formative effects and morphological changes induced by these substances. Later experiments were of a more practical nature in which the hormones were tested to determine their numerous commercial applications. The results of morphological investigations disclose the most common reactions to be: (1) cell division, (2) cell enlargement, (3) differentiation of the newly formed tissues, especially into vascular structures, (4) changes in the thickness of cell membranes, and (5) organ building manifested in the development of root primordia, or rarely as bud primordia (Bausor et. al., 1940). Only a few studies have been concerned with the response of leaves to 2, 4-D (Burton, 1947, Felber, 1948). The major emphasis of other morphological reports has been placed on the response of stems and other plant organs to this hormone.
Proceedings of the Iowa Academy of Science
©1949 Iowa Academy of Science, Inc.
Postlethwait, S. N.
"Cupule Formation on Seedlings of Galinsoga Ciliata (RAF.) Blake and Helianthus Annuus L. Following Exposure to 2, 4-Dichlorophenoxyacetic Acid,"
Proceedings of the Iowa Academy of Science, 56(1), 167-178.
Available at: https://scholarworks.uni.edu/pias/vol56/iss1/24