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The Growth Physiology of Coleoptiles in Continuous‐Record Vessels: Anomalous Kinetics of Cycloheximide Action on Auxin‐Controlled Growth
Author(s) -
BLACK M.,
DHEIDAH M.
Publication year - 1976
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1976.tb01878.x
Subject(s) - coleoptile , cycloheximide , auxin , biology , etiolation , biophysics , biochemistry , microbiology and biotechnology , botany , protein biosynthesis , enzyme , gene
The interacting effects of auxin and cycloheximide upon the growth of Triticum coleoptiles depends upon the incubation conditions. In the growth vessel developed by Evans and Ray (1969) the action of cycloheximide is severe and the growth kinetics show a rapid nullification of auxin action by the inhibitor; hormone action is also totally prevented by a relatively short period of pre‐treatment with cycloheximide. The kinetics of response to the two substances are quite different when coleoptiles are floating on the test solutions; here, cycloheximide is much less severe in its action. These differences are due to a heightened sensitivity to cycloheximide induced by exclusion of the air bubble from the coleoptile cylinder in the Evans and Ray chamber. The outer surface of the coleoptile wall is a less efficient respiratory surface than the inner one. When coleoptiles are filled with a stagnant solution insufficient oxygen can be taken up through the inner surface and the tissue therefore suffers oxygen deprivation. This exacerbates the action of cycloheximide as a potent respiratory inhibitor. The results raise questions concerning the use of conditions in which coleoptile sections are filled and submerged, which is a feature of recently introduced continuous‐record growth vessels. In particular, interpretation of the interactions between cycloheximide and auxin under such conditions must be made cautiously.